e-book proof of design dfm and concurrent engineering

1 Proof Of Design DFM/CE PART 3

POD DFM/CE - REVISION 3

PROOF OF DESIGN (POD) – THE DFM/CE BOOK FOR PRINTED CIRCUIT BOARDS, ASSEMBLIES, AND ALL MANNER OF OTHER THINGS TECHNICAL (PART 3)

Revision 3 provides more detailed supplier evaluation/qualification guidelines, checklists, procedures, and requirements. It includes PCB/PCBA operational

information, Manufacturing Operations Procedures, Failure Analysis information, requirements, and details. It has a complete section on Lean

Manufacturing – plus much more DFM/CE and other vital information for those needing/wishing/wanting/desiring to manage processes instead of reacting to

results as poor quality and reliability. by

MoonMan

The MoonMan without DFM/CE The MoonMan with DFM/CE

Product without DFM/CE Product with DFM/CE



FORWARD (advance – or move positively in one direction – or never move backward - or never do it over – or never effect defect and have to correct it): THIS BOOK IS ABOUT DOING IT RIGHT THE FIRST TIME, ON TIME, EVERY TIME, AT THE LOWEST COST. THIS SIMPLY IS DONE BY MANAGING PROCESSES INSTEAD OF RESULTS. Nike says Just do it. MoonMan says Just do it but do it right. MoonMan also says let’s Boogie (MoonMan’s expression for let’s move forward or let’s get it on) and get down to it. You should ask the MoonMan about product with DFM/CE above.

IMPORTANT NOTES: THOUGH THIS BOOK FOCUSES MOSTLY ON ELECTRONICS, WITH PRINTED CIRCUITRY AT ITS CORE, ALL THE PRINCIPLES APPLY TO ALL APPLICATIONS WHETHER TELCCOMMUNICATIONS, AUTOMOTIVE, MEDICAL, MILITARY, AEROSPACE, OR WHATEVER PRODUCT DEMANDING QUALITY AND RELIABILITY. THIS BOOK IS DESIGNED TO BE USED ANY WAY ONE SEES FIT. IF YOU NEED TO USE ANY INFORMATION HEREIN – SIMPLY COPY AND PASTE IT INTO YOUR DOCUMENTS OR PROCESSES. THIS BOOK IS DIVIDED INTO FOUR SEPARATE PARTS TO FACILITATE USE BY ANYONE WITH A COMPUTER SYSTEM CAPABLE OF MANAGING IT. EACH PART SHOULD BE LOADED SEPARATELY TO ENSURE COMPUTERS WITH LIMITED RESOURCES CAN READ AND USE THE FILES. EACH PART (PODDFMCE 1 -4) HAS A SEPARATE TABLE OF CONTENTS AND EACH PART BEGINS ON PAGE ONE. THIS BOOK IS WRITTEN USING MS WORD 97 AND APPEARS TO BE UNIVERSALLY ACCEPTABLE TO ALL. I TRIED WRITING IT USING XP PROFESSIONAL BUT IT DID NOT TRANLATE EXACTLY TO 97. THIS IS PART 3... IT CONTAINS 94.6MB (99,202,560 bytes). YOU NEED TO ASSESS YOUR COMPUTERS' CAPABILITIES AS AMOUNT OF RAM, HARD DRIVE CAPACITY, AND VIDEO CARD.



POD - DFM/CE PART 3 TABLE OF CONTENTS

SECTION PAGE 12.0 PCBA MANUFACTURING OPERATION PROCEDURES 4 12.1 SOLDER PASTE AND STENCILS 5

12.2 STENCILPRINTING 19 12.3 A FEW WORDS ABOUT THROUGH HOLE TECHNOLOGY 57 12.4 SMT COMPONENT PLACEMENT 60 12.5 REFLOW SOLDERING 124 12.6 WAVE SOLDERING 160 12.7 HAND SOLDERING 202 12.8 WINESCO REPAIR/REWORK 234 12.9 SRM4 REPAIR/REWORK 246 12.10 BGA REPAIR/REWORK 264 12.11 MSD AND VACUUM SEALING PROCEDURES 350 12.12 LIQUID SOLDER MASKING PROCEDURES 366 12.13 PANELIZATION AND DE-PANELIZING 385 12.14 FINAL ASSEMBLY (SYSTEM OR "BOX" BUILD) 389 12.15 CLEANING AND CLEANLINESS 399 12.16 INSPECTION AND TEST 407 NOTE: PCB FABRICATION PROCEDURES ALSO AVAILABLE ON A CUSTOM BASIS THOUGH I HAVE MANY

OF THESE FOR VARIOUS SHOPS THROUGHOUT THE WORLD. HOWEVER, THERE ARE SO MANY PROCESSES AND DIFFERENT WAYS OF DOING THEM, I CANNOT POSSIBLY INCLUDE THEM HEREIN.



12.0 PCBA MANUFACTURING OPERATION PROCEDURES As part of any good quality system or program, clearly written procedures must be developed, written, and used to train people to do their jobs properly. Then, they must be empowered to do them while accepting accountability for their performance. Management must assure performance measurements are made in as close to real time as possible so immediate feedback is available to everyone to continuously improve what everyone does. This, then, feeds back to the DFM/CE process. DFM/CE, within a total process management system, would not be effective if everyone in the organization was not trained, then empowered and made responsible, to work in accordance with these procedures they help write. I wrote the following procedures at some of the finest companies in the land. They include H-P, Celestica, UASC, Nortel/Arris, and many others. Actually, I began "writing" photo documents, as H-P (now Agilent) began naming them. I started this when digital photography began - in 1990 with my trusty Canon "ZapShot." Actually, I began using 35mm cameras and scanning images before then. It's not that I enjoy writing procedures. It's just that this must be done especially when working as a new product development, process, or manufacturing support engineer. So, here they are for your reading, viewing pleasure, and use - as you wish. NOTE: THE FOLLOWING PROCEDURES ARE BUT A FEW I'VE WRITTEN OVER MANY YEARS. THERE ARE SO MANY MORE (ISO, PCB FAB, QUALITY, INSPECTION, SALES, ENGINEERING, ETC.), IT IS IMPOSSIBLE TO INCLUDE THEM ALL. HOWEVER, IF YOU NEED ANY OTHERS JUST LET ME KNOW AND I'LL PROVIDE A LIST AND WHATEVER YOU REQUEST.



12.1 SOLDER PASTE AND STENCILS In the early days, all things SMT were crude by comparison with today's technology though we still have a long way to go, but that's the way it's always been. The following information provides something of a history of solder paste and stencil evolution: SOLDER PASTE Solder paste has been with us for a long time. Early on, I used it first in hybrid thick film applications. Later it was used in military SMT applications in mid to late 1970's. In the early 1980's it was beginning to be formulated for commercial applications with a bit more sophistication though still somewhat of a witch's brew. I worked with some folks, in the dark ages, creating our "special" formulations as little was available from proven, qualified suppliers. We thought we were doing great but compared with today's product, we had nothing. It did work reasonably and we could claim a "proprietary" status hoping to bring in more business. Later, consulting with many OEM's and CM's, I assisted in the evaluation and qualification process for about every solder paste supplier available at that time and since. I'm not advertising for anyone but one company stands out. That is Indium and their SMQ family of solder pastes. I also have qualified, happily, various Kester and Alpha formulations. The earliest evaluation criteria were based primarily on: 1) Formulation as tin-lead (63/37) sometimes with 2% silver as (Sn63 Pb35 Ag2) 2) Percent metal to binder ratio (87% metal in a 13% flux binder) 3) Viscosity in the range of 900,000 centipoise 4) Spherical solder balls 5) Mesh size through which solder paste could pass (first based on using silkscreen stencils) "MODERN" SOLDER PASTE FORMULATIONS AND REQUIREMENTS



The following procedures I wrote for H-P Spokane: SOLDER PASTE MANAGEMENT PROCESS Purpose This document's purpose is to define and standardize the minimum operating and maintenance procedures for the solder paste management process. Scope This procedure's scope applies to all solder paste application at the TMO PCA, Spokane shop. Theory of Operation Solder Paste is applied by placing a stencil over a printed circuit board with apertures where the solder shall be left on the board. A squeegee is used to spread the solder paste over the stencil and deposit it in the stencil apertures. The process's success is dependent on stencil alignment, solder paste quality, and printing equipment used. References HP Health and Safety Manual http://hpehs.corp.hp.com/ehs/stds/hs_man/535-000.htm#1. Material Safety Data Sheets: Isopropyl Alcohol Solder Paste PNP Training Instructions: Filename: Q:\SPOKANE\PICKPLAC\PNPINSTR.SAM

Chemical Safety Solder Paste The stencil printing process involves the use of lead in the form of solder paste. Lead is a known toxin. It is required that safety glasses and rubber gloves be worn whenever the paste is handled. Paste handling includes moving the paste from stencil to stencil, stirring paste, cleaning stencils, and replenishing paste on stencils. Any time there is a possibility that solder paste shall come in contact with the operator that operator SHALL wear gloves. Refer to the MSDS for solder paste for more safety information. Lead Waste Dispose of spent solder paste in the designated 55 gallon hazardous waste accumulation barrel, (covered and labeled container) ONLY. Dispose of lead impregnated wipes and used gloves in the small trash compactor. When trash compactor reaches capacity place the sealed bag in the designated 55-gallon hazardous waste accumulation barrel (covered and labeled container) ONLY.



Compressed Air NOTE: AT NO TIME SHALL STENCIL APERTURES BE BLOWN OUT WITH COMPRESSED AIR IF PASTE IS PRESENT IN THE APERTURES. REMOVE PASTE BY WASHING AND WIPING ONLY. BLOWING SOLDER PASTE FROM APERTURES COULD CAUSE THE LEAD PARTICLES TO BECOME AIR-BORN. IPA Isopropyl Alcohol is used in the solder paste process to clean off misprinted boards, clean stencils, and wipe down the process area. It is required that safety glasses and rubber gloves be worn whenever the IPA is being used. Refer to the MSDS for Isopropyl alcohol for more safety information. Material and Supplies Reference the process router for the correct solder paste to use for each of the individual PWB,s.

NAME DESCRIPTION SUPPLIER PART NUMBER Solder Paste Indium SMQ92 no-clean

paste Indium SMQ62

Delta no-clean

Indium Corporation of America

Indium Corporation of America

Qualitek International, Inc.

8090-1402

8090-1273

8090-1158 Texwipe Technicloth Lint Free Wipes for circuit

boards and stencils Not Specified Not Specified

Isopropyl Alcohol Used to clean stencils, and misprinted boards

Not Specified 6030-0010

Rubber Gloves Not permeable by solder paste or IPA.

Not Specified 8650-0031

Spatulas Plastic Spatulas with rounded corners

Not Specified Not Specified

Equipment

NAME DESCRIPTION

Pump can for Isopropyl Alcohol The can is used to store and dispense IPA

Air gun dispenser Used to dispense solder paste from tubes

Trash Compactor used to dispose of gloves and wipes contaminated with solder paste

Cleaning Equipment and Area

Shift Maintenance The following maintenance items shall be completed once every 8 hours during the time when the production line is running. Put on protective gloves Clean solder paste from squeegees using plastic tool, alcohol and Texwipe.



Wipe down the work area Dispose of spent solder paste in the designated 55-gallon hazardous waste accumulation barrels (covered and labeled containers) ONLY. Clean stencil. (Refer to Stencil Cleaning.12.2 of PNP Training Instructions) Return Stencil to storage. (Refer to Stencil Storage 12.1.2 of PNP Training Instructions) Dispose of rubber gloves and Texwipes in trash compactor Do any maintenance required in the printer documentation. Solder Paste Receiving and Handling Solder paste shall be moved as quickly as possible from receiving to the refrigerator in the surface mount center. Upon receipt of a new shipment of solder paste from the supplier all new paste shall be put into the refrigerator and the older paste put on top. This helps to ensure that paste gets used in a first in first out order. (FIFO) Syringes and cartridges shall be stored tip down with the older solder paste stored to the front. Solder paste Temperature

Store solder paste in a refrigerator at a temperature between 35 and 50 degrees F. (-20 degrees to +5 degrees C) Dispose of any solder paste that has exceeded its expiration date in the designated 55-gallon hazardous waste accumulation barrels. All new containers of solder paste shall be brought up to ambient room temperature (+/- 5F) before being used. When a solder paste container is empty and properly disposed, replace it immediately. There shall be sufficient solder paste removed from the refrigerator for any production day. Use the temperature probe to verify solder paste is up to room temperature. Insert the probe into the solder paste until it touches the bottom of the container. Wait for temperature reading to stabilize. Temperature is displayed in degrees F. It shall be within 5 degrees of room temperature.



PROCESS CONTROLS AND MONITORS

Solder Paste Handling Guidelines The following guidelines shall be followed at all times during the solder paste process. The quality of the solder paste is dependent on the guidelines, as it the print quality, and ultimately the board quality.

SOLDER PASTE REFRIGERATED

LIFE LIFE AT ROOM TEMPERATURE

STENCIL LIFE

MIX BEFORE USE?

INDIUM SMQ92 INDIUM SMQ62 DELTA SN63

6 MONTHS 6 MONTHS 6 MONTHS

2 MONTHS 2 MONTHS 2 MONTHS

8 HOURS 8 HOURS 8 HOURS

NO NO NO

Gloves SHALL be worn whenever solder paste is being added or removed from a stencil, and whenever misprints are being wiped. New solder paste shall be used at the beginning of each shift and spent solder shall be thrown away at the end of each shift. Paste shall reach room temperature prior to use. Consequently, paste shall be removed from refrigeration at least two hours before printing. Rapid warming of paste on top of ovens is strictly prohibited. It is much better to print with cool paste than to ruin the paste by heating it on the oven. Paste taken off a stencil that has life remaining shall be put into a clean storage container with a clean lid each time it is re-stored. The container shall be labeled with the paste type, date used, and shift during which it was used. Keep spatulas and plastic scrapers free of dried paste by cleaning them with IPA after each use. Airflow over the paste is detrimental to paste printability. Keep paste from the direct path of a fan or other sources of direct airflow until after reflow. Printed boards shall be reflowed within 4 hours of when they are printed. Mark the time that each board is printed on the edge of the panel. Misprint Organic Copper Coated boards shall be re-printed and through the reflow process within 4 hours of when they are washed. Mark wash time on the edge of the panel. Paste retainers shall be used at all times on squeegee holders that have retainers. When paste retainers are not standard equipment fold the excess side paste into the paste bead at least once every 20 minutes. Syringes and cartridges shall be stored tip down. Solder paste is a shelf life item and shall be managed as a FIFO supply



Kneading Solder paste

CAUTION: ALWAYS WEAR PROTECTIVE GLOVES WHEN HANDLING SOLDER PASTE AND ISOPROPYL ALCOHOL. REQUIREMENTS Start with a new container of solder paste at the beginning of each shift. Knead solder paste whenever taking paste from container or tube and placing it on the stencil. Knead solder paste after 5 minutes of inactivity. Use a five-minute timer if available. Put paste back in container and wash stencil if it shall have 10 min. of inactivity. On DEK , if delay anticipated, clean screen’s followed by 2 knead strokes and checking bricks. Knead solder paste whenever adding paste with the air gun dispenser. Do not add paste to try to refresh dry paste. Dispose dry solder paste in a designated 55-gallon hazardous waste accumulation barrels. Kneading is defined as 8 passes of the squeegee across the stencil or four passes for SMQ62. Kneading is not necessary for SMQ92 solder paste. SUMMARY Solder pastes are the glue "holding" it all together, once reflowed. It must be evaluated, qualified, stored, and used properly to ensure solder joints acceptable. In the preceding procedures, you can see much is required. Much also is overlooked that must not be. Follow, first, supplier recommended requirements. Then, perform exacting evaluations to ensure the "glue" works for you. STENCILS Before modern stencils, we used silkscreen "technology" much as used to print legend on bare PCB's and tee shirts. This definitely was crude and solder paste, or whatever medium, was stenciled by near artists using rubber blade hand squeegees. It got jobs done involving hybrid thick film circuits to very early PCB/SMT requirements. A little later we began making and using metal foil stencils but they to very limited though did the job well enough, with some effort, on early SMT product. SMT stencil printing machines were just being developed and produced. They too, had very serious limitations though, again, did the job well enough considering what needed to be done.



I created the following images, over twenty years ago, showing early stencil design considerations:

You can see stencil evolution in the first figure with mesh screen and flexible mask becoming extinct. We used step down stencils early on because of serious transitions taking place from 1206 and 50 mil pitch devices getting smaller. Some design requirements still apply especially concerning step down requirements and applications. What's important in stencil printing (that differs from screen-printing) is providing a consistent paste volume on every solder termination pad. Process windows vary in proportion to pitch. NOTE: MORE THAN 60% OF ALL DEFECTS ARE RELATED TO SOLDER DEPOSITION. A major key is maintaining process parameters as temperature, humidity, squeegee pressure and print speed, and paste parameters and condition. One example is if all paste was removed from the stencil, after 4 hours and new material was added, it completely changes paste chemistry. From IPC 7525, the following image is presented showing key stencil design requirements as aspect and area ratios:

Things have greatly changed as CPI. ADDITIONAL STENCIL DESIGN CONSIDERATIONS As with all successful product design, DFM/CE must be used at the earliest PCB design phase. For stencils, this is no less important as much data is derived from the design process and used to create stencil artwork. The data is used to image and etch stencils and for use in automated optical inspection (AOI) ensuring the stencil meets design intent.



My thanks to Mastercut Technologies for the following design criteria: Dimensions Because of the nature of the etching process and the undercutting at the edges of the resist pattern on the surface all dimensions, tolerances and configurations are functions of the thickness of the material being etched, the material and to a lesser extent, the process variations. In the section on tolerances and materials which follows, tolerances, overall pattern sizes, etc. These are generally applicable to equipment, processes, metals and configurations currently being used. They do not, however, express the ultimate capabilities of the photo chemical machining. For dimensions such as slots, corners etc., there are a few guidelines for designers which express practical limitations as the dimensions under consideration approaches the thickness of the metal. Relationship of Hole Size to Metal Thickness As a general rule, it is normally stated that the diameter of a hole cannot be less than the metal thickness. This relationship however, does vary as the metal thickness changes. A more exact relationship might be as per the table below. Relationship of line width to metal thickness. (Fig. 1 & 2) Generally speaking the width of metal between holes is not a particular problem in Photo Chemical Machining. However, when this space is the remaining surface area in a large field of slots or holes, there are limitations as to how small the metal width between holes can be. This relationship is as follows: Metal Thickness (t) Space between holes (W) Less than .025mm At least 1.25 times metal thickness .127mm or over At least 1.25 times metal thickness Metal Thickness (t) Smallest Hole Diameter (D) Less than .025mm Must be determined by test run .025mm - .127mm At least 1.25 times metal thickness .127mm or over At least 1.25 times metal thickness Relationship of Hole Size to Metal Thickness As a general rule, it is normally stated that the diameter of a hole cannot be less than the metal thickness. This relationship however, does vary as the metal thickness changes. A more exact relationship might be as per the table below. Metal Thickness (t) Smallest Hole Diameter (D) Less than .025mm Must be determined by test run



.025mm - .127mm At least 1.25 times metal thickness

.127mm or over At least 1.25 times metal thickness Relationship of line width to metal thickness. (Fig. 1 & 2)

Generally speaking the width of metal between holes is not a particular problem in Photo Chemical Machining. However, when this space is the remaining surface area in a large field of slots or holes, there are limitations as to how small the metal width between holes can be. This relationship is as follows: Metal Thickness (t) Space between holes (W) Less than .025mm At least 1.25 times metal thickness .127mm or over At least 1.25 times metal thickness Etching After exposure, the panels are developed leaving the image as bare metal. Etching is achieved using a heated acid solution. The panels are passed through the etcher on a conveyor at various speeds to achieve dimensions required. After etching the photo resist is stripped using a alkaline solution. Relationship of inside corner radius to metal thickness (Figure 3) In general, the smallest corner radius is directly proportional to the thickness of the metal ie., for metal thickness or .05mm, corner radius would be a minimum of .05mm. Relationship of Inside Corner Radius to Metal Thickness (Figure 3)

Outside corners tend to etch more sharply than inside. Therefore, radii of less than metal thickness are obtainable. As a general rule outside radii are considered to be at least .75 metal thickness, (t).



Relationship of Bevel to Metal Thickness. Etching one side - (Figure 4a) an etchant attacks the material laterally as well as vertically. The result, therefore, is the condition of etch configuration for a hole which is known as the "Bevel". As a rule of thumb, for material with a thickness (t), the bevel (A) would be approximately .75t. Etching two sides - (Fig 4b) assuming that the material is being etched equally from two sides, it can be easily seen that the bevel is appreciably reduced.

As a general rule, when etching from two sides, the bevel (A) is approximately .4t. Inspection Once the panels have been stripped and cleaned the parts are passed to our Q.A. Department to be inspected with various measuring equipment to ensure that dimensions and tolerances specified have been maintained.

NOTE: A MUCH BETTER INSECTION PROCESS USES AOI, INSTEAD OF OPTICAL COMPARITORS, AS THIS DIRECTLY CORELATES INSPECTION FINDINGS TO GERBER OR ODB DESIGN DATA. After final inspection the parts are packaged ready for delivery to the client. ALPHA TETRA STENCIL FOIL TECHNOLOGY I had the pleasure of researching and using sample Tetra Foils in prototype operations at H-P Spokane. We had over 3,000 active stencils, in DEK frames, in our huge inventory using more space than I knew. The following is a brief excerpt from a proposal I wrote to management concerning the Tetra Foil system:



1.0 PURPOSE AND SCOPE The purpose of this outline is to provide basic information concerning an exciting and very useful new tool for our SMT stencil printing and storage requirements. The scope of this outline extends to all H-P SMT manufacturing operations and to immediate and long term process and product quality improvement possibilities. 2.0 INTRODUCTION Alpha Metals, Inc., part of the Cookson Industries Group, has made H-P manufacturing an offer it cannot refuse. Based upon their capability to provide “frameless” stencil foils (only the print medium without frames) and a support system capable of assembling foils into “on demand” frames, or those only needed for specific production runs, Alpha has rendered a proposal for our consideration. The Alpha proposal provides H-P the opportunity to use their system for a 60 day period at no cost. The exception is we buy the foils used to apply solder paste – at a greatly reduced price compared with conventional foil/frame technology. This proposal, should it be accepted, provides H-P the opportunity to “test to break” Alpha’s system. If the system doesn’t break, and provides certain expected benefits, H-P will reap many benefits. 1) Massive gains in storage space as only foils require simple, less cumbersome storage capabilities. As there are no frames to store, a 5 fold increase in storage space is immediately available. 2) The system relies on a simple assembly mechanism to insert foils into frames for particular production runs. Operators easily will be trained. 3) Cleaning is as straightforward as foil into frame installation and uses the same cleaning system H-P currently employs. 4) Either Fuji or DEK frames and their parameters may be used (I suggest using only DEK as outlined later). 5) There is no traditional mesh interface between stencil foils so frames provide much better tension and retention capabilities consistently over time. 6) Foils cost about ½ that of current foil/mesh/frame types currently used. 7) Alpha owns patents and licenses to all patents and other requirements. 8) Alpha licenses this technology to other stencil foil fabricators including PSI – our current supplier. 9) Alpha’s foil fabrication facility, in Santa Clara, is close and offers AOI inspection capabilities based on downloaded Gerber files matching board and assembly design parameters.



10) Delivery times will be the same as currently provided as the foil fabrication process is the same. 11) Stencil design and fabrication parameters are the same as current – chem milling, laser cutting, and all attendant features exactly match current requirements (step downs hybrids, electro-polishing, and required aperture profiles, as examples) 12) Did I mention storage gains? The Alpha Tetra is a revolutionary stencil management system that, unlike the traditional epoxy-to-mesh stencil: eliminates the need for a dedicated frame for each stencil, provides superior print quality and performance, and saves you valuable manufacturing floor space. The result is substantial time and cost savings. This unique equipment along with our patented stencil foil design is only available through Alpha. All Tetra supplies are guaranteed. Equipment failures resulting from defects or worn parts will be replaced at no cost.” Equipment consists of two frames per line, two loading terminals per line, and assoicated accessories. Accessories consist of a stencil washing chase, a work station with storage capabilities for 150 stencils, and a stencil archive with storage capacity for 400 stencils (if required). Again, all this at no cost during the evaluation/qualification phase (is this stuff free upon acceptance by us?). As there is zero cost for the system elements (see quotation dated April 20, 1999) needed for evaluation and qualification, a purchase order needs to be generated and forwarded to: Curt Wright Sales Mgr. Eclipse Marketing 6240 E. Lake Sammamish Pkwy, N.E. Redmond, WA 95082. Another purchase order must be generated to buy at least two foils, representing our finest designs and production requirements. Each foil costs $245 each for chemically milled types including electro-polishing and with one hour of free CAD data editing time ($45/hour for each additional hour. NOTE: STEP DOWN TYPES AND LASER CUT PLATES ARE PROVIDED AT A HIGHER COST. All equipment and stencils are designed to work with our 265 GSX machines. It is suggested, as it will be outlined later, we concentrate on DEK frames.



STENCIL IMAGE EXAMPLES The following images show typical stencils along with micro-stencils used for repair, rework, and/or modification:



PAGE LEFT INTENTIONALLY BLANK



12.2 STENCIL PRINTING PURPOSE AND SCOPE The purpose of this document is to provide the trainers and trainees on the pick and place line with DEK stencil printing machine operation procedures. The scope of this document extends to all PNP operators and associated personnel as everything done on the DEK affects all other operations in this area. These instructions are to be used as a training vehicle, and no deviation shall be allowed. If there is a modification to be made to this document, it shall be brought to all the trainers to gain consensus, before being changed. The new revision date shall be noted on the bottom of all pages of this document. SAFETY, ESD, AND MATERIAL HANDLING Follow all ESD procedures Emergency stop buttons located on the front corners of the machine. DO NOT HESITATE TO USE THEM WHEN NECESSARY. After raising the print head cover, the red safety bar shall be inserted before working inside the machine. Remember to remove the safety bar before trying to lower the print head. CAUTION: BOARD CLAMPS, IN THE MIDDLE OF BOARD TRANSPORT RAILS, HAVE RAZOR SHARP EDGES. Solder paste is hazardous. Wear gloves when handling or working with it. If solder paste gets on skin, immediately wash with soap and water. See the MSDS for more information. Dispose of paste and contaminated waste in designated containers. The alcohol used in cleaning solder paste dries the skin. It is required that protective gloves be worn to prevent alcohol from getting on your hands. Handle boards only by their edges to prevent contaminating solder surfaces.



ESD as required in all areas – self explanatory Don’t hesitate to use E-Stop when required

Don’t get caught under here – there’s but a single support other than the print head support mechanism Prevent solder defects by handling PCB’s properly

Board edge clamps are RAZOR sharp & VERY dangerous Always wear gloves when handling solder paste



STENCIL PRINTING PROCESS - PRELIMINARY Before starting stencil printing operations, ensure the following requirements are met: Safety, ESD, material handling as required Machine working as required Inspect inside machine before proceeding – any items (tools, broken pins, etc.) or material (mylar, solder paste, rags, etc.) that might be a safety hazard or cause machine damage – remove items or material before proceeding – call maintenance if machine parts damaged or broken.

Get the crud out as well as unsafe material

Broken pin problem now eliminated?

Always look inside machine before starting any job

If broken pins found, notify engineering immediately



WHAT TO BUILD SOPT (Setup Optimization) list - determine PCA to be built Staging area - locate PCAs to be started – verify correct number with SOPT list

CAUTION: SOME PCAS DIFFER BY ONLY ONE DIGIT – ENSURE SOPT LIST, ROUTER, AND PANEL LABEL IDENTICAL Count panels and routers - one router - each panel - ensure quantities match SOPT – if not, check with logistics If a panel has one or more skipped images - router has decreased build If routers, panels, and images do not match - contact material logistics Barcode routers - staging area - read all routers to be started before taking into PNP area Take bar-coded routers and panels to DEK on appropriate line Read router to determine what process and what side of PCA shall be processed. Also, determine solder paste types, special fixtures, and/or special processes that shall be followed.

You know where this is You know where this is. Are required boards there?



NOTE: USE REQUIRED SMT FLOW CHART AND OPERATION NUMBERS TO ENSURE "FLOOR SHIFT" SOFTWARE WORKS PROPERLY.



Fill out placement logbook - PCA being started Determine if rest of line setup and ready to run - no excessive delays are encountered because of setups, missing parts, etc. If PCA placed on hold it is the operator’s responsibility to determine and follow procedures Reference On Hold process

STANDOFFS AND TEMPLATES Required Fuji standoff templates - to set standoffs on downline Fuji equipment - double sided boards Check standoff data base – determine if premade Fuji standoff template available If no pre-made Fuji standoff template - create - using Plexiglas sheet Clean old markings off Plexiglas with alcohol Wipe down both sides of Plexiglas with antistatic spray Place Plexiglas over side of board with parts on it - align tooling holes - keep aligned while tracing - trace around images/parts with marker and indicate location Turn Plexiglas over - mark this side as “up”

Fill out the book Check the rest of the SMT line before proceeding



STENCILS Get stencil (s) for PCA - stencil library Obtain tooling number from router, or stencil report for production assemblies or documentation for proto assemblies At stencil library terminal - part search (F5) if in part search mode - if not - change search (F6) - change to part search mode – part search (F5) Type tooling number - enter/return F4 (alpha character = locations carousel #2) Retrieve stencil from position shown in the location field

Once stencil retrieved - verify tooling number – F10 (keyboard)

One stencil library location Stencil library/location terminal database

Get the right stencil & be sure it is clean Verify the right stencil number and name



If stencil missing - check “stencils to be repaired log” - training manual storage location, or stencil cleaner, or on other lines Ensure stencils properly placed back in storage when finished Obtain tooling number from stencil Stencil library terminal – part search (F5) if in part search mode. If not – change search (F6) - change to part search mode - then part search (F5) Type tooling number - enter/return F4 (alpha character = locations carousel #2) Verify tooling number correct - place stencil in position shown in location field F10 (keyboard)

Return stencils to proper location Inspect stencils to ensure they are clean and undamaged



SOLDER PASTE Solder paste - hazardous material - wear gloves when handling paste - dispose of paste and contaminated waste in designated containers Solder paste types - 8090-1158 - Qualitek Delta solder paste jars - unless router says otherwise Solder paste types - 8090-1273 - Indium SMQ-62 solder paste jars - used when router indicates Solder paste types - 8090-1289 - Qualitek Delta type 615D syringes - used in PNP inspection as required by process documents and minor solder repairs on misprinted panels

Solder paste stored - refrigerator - temperature - 35 to 50 degrees F Solder paste shelf life - not used if older than expiration date Solder paste removed from refrigerator - brought to room temperature +/-5 degrees before use - warm-up area – one jar per line - Qualitek and SMQ-62 and one cartridge of Qualitek staged before use When jar or cartridge taken from warm-up area - replace with one from refrigerator Before using a new jar - use temperature probe to verify temperature - room temperature +/-5 degrees NOTE: IT IS ESSENTIAL SOLDER PASTE VERIFIED TO BE AT ROOM TEMPERATURE BEFORE USING Use fresh jar of solder paste - start of each shift - when stenciling board with extra fine pitch - jar in use four or more hours - anytime jar producing unacceptable prints

Indium solder paste and specifications Qualitek Delta solder paste and specifications



DEK 265GSX Turn power on - rotate main power switch clockwise - quarter turn (switch located on lower front right side of machine) When prompted by computer - press green system button to initialize machine (button located on control console) Use router - identify tooling number to be loaded - file name same as stencil tooling number minus dashes - be sure to load tooling number of side to be processed on double sided boards With main screen status displayed (F6) - if different screen displayed exit (F8) - back to main screen.

Load data (F2) Keyboard - type filename - (example T123456) - if stencil filename not in database - call PIM When correct filename highlighted - load (F1) - to load data file - exit (F8) - return to main screen Load data file - before loading stencil

Machine power on System button to initialize

Main screen status Load data



Determine if PCA requires tooling change

NOTE: DEK’S WITH FINE PITCH AUTOFLEX (FPA) DO NOT USE MAGNETIC STANDOFFS – GO TO SQUEEGEES SECTION OF THIS PROCEDURE Use tooling number - search template database - determine if DEK magnetic standoff template available for board side being built If no template in database - skip to install squeegees part of this procedure – If template found - continue setting magnetic standoffs Change Tooling (F6) Head (F2) Wait until "raise head using 2-button control" message appears in message status window - press and hold in two green buttons on machine front - until head in full up position Remove red safety bar (print head support mechanism) from its holder on machine front Install red safety bar - front left machine corner in corresponding female receptacles - black arrow facing operator - pointing up WARNING: BOARD CLAMPS IN MIDDLE OF BOARD TRANSPORT RAILS - RAZOR SHARP EDGES

Last data file ran Select new data file



Select required magnetic board support template Place template over raised board support pins Place magnetic standoffs in template openings-to insure accurate locations

Correctly install safety bar (print head support mech) Razor sharp board clamps exposed

Use two button control to raise print head Remove safety bar



Verify stencil cleaning paper roll has not been dislodged Remove red safety bar - secure it in its holder

Required tooling pin template Place template over non-FPA pins programmed up

Place required magnetic pins as required in template All pins in place as required for specific job

Stencil cleaning paper roll in required position Remove and replace safety bar in its holder



Head (F2) Press and hold in two green buttons on machine front - until head fully lowered

Press green system button to clear red system power down (safety interlock) message Exit (F8) When job completed, remove magnetic standoffs and template so that magnetic standoffs do not interfere with autoflex pins

Press head (F2) Lower print head into position

Press green system button Exit (F8)



SQUEEGEES Determine size squeegees required ½ panel size printed circuit board - 350 millimeters (large squeegees)

1/3 panel size printed circuit board - 200 millimeters (small squeegees)

Large (1/2) panel 350 mm squeegee on top

Small (1/3) panel 200 mm on bottom



From main status menu - setup (F6) Setup squeegee (F4) Change squeegee (F1) - print head moves to machine front Lift printer cover

Setup (F6) Setup squeegee (F4)

Change squeegee (F1) Lift print head cover



Place rear squeegee into holder - tighten screws finger tight Rear squeegee - mounting screws farther apart than front squeegee - squeegee has slot - matches with pin in holder - prevents installing squeegee backwards Place front squeegee into holder - tighten finger tight Close printer cover Press green system button Continue (F1) Verify front and rear squeegee pressures set - 10kg NOTE: SOME PROGRAMS MAY BE SET TO 11 OR 12 KG - IF PRESSURES NOT SET CORRECTLY - CALL PIM OR MAINTENANCE Verify front and rear squeegee pressures set to 6 kg NOTE: SOME PROGRAMS MAY BE SET TO 7 OR 8 KG - IF PRESSURES NOT SET CORRECTLY - CALL PIM OR MAINTENANCE

Front squeegee placed in holder and hand tightened Rear squeegee placed in holder and hand tightened



CALIBRATE SQUEEGEE REFERENCE HEIGHTS WARNING: DO NOT PERFORM THIS PROCESS WITH STENCIL IN MACHINE - DAMAGE SHALL OCCUR NOTE: THE ABOVE WARNING IS APPLICABLE EVEN THOUGH THE SOFTWARE DOES NOT PERMIT CALIBRATION WHEN STENCIL INSTALLED Perform calibration each time clean set of squeegees installed NOTE: THIS ENSURES LOAD AMPLIFIER ON SQUEEGEE ASSEMBLY STAYS IN SYNC WITH SQUEEGEE PRESSURES FOR EACH STENCILING PROCESS Calibrate heights (F2) - setup squeegee menu Display prompts - ensure correct squeegees fitted Physically verify correct length squeegees installed for correct program

Press green system button Close printer cover



When correct size squeegees fitted and verified - continue (F1) If correct size squeegees not fitted - exit (F8) - reload correct size squeegees - at this point - operator press calibrate heights (F2) - restart process CAUTION: NEVER PRESS RESTORE DEFAULTS (F3) - MAINTENANCE AND ENGINEERING USE ONLY F1 – continue key pressed - print carriage positions squeegees over front rail board clamp pressing front squeegee onto board clamp to calibrate the reference height - followed by rear squeegee During calibration - display prompts – calibrating pressure heights – do not open covers Process lasts 30-45 seconds – with no error indicators If error displayed during calibrations - call machine technician or engineer immediately After completion of successful calibration - exit (F8)



INSTALL STENCIL Load stencil software (stencil = “screen”) Again, ensure correct stencil (s) for job If present, remove any shims on stencil’s long side Using permanent marker, darken fiducials before proceeding (DO NOT WAIT UNTIL AFTER INSTALLING STENCIL IN MACHINE AND HAVE TO REMOVE IT TO DARKEN) CAUTION: AGAIN ENSURE NO FOREIGN MATTER ON ANY STENCIL SURFACE – PREVENT INADVERDANT PIN CONTACE AND IRREVERSIBLE DAMAGE TO STENCIL AND PINS – AND ENSURE EFFECTIVE PASTE PRINT HEIGHT/AMOUNT Lift printer cover With etched writing (corresponding to PCB tooling hole side - LEFT) - slide stencil onto chase rails until screen frame about even with rails – just past red laser mark Lower the printer cover Press green system button to clear red system power down (safety interlock) message)

Darken fiducials before loading stencil Ensure correct stencil for job



Change screen (F5) - observe machine pulling stencil in and clamp in position Exit (F8) VERIFY PROGRAM Mode (F1) - change mode to step Exit (F8) - machine automatically adjusts rails and board support pins - per the board’s program Run (F1) Auto board (F1) Ensure board properly marked only panel edges – not on images When prompted by display - load board - slide a board onto conveyor rails - most of board to be supported by rails - tooling holes shall be on board’s trailing edge (left facing) - match stencil and program - press confirm (F1)

Stencil in position just beyond laser sensor Insert stencil

Mark information only on panel edge – not images Correctly load board on conveyor



Step (F1) - step (F1) Board fiducial #1 - near center - left half of monitor split screen – displays good contrast NOTE: MOST PROGRAMS USE ROUND FIDUCIALS ON DIAGONALLY OPPOSITE BOARD CORNERS - CORRESPONDING “DONUT” FIDUCIALS ON STENCIL BOTTOM - THESE PROGRAMMED AS CIRCLES - WHEN STENCIL DOES NOT HAVE “DONUTS” - PADS AND APERTURES TAUGHT AS RECTANGULAR FIDUCIALS - SOME BOARDS USE VIDEO MODEL - ON A CUSTOM BASIS - PROGRAM LISTS COORDINATES FOR FIDUCIALS USED - IF UNABLE TO DETERMINE WHAT FIDUCIAL TAUGHT - CONTACT PIM Step (F1) - move to board fiducial #1 - if position not good correct as follows Step (F1) - to move to stencil fiducial #2 - if position not good correct as follows Step (F1) - to move to board fiducial #2 - if position not good correct as follows Step (F1) - to move to stencil fiducial #2 - if position not good correct as follows

Board fiducial location Board fiducial on split screen located and identified



If position close to edge or partly off monitor - adjust (F4) - increase (F6) - or decrease (F7) - move image right or left in X-axis - roughly center fiducial - next (F4) - select Y-axis - press increase (F6) - or decrease (F7) - move image up or down if necessary - image not needed to be perfectly centered - shall be well away from edges - press exit (F8) If fiducial not visible - search step (F5) - begin manual spiral search pattern - repeat until fiducial found - adjust per above to center image - search reset (F6) - may be pressed at any time to return to original position If fiducial not found - error message - or cannot find fiducial - refer to troubleshooting tips before calling maintenance, PIM, or process engineering Step (F1) - machine saves new information - steps through all four fiducials - verify their finding Exit (F8) NOTE: WHEN PROGRAM VERIFIED, VISUALLY VERIFY STENCIL APERTURE TO BOARD PAD ALIGNMENT – SEE ONLY COLOR OF PADS – NO PCB GREEN SHOWING ANYWHERE – USE PASTE LOAD (F3)(F2) COMMANDS FROM SECTION 3.12. (FOLLOWING

Red arrow pointing to board fiducial Red arrow pointing to stencil circle fiducial

Red arrow pointing to board fid on split screen Red arrow pointing stencil aperture fid on split screen



PROCEDURE) AND SQUEEGEES MOVE TO MACHINE’S REAR PROVIDING THE REQUIRED VIEW WHEN PRINTER COVER RAISED

Conductor patterns clearly visible through apertures Conductor patterns clearly visible through apertures



LOAD SOLDER PASTE Refer to router to verify type paste to be used From main menu - paste load (F3) Manual load (F2) - squeegee head moves back out of way – eases paste loading – allows view of solder termination area alignment through stencil apertures Raise printer cover Using only specified spatula – knead paste in jar and load solder paste onto stencil - spread paste out across blade’s width - minimize knead stokes needed to level paste log Close printer cover Press green system button Continue (F1) - print head returns to front Exit (F8)

Raise printer cover

Specified solder paste spatula with chamfered edges so as not to scrape plastic contaminates from jar into paste



KNEAD SOLDER PASTE NOTE: UNPOPULATED BOARDS (WITHOUT COMPONENTS ON EITHER BOARD SIDE) MAY BE USED FOR KNEADING - WITH MYLAR FILM - POPULATED BOARDS (FOR EXAMPLE - SECOND SIDE OF SMT-6) CANNOT USE MYLAR - ESD REASONS - UNPOPULATED BARE BOARD USED - OR DUMMY BOARD

Mylar - hard for machine to find fiducials – cut/clearance mylar around global fiducials (DON’T CUT IMAGE) - help recognize pads as fiducials - use eraser - remove shine from mylar surface - to press mylar tight against board surface - remove 1/8” mylar strip - both narrow board ends NOTE: IT IS IMPORTANT NOT TO HAVE ANY MYLAR HANG OFF ANY BOARD SIDE Using a blank dummy board - board program temporarily edited to run without fiducials as follows Main menu - setup (F6) - edit data (F3)

“Kneading” solder paste in jar Carefully applying solder paste on stencil

Place panel on mylar Cut mylar to fit panel



CAUTION: IN EDIT MENU - BE EXTREMELY CAREFUL NOT TO PUSH WRONG BUTTONS - MAKING CHANGES IN WRONG PLACES - USING NEXT AND PREVIOUS MOVES THE CURSOR FROM ONE BOX TO ANOTHER - USING INCREASE AND DECREASE CHANGES THE VALUE WITHIN A GIVEN DATA BOX - IF DATA CHANGED IN THE FIRST BOX (PRODUCT NAME) BY ACCIDENT - OPEN KEYBOARD TRAY AND PUSH ENTER TO RESET NAME - IF MACHINE PROMPTS TO COPY INSPECTION FILE - NO - F9 - IF ANY OTHER BOX CHANGED BY ACCIDENT - OR IF UNSURE ABOUT ANY CHANGE MADE - RELOAD PROGRAM - BEGIN EDITING AGAIN Scroll down - next (F4) - or scroll up with previous (F5) - until alignment mode highlighted Scroll up or down through choices using increase (F6) - or decrease (F7) - until non-vision displayed Exit (F8) - do not press save (F2) From setup menu - mode (F1) - until auto mode displayed Exit (F8) If prompted screen not changed - use screen (F1) NOTE: THIS MESSAGE DOES NOT APPEAR WHEN PROCEDURES FOLLOWED PROPERLY. Run (F1) Load board (with mylar) onto rails on machine’s left side Ensure knead cycle done (two print strokes instead of one) - knead paste (F6) Board moves to machine’s right side for unloading - screen prompts to unload board - carefully unload board - screen changes to load board prompt - if it returns to main menu - press run (F1) Repeat kneading process - minimum of 4 print strokes total Examine print - incompletes and bridges - or other print defects as mis-alignment more than 25%



After completing kneading (on mylar) - perform automatic screen cleaning before running real boards - exit (F8) - press clean screen (F4) – NOTE: TO INCREASE PROCESS SPEED - PRESS CLEAN SCREEN (F4) - BEFORE REMOVING KNEADING BOARD FROM RAILS - THIS CAUSES DEK TO GO INTO CLEAN MODE AUTOMATICALLY - MACHINE WIPES STENCIL BOTTOM - AND VACUUM PASTE FROM APERTURES - FAILURE TO DO SO CAUSES PASTE TO BRIDGE ON SUBSEQUENT BOARDS. If 2 fiducial vision used to knead - proceed to stencil print boards If non-vision mode used to kneading - reset program to 2 fiducial. Setup (F6) - edit data (F3) - scroll to alignment mode - press previous (F5) - change mode to 2 fiducial using increase (F6) - exit (F8) - do not save (F2) If at any time wrong data entered into program recover by reloading program

Load board correctly onto conveyor Solder paste kneading – simulation with cover open

Low magnification print inspection Higher magnification print inspection



Exit (F8) - return to main menu

STENCIL PRINT BOARDS After setup and kneading complete - and vision reset to 2 fiducial - use auto mode - automatically print boards - step or single modes allowed REMINDER: ENSURE 2 FIDUCIAL VISION IS SELECTED BEFORE PRINTING REAL BOARDS From main menu - run (F1) When prompted to load board - load board onto rails on machine’s left side - continue (F1) - machine completes print cycle automatically - when prompted to unload board - remove from machine’s right side - machine prompt resets to load board If machine does not find board or stencil fiducials - refer to troubleshooting Use magnifying glass to inspect every board for incompletes, bridges, and stray solder paste - inspect paste alignment paste to pad - if paste more than 50% off pad (non fine pitch)25% fine pitch and XFP - print rejected and washed - use microscope or vision system to complete FP and XFP pad inspection Mark line number, technology (example - 6B), assembly number (last three digits as 10857-68002 -857-002), and time on all boards - if panel has skips - mark skip number - if SMQ solder paste used mark SMQ on first panel - on first panel mark first – last panel mark last - (EXAMPLE – L1 6B 857-002 ”time” skip # SMQ 1ST or LAST) CAUTION: BE CAREFUL NOT TO MARK ON BOARD’S IMAGE AREA

Run (F1) Load board correctly



Machine automatically (only in auto mode) wipes stencil bottom on programmed frequency - stencil can be cleaned on demand by pressing clean screen (F4) - during this cycle - do not interrupt process If delay exceeds10 minutes - knead blank or dummy panel every 10 minutes to keep paste active - remember - clean screen after running mylar boards - before running actual board Three hour window from stencil to reflow - do not stencil print more boards than can be processed in this time - boards not reflowed during this time shall be washed - loaded boards may be waived by process engineering or PDA - contact them before scraping parts off and washing Wash the stencil and squeegees after two hours of use or on jobs lasting more than two hours Wash squeegees at least every two hours and when changing paste types

Write only on panel edges only with fine tip pen Inspect actual print (up to 25% misregistration allowed)



CLEANUP After completing build, or when a long delay is anticipated (when unable to kneed paste at ten minute intervals), clean off the stencil and squeegees, and return paste to jar as follows: CAUTION: DO NOT USE MYLAR SHEETS INSIDE MACHINE From automatic running menu - exit (F8) - then setup (F6) Setup squeegee (F4) - change squeegee (F1) Lift printer cover - remove squeegees - wipe off excess paste CAUTION: USE CARE HANDLING SQUEEGEES - AVOID DAMAGING BLADE EDGES Close printer cover - system button Continue (F1) Exit (F8) Change screen (F5) - machine brings stencil machine front When prompted - lift printer cover - remove stencil – remove solder paste from screen - plastic scraper or spatula - return paste to jar - remove ALL remaining paste from screen - lint free cloth and alcohol - clean remaining paste from the scraper or spatula and around jar Wipe up any paste drips inside machine - lower printer cover and press system button Dispose of any lint free cloths and gloves in the hazardous waste bin Clean stencil in stencil cleaner Clean squeegees by wiping - clean in stencil cleaner CAUTION: USE ONLY LINT FREE CLOTH OR PLASTIC TO CLEAN METAL BLADES. DO NOT USE METAL SPATULA FOR THIS OPERATION Clean up station Clean up any solder dropped on floor BOARD SUPPORTS - SUPPLEMENTAL CAUTION: IF BOARD SUPPORT MAGNETS WERE MANUALLY PLACED, THEY SHALL BE REMOVED AFTER COMPLETING PRINTING THAT BUILD. FAILURE TO REMOVE MAGNETS CAN CAUSE DAMAGE TO SUBSEQUENT BOARDS, OR TO THE MACHINE.



Return to main menu - exit (F8) - until main menu screen appears Head (F2) - press and hold two green buttons on machine front to raise printer head Install safety bar under the print head Push down all the AutoFlex pins - if desired - to make removing the plastic template easier Remove magnets and template Remove safety bar and return to holder Head (F2) - press and hold two green buttons to lower head Press system button to clear cover interlock message Turn power off only when required NOTE: TURNING POWER OFF IS NORMALLY DONE ONLY ON WEEKENDS (AFTER COMPLETING CLEANUP), OR TO RESET MACHINE IN ORDER TO CLEAR COMPUTER PROBLEMS. Turn power off by rotating main power switch - lower right front of machine - quarter-turn counter-clockwise TROUBLESHOOTING The DEK stencil printer has many safety interlocks, especially the two e-stops, and front and rear cover interlocks. Tripping any of these, even momentarily, shall cause the machine to stop immediately, and display a red error or warning message. Most of these are cleared by releasing the e-stop or closing the covers, then pressing the green system button on the control console. Some messages have the options displayed to press continue (F1), or exit or abort (F8). Fiducial not found If contrast not good on screen fids – darken them with black marker – wipe off excess ink with lint free cloth and alcohol. This error often happens due to machine variations in stencil position, causing the fiducial to appear too far off-center on the monitor. Adjust fiducial position as required. Mylar makes it hard for the machine to find a fiducial. Cutting out the mylar around a global fiducial solves this. Using an eraser to take the shine off the mylar surface and to press the mylar tight against the board helps to read pads as apertures. This error message also can be caused by loading the stencil or board incorrectly, or having the wrong stencil, board, or program. Some boards have apertures taught as fiducals. If the aperture is not clean enough, this error can occur. Perform screen clean, and retry printing.



Sometimes, the machine will not find a fiducial if proceeding directly from auto mode using non-vision to auto mode using 2 fiducial. Simply running through one cycle in step mode usually allows printing without having to actually use the adjust feature. System suspended while covers open This message shows when the front cover or the rear cover is raised. It resets when both are closed all the way. Alignment out of range This error is due to stencil being too far out of position. Remove and reload stencil, and try again. If problem persists, call process engineering for help. Board stuck in rails, board on rails, command timed out, or motor comms failure These messages usually mean a board is stuck inside the machine. Raise the head, carefully remove the board, lower the head, and press system button. Alternatively, push in an e-stop, carefully remove the board, release the e-stop, and press system button. Message should clear. NOTE: DETERMINE IF CONVEYOR BELT HAS COME OFF PULLEYS Squeegee pressure error This indicates a high or low squeegee pressure. This typically occurs during the initial kneading, as the machine adjusts the pressure. Press continue. After one or two strokes each direction, this message should not repeat. Out of paper Paper roll for stencil underside clean has run out, or fed improperly. Call line maintenance. Program edited incorrectly If it is suspected the wrong parameter in a program was edited, reload the data file. Unless save was pressed instead of exit, original program shall be intact still. If program was altered on hard drive, or if uncertainty exists, call process engineering. Some AutoFlex pins are pushed down, but shall be programmed to stay up From main menu, press setup (F6). Then press change tooling (F6), adjust (F1), then change AutoFlex (F1). Now press reset (F3). Press exit (F8) four times. Machine shall reset AutoFlex pins and return to main menu. NOTE: DO NOT PERFORM THE FOREGOING OPERATION WITH TWO SIDED ASSEMBLIES – ON THE SECOND SIDE – ONCE RESET IS HIT, ALL STANDOFFS ARE BROUGHT BACK UP – INCLUDING THOSE PROGRAMMED TO REMAIN DOWN – RELOAD PROGRAM INSTEAD.



SMARTSONIC STENCIL CLEANER The Smartsonic cleaner is used to remove solder paste from stencils, squeegees and misprinted panels. Caution – do not use the Smartsonic to clean a misprinted panel if the panel has components on it.

Smartsonic safety The 440-r detergent can cause skin irritation. Use of gloves is recommended. If concentrate gets on skin, wash with soap and large amounts of water. If detergent gets in eyes, wash eyes in eye wash for at least 15 minutes and then get medical attention. See the MSD's for more information. To stop any operation of the Smartsonic cleaner, push the red emergency stop button. NOTE: DOWNWARD MOVEMENT OF THE COVER shall BE STOPPED BY BREAKING THE LIGHT CURTAIN. TO RESET INTERRUPTED OPERATION PRESS THE GREEN “+” BUTTON ON THE FRONT OF THE MACHINE. Smartsonic stencil cleaning Remove excess solder paste from the stencil before placing it in the Smartsonic. Place the stencil in the basket with the dirty side towards the rear of the machine and the longest dimension of the stencil horizontal. Engage the top of the stencil frame in the upper retainer of the basket, lift up and set the bottom of the stencil frame in the lower part of the basket. Press the cycle start button to start the cleaner. When the cleaning cycle is complete the stencil shall move to the front of the machine and stop. The monitor shall say “main menu ready for process” Verify that stencil is clean and place in storage cart to air dry. If stencil is needed immediately, blow dry with air gun and verify that stencil is clean and dry before using. Before end of each shift .put away all stencils in storage cart.



Cleaning misprinted panels with Smartsonic NOTE: DO NOT USE SMARTSONIC IF PANEL HAS COMPONENTS LOADED ON IT. DO NOT USE SMARTSONIC IF PANEL HAS GLUE FROM GL2 ON IT. Place misprinted panel in Smartsonic basket with dirty side to rear of machine. Press the cycle start button to start the cleaner. When the cleaning cycle is complete the basket shall move to the front of the machine and stop. The monitor shall display “main menu ready for process”. Remove the panel and wash it in the inline wash machine located in wave/wash area. Inspect both sides of the cleaned panel for solder residue. Wash panel again if necessary. All labels shall be replaced after wash. See label area in stores. Squeegee cleaning with Smartsonic Place dirty squeegees in Smartsonic basket. Press the cycle start button to start the cleaner. When the cleaning cycle is complete the basket shall move to front of machine and stop. The monitor shall display “main menu ready for process”. Remove squeegees from basket. Use air gun to blow dry squeegees if necessary.



CONCEPTRONIC CLEANER The Conceptronic cleaner may be used to remove solder paste from misprinted panels and squeegees. The Conceptronic shall be used to clean misprinted panels that have components loaded on them. The Conceptronic shall be used to clean panels that have glue from gl2 on them

CONCEPTRONIC CLEANER SAFETY The chemicals used in this process are an irritant. If they get on skin, it shall be washed with soap and water. If any chemical gets in the eyes they shall be flushed at the eye rinse station for a minimum of 20 minutes and then the person should receive medical attention to ensure no further damage is done. See Aquanox SSA MSD's for more information. Use protective gloves to remove cleaned items from machine as they are hot (160° F.). Conceptronic cleaner operation The green ready light shall be lit to indicate that the cleaner is ready for a new process cycle. Open door and load dirty panel or squeegees into basket Close the door and latch both latches Press the green start wash button When the cleaning cycle is complete an alarm shall sound Press the red acknowledge button and remove cleaned panels or squeegees from cleaner Close the door and latch both latches For misprinted panels perform the following process steps as required If the panel has glue from gl2 process on it, wipe panel with a lint free rag that has been dampened with “Zestron SD300 adhesive remover” to remove glue after Conceptronic wash.



All panels that have been cleaned in Conceptronic cleaner need to be washed in the inline wash machine located in the wave/wash area After inline wash inspect both sides of the panel for solder and glue residue. Repeat wash process if necessary All labels shall be replaced after wash. See label area in stores. Washed panels with tsops loaded on them need to be inspected by process engineering before further processing. Put on-hold if process engineering is not available.

PRE-PROCESS AUDIT CHECKLIST The following checklist shall be used by all stencil print process managers (operators) to ensure nothing defective enters or leaves the DEK stencil printing machine. This checklist also is designed to promote long term continuous improvement based on vital information derived from operator use and feedback. 1 STENCIL AS REQUIRED 1 STENCIL CLEAN AND FREE OF FOREIGN MATTER 1 STENCIL FIDUCIALS EASILY RECOGNIZABLE 1 PCB AS REQUIRED 1 PCB MATCHES STENCIL AND ROUTER 1 PCB FIDUCIALS EASILY RECOGNIZABLE 1 MACHINE PROGRAMMED AND SETUP AS REQUIRED 1 STENCIL ORIENTATION AS REQUIRED AND INSTALLED PROPERLY 1 PCB ORIENTATION AS REQUIRED 1 SQUEEGEE CONDITION AS REQUIRED 1 SQUEEGEES CORRECTLY INSTALLED 1 PASTE APPLIED AND KNEADED AS REQUIRED 1 BOTTOM SUPPORT PINS CORRECTLY PROGRAMMED AND POSITIONED 1 SQUEEGEE CALIBRATION AS SPECIFIED 1 FIDUCIAL RECOGNITION AND ALIGNMENT AS SPECIFIED 1 STENCIL/BOARD ALIGNMENT AS REQUIRED (SEE ALL SILVER THROUGH APERTURES) 1 BOARD STOP WORKS AS REQUIRED 1 PRINT PROGRAM PROPERLY SETUP 1 MYLAR PRINT FIRST ARTICLE AS SPECIFIED 1 PCB PRINT AND ACCEPT FIRST ARTICLE AS SPECIFIED



12.3 A FEW WORDS ABOUT THROUGH HOLE TECHNOLOGY Yes, no matter how hard we try to forget, through hole technology is alive and well. Well, at least, it isn't dead yet as many of us predicted many years ago. The following information is not about procedures. It just provides some general considerations. How many still have this stuff in their assembly operations?

I read on the IPC Technet the other day that some SMT folks don't associate with through hole folks. I was shocked but not totally amazed. I mean, how in any process managed, cross-trained, manufacturing organization could this be? How absurd! What total nonsense, or maybe not. I also have been reading and hearing old questions being asked, by SMTers, how long lead lengths should be to ensure acceptable protrusion. Another question asked about 1W resistors concerning the distance they should be raised above the board substrate surface to effect acceptable thermal dissipation. Even current IPC's documents no longer address these issues. Now one must look to older, near ancient (by today's standards), design standards and acceptance specifications. This seems ludicrous, but I'm just an old fashioned kinda guy. MIL standards like 275 practically no longer exist but they had the answers to the above questions and many more. Even MIL standard's evolution to IPC has lost content concerning through hole requirements.



The following image is taken from MIL-STD-275 showing some through hole requirements including thermal dissipation:

Someone suggested people "might" go back to IPC's earlier 610 versions to see if they held answers to these questions. They do, but does anyone care and what about the vital through hole assembly team members? Folks, we're a long way from replacing many through hole components with those SMT. The following few images show some replacement examples:

REPLACE THIS WITH THAT? REPLACE THAT WITH THIS?



Well, I don't have to say much here. I just know, as do you all, through hole components and technology will be around a long time. That's all I have to say about that - FOR NOW.

REPLACE THIS WITH WHAT? REPLACE THIS WITH WHAT?

WHAT ABOUT ALL THIS STUFF?



12.4 COMPONENT PLACEMENT

MANUFACTURING OPERATIONS PROCEDURES

MOP-5035-2 (SAPPHIRE) COMPONENT PLACEMENT



1.0 PURPOSE AND SCOPE The purpose of these procedures is to provide detailed instructions concerning SMD placement manufacturing operations at POD. This is done to ensure product quality consistently meeting or exceeding POD acceptance criteria. The scope of these procedures extends to all personnel responsible for ensuring effective surface mount device (SMD) placement manufacturing operations at POD. 2.0 RESPONSIBILITY AND AUTHORITY The following responsibilities shall be fulfilled to SMD placement manufacturing operations are properly effected to assure quality at POD: Manufacturing Engineer The Manufacturing Engineer is responsible and has authority to provide everything needed by manufacturing operations personnel to fulfill their responsibilities at POD. This includes procedures, training, equipment, tools, adequate and safe working conditions, ESD requirements, and all other required elements. Maintenance Technician The Maintenance Technician is responsible and has authority to ensure all operational elements (equipment, tools, etc.) are maintained and calibrated as specified. This assures all facilities, equipment, and tools are capable of being effectively and efficiently managed to assure product quality meeting specified requirements. Manufacturing Supervisor The Manufacturing Supervisor is responsible and has authority to provide proper direction to all manufacturing operations personnel at POD. This includes operational procedures, special instructions, schedules, product changes, drawings, and required materials and components. This also includes management directives, performance evaluations, and timely individual and team performance feedback. Manufacturing Operations Personnel Manufacturing Operations Personnel are responsible and have authority to assure manufacturing operations are carried out in an effective, efficient manner. They are responsible for performing all manufacturing operations in accordance with current procedures, checklists, and supervisory direction. All personnel are responsible for effecting management policies and directives to assure quality meeting or exceeding specified POD requirements. Quality Assurance Inspection Personnel Quality Assurance Inspection Personnel are responsible and have authority to determine product quality does or does not meet specified POD acceptance criteria. They also are responsible for providing appropriate feedback concerning product quality to management and manufacturing process managers so corrective or continued manufacturing action may be effected.



3.0 BACKGROUND SMD placement operations are one of the first required to make high quality solder joints and assemblies at POD. As part of these operations, all placement processes, sub processes, and attendant activities shall be effectively managed to assure required quality. Primary focus is placed on placement requirements affecting solder joint acceptability. This also is true for all subsequent surface mount technology (SMT) operations and their processes. To ensure effective SMD placement process management, primary focus is placed on SMD placement accuracy (in all axes as X, Y, and Theta). Also, it is essential that SMD orientation and value requirements be met to ensure specified electrical performance. Component damage and loss shall be minimized as well. To assure and effect solder joint quality, placement accuracy is essential. If a device is placed out of location or tolerance, it may not automatically realign itself during reflow soldering to the extent required to assure acceptable solder joints. This is especially true for PLCC and other “heavy” device types that “sink” into the solder paste when placed. X and Y axis placement accuracy is important. So is Theta or rotational accuracy. If a fine pitch leaded device is misaligned about its center (perpendicular to the X and Y axes), by more than even one degree, it may not realign automatically. This presents the possibility of opens, shorts, unacceptable solder joints, or all. Today and tomorrow’s device types are becoming smaller as the demand for higher density interconnect system technology increases. Whereas many of yesterday’s leaded devices were on 50 mil centers or were large chip types, today’s are in the range of .020” or below. Today’s chip device types are shrinking in size to below 0402 sizes as 0201’s become available and are being placed by more people in industry. Not only does this place demands on placement accuracy, it also places them on retrieving (picking) and aligning capabilities. Many current device types defy logic in terms of being visible let alone being placeable. This extends to increased demands on soldering processes to effect acceptable solder joints. Simply, SMD placement equipment, processes, and attendant mechanisms or tools have continuously increasing demands placed on them. The same is true for SMD placement process managers who shall be highly trained to become capable of carefully fulfilling increasing responsibilities. Types other than leaded or chip devices also push the edge of the envelope. Other types include ball grid array (BGA), micro BGA (uBGA), tape ball grid array (TBGA), ceramic ball grid array (CBGA), ceramic column grid array (CCGA), flip chip technology, chip scale packages (CSP), and sub uBGA devices. Some of these devices have terminations on 12 mil centers (micro and sub micro BGA as examples). Some are bonded directly to the PCB substrate (flip chips and CSP’s) requiring tremendous placement accuracy and even more advanced attachment capabilities. From the above, it is clear true design for manufacturing (DFM) and concurrent engineering (CE) efforts are required to ensure SMD land pattern dimensions, tolerances, and location accuracy is achieved. It all starts at the design level. For a design to be proven (made acceptable) in all subsequent processes, it shall be processed after all responsible process managers providing input



concerning how capable the design is of being made acceptable in each process step. This shall be understood and planned from design through test and customer acceptance. From design through test, process managers shall have a clear view of all affects all processes, sub processes, and activities have on design rule selections. Conversely, process capabilities shall be better planned, implemented, and managed to assure design with process compatibility. This shall be done to ensure designs and product meeting customer contract requirements on time, the first time, every time. Ideally, all processes shall be statistically characterized. Determining process capabilities provides a clear indication about how well designs may be produced within them. If everything does not come together as planned, repair or rework considerations must made. This too includes emphasis on replacement accuracy concerning rework equipment. Again, all SMT equipment types are constantly evolving to meet these ever increasing demands. Some equipment designs are moving away from single turret, lead screw driven types. It is thought lead screw machines may not be completely capable across the entire range of motion required to ensure accuracy and repeatability. For this reason, belts sometimes replace lead screws. This is done while linear encoders provide very accurate feedback to drive motor controllers to assure head placement location and positioning requirements are met. The most important advances in machine placement accuracy have been made with “touchless” device centering systems. No longer are alignment “dies” or stations required to pre-align devices before picking and placement. These systems are guided by sophisticated vision cameras, lasers, and microcomputer capabilities. Vision systems now provide very high resolution cameras to very closely correlate component and PCB placement feature requirements (leads, spheres, edges, columns, and fiducials as examples). This ensures the accuracy and repeatability required for effective placement. Laser systems also complement vision systems, or provide a unique tool for placement accuracy vision systems may not. This is true for certain device types. Examples are small chip devices. Much of this technology is advancing to keep pace with speed and throughput (efficiency) requirements. Efficiency also is improving via improved process management to minimize wrong or missing components. Touch-up and/or rework demanded not long ago with less advanced technology is now minimized. However, problems may exist when increased production speed overdrives design for manufacturability or test requirements, as examples. Advances also have been made in areas of component delivery systems. Tape and reel mechanisms or tape feeders have been greatly improved. This also is true of the ability to place many more device types using these systems. “Waffle” trays and pallets still provide pickup access to QFP’s and some other leaded types as well as BGA’s. Newer bulk feeders, belts, and vibratory mechanisms are on the horizon for smaller chip device types. Virtually gone are “stick” feeders except in low volume, less demanding applications.



Newer programming software is evolving to ensure more effective, efficient process management. Geometric dimensioning and tolerancing (GDT) is finding its way into the printed circuit fabrication and assembly worlds. Together with CE, this allows improved focus concerning DFM. Software now includes advanced, “off line” programming capabilities for SMT assembly lines. This allows better coordination between all manufacturing and associated responsibility areas. Design, fabrication, assembly, test, purchasing, material control, inventory, and kiting is much better managed. This software is called computer aided manufacturing (CAM). It usually is capable of being integrated into computer integrated manufacturing (CIM) programs or material management systems (MRP types). CAM capabilities are used to program entire SMT assembly processes or lines. The software is especially useful for programming pick and place equipment and processes. It greatly improves line balancing and optimizing wherein processes and machines are made more efficient because they place more compatible component types. An example to optimize high speed chip placement requires programming only the best suited machine to carry out these placement requirements. The same is true for larger leaded or fine pitch devices as they are best placed by machines more capable than chip shooters. POD uses CAM software called UNICAM. It is becoming an industry standard and may find its way into all machine programming areas. It almost is a universal tool replacing often cumbersome, machine specific programs and proprietary languages (Fuji, Panasonic, etc.). This especially is true as more interface software becomes available. POD has evaluated, qualified, accepted, purchased, and installed Philips SMD placement equipment. POD operates the Philips “GEM” and “Constellation” series equipment. The “Gem” series consists of the “Emerald” and “Sapphire” placement machines. The “Constellation” series is made up of the “Eclipse” and “Orion” models. Each machine model is capable of very accurate placement of all currently “popular” device types. This includes fine pitch QFP’s, BGA’s, and chip devices to 0402 size. Placement accuracy typically is .0001”. This is repeatable and is maintained as discussed earlier based on preventive maintenance and calibration together with designed in process capabilities as high resolution vision and laser systems. Placement speed is dependent upon device type with “chip shooter” speeds reaching 25,000 components per hour (cph) on some machines. Leaded device placement focuses mostly on accuracy with speeds reaching 7,000 cph for SOIC’s, as an example. Again, this is dependent on device types used. To ensure effective, efficient process management, one of the most critical factors is preventive maintenance (PM). Calibration also is required to return equipment and attendant process elements to specified capabilities after maintenance. To maintain process effectiveness and efficiency, it is required that each manufacturer have on board well trained maintenance and calibration personnel. Spare parts and backup plans are equally necessary in the equation.



With all the advances in placement technology , effective process management is that much more essential. Only highly trained operational personnel can effectively and efficiently manage such sophisticated processes. These procedures form part of the training required to effective such management. Machine operation is reasonably straightforward due to fairly simple machine designs. Each machine has two heads driven by servo and stepper motors, and precision ground lead screws. Each machine is capable of using stick, tape, bulk, and tray/pallet feeders for nearly all available device types. A particular machine type provides capabilities either for fine pitch or chip devices as indicated in the following:



SAPPHIRE Sapphire, the fastest mounter in the GEM Platform range, is capable of placing up to 25,000 SMDs per hour. This machine employs Philips patented parallel processing technology, whereby two or more operations can be performed simultaneously. Its design means that fewer moving parts are required and unproductive time is minimized. The result is a higher output efficiency, increased reliability, and significantly reduced cost per placement.

The compact GEM Sapphire employs two independent placement beams. Each is equipped with 12 pick-and-place heads. Individual heads can simultaneously collect components from any mix of feeders for placement on two PCBs at the same time. The placement heads pick components while a walking beam transport conveys three boards simultaneously through the Sapphire. This virtually eliminates delays due to machine overhead for loading and unloading. Each placement beam has a line sensor camera and vision processor. This permits parallel on-the-fly device alignment and lead verification at very high speeds. Placement accuracy is 0.1 mm for chips and 0.08 mm for ICs. Similarly, twin camera systems monitor fiducial marks at board, circuit, and component levels. A unique bad mark sensing capability enables multi-circuit panels to be run as large single boards, thereby maximizing placement rates while avoiding component wastage. A flexible board transport system enables the Sapphire to handle virtually any type PCB. Conventional tooling pins are used to align boards with standard location holes. Substrates without tooling holes may be edge-positioned by push pins or by full-length front and rear clamps. Where required, magnetically attached push-up pins provide underside support. Automatic conveyor width adjustment enables size changes to be completed in seconds. Advanced electronics, and a vibration-free frame designed with the aid of sophisticated computer simulation, make the Sapphire ideal for heavy duty, round-the-clock operation. Two versions of the chip-shooter are available. The standard configuration accepts boards up to 330 x 407 mm (13” x 16”) and provides 112 total feeder positions. A large-board model accommodates a 457 x 407 mm (18” x 16”) maximum substrate size with up to 96 feeders. Tape, stick, and bulk feeders can be fitted in any combination. The following figure represents key machine features, part names, functions, and operational elements:



NOZZLES The images in the following figure show the available nozzles for the Sapphire:



CONVEYORS The SYSTEMS conveyor assembly consists of four units as “carry in conveyor,” “carry out conveyor,” “A table conveyor,” and “B table conveyor.” Each conveyor’s function and PCB transfer direction is described in the following figure:

NOTE: POD EMPLOYS THE LEFT TO RIGHT FLOW OPTION IN ITS SAPPHIRE PLACEMENT MACHINE.



AXIS CONFIGURATION AND OPERATION The following figures, on this and the following page, show the Sapphire’s axis configuration and operation:



PCB LOCATION AND POSITIONING ELEMENTS The following location and positioning elements are used to secure and position PCB’s in the machine for component mounting: Main Stopper When a PCB is carried in on the conveyor, the main stopper halts its travel in the component mounting position. It is shown in the figure below (lower right corner - inside circle) with a board stopped against it. Also note board clamp in the first figure.

Locate Pins Locate pins are engaged with the positioning holes in a PCB (when available) to secure it in place for mounting. The moveable locate pins are adjusted according to PCB size. At this time, locate pins are not used at POD because board designs have no tooling holes in which locate pins would be inserted. Push In Unit The push in unit presses the PCB against the main stopper securing it in position for mounting. The push in unit is shown in the lower left corner (second image above - inside circle) pushing the board securely to the board stop shown again on the board’s lower right corner. Edge Clamps Edge clamps are shown in first figure above inside the circle. They secure the PCB in place ready for mounting by clamping its edge. Edge clamps are located just above a push up bar as the bright silver object extending from left to right in the photo’s center. The push up plate also is shown in this figure with support pins magnetically adhering to it to support the board secured above them. Push Up Plate The push up plate clamps the PCB up against the conveyor rails – with the support pins attached by magnets on the plate. The plate is shown in the figure above supporting the push up pins ready to support a board when placed in position above them.



Push Up Pins Push up pins are shown in the first figure below as they are arranged on the push up plate to secure the PCB by pushing it up from the bottom.

Edge Push Up Bars Edge push up bars are used to secure the PCB by pushing its edges up against the PCB support plates. The second figure above shows a process manager pointing to a push up bar with the edge clamps again in view above the bar.



INPUT AND CONTROL DEVICES The next two figures represent the machine’s input and control devices as a hand held keyboard (HHK) and standard keyboard:



The next figure shows the HHK attached to the machine’s front.

To ensure effective, efficient process management, one of the most critical factors is preventive maintenance (PM). Calibration also is required to return equipment and attendant process elements to specified capabilities after maintenance. To maintain process effectiveness and efficiency, it is required each manufacturer have on board well trained maintenance and calibration personnel. Spare parts and backup plans are equally necessary in the equation. With all the advances in placement technology and resulting accuracy, repeatability, speed, efficiency, and reliability, effective process management is that much more essential. Only highly trained operational personnel can effectively and efficiently manage such sophisticated processes. These procedures form part of the training required to effective such management.



DEFINITIONS The following definitions are provided for all process managers to better visualize each process for which they are responsible: Operations Operations are defined as a series of processes required to provide product or services meeting certain requirements. Usually these requirements are based on customer needs, desires, or demands. POD employs many operations as management, engineering, marketing, sales, manufacturing, accounting, quality assurance, and others to ensure all its customers receive product meeting their requirements. Process A process is defined as a method or procedure. A process may be a single method or procedure, or may be made up of sub processes and activities. In a manufacturing operation, a process is employed to turn acceptable raw materials, components, and designs into acceptable product using various tool and equipment types. Sub Process A sub process may be part of a process. In the pick and place process, several sub processes are involved to effect acceptable component placement. They are discussed in the foregoing section. Activity Processes and sub processes most often rely on individuals or teams performing activities to make product. In manufacturing, such activities may consist of moving or handling materials and components, changing machine or tool settings, turning equipment on or off, etc.. It is at the activity level most variability is introduced to manufacturing operations effecting varying degrees of quality. For this reason, it is vital process managers be well trained to fulfill their responsibilities by following procedures concerning specific process management requirements. Process Management Process management is the act of preventing defect by fulfilling individual responsibilities instead of reacting to it as the result of not fulfilling them. When process instead of results management is practiced, product quality is consistently acceptable. Process management differs from process control in that control means only consistent quality is produced. In a controlled instead of managed environment, that quality may be consistently good or bad. Process Capability Process capability is the measure of how well a process is being managed. Usually, a processes’ capability is expressed in statistical terms as a capability profile or Cpk. When a process is managed effectively, its Cpk shows how well while often providing an indication of what is needed to continuously improve. Continuous process improvement assures continuous quality improvement and that is what process managers focus on most. Pick And Place Pick and place is the process required to adequately retrieve (pick) a surface mount device and place it on a specified location. This shall be done in a prescribed manner with the specified accuracy in all axes. All this is done without damaging the device, or the substrate on which it is placed.



Accuracy Accuracy is defined as the ability to reach a specified target or location within a specified range or tolerance. Repeatability Repeatability is defined as the ability to reach a specified target or location within a specified range or tolerance every time the process is effected. Fiducial A fiducial is a locator or target placed on a PCB substrate’s surface to aid SMD equipment placement accuracy and repeatability. As “targets,” they aid vision systems more precisely find prescribed placement locations with respect to solder termination areas. Fiducials usually are of two types. One is a general or “basic” locator often placed at PCB edges or corners. The other is more closely located relative to specific target areas as fine pitch land patterns. Fiducials may be of varying shapes and are etched on the PCB surface as permanent locators for placement process management. Vision System A vision system consists of high resolution cameras. One is mounted “looking up” to the bottom of a component to be placed on a PCB substrate. Another “looks down” on the PCB surface locating fiducials or SMT land patterns to assist in placement accuracy. Vision systems may be best used to locate, align, and place larger leaded devices whereas laser systems may be best used for small chip devices. Laser System A laser system is used like a camera based vision system. It is used primarily to locate, align, and place small chip device types. SMD Placement Machine Head An SMD placement machine head is the key mechanism mounted either stationary or on a moving mechanism that mounts single or multiple placement nozzles or “quills.” A traveling head (or heads) moves along a lead screw aided by servo or stepper motors. It also may be propelled with belts linked to these motors. Heads house all electrical, mechanical, and pneumatic elements required to serve the nozzles to pick and place devices. This is done while receiving and executing commands given by a computer to effect accurate component location, pickup, alignment, and placement. Nozzles Or Quills Nozzles or quills usually are vacuum activated tubes capable of picking up SMD’s and placing them on specified PCB substrate locations. Nozzles vary in size, configuration, quantity, and capability according to pre programmed demands. Nozzle selections are based primarily on device types to be picked up and placed. As an example, larger devices require larger nozzles. Lead Screw Lead screws in highly accurate placement machines are made of surface hardened steel rods of specified lengths. They have a highly precision ground surface with equally precision grooves ground through that surface to a specified depth and shape. The grooves “spiral” about the rod and act much as common screws used as fasteners. A lead screw may have single or multiple grooves depending on applications. This is based on accuracy requirements.



The screw is driven at specified revolutions propelling a mating mechanism (bearings or followers) along its length to and from pre programmed points. These points are where pick and place processes are effected. The screw is driven by high speed servo motors providing high speed positioning. Lead screws generally are very accurate over short distances (1’ – 3’). Often however, they tend to “runout” of tolerance over distance and time. This is because they are susceptible to inconsistent wear though they often are frictionless bearings. Also, inconsistencies inherent in machining processes render them inconsistent. For these reasons, lead screws need to be calibrated or “mapped” to ensure specified accuracy and repeatability requirements are met. Preventive maintenance consisting mostly of lubrication is essential to assure effective operation and to minimize wear. The first figure bellow shows a precision lead screw of the type required for exacting movement and precise positioning of placement heads, as an example. The second figure shows one not required so much for precision positioning as it is for simpler movement and transfer of tables, as an example. X and Y Axes X and Y axes describe directions perpendicular to one another across a PCB substrate’s surface or plane (horizontal motion). X and Y axes motion and positioning is critical to placement accuracy and repeatability.

Z Axis Z axis describes the direction perpendicular to the X and Y axes (vertical motion). Z axis motion is critical to head and nozzle pick up and placement depth. If the motion is to short, no device is picked up or it is dropped onto the designated area. If the motion is to long, component and/or PCB substrate damage is realized. Some placement machines still have sensors that see or “feel” their distance from a device or board surface. More sophisticated equipment is programmed to a specific Z axis range to prevent insufficient, excessive, or otherwise erroneous motion and positioning. Theta Axis Theta axis describes the directional movement about (perpendicular) the X and Y axes through all degrees of a circle or compass (circular motion). If Theta axis (may be termed “R” axis) accuracy is not met as specified (often not more than 1 degree), device placement accuracy shall not be met.



This means misalignment is effected though center line (with respect to land pattern) though X-Y accuracy requirements may be met. Chip Shooter A chip shooter is an SMD machine capable of placing chip device types at high speeds. Placement speeds can reach 25,000 cph or more. Speed depends on machine capabilities, PCB designs, board sizes, and device types. Fine Pitch Placement Machine A fine pitch SMD machine is (by definition) capable of placing leaded device types with finely spaced leads. This is done with great accuracy. These machines primarily place leaded devices ranging in pitch from 50 mils down to 12 mils. These machines primarily depend on optical vision systems for alignment and placement operations whereas small device placement machines depend mostly on laser systems. Pitch Pitch is defined as the distance between lead centers on leaded device types (SOIC, QFP, etc.). Quality Quality is defined as conformance to clearly specified, understood, and accepted customer contract requirements. Repair Repair is defined as the process required to restore the functional capability and/or performance characteristics of a defective article. This is done in a manner that precludes compliance of the article with applicable drawings or specifications. Modification Modification is defined as the process required to revise the functional capability or performance characteristics of a product to satisfy new acceptance criteria. Modifications usually are required to incorporate design changes that can be controlled by drawings, change orders, etc.. Modifications only shall be performed when specifically authorized and described in detail on controlled documentation. Rework Rework is defined as the act of reprocessing non-conforming or defective articles. This is done using original or equivalent processing to assure full conformance of the article with applicable drawings or specifications. Rework is doing something over that should have been done right the first time. Other Other terms are defined in IPC-T-50 and in specific guidelines, standards, and specifications indicated in Section 8. herein.



4.0 REQUIRED EQUIPMENT/TOOLS Designated Placement Machine Specified Nozzles Specified Feeders Specified Components Specified Tooling And Support Equipment



5.0 OPERATIONAL AND QUALITY SYSTEM REQUIREMENTS Operational and quality system requirements are steps required to maintain process management effectiveness to assure product quality meeting specified requirements. Traveler and drawings as required Safety, handling, and ESD procedures as required Operational and work specific instructions as required Quality system documentation as required Component Placement Operations Requirements The component placement process manager shall ensure the following requirements are met before beginning production: All required tools and equipment are properly prepared before production Printed circuit boards properly cleaned Components and feeders as specified Equipment properly maintained, calibrated, and in good working order All safety requirements in place and being met All ESD requirements in place and being met All material handling requirements in place and being met Work area in clean and orderly condition Required stencils clean and ready for production for specified board type All support elements, tools, and personnel available Work order or traveler correct and available for job Supervisory direction and work instructions available and being used Fiducials bright, shiny, and clearly visible.



6.0 OPERATIONS USING THE PHILLIPS “SAPPHIRE” SMD PLACEMENT MACHINE These procedures are used to ensure effective, efficient manufacturing operations concerning SMD placement at POD. POD uses specified and approved SMD placement equipment, tools, and attendant manufacturing operations to place components on PCB’s. SMD placement process management procedures shall be used to effect product quality meeting requirements indicated in applicable documents listed in Section 8. herein. The following figure shows machine part names and functions: 6.1. Machine Overview The first figure below provides a front elevation view of the placement machine. The second shows the machine outline and in an operational setting at POD.

Vision display (1) Operation display (2) Warning lamp (3) HHK (4) Keyboard (5) Main power switch (6)



Basic Operations Requirements The following requirements shall be met before beginning component placement operations: Ensure proper handling and ESD protection. The first figure indicates ESD protection required symbol. The second figure indicates ESD handling requirements shall be effected. The third figure shows the preferred method for handling Class III PCB assemblies. The fourth figure shows an acceptable handling method. In all cases it is required that ESD protection be provided all assemblies and all boards be handled so no damage, contamination, or other defect causing possibilities exist.



Basic Safety Requirements At this time, inspect inside the machine for articles or substances that might cause damage, or other process problems, and remove or correct them as necessary to effect safe operations.

NOTE: TO GAIN PHYSICAL AND VISUAL ACCESS TO MACHINE’S INNER WORKINGS (FOR SAFETY INSPECTIONS AND SETUPS), MANUALLY MOVE THE HEADS WITH THE ATTACHED HANDLE. ENSURE ALL WARNING, CAUTION, AND DO NOT TOUCH LABELS ARE OBSERVED AND OBEYED. DETAILED SAFETY REQUIREMENTS ARE PROVIDED IN POD, PPM-2005, SAFETY PROCEDURES



Production Operations Overview And Flow Chart After preparing all required elements, production operations may begin. The procedures on the following pages reflect the basic operational flow represented in the chart below: NOTE: THE FOLLOWING IS A FLOW CHART REPRESENTING THE BASIC MACHINE SEQUENCE OF OPERATIONS:



Start And Stop Operations Procedures: Perform routing operation as required Perform required inspection before operation ensuring all safety requirements are met inside and surrounding the machine. Starting Operation And Operation Flow Chart Perform the following operations before beginning any work such as creating new PCB data and PCB production:

CAUTION: CHECK THE SURROUNDING AREA FOR SAFETY AS EACH AXIS MOVES WHEN RETURN TO ORIGIN IS PERFORMED - MAKING IT DANGEROUS IF ANY PART OF THE HUMAN BODY ENTERS THE MOVEMENT RANGE OF THE HEAD ASSEMBLY DURING RETURN TO ORIGIN. BECAUSE OF THIS, STAY OUT OF THE MOVEMENT RANGE.



Ensure specified air pressure indicated on gauge at back of machine. Turn main power on. Observe as the machine begins loading programs necessary for machine operation. Wait until the complete VIOS operating system is loaded before continuing with the next step. When the VIOS main menu screen is displayed, turn the servo ON. Observe the EMERGENCY STOP message as it disappears and each axis becomes servo controlled.

Select and execute <1/1/RUNNING>. Observe as this operation returns each machine axis to the reference position (machine origin). NOTE: AFTER THE POWER IS TURNED ON, RETURN TO ORIGIN SHALL BE PERFORMED BEFORE BEGINNING ANY WORK SUCH AS CREATING A NEW PCB DATA AND PCB PRODUCTION. Observe a list of the registered PCB names as they appear on the screen. Select the required PCB name to be produced. NOTE: IF THE PCB TO BE PRODUCED HAS NOT BEEN REGISTERED YET, ANY PCB NAME MAY BE SELECTED. Load the selected PCB data. Observe <1/1/D2 INIT. SERVO ORIGIN> displayed. Select and execute <1/1/D2 INIT. SERVO ORIGIN> command to return to servo origin. Observe as each axis begins returning to its origin. NOTE: RETURN TO ORIGIN CAN ALSO BE PERFORMED IN MANUAL MODE. EACH MANAGER, EXCEPT FOR <4/SHELL/M>, HAS MANUAL MODE.



Warm Up Operations Be sure to warm up the machine before starting PCB production, especially for the X and Y axes. Normally, a 10 minutes warm up is recommended. If less than two hours has elapsed after the machine was last used, no warm up is necessary. When the mounter starts warm up, the tray changer also starts warm up - if it is connected.

Be sure the emergency stop is canceled, and the return to origin has been performed. Also be sure the push up pins are securely attached while ensuring the safety covers are closed. Select and execute <1/1/D1 WARM UP>. Observe as the warning message appears on the screen. Check the surrounding area for safety. When no PCB data has been selected, select a PCB name first.



Set required warm up time. NOTE: A WARM UP TIME IS DISPLAYED IN MINUTES IN THE WARNING MESSAGE BOX. EACH TIME THE SPACE BAR IS PRESSED, THE WARM UP TIME SETTING CHANGES IN ONE MINUTE INCREMENTS. THE RECOMMEND SETTING IS 10 MINUTES UNDER NORMAL CONDITIONS. THE IMAGES COMPROSING THE NEXT FIGURE SHOW WARM UP MESSAGES ON THE DISPLAY SCREEN.

REFERENCE: Warm up may be started without setting the warm up time by omitting this step and directly pressing the ENTER key as in the next step. Start warm up NOTE: THE MACHINE STARTS WARM UP SLOWLY AT FIRST WITH A GRADUALLY INCREASING SPEED OVER TIME. THE CURRENT DATE, TIME, AND ELAPSED TIME DURING WARM UP ARE DISPLAYED ON SCREEN. WARM UP OPERATION AUTOMATICALLY STOPS WHEN THE PRESET WARM UP TIME HAS ELAPSED. IF THE WARM UP TIME HAS NOT BEEN SET - SET THE WARM UP TIME. PRESS THE ESC KEY TO STOP WARM UP.



CAUTION: IF AN ABNORMALITY OCCURS DURING WARM UP, STOP OPERATION IMMEDIATELY - CHECK CAUSE AND ELIMINATE IT BEFORE CONTINUING. Quit warm up NOTE: THE ABOVE STEPS EXPLAIN A WARM UP PROCEDURE IN RUNNING MODE OF THE OPERATION MANAGER, SUPPOSING THE NEXT WORK IS PCB PRODUCTION. WARM UP CAN ALSO BE PERFORMED IN MANUAL MODE OF EACH MANAGER EXCEPT FOR THE SHELL MANAGER.



Pre-Operations Procedures The following procedures are used by process managers to ensure all process elements are as required to begin production: The production supervisor provides a component/feeder setup report to placement process managers at the start of a production run as in the next two images.

NOTE: THE REPORTS INDICATE NUMBERED LOCATIONS, ON VARIOUS FEEDER STORAGE CARTS, WHERE LOADED FEEDERS ARE RETRIEVED BY PLACEMENT PROCESS MANAGERS TO BE PLACED ON SPECIFIC FEEDER POSITIONS. THESE POSITIONS CORRESPOND TO INFORMATION DISPLAYED ON THE MAIN MACHINE MONITOR INDICATING PROGRAM REQUIREMENTS FOR LOADING AND PLACEMENT.



Ensure all production equipment, tools, and other required elements are available for production operations Again, inspect inside the machine for articles or substances that might cause damage, or other process problems, and remove or correct them as necessary to effect safe operations. Prepare for operations as in the following: Using the feeder setup report, verify feeder locations and components as they are required on the machine for a particular production run. This is done using the display screen and keyboard to audit the displayed component list and feeder locations. Also, strike through, mark off, check, or otherwise identify those feeders that have been installed to avoid repetition and mistakes.

Operation of Each Axis To ensure proper axis movement availability, in the MANUAL mode, manipulate the hand held keyboard’s (HHK’s) joy stick to move the axis in the desired direction.



Selecting The Axis To select the axis to operate in MANUAL mode, proceed as follows: Execute the SEL AXIS or AXIS GROUP command from the HHK. Observe, on the DI/DO monitor, that the axis is directly switched each time the command is executed. Observe that the selected axis is displayed at the upper right of the screen. In MANUAL mode observe that, other than the DI/DO monitor, the axis selection box appears. Select the axis needing to be moved.

NOTE: ON THE DI/DO MONITOR SCREEN, THE SELECTED AXIS CHANGES IN ORDER, FOR EXAMPLE “A_TABLE XY” EACH TIME THE AXIS GROUP KEY IS PRESSED. Selecting The Axis Speed To select the axis speed in MANUAL mode, proceed as follows: Use the HHK to select axis speed directly from the five step speed settings when the DI/DO monitor is displayed. Observe the selected speed is displayed at the upper right of the screen. In MANUAL mode, observe that (other than the DI/DO monitor) the axis speed selection box appears. Select the desired axis speed when the axis speed selection box is displayed. CAUTION: 5-STEP SPEED SETTINGS ARE PRESET WITH <A6 EDIT 5_WAY SPEED>. IN MANUAL MODE, USE THIS COMMAND TO MAKE CHANGES TO THE SPEED SETTINGS.



Switching Between Tables Switch the vision monitor display from the A table to B table or vice versa, as required. Select Manual Mode as required. Select and execute <B5 SEL. VISION DISP> to switch the vision display monitor from the A table to B table or B table to A table as required. NOTE: AS THE BOARD ENTERS THE MACHINE ON ITS CONVEYOR, AUTOMATICALLY IT IS CONVEYED FURTHER TO TABLE “B” FOR PLACEMENT AT THE MACHINE’S BACK SIDE. ALWAYS, THE FIRST COMPONENT MOUNTING TAKES PLACE HERE WITH COMPONENTS SPECIFICALLY PROGRAMMED FOR OPTIMUM PRODUCTION EFFICIENCY. THEN, THE BOARD IS TRANSFERRED TO TABLE “A” WHERE THE FRONT SIDE FEEDER’S COMPONENTS ARE PLACED. IT ALSO SHALL BE NOTED THAT BOTH TABLES ARE CAPABLE OF PLACEMENT OPERATIONS SIMULTANEOUSLY. IT IS POSSIBLE TO PROGRAM THE MACHINE TO EFFECT PLACEMENT USING IDENTICAL COMPONENTS ON BOARDS LOCATED ON EACH TABLE. THE FOLLOWING FIGURE CLEARLY SHOWS BOARDS ON TABLES “B” AND “A” WITH THE TRANSFER BAR (CONVEYOR MECHANISM) SHOWN IN POSITION ABOVE THE BOARDS.

ADDITIONAL NOTE: POD “SMTEAM” MEMBERS HAVE DETERMINED ALL SETUP AND VERIFICATION REQUIREMENTS SHALL BE MET USING TABLE “A” AT THIS TIME. SETUP AND VERIFICATION ON TABLE “B” DOES NOT ALWAYS PROVIDE ACCURATE INFORMATION CONCERNING PROGRAM AND PLACEMENT REQUIREMENTS.



Conveyor Unit Operation (to position and secure a PCB) Execute the <CONVEYOR UNITS> utility to operate the conveyor unit push up and locate pin as required.

Also, select and execute <2/1/B7 CONVEYOR UNITS> to operate the conveyor units in the <1/1/D4 RUNNING UTILITY> command as required. Select the unit to be operated. NOTE: EACH TIME THE ENTER KEY IS PRESSED, THE SELECTED UNIT ALTERNATELY SWITCHES ON AND OFF. THE CONVEYOR UNIT ALSO CAN BE OPERATED FROM THE DO (DIGITAL OUTPUT) MONITOR IN MANUAL MODE EXPLAINED LATER.



Operating The DI/DO Monitor Operate the monitor in the Manual mode. Select Manual mode Select and execute <C1 OUTPUT MONITOR>. Select the item to check or operate. Switch on and off as required.



Set Feeders Install feeders required for production if not done previously at start. Observe tape feeder requirements, and those for general handling and problem determination. Grip the handle when handling the feeders Do not apply excessive force to the feeder Do no use the feeder if its tape guide is deformed as this may cause feeding errors Determine if any components are missing Determine if any components are damaged or broken Determine if any screws are loose NOTE: IF ANY OF THE ABOVE ARE PROBLEMS, TAKE CORRECTIVE ACTION OR REPLACE COMPONENTS AS REQUIRED. Ensure the knockpins (positioning pins) are properly inserted into the holes on the feeder plate and the clamp lever is moved in the direction indicated. When removing a tape feeder from the feeder plate, move the clamp lever in the direction indicated and lift the feeder up. Be sure not to hold the tape guide as doing this may damage the tape guide or other parts. In addition, avoid moving the feeder back and forth to prevent excessive force from being applied to the feeder. Fit a tape reel to a tape feeder, as required, ensuring the lock lever is released and the tape guide is properly raised. Fit the tape reel to the feeder and separate the clear “top tape” (adhesive bottom tape for 32 mm adhesive tape) from the “carrier tape” (carrying components) and route each tape as required. Be sure to align the electronic component center line with the pickup point so the center of the first component on the tape lines up with the line or notch on the tape feeder (16 mm to 44 mm tape feeders). This line indicates the pickup point.



Lower the tape guide ensuring the tape guide shutter is moved to the front side and lower the tape guide slowly. Also, be sure to lower the tape guide with the shutter positioned on the rear side so the shutter drive lever does not damage the shutter. If done improperly, feeding errors result as the shutter cannot move smoothly. Set the tape guide being sure its curved end is positioned inside the lower guide of the feeder. If it is positioned outside the lower guide, feeding errors shall occur.

Feeder preparation and fitting a tape reel before attachment or removal of tape feeders. Before fitting a tape reel to the tape feeder, release the lock lever so the tape guide is raised.

Fit the tape reel to the feeder then separate the clear “top tape” (adhesive bottom tape for 32 mm adhesive tape) from the “carrier tape” (carrying components), and route each tape as shown in the figures on following pages. Align the electronic component center line with the pickup point. A line or notch on the tape feeder (16 mm to 44 mm tape feeders) indicates the pickup point. Align the tape so the center of the first component on the tape lines up with the line or notch. When the tape reel has been set, lower the tape guide and slide the tape guide shutter to the front side, then lower the tape slowly.



NOTE: IF THE TAPE GUIDE IS LOWERED WITH THE SHUTTER POSITIONED ON THE REAR SIDE, THE SHUTTER DRIVE LEVER MAY DAMAGE THE SHUTTER RESULTING IN FEEDING ERRORS, AS THE SHUTTER CANNOT MOVE SMOOTHLY. Set the tape guide so its curved end is positioned inside the lower feeder guide. NOTE: IF THE FEEDER GUIDE IS POSITIONED OUTSIDE THE LOWER GUIDE, FEEDING ERRORS shall RESULT.



Select and execute COMPONENT ASSIGNMENT using COMPONENT ASSIGNMENT command. Observe information for all components to be used with the selected PCB being displayed. NOTE: USING THE ARROW KEYS TO SCROLL UP OR DOWN THE DISPLAY, VERIFY ALL COMPONENT NAME AND SET NUMBERS CONTAINED WITHIN THE COMPONENT INFORMATION. Set the feeder onto the main unit assuring proper handling and attachment care and observe the display screen for location. Ensure all feeders properly attached and secure.

SPECIAL NOTE: ALL FEEDER POSITIONS ARE NUMBERED IN TWO LOCATIONS TO ENSURE FEEDERS ARE PROPERLY POSITIONED. WARNING: WHEN INSTALLING THE FEEDER, BE SURE TO PRESS THE EMERGENCY STOP BUTTON SINCE THE OPERATOR’S BODY MAY COME INTO THE MACHINE HEAD’S RANGE OF MOVEMENT. NOTE: IF A FEEDER IS NOT ATTACHED CORRECTLY ONTO THE FEEDERBAR, THE FEEDER FLOATING SENSOR (NJ10) shall BE ACTIVATED AND MOTOR MOVEMENT shall BE DISABLED.



After setting the components in the feeder and the feeder on the feeder plate, check that the feeder operates correctly as below.

Exit From The Feeder Set and observe the UTL. FOR RUNNING screen display A1 STOP RUNNING.



Stick Feeders Install stick feeders as required.

.



Feeder Operation Select and execute <A4 FEEDER ON/OFF> in Manual mode to check feeder operation. Select Manual Mode as required. Select and execute <A4 FEEDER ON/OFF> and observe the screen appearance when this command is selected. Select the feeder to be operated.



PCB, Nozzle, And Component Specifications Before mounting components, ensure the following requirements are met: PCB’s as specified for production.



Nozzles specified for components to be mounted.

NOTE: IT IS VERY IMPORTANT THE CORRECT NOZZLE BE SELECTED FOR THE SPECIFIED COMPONENT TO BE PLACED. THE FOLLOWING FIGURES PROVIDE INFORMATION CONCERNING THIS SELECTION.



Components specified for mounting process.



Before Starting PCB Production Ensure the following requirements are met before starting PCB production:

Select and execute the <1/1/RUNNING> command. Select the PCB name to be produced. NOTE: WHEN THE LIST OF PCB NAMES IS NOT DIRECTLY DISPLAYED, PRESS THE F2 KEY (OR EXECUTE <D3 SWITCH PCB>) AND SELECT THE PCB NAME FOR PRODUCTION. THE MACHINE THEN LOADS THE SELECTED PCB DATA. Select and execute the <1/1/D4 RUNNING UTILITY> - <REQUIRED NOZZLE> command to determine required nozzle type. Then, referring to the display, check that the correct nozzle is attached to each head. If the nozzle attached is not correct, reattach the correct nozzle. Exit the RUNNING UTILITY screen. Check inside machine and surrounding area for safety.



CAUTION: IT CAN BE DANGEROUS IF ANY PART OF THE HUMAN BODY ENTERS THE MOVEMENT RANGE OF THE HEAD ASSEMBLY DURING OPERATION. BE SURE TO STAY WELL OUT OF THE MOVEMENT RANGE. Install or exchange nozzles as required.



Change operation speed as required. Change conveyor setup as required.



Make conveyor width adjustment as required.

To adjust the conveyor width to match the PCB’s width, select and execute <CONVEYOR UNITS> in the <1/1/D4 RUNNING UTILITY> or <2/1B7 CONVEYOR UNITS>. Then, select and execute



<CONVEYOR WIDTH> and observe the PCB width input box appear so the specified width can be adjusted. CAUTION: BE SURE OTHER CONVEYOR UNITS DO NOT INTERFERE WITH CONVEYOR RAILS WHILE ADJUSTING THE CONVEYOR WIDTH. NOTE: POD DOES NOT DESIGN OR USE PCB’S WITH LOCATION HOLES. THEREFORE, THE LOCATE PIN ADJUSTMENT PROCESS IS NOT PERFORMED AT THIS TIME. Adjust PCB support plates as required.



Adjust push up pin as required.

Set a PCB on the conveyor. Select and execute the <CONVEYOR UNITS> command to raise the main stopper. Then, set a PCB on the conveyor and bring it up against the main stopper. Before raising the push up plate, check that all push up pins are removed from the plate to avoid interfering with the conveyor rails. Select and execute <CONVEYOR UNITS> to raise the push up plate. Adjust the pin height to ensure the upper surface of the PCB contacts the PCB support plates and secure it. Adjust the height of the other pins to the same height as the adjusted pin. Align all push up pins on a flat surface and check that all heights are the same as the adjusted pins. Place the push up pins in correct position on the plate to ensure proper PCB edge support at this time. When adjustment is complete, lightly tap on the PCB while checking for PCB warpage from the side. NOTE: IF THE PCB IS SUPPORTED EVENLY WITH NO WARPING, THE ADJUSTMENT IS OKAY. RAISE AND LOWER THE PUSH UP PLATE SEVERAL TIMES TO ENSURE THE PINS DO NOT FALL OVER. ALSO, THE PINS FOR THE SAPPHIRE HAVE SPRING LOADED TIPS AS OPPOSED TO THE RIGID PINS USED IN THE EMERALD, ORION, AND ECLIPSE. THIS MAY MAKE IT DIFFICULT TO “FEEL” PROPER CONTACT WHEN TAPPING A BOARD’S SURFACE.



REFERENCE: It is convenient to mark the positions of the push up pins on the plate, with label, magic marker, etc., for each PCB type. Adjust push in as required.

NOTE: THE PUSH IN UNIT SUPPORTS THE PCB FROM THE UPSTREAM DIRECTION TO SECURE THE PCB IN PLACE BETWEEN THE MAIN STOPPER AND PUSH IN UNIT. THIS UNIT IS ONLY USED WHEN THE PCB IS SECURED BY THE EDGE CLAMP METHOD. Adjust the push in and move it to a position where it does not interfere with the PCB. Set a PCB on the conveyor and secure it in the mounting position. The first figure below shows the push in pressing against the left board edge pressuring the board against the board stop at its right end. This is table “A.” For table “B,” positions are the same but appear reversed (second figure below) when viewing in toward it from the machine’s back.

While sliding the push in unit to the right of left, position it at a point where the PCB can be properly brought up against the main stopper. Temporarily secure the push in unit. Select and execute the <CONVEYOR UNITS> command and ensure the push in unit securely supports the PCB against the main stopper.



After adjustment is complete, secure the push in. NOTE: BECAUSE THE PUSH IN UNIT MOVES UP AND DOWN ALONG WITH THE PUSH UP PLATE, BE SURE TO CHECK THAT THE PUSH IN UNIT DOES NOT INTERFERE WITH THE PCB WHEN THE PUSH UP PLATE IS RAISED. Adjust edge clamps as required. Use edge clamps to secure the PCB in the mounting position by clamping the edge of the PCB from the side. If necessary, adjust the position of each edge clamp unit according to the size of the PCB.

Set a PCB on the conveyor and secure it in the mounting position. Remove the edge clamp together with the stay. Reattach the edge clamp to a position at which it securely supports the PCB edge. Select and execute the <CONVEYOR UNITS> command and ensure the edge clamp securely supports the PCB.



Verify setup using the machine keyboard while “manually” acquiring fiducials and some component placement areas on the vision screen as location and verification is effected.

Start PCB Production Begin the SMD mounting process by executing the A2 AUTO RUNNING command. NOTE: ONCE THE DISPLAY SHOWS AUTO RUNNING, THE PROCESS SHALL INITIATE AND A BOARD SHALL ENTER THE CONVEYOR ENTRANCE FROM ITS LAST PROCESS AND BE LOCATED AT ITS PROGRAMMED POSITION FOR PLACEMENT. THE FIRST MOUNTING POSITION SHALL BE TABLE “B” FOLLOWED BY TABLE “A” WITH A CAPABILITY TO USE BOTH TABLES AND PLACEMENT HEADS SIMULTANEOUSLY. ESSENTIALLY, THE SAPPHIRE IS TWO MACHINES BUILT INTO ONE.



Sequence of board conveyance entering machine and to specified tables for setup and placement The first figure below shows a board being conveyed into the machine by the transfer bar and positioned on table “B.” The second figure below shows boards positioned on both tables (“A” and “B”).

NOTE: ONLY WHEN PLACEMENT FINISHED ON TABLE “B” IS THE BOARD TRANSFERRED TO TABLE “A.” THIS MEANS ONLY ONE BOARD SHALL BE IN THE MACHINE UNTIL THE FIRST BOARD IS COMPLETED ON TABLE “B.” THEN, THE REMAINING BOARDS SHALL FOLLOW IN SEQUENCE WITH BOARDS BEING PLACED ON BOTH TABLES UNTIL OPERATIONAL RUN FINISHED. The figure below shows a board in placement position on table “B.”

NOTE: ALL SETUP REQUIREMENTS ARE DONE BY MANUALLY MOVING THE TABLES NEAREST THE OPERATOR FOR ACCESS. THE MACHINE AUTOMATICALLY POSITIONS EACH TABLE OFF THE CONVEYOR CENTER-LINE FOR PLACEMENT OPERATIONS. ALSO, BOARDS ARE AUTOMATICALLY POSITIONED ON SPECIFIED TABLES, AND SECURED OVER THE PUSH UP PLATE AND PINS WITH EDGE CLAMPS AND SUPPORT PLATES. THIS IS TRUE FOR THE PUSH IN AS IT SECURES THE BOARD AGAINST THE STOP. Observe the display screens and monitor any error messages so corrective action may be taken. Messages might include:



“VISION CANNOT FIND” requiring feeder components to be checked to determine if component reels empty. If so, load new reel with same components. NOTE: THE VISION CANNOT FIND MESSAGE APPLIES TO BOTH OPTICAL AND LASER SYSTEMS The same message as above may appear if feeders are loose requiring reattachment. When correction made, resume production. “COMPONENT PICK HEIGHT” may appear requiring manual height adjustment to ensure correct pick and placement height. An error may occur if a fiducial not recognizable or located. This machine capable of camera movement to “hunt” for fiducial. If not found, check board and clean fiducials as required. NOTE: THE FOREGOING ERRORS SERVE ONLY AS EXAMPLES OF MANY OTHERS TO BE USED IN ACCORDANCE WITH THE POD/PHILIPS OPERATIONS MANUAL, TROUBLE SHOOTING SECTION. When required corrections made, resume production. When first article placement process complete, perform 100% visual inspection to determine placement effectiveness as correct alignment, specified orientation, wrong or missing components, etc.. Perform corrections on board and provide required correction information to engineering so program may be updated. Move first articles, after reflow, to inspection and await acceptance before initiating production.



Finish PCB Production

Stop machine operation by pressing the STOP key on the HHK or select and execute the <1/1/A1 STOP RUNNING> command. To restart the operation, press the RUN key on the HHK or select and execute the <1/1/A2 AUTO RUNNING> command. To reset the operation, Press the RESET key on the HHK or execute the <1/1/E2 RESET RUNNING> command. CAUTION: DO NOT PRESS THE EMERGENCY STOP BUTTON DURING THE OPERATION AND DO NOT USE THE EMG BUTTON TO STOP REGULAR PRODUCTION EXCEPT IN CASE OF EMERGENCIES. Turn Power Off.

Exit current mode and observe the mode selection screen close. Quit application and observe the warning message for turning off the power appear on the screen. Press any of the emergency stop buttons on the main unit or HHK. Press any key and observe the screen display disappear.



Turn off main switch. CAUTION: IF THE POWER IS TURNED OFF WITHOUT FOLLOWING THE SEQUENCE ABOVE, THIS MAY DAMAGE THE HARD DISK DATA.



8.0 APPLICABLE DOCUMENTATION POD Statement Of Work and Detailed Processes POD, PPM-2045, Electrostatic Discharge Procedures POD, PPM-2015, Material And Assembly Handling Procedures POD, QIPM-4030, Audit Of Processes And Procedures POD, PPM-2050, Safety Procedures Planning Documentation Lot Control Documentation Maintenance Requirements, Specifications And Procedures Compressed Air Test Results POD, QPM-3020, Equipment Calibration Procedures Equipment Calibration Logs POD Quality Assurance Inspection/Test/Analysis Logs POD Operator Operations, And Process Logs QQ-S-571 Solder Test Results MIL-F-14256 Flux For Assembly Operations Test Results MIL-P-55110 Printed Wiring For Electronic Equipment MIL-P-28809 Printed Wiring Assemblies POD, POD-5135, Hand Soldering Procedures ANSI/J-STD-001B Requirements For Soldered Electrical And electronic Assemblies ANSI/IPC-A-610 Acceptability Of Printed Board Assemblies IPC-600C Acceptability Of Printed Boards IPC-7721 Repair And Modification Of Printed Boards And Electronic Assemblies IPC-7711 Rework Of Electronic Assemblies IPC-TM-650 Test Methods Manual IPC-T-50 Terms And Definitions IPC-D-275 Printed Wiring For Electronic Equipment POD Pre-operational, Operational, And Post Operational Checklists POD/TDC Operation and Maintenance Procedures For Tools And Equipment Used To Train Personnel To Manage SMD placement Processes



9.0 PRE-OPERATIONS, OPERATIONS, AND POST OPERATIONS AUDIT CHECKLIST Pre-Production Operational Requirements Understood And Met Pre-Operational Safety Requirements Understood And Met Production Operations Overview And Flow Chart Understood Start And Stop Operations Procedures Understood Warm Up Process Effected Pre-Operations Procedures Understood And Effected Operation of Each Axis Process Effected Switching Between Tables Process Effected Conveyor Unit Process Effected Feeder Process Effected DI/DO Monitor Process Effected Set Feeder Process Effected PCB, Nozzle, And Component Specifications Understood And Met Before Starting PCB Production Procedures Understood And Met Start PCB Production Process Effected Finish PCB Production Process Effected



12.5 REFLOW SOLDERING

MANUFACTURING PROCESS MANAGEMENT PROCEDURES

POD-5040 REFLOW SOLDERING



DOCUMENT MANAGEMENT AND APPROVALS

This document is managed, as are all documents in the POD Process Improvement Program (outlined in the POD, QPM-3000-1, Process Improvement Assurance Manual, Section 4.0), by POD Engineering Process Management. Revisions to this document shall be effected using POD Engineering Change Procedures. These procedures assure any individual may use change requests, submitted to Engineering Process Management, indicating the change needed. Change requests shall be reviewed and accepted, or rejected, based upon merit and justification (as detailed in POD, EPM-0150, Engineering Change Notice (ECN) Procedures. When approved, revised documents shall be released and issued by Engineering Process Management at the appropriate, new revision level in accordance with POD, EPM-1045, Document Management Procedures. It shall be required that each document use the specified document format indicated on each page herein. Also, it shall be required the author's name be clearly indicated on each page while properly numbering it to ensure document integrity and traceability. The following approvals are required before release at the required revision level:



1.0 PURPOSE AND SCOPE The purpose of these procedures is to provide detailed instructions concerning reflow solder manufacturing process management at POD. This is done to ensure product quality consistently meeting or exceeding POD acceptance criteria. The scope of these procedures extends to all personnel responsible for ensuring effective reflow solder manufacturing process management at POD. 2.0 RESPONSIBILITY AND AUTHORITY The following responsibilities shall be fulfilled to ensure reflow soldering process management is properly effected to assure quality at POD: Manufacturing Engineer The Manufacturing Engineer is responsible and has authority to provide everything needed by manufacturing process managers to fulfill their responsibilities at POD. This includes procedures, training, equipment, tools, adequate and safe working conditions, ESD requirements, and all other required elements. Maintenance Technician The Maintenance Technician is responsible and has authority to ensure all operational elements (equipment, tools, etc.) are maintained and calibrated as specified. This assures all facilities, equipment, and tools are capable of being effectively and efficiently managed to assure product quality meeting specified requirements. Manufacturing Supervisor The Manufacturing Supervisor is responsible and has authority to provide proper direction to all manufacturing process managers at POD. This includes operational procedures, special instructions, schedules, product changes, drawings, and required materials and components. This also includes management directives, performance evaluations, and timely individual and team performance feedback. Manufacturing Process Managers Manufacturing process managers are responsible and have authority to assure manufacturing operations are carried out in an effective, efficient manner. They are responsible for performing all manufacturing operations in accordance with current procedures, checklists, and supervisory direction. All personnel are responsible for effecting management policies and directives to assure quality meeting or exceeding specified POD requirements. Quality Assurance Inspection Personnel Quality Assurance Inspection Personnel are responsible and have authority to determine product quality does or does not meet specified POD acceptance criteria. They also are responsible for providing appropriate feedback concerning product quality to management and manufacturing process managers so corrective or continued manufacturing action may be effected.



3.0 BACKGROUND Effective, efficient reflow solder process management is required to produce acceptable solder joints and assemblies. The reflow solder process is made up of several sub processes. Each process and sub process is supported by individual activities. It is at the activity level most impact is made on quality. This is because trained process managers consistently fulfill their responsibilities to assure quality. At POD, one of the most important products is a quality solder joint made right on time, the first time, every time. Only trained individuals fulfilling their responsibilities can do this. To assure effective reflow solder process management, primary concern is focused on key process elements, parameters, and factors capable of influencing product quality. Solder pastes, solder paste composition, flux types in solder pastes, reflow thermal profiles, and all solder process management activities must meet specified requirements. Additionally, equipment shall be maintained and calibrated to ensure processes capable of producing specified quality. When everything is as specified, reflow solder process management is effected. Then, process effects become apparent as solder joints meeting specified acceptance criteria. This is a highly interactive, interrelational, and manageable process. It has clearly defined cause and effect relationships (processes, sub processes, and activities managed instead of results as defect). All process management requirements are detailed in these procedures. This is done in conjunction with all other process considerations. Product acceptance is based on conformance to POD and appropriate industry acceptance specifications (IPC as an example). This is true of all components and materials comprising product. Soldering is a process in which two metal surfaces are metallurgically joined. A specified solder medium (metal filler with a melting point below 800 degrees F.) is used to “wet" and bond them. It is a process requiring diffusion and intermetallic growth to effect an acceptable solder joint. This definition emphasizes the term "surfaces" (an object’s area having no depth) to clarify the distinction between soldering and welding, as an example. Welding is a process in which diffusion and intermetallic formations are effected to metallurgically join metals beyond their surfaces to a specified depth. This distinction also provides evidence that solder joining is a reversible process as it relies on heat to "undo" the solder joint. Welding requires complete joint destruction thus making repair and/or rework impossible at the component level, as an example. The term "wetting" requires a solid surface to be completely "coated" by a liquid. This means the liquid maintains intimate contact with all solder termination areas without resistance or the indication of dewetting ("pulling back” from the surfaces). In solder joining, the liquid is molten solder. What distinguishes "liquid" metal from some other liquid media is its change back to a solid when cooled below its melting point. When two metal surfaces are wetted, they may become joined upon solder medium solidification (often referred to as freezing). Again, this is done through effective process management.



Another important term is eutectic. Eutectic is defined as a combination of two metals (forming an alloy) that melts at a lower temperature than either individual metal. Also, eutectic is defined as alloys that change directly from liquid to solid, and the reverse, with no intermediate plastic states. Various solder types, their compositions, and melting points are found in ANSI/J-STD-006. Reflow soldering and other machine dependent methods (wave or vapor phase as examples) are not thought of as art forms. This often is the case with hand soldering as it requires considerably more human intervention to effect acceptable joints. However, reflow soldering uses the same objective principles as wave or hand soldering. The primary difference is the less personal "touch" applied during this and the reflow solder process. Reflow and reflow soldering processes rely less on personal process management as they are less "subjective." This is because they are less sensitive to "feel" or touch. To effect (make) acceptable solder joints, the process manager is trained to visualize the cause and effect relationships existing each time the process takes place. Time, temperature, conveyor speed through various thermal zones, and solder paste types are important. Type and condition of solder surfaces, flux, flux action, and where along with how much is applied also is critical. The first image below shows what was considered a "good" profile in early SMT days - using a very old Heller, focused IR, table top machine. Notice the ramp and soak zones used here, but they were moderate compared to most at that time. The day's thinking was that long soak zones were required. The second figure shows a current solder paste supplier's recommended reflow profile. It shall noted it is a bit more steep thus, it is called a "tent" profile, with now ramp and soak zones, and works for a wide variety of applications though modifications obviously need to be made for special applications. However, there shall be a minimal number of profiles required for most reflow soldering operations I've never had to use more than three, once machine, solder paste, and board type characteristics were matched well.

During this process, the affects all the above factors have on solder joints are seen (see solder joint figures below). In all soldering processes and activities, surfaces shall be solderable. This requires PCB's and components to be free of contamination. Such contamination may consist of oxidation or other conditions (grease, fingerprints, dirt, etc.) deleterious to solder joint quality and reliability.



However, all surfaces are contaminated to some extent. Simply, solder termination areas shall be "wettable" and excess contamination is a barrier to this. When mild contamination is present, flux is capable of removing, or cleaning, it from the surfaces to be soldered. When excessive, nothing can be done to make acceptable solder joints. Therefore, it is critical that operational personnel be supplied only with highly solderable components and boards. In the reflow solder process, all other factors are equally critical. Flux is, applied from the solder paste, so mild contamination is removed. Preheating must raise the board temperature to a level capable of activating the flux, so it works as specified and the board is not thermally shocked. The reflow temperature, in the “liquidous” zone shall be capable of effecting an acceptable solder joint. The conveyor speed is set to assure specified times are realized in each thermal zone as well as time during solder reflow. The two figures on the previous page clearly show the physical process profile used in reflow soldering operations. The entire process is completed in stages corresponding to increasing temperatures in several zones until the highest temperature is reached in what is called the liquidous zone. Two hundred twenty degrees C. is the maximum temperature in this zone required to melt (liquefy) solder, wet all solder termination areas, and prevent component and/or PCB damage. Total time in “liquidous” shall be carefully controlled as well. For reflow solder process managers to improve their "skills," it is advisable for them to become proficient hand or reflow solder process managers. This is done so a more intimate contact and visualization of what makes an acceptable solder joint is appreciated. In reflow soldering everything must come together, under effectively managed conditions, to create solder joints equally reliable and acceptable as those effected during other solder processes, sub processes, and activities. This set of procedures details all requirements to assure effective, efficient reflow solder process management at POD. To effectively manage the reflow soldering process, POD employs the Conceptronic, Model HVA-102, reflow soldering machine. It’s capabilities are:

True-Windows™ control system software • 133 MHz CPU

• 7 vertical heat zones • Total length of heat chamber - 102 inches/259 cm

• Total linear convection in heat chamber - 70 inches/177.8cm • Total cooling section length - 30 inches/76.2cm • Typical processing speed - 32 IPM/81.3 CPM

• Total system length - 172 inches/436.9cm (HVA versions) • Total flux and flow management technology (patents pending)

- heating and cooling chambers Conceptronic’s air-only (HVA) or air/nitrogen (HVN) configurations, HVC 102 ovens provide the highest heating and cooling efficiency. This is assured along with "Total Flux and Flow Management" technology (patents pending).



HVC 102 systems are the only forced convective reflow soldering ovens capable of maintaining maximum impingement flow levels (i.e., convective efficiency). This is true regardless of operating atmosphere, component type or quantity of flux emitted into the chamber. Through a revolutionary "Total Flux and Flow Management" technology, Conceptronic guarantees flow levels and profiles within the heating chamber shall be consistently maintained. This is assured without filter changes or maintenance – for a five year period. The new cooling systems also incorporate filterless "Total Flux and Flow Management" technology for consistent, long term cooling performance. Our new "Polaris" ambient air cooling units include no flow-restricting filters. Instead, flux is isolated and collected using "inertial separation" collectors. Even if these collectors are fully saturated with flux, flow levels shall not vary and performance is maintained. They are also removable in seconds. Conceptronic Reflow Machine (Oven) Theory Of Operation Conceptronic ovens are designed to heat SMT circuit assemblies for reflow soldering or epoxy curing applications via high velocity hot gas forced convection. Ovens are comprised of vertical heat zones, cooling zones, and a transport system that moves product horizontally through the oven. Ovens have 4 to 10 vertical heat zones, depending on model. Each heat zone is 12” (30.5 cm) long, and is comprised of identical top and bottom sections. Each top and bottom section includes a blower, a heater enclosure, and a thermocouple. The blower forces air or nitrogen through the heater enclosure where the gas is heated by a 4500 watt electrical heater. Pressurized hot gas exits the heater enclosure to heat circuit assemblies.

Thermocouples positioned at specific locations measure the temperature of the gas as it exits the heater enclosure. The oven control system compares these temperature measurements to Operator set points and precisely controls oven temperatures. A heat exchanger located after the heat zones provides product cooling. A transport system as a conveyor belt and/or an edge rail conveyor moves circuit assemblies through the oven at a precise speed set by the operator. A Windows based computer control system allows operators full control of oven parameters. This is done when the operator selects and edits “Profiles” that set zone temperatures, transport speed, and rail width.



In reflow soldering, a hot gas envelopes the entire printed circuit assembly. In doing so, it activates the flux then melts the solder medium having been “printed” on the board’s surface onto which components have been attached. Upon melting, solder wets all termination areas. Upon cooling, the solder joint is made. Solder Connection (Joint) Acceptability Acceptable solder connections often are bright and shiny (not always necessary) while clearly revealing solder termination area surface contours. They feather completely out to the joint's edge. They are free of any residue or foreign matter. The joined surfaces are completely wetted showing no signs of being "cold.” They exhibit no evidence of dewetting, disturbance, or other unacceptable attributes. Based on the foregoing requirements, the first two figures show preferred and minimally acceptable solder joints while the third shows one that is unacceptable. POD requires solder joint quality conformance to IPC-A-610C, Class III requirements.

Solder joint reliability is another issue requiring careful determination. Though a solder joint exhibits visible quality, it may not have sufficient integrity, composition, or formation to ensure long term reliability. The reasons for this are many and this discussion is best left for more advanced study. However, visible quality is the primary starting point especially concerning its correlation to process management and capabilities. Root cause (process management and capabilities) and effect (solder joint quality) relationships are first established using visual quality verification methods. If process management is effected using proven process capabilities, solder joint quality shall be acceptable. Effecting An Acceptable Solder Joint Some of the most important requirements for effective reflow soldering process management are clean solder surfaces, calibrated conveyor speeds, and controlled and verified temperature profiles. Also required are specified solder temperatures, specified solders and fluxes, calibrated wave contact areas and times, specified preheat temperatures and times, and specified top side board temperatures. All these requirements shall be met to ensure effective process management. Other equally important requirements are well trained operators, clearly defined procedures, and the attendant tools to promote process management. Solder Process Management The most important factor needed to effect process management is proper training. Each reflow solder process manager shall be trained, evaluated, qualified, certified, and empowered to accept and fulfill responsibilities for ensuring solder process management is possible and effected. This shall



be done to ensure acceptable solder joint quality. Each reflow solder process manager must understand the following: Solder Termination Area Conditions Solder termination area (surfaces as PCB pads or component leads) shall be free of excessive contamination. Printed circuit board pads and/or component leads having excessive contamination (oxidation, grease, dirt, etc.) are not capable of being solder "wetted." It is not possible under any conditions to effect acceptable solder joints when excessive contaminates are present. No amount of heat, flux, or time shall help. Each solder process manager must determine that surfaces to be joined are clean enough to be wetted and soldered so specified solder joint quality is assured and effected. If this determination cannot be made, the soldering process shall be stopped until corrective action is taken to return the process to a manageable state. Solder Termination Area Condition Examples To ensure solder process managers have solderable surfaces, only qualified suppliers, managing qualified processes, shall be selected to provide required PCB and component solder termination areas. This means that only "clean," solderable PCB's and components shall be purchased and introduced to soldering operations. The first figure is an example of a contaminated J-lead on a PLCC surface mount component. The second figure shows the results of a test using scanning electron microscopy (SEM) with energy disperssive X-Ray (EDX). It is a graphic clearly indicating excessive tin oxide contamination (18:1 oxide to surface metal ratio) on the J-Lead’s surface. This condition absolutely prevents solder wetting under any conditions. The third figure shows completely non-wetted SMT pads. They also prevent solder wetting under any conditions. The fourth figure shows effect as an unacceptable PLCC solder joint caused by its excessively oxidized J-Lead. However, the PCB surface (not having the condition shown in figure 12) soldered well as it exhibited complete wetting.

NOTE: AGAIN, THE FIRST FIGURE SHOWS J-LEAD CONTAMINATION AS OXIDATION (18:1 OXIDE TO SURFACE METAL RATIO). THIS CONDITION COULD EXIST ON THROUGH HOLE COMPONENTS, CHIP DEVICES, AND LEADED OR LEADLESS SMD’S. LOOK FOR THIS CONDITION AND THOSE ON PCB PADS. DO NOT ATTEMPT TO SOLDER UNDER THESE CONDITIONS. Reflow Solder Thermal Management The reflow solder process shall be managed using verified temperature profiles, as gradients, capable of first providing increasing heat to “ramp” the board temperature gradually. This is done so it is not “shocked.” because of the thermal change (delta T) when leaving the preheat zone and



contacting the much higher temperature solder wave. This prevents damage to boards or components as board temperature is gradually raised - also ensuring flux activation. Then, the process shall be managed to assure the solder wave is at the specified temperature to effect acceptable solder joints. The time required is not less than 2 nor more than 4 seconds within a specified contact area (contact time is a function of contact area and conveyor speed). Board and/or component overheating is prevented when times are correct. If overheating does occur, primary damage is done to the PCB as pad lifting (or rotation) from the board surface as in the first three figures. PCB damage also may be done as the cracked hole in the fourth figure. Component damage (cracking as an example) also may be effected due to excessive heat or thermal shock.

Multilayer board (MLB) delamination may also be caused by too much thermal stress or shock. The first figure shows this condition as viewed from the MLB surface. The second figure shows it in X-Section looking at the board’s inside as if it was cut in the Z axis. The third figure shows meazling also often induced by thermal stress.

Solder Termination Area Surface Coating Types Solder termination area surface coating types often are electroplated or hot air solder leveled (HASL) tin/lead, or electrolessly deposited tin. Newer coatings are electroless gold, silver, palladium, “white” tin, and organics. They have been developed to overcome problems associated with the above types. Problems consist of non-wetted, uneven, and/or oxidized surfaces often with excessive intermetallic formations. All these plating or coating types are compatible with the solder medium to the extent deposited amounts do not “contaminate” the solder medium and joint. Contamination would be in excess of that specified in ANSI/J-STD-001B (Figure 5-1) during soldering operations. If the surface is coated or plated with other metals (electroplated or electrolessly deposited gold in excessive amounts, as an example), they shall be removed to assure solder compatibility or the solder medium shall be changed. Acceptable solder joints often have acceptable intermetallic growth effected as part of the joining process although some unacceptable joints are formed when wrong or excessive intermetallics form. Gold is an example of a metal (in excessive amounts) that is not compatible with tin/lead eutectic soldering. This metal causes embrittlement and subsequent solder joint failures over time - under mechanically induced stresses.



NOTE: EXCESSIVE AMOUNTS MEANS GOLD, OR OTHER COATING, CONTAMINATING SOLDER JOINTS BEYOND THAT WHICH IS ACCEPTABLE TO ENSURE INITIAL QUALITY AND LONG TERM RELIABILITY. REFERENCE TABLE 5-1, ON PAGE 5, IN ANSI/J-STD-001B CONCERNING SOLDER LIMITS FOR TIN/LEAD ALLOYS. Flux Types Flux is composed of acid or caustic chemicals (high or low pH components [over 7 = alkaline, under 7 = acidic]). It is used to clean contaminates (mild oxidation, grease, or other residues) from solder termination areas. Fluxes become fluid at lower temperatures than solder. This means that when heated, flux flows onto solder termination areas first. As it does, it cleans and protects (when properly activated) the heated metal surfaces until the solder becomes molten and flows onto and wets solder termination areas. Then, the solder solidifies (“freezes”) upon cooling to make the solder connection. Flux Requirements Flux is vital to most soldering processes. This is true though fluxless or no clean solutions are being sought as part of an ongoing effort to reduce environmental contamination produced during soldering and cleaning operations. The two flux types generally used are rosin flux or aqueous (water soluble acid) flux. After soldering operations, rosin flux shall be cleaned with isopropyl alcohol (one of its components). Aqueous flux shall be cleaned with water (a component in its binder). This is required because of the deleterious affects flux residues have when left on board, component, and soldered surfaces. They continue to act as a removal or cleaning mechanism. This causes damage and solder joint failures. Some flux residues are conductive providing paths for unwanted current flow capable of causing electrical shorts between surface conductors. Newer “no-clean” fluxes are composed of chemicals capable of removing contamination while needing little or no cleaning after reflow soldering. Their residue remains on or near the solder connection and provides none of the concerns stated in the above paragraph. However, rework or repair operation results often require localized cleaning to remove the then visibly exposed residue. NOTE: THE ONLY REASON METAL SURFACES ARE COVERED, COATED, OR PLATED IS TO PROTECT THEM FROM OXIDATION OR OTHER CONTAMINATION UNTIL THE SOLDER JOINT IS MADE. COPPER SURFACES (COMPRISING MOST PRINTED CIRCUIT CONDUCTORS) OXIDIZE ALMOST IMMEDIATELY UPON EXPOSURE TO AIR. SCRATCH A PENNY’S SURFACE AND SEE HOW LITTLE TIME IT TAKES FOR THE SHINY SCRATCHED AREA TO TURN DULL BECAUSE OF OXIDATION. Thermal Mass Considerations A single pad on a single sided circuit board involves relatively little thermal mass. A double-sided board with a plated through hole can double that mass. Multilayer boards (MLB’s), increased component leads, larger device types, different device types and MLB materials, terminals, connectors, and connecting wires further increase thermal mass. This means that temperature rise shall not be as rapid or as much when using a thermal profile designed for a board with less thermal mass. This means each board type and its unique thermal mass shall have a correspondingly unique thermal profile. There may be specific or unique profiles for single and simple double sided boards, for higher density four and simple six layer types, and those for eight to ten layers, and so on.



Experiments (trials) shall be performed to determine which profile works for which board type. This is done using thermocouples mounted on PCB’s, “MOLES,” or other thermal profilometers that are run through the reflow solder process. These setups provide precise thermal information at various stages in the soldering process along the conveyor’s path. Clear temperature readings are printed out, viewed, and/or graphed to make determinations concerning more effective thermal profile considerations so processes and solder joint quality is continuously improved. During experimentation, each board type is inspected and effects (acceptable or unacceptable solder joint quality) are correlated to cause. Cause is how well a process is managed relative to machine and required sub process settings made in accordance with specifications and procedures. When effects are positive, cause is recognized as effective process management and processes may be effectively managed during production. When negative, experiments continue until positive effects are found and process settings are recorded and made available for use in production. Ongoing pre process audits and sample inspections promote continuous process improvement as part of statistical process control (SPC). As previously discussed, an important factor concerning thermal profile management is a solder termination area's surface condition. In addition to what was said earlier, oxides particularly act as thermal barriers to heat transfer. Even if a thermal profile provides the right properties for that board type, excessive oxidation always prevents enough heat reaching the solder termination areas to melt solder. Even if a specified flux type is used to clean mildly contaminated areas, excessive oxidation is a barrier to all solder process management efforts. Solder Joint Formation Time Requirements Time is a major factor affecting acceptable solder joint quality and preventing damage to boards, components, or finished assemblies. For reflow soldering process management to be effective, the specified heat shall not be applied to solder termination areas for more that 4 seconds. Beyond this time, the board may be damaged (as in previous examples). If more time is required to wet solder termination areas, something is wrong as either the design is deficient or the board has much more thermal mass than capable of being soldered under "normal" conditions. There may be too much thermal mass, the wrong thermal profile, too little heat input, or excessive oxidation. Corrective action shall be taken. The figure atop the next page shows a cross section of the perfect J-Lead solder joint effected in well managed solder processes.

NOTE: ACCEPTABLE SOLDER JOINTS ARE NOT AN ART FORM. THEY ARE NOT EFFECTED BY ARTISTS. ACCEPTABLE SOLDER JOINTS ARE OBJECTIVE EVIDENCE OF PROCESS



MANAGERS USING THE RIGHT TOOLS WITH PROPER INSTRUCTIONS FOR THEIR USE TO ASSURE SPECIFIED QUALITY. Unacceptable Solder Joints And Other Conditions As Cause For Rejection.

Cold Solder A cold solder joint is effected by poor solder process management. This means insufficient heat, contact time, and/or adequate solder surface contact is effected during the soldering process. The solder generally shall not flow to feather solder termination area edges. It also tends to form "globs" or uneven "balls and not completely cover all parts of connection. The solder appears dull, grainy, and uneven.

Insufficient Solder Insufficient solder is apparent as solder termination areas not being soldered or completely covered by solder. Insufficient solder defects do not meet specified solder joint acceptance requirements.



De-wetting Dewetting is evident as solder that first has attempted wetting all solder termination areas then "withdraws" from them. This forms "puddles" with thin and thick solder not providing acceptable solder joint coverage. Also, portions of the solder connection typically are identified by a convex boundary between the solder and conductor. The major cause of de-wetting is contamination as oxidation, grease, or other dirt or debris. Excess Solder By definition, excess solder means too much. Solder surface contours are not visible because there is an overflow of solder forming excessive peaks.

Disturbed Solder A disturbed solder joint has a crystalline appearance may be fractured or separated at the solder termination area junction. Overheated Solder An overheated solder connection appears dull and crystallized. Areas around overheated solder joints often appear discolored or burnt. Contaminated Solder A contaminated solder joint is unacceptable as it contains foreign matter such as insulation or other debris, etc.



Solder Bridging Solder bridging is a web or film of solder between adjacent vertical terminations (formed over the insulating PCB material). If extensive, it can be a web of solder between adjacent conductors. Some causes of bridging can be low solder temperature, insufficient flux, poor flux activation, or the presence of impurities in the molten solder. Other factors may involve the wetting angle, and the angle at which the board approaches and contacts the wave.

Icicling Icicling is solder extending out perpendicular from the PCB bottom side usually at the component leads. It is caused by a drainage restriction of molten solder from the board, lower than specified solder temperature, or faster than specified conveyor speed. Other causes may be wrong PCB angle over the wave, shorter than specified wave contact time, too little wave/board contact area, inadequate flux activity, and/or unacceptable solder purity.



Blowholes And Voids Blowholes are voids having exited, or outgassed from within PCB plated holes or solder joints. Voids are small spherical cavities within the PCB plated hole wall in the first figure, or under/in a solder joint shown in the second figure. Causes of blowholes are excessive flux, flux residue left inside a solder joint, insufficient evaporation of the flux solvent before soldering, or moisture or organic plating residues having been entrapped in plated-through holes that “outgas” through the hole wall plating. Blowholes can be caused by PCB's not meeting supplier acceptance criteria such as minimum copper plating thickness. They and voids may also be caused by flux remaining in solder joints fighting contamination such as excessive oxidation.

Solder Balls Solder balls are small spheres that may cause shorting between conductors or component leads. Solder balls often are dynamic meaning they move randomly across a board’s surface. They are caused when thermal profiles are not as specified, solder mask is not properly cured, or dry film solder masks are used. They may also be caused as flux within the solder paste rapidly expands when overheated spattering molten solder across the board’s surface. They too are caused when blowholes are effected through outgassing as indicated above.

Correction And Prevention Of Unacceptable Solder Connections. Action to correct and prevent unacceptable solder connections shall be taken by reflow solder process managers. The action taken depends on the frequency and type of unacceptable connections found. When excessive or major defects are found, supervisors shall be notified so



required correction can be made. When minor or minimal defects are found, the process managers shall correct the process to assure quality meeting specified requirements Repair, Modification, And Rework Repair, modification, and rework of unacceptable solder joints and/or assemblies shall be done using hand soldering with flux cored solder and temperature regulated soldering irons. Cleaning shall be done on the board after touch-up using the proper cleaning solution depending on the flux type used. NOTE: ALL TOUCH UP OPERATIONS AND ACTIVITIES SHALL BE PERFORMED IN ACCORDANCE WITH POD, POD-5055, REPAIR, MODIFICATION, AND REWORK PROCEDURES.



4.0 DEFINITIONS The following definitions are provided for all process managers to better visualize each process for which they are responsible: Operations Operations are defined as a series of processes required to provide product or services meeting certain requirements. Usually these requirements are based on customer needs, desires, or demands. POD employs many operations as management, engineering, marketing, sales, manufacturing, accounting, quality assurance, and others to ensure all its customers receive product meeting their requirements. Process A process is defined as a method or procedure. A process may be a single method or procedure, or may be made up of sub processes and activities. In a manufacturing operation, a process is employed to turn acceptable raw materials, components, and designs into acceptable product using various tool and equipment types. Sub Process A sub process may be part of a process. In the reflow solder process, several sub processes are involved to effect acceptable solder joints. They are discussed in the foregoing section. Activity Processes and sub processes most often rely on individuals or teams performing activities to make product. In manufacturing, such activities may consist of moving or handling materials and components, changing machine or tool settings, turning equipment on or off, etc.. It is at the activity level most variability is introduced to manufacturing operations effecting varying degrees of quality. For this reason, it is vital process managers be well trained to fulfill their responsibilities by following procedures concerning specific process management requirements. Process Management Process management is the act of preventing defect by fulfilling individual responsibilities instead of reacting to it as the result of not fulfilling them. When process instead of results management is practiced, product quality is consistently acceptable. Process management differs from process control in that control means only consistent quality is produced. In a controlled instead of managed environment, that quality may be consistently good or bad. Process Capability Process capability is the measure of how well a process is being managed. Usually, a processes’ capability is expressed in statistical terms as a capability profile or Cpk. When a process is managed effectively, its Cpk shows how well while often providing an indication of what is needed to continuously improve. Continuous process improvement assures continuous quality improvement and that is what process managers focus on most. Solder Solder is defined as a metallic medium (as an alloy) that melts at temperatures below 800 degrees Fahrenheit to join metal surfaces having much higher melting points. Solder may be in different forms. It may be bar solder as used in reflow solder machines, or it may be wire with a flux core used



to perform hand soldering. It may also be in the form of a paste composed of solder balls suspended in a binder with a flux component. None of these forms changes its definition. Solder Paste Solder paste is a metallic medium (as an alloy) formed into solder balls (ranging in diameter from about 4 to 40 microns). The balls are suspended in a binder (composed of flux and other chemicals). Solder paste, as all solder media, melts at temperatures below 800 degrees Fahrenheit to join metal surfaces having much higher melting points.

The more spherical are the solder balls, the less surface area they have. This reduces their oxidation amount and rate at which they oxidize. This is important because more oxidation means less solderability. The solder paste composition has a high viscosity of approximately 900,000 centipoise. Higher viscosity aids in preventing solder paste spread on SMT pads. When too high, printing problems may occur relative to dispensing paste through stencil openings. Solder paste is applied to solder termination areas using a printing machine, squeegees, and stencils with openings of specified sizes, shapes, and aspect ratios. All this is done to assure a precise amount is printed where and in the condition required to effect acceptable solder joints. Wire/Core Solder Wire/Core solder is a solder medium composed of a eutectic alloy. Usually it is 60/40 tin-lead formed into a wire with a hollow flux filled core. Wire/Core solder is specified in varying diameters (typically from about .012” to .060”) for specific hand soldering activities. It provides a mechanism to apply flux from its core to the solder termination areas before solder melts, flows, and wets them to effect an acceptable solder joint. Flux Flux is defined as a chemically and physically active compound that when heated to specified temperatures it promotes base metal surface wetting by molten solder. It does this by removing minor surface oxidation, surface films, or other contamination. It then protects the surfaces from reoxidation during the soldering process. Various flux types (see POD Hand Soldering and Final Assembly Course) include:



Rosin Rosin flux primarily is composed of natural resin extracted from oleoresin of pine trees and refined. Typically, these fluxes are made up of 60% solvent and 40% solids. Rosin flux (Type R) is an organic material distilled from pine tree sap. The active ingredients in this flux type primarily consist of abietic and pimaric acids. After rosin is extracted from pine trees, it is superficially processed to remove undesirable impurities while neutralizing the acid residues remaining from the extraction process. The purified material is called water-white rosin. It is used to manufacture rosin based flux. Some manufacturers hoping to overcome difficulties associated with obtaining and processing natural rosin, chemically synthesize substitute materials. These materials are called “resins.” Pure rosin is a solid at room temperature and is chemically inactive while being insulative. Rosin melts at about 72 degrees C. (160 degrees F.) and the organic acids become active at around 108 degrees C. (225 degrees F.). This flux type’s peak capability is effected around 262 degrees C. (500 degrees F.). This is the temperature rosin begins decomposing into reducing gases. At temperatures above 346 degrees C. (650 degrees F.), the flux becomes inactive and polymerizes. This causes residue removal difficulties from board and solder joint surfaces. When solder surfaces require a more active flux, chemical compounds called activators are added to the rosin. The most commonly known rosin flux containing activators is called rosin, mildly activated or RMA. Activators are thermally reactive compounds (such as amine hydrochlorides) that break down at elevated temperatures. At these temperatures, hydrochloric acid is released to dissolve the surface oxides, tarnishes, and other contaminates. Mildly activated rosin flux (RMA) may contain a variety of activators in amounts less than 1%. Limits are placed on their electrical and chemical properties before and after soldering. Rosin activated flux (RA) typically contains 1% - 5% activators. RA flux is used in applications when RMA is not strong enough. For military purposes, their use usually is limited to component tinning of sealed devices and solid wire. When warm, these fluxes can conduct electricity and can leave residues that can cause corrosion or shorting path formation between conductors. Organic Acid Flux Organic acid (OA) fluxes are types having active ingredients such as organic acids, organic hydrohalides, amines, and amides. These fluxes are water soluble since they contain no rosin. Good cleaning is critical with these flux types since the salt residues left by them are corrosive and conductive. OA fluxes also are referred to as water soluble fluxes (WSF’s). These fluxes are more aggressive. They generally are classified in J-STD-004 as types M or H. OA fluxes have active ingredients such as organic acids, organic hydrohalides, amines, and amides. All are corrosive activator materials. These fluxes are water soluble or water washable since they contain no rosin, or any low rosin or resin levels. Good cleaning is critical with these flux types as their residues are corrosive and electrically conductive.



Resin Resin flux primarily is composed of natural resins other than rosin types and/or synthetic resins. Organic Organic elements are based on carbon atom structures. All life forms are organic. Organic fluxes are primarily composed of organic materials other than rosin or resin. Inorganic Inorganic elements are based on other than carbon atom structures. Inorganic fluxes are solutions composed of inorganic acids and/or salts. LR, or No-Clean Fluxes Low residue (LR) fluxes usually have lower solids content (less than 5%) than traditional high-solids rosin fluxes. LR fluxes also are referred to as no-clean or “leave on” fluxes. Their residues are not intended for removal from assemblies so cleaning is not required. Their primary activator materials are weak organic acids (adipic or succinic acid). These materials are benign on a board surface and act as electrical insulators. LR fluxes may be higher solvent borne (usually isopropanol) or water borne in the case of volatile organic compound (VOC) free no clean fluxes. Low residue fluxes are not no-residue fluxes. Although benign, visible residues do remain on the assembly. For this reason, customers may require them to be cleaned. This often is requested for cosmetic rather than functionality reasons. If the flux residues have a significant thickness, they could interfere with electrical testing as “bed of nails” types. However, a different probe point, greater spring strength, or rotating probes often solve this problem. Low residue fluxes also might build up on test pins over time. This requires preventive maintenance as regular cleaning. Halides Halides are organic salts added to flux as activators. Halides are corrosive. Fluxing Activities And Classes A liquid flows freely over a surface only if in doing so the total free energy of the system is reduced. In soldering, the free energy of a clean surface is higher than a dirty one. Therefore, it is more likely to promote solder flow. With respect to this, fluxing activities are: Chemical Chemical fluxing activity reduces the oxides from the surface to be soldered and protects this surface from oxidation by covering it. Thermal Thermal fluxing activity assists transferring heat from the heat source to the material being soldered.



Physical Physical activities allow the transportation of oxides and other reaction products away from the material surfaces being soldered. In consideration of these three fluxing activities, the following shall be noted: 1) There are two basic ways fluxes eliminate oxidation. They dissolve it into "solution" or they reduce it back to metal. If reduced, it clearly "disappears" and should not be re-deposited as an oxide (to be determined through supplier qualification). Some old flux types "dissolved" oxides by reacting a fatty acid (rosin) with the metal in the oxide. Then, it was “pushed aside” by solder flow and wetting action. In which mode a flux works, clearly depends on which flux is used. Some fluxes use both modes. 2) ANSI/J-STD-004 differentiates flux activities into three classes. They are Low (type L), Medium (type M), and High (type H). ANSI/J-STD-004 further classifies fluxes as to whether or not they contain halides. For example, a type L0 flux is a low activity, halide free flux. An L1 flux is a low activity flux containing some halide amount. 3) Numbers of industry and consortia studies have been conducted concerning low residue flux reliability. Type L fluxes have been shown relatively benign concerning corrosion and electrolytic failure mechanisms. For this reason, Section 4.2 allows the manufacturer to use a type L flux (L0 or L1) without going through the testing outlined in Appendix D. If the manufacturer chooses to use a more aggressive flux (types M and/or H), the potential exists for corrosive flux residues. If so, the manufacturer must go through the Appendix D testing to demonstrate adequate removal of potentially harmful flux residues. 4) It is highly recommended that the manufacturer not use a type H flux on printed wiring assemblies in any way – at any time. It is recommended that, if used at all, a type H flux be limited to component lead tinning. Even then, this may be done only when it can be demonstrated that the highly aggressive flux residues can be thoroughly removed. Electrochemical Migration Electrochemical migration is defined as the movement of metals across an intervening space between a cathode and anode. This movement is induced by the difference in electrical potential in the presence of fluid producing a micro-film of water on a substrate’s surface. Soldering Soldering is a process in which two metal surfaces are metallurgically joined, using a specified solder medium (metal filler with a melting point below 800 degrees F.). The process is effected by "wetting" the surfaces to be joined requiring diffusion and internetallic growth. The effect of this process is called a solder joint. Intermetallics In light of the previous definition (soldering), intermetallics always are formed when heated solder surfaces are brought into contact with solder melted upon them. As soldering requires diffusion and internetallic growth, each occurs as part of the soldering process. This is immediately so and time effects intermetallic growth as a continuous process.



Intermetallic compounds have much different physical and mechanical properties than the metals comprising them. Typically, intermetallics are very brittle and have poor electrical conductivity. Also, when exposed to air, they oxidize very rapidly. Therefore, excessive intermetallics, formed either during the soldering process or over time, cause unreliable solder joints capable of failing under stressful conditions as thermal, or mechanical shock and/or vibration. Oxidation (oxide, oxidize) Oxidation is the act of burning. When oxygen is present in an atmosphere, it “burns” or oxidizes all material with which it comes in contact. When this happens, oxides are formed that resist thermal input as well as solder wetting. Some materials resist oxidation better than others. Most solder termination areas are copper (oxidizes very rapidly) covered with some protective coating to prevent further oxidation than that which was present before the coating’s application. In an inert atmosphere, oxidation is prevented (there is no oxygen or oxidizing agent). This means that if all processes relating to the use of materials capable of rapid oxidation were performed in an inert atmosphere, they would be more capable of solder wetting. Inert Atmosphere Inert means inactive or static. An inert atmosphere is one without activity such as that containing oxygen which is one component in our life sustaining atmosphere surrounding earth. Nitrogen is an inert gas. When totally comprising an atmosphere (as inside a soldering machine), activity is eliminated concerning oxidation thereby providing protection to solder termination areas. This promotes or improves thermal input and solder wetting (solderability). This assures a higher rate of higher quality solder joints. Surface Surface is defined as an object’s area having no depth. Welding It shall be noted there is a distinction between soldering and welding. Welding is defined as a process in which diffusion and intermetallic formations are effected to metallurgically join metals beyond their surfaces to a specified depth. The welding process is effected at temperatures well above 800 degrees F.. This distinction also provides evidence that solder joining is a reversible process as it relies on heat to "undo" the solder joint. Welding requires complete joint destruction thus making repair and/or rework impossible at the component level, as an example. Solderability Solderability is defined as the ease with which solder adheres to a basis metal surface such as a component lead, PCB solder termination pad, or PCB conductor hole pad and wall. The presence of contamination (as oxides or residues) interferes with solderability. Acceptable solderability and solder joint formation, requires good solder wetting and a small contact angle. Wetting Wetting is defined as the formation of a relatively uniform, smooth, unbroken, and adherent solder film to a basis metal. Wetting requires a solid surface to be completely "coated" by a liquid. This means the liquid maintains intimate contact with all solder termination areas without resistance or any indication of "pulling" back from their surfaces. In solder joining, the liquid is molten solder. What distinguishes "liquid" metal from some other liquid media is its change back to a solid when cooled



below its melting point. When two metal surfaces are wetted, they may become joined upon solder medium solidification (often referred to as freezing). This only is done under effectively process managed conditions. Contact Angle Contact angle is defined as the angle at which a solder fillet meets the basis metal. A small contact angle indicates good wetting whereas a large angle indicates poor wetting. Eutectic Eutectic is defined as a combination of two metals (forming an alloy) that melts at a lower temperature than either as individual metals. Also, eutectic is defined as alloys that change directly from liquid to solid, and the reverse, with no intermediate plastic states. Various solder types and their compositions and melting points are found in ANSI/J-STD-006. Solder Joint A solder joint is effected in the soldering process. Under effectively managed conditions, solder joints exhibit acceptable attributes as smooth, usually shiny, clearly defined, well feathered, completely wetted metallic bonds between two metal surfaces. Aqueous Cleaning Aqueous cleaning is defined as process using water as the primary cleaning agent or solvent. It shall be noted that water is termed the “universal” solvent because it is capable of dissolving all material types to some extent over time. This type cleaning can mean using pure water, with detergent additives, or with a saponifier solution. Aqueous cleaning is done most often with water soluble fluxes, but can be used on rosin and low residue fluxes as well as with the appropriate additives. Aqueous cleaning generally is a multi-stage operation with most cleaning effected in the first wash stages with the dirtiest water while rinsing is done in later stages using the cleanest water. Manual Cleaning Manual cleaning is a process used to spot clean flux residues from assembly surfaces. It includes using a bristle brush with isopropyl alcohol as the cleaning agent or solvent. This process is not recommended for final cleaning. Saponification Saponification is defined as a cleaning process using a biodegradable rosin cleaner. In the process, the rosin is changed chemically to become water soluble. Reflow soldering Reflow soldering requires intimate contact be made between molten solder and the assembly’s bottom side solder termination areas to effect solder joints. Conversely, reflow soldering is accomplished in a machine using air or an inert gas (nitrogen) as the solder reflow mechanism. Reflow soldering requires attention to conveyor speed, flux action and activation, preheat and topside board temperatures, solder pot temperatures, wave contact times and areas, and solder purity. In reflow soldering, a hot gas envelopes the entire printed circuit assembly. In doing so, it activates the flux then melts the solder medium having been “printed” on the board’s surface onto which components have been attached. Upon melting, solder wets all termination areas. Upon cooling, the



solder joint is made. In reflow soldering, wave contact with solder termination areas wets them as wave pressure, and wetting and capillary action provides the mechanism for the solder to flow up holes and component leads to wet them to the board’s surface. The entire reflow process is completed in stages corresponding to increasing temperatures in several zones until the highest temperature is reached in what is called the liquidous zone. It is in this zone the solder melts (liquefies) and wets all solder termination areas. Reflow soldering requires similar stages to ramp boards and components up to temperatures required to activate flux, and prevent thermal shock upon entering the liquidous zone. Quality Quality is defined as conformance to clearly specified, understood, and accepted customer contract requirements. Repair Repair is defined as the process required to restore the functional capability and/or performance characteristics of a defective article. This is done in a manner that precludes compliance of the article with applicable drawings or specifications. Modification Modification is defined as the process required to revise the functional capability or performance characteristics of a product to satisfy new acceptance criteria. Modifications usually are required to incorporate design changes that can be controlled by drawings, change orders, etc.. Modifications only shall be performed when specifically authorized and described in detail on controlled documentation. Rework Rework is defined as the act of reprocessing non-conforming or defective articles. This is done using original or equivalent processing to assure full conformance of the article with applicable drawings or specifications. Rework is doing something over that should have been done right the first time. Other Other terms are defined in IPC-T-50 and in specific guidelines, standards, and specifications indicated in Section 8. herein.



5.0 REQUIRED EQUIPMENT/TOOLS Specified Reflow Soldering System



6.0 PROCESS MANAGEMENT AND QUALITY SYSTEM REQUIREMENTS Process management and quality system requirements are steps required to maintain process management effectiveness to assure product quality meeting specified requirements. Traveler and drawings as required Component placement/insertion as required Safety, handling, and ESD as required Read, understand, and use solder audit checklist before each run, lot, or different board type Conveyor speed as specified. Thermal profile as required. Time in liquidous as specified.



7.0 REFLOW SOLDERING These procedures are used to ensure effective, efficient process management concerning reflow soldering operations at POD. POD uses specified and approved soldering tools to effect acceptable solder joints on printed circuit assemblies. This includes both through hole and surface mount devices. The Oven The Conceptronic HVC-102 (High Velocity Convection) reflow oven.



PROCESS These procedures are used to ensure effective, efficient process management concerning reflow soldering operations at POD. POD uses a Conceptronic reflow soldering machine as a process capability to effect acceptable solder joints on printed circuit assemblies.

Reflow Solder Process Preparation Prepare all solder process elements for reflow solder processes and proceed as follows while confirming all safety, material handling, setup, maintenance, calibration, and machine functions in accordance with these procedures. Ensure proper handling and ESD protection. The first figure indicates ESD protection required symbol. The second figure indicates ESD handling requirements shall be effected. The third figure shows the preferred method for handling Class III PCB assemblies. The fourth figure shows an acceptable handling method. In all cases it is required that ESD protection be provided all assemblies and all boards be handled so no damage, contamination, or other defect causing possibilities exist.

Ensure PCB date codes not older than six weeks. If so, ensure boards baked to remove moisture.



7.0 OPERATIONS The following procedures shall be used by all reflow soldering process managers to ensure product quality meeting POD acceptance specifications: Operator's Panel An operator's control panel and monitor are located at the unload end of the oven. The operator's panel includes the following:

Control Power ON/OFF Switch START Push Button Bonnet Up-Down Switch Rail IN/OUT Switch Thermocouple Probe Connectors SPECIAL NOTE: FOUR (4) EMERGENCY STOP SWITCHES ARE LOCATED AT THE CORNERS OF THE OVEN). DO NOT HESITATE TO USE THEM WHEN NECESSARY.



Oven Start Procedure Turn the control power ON and ensure control power light turns on. Push the START push button and ensure the blowers turn on and the computer boots up. Oven Stop Procedure Click on the Main Monitor STOP button. Wait for COOLDOWN, then IDLE mode. Exit Main Monitor Exit Program Manager Exit Windows. Turn Control Power OFF. Emergency Stop Reset Turn Control Power OFF. Reset Emergency Stop switches. Reset shunt trip breaker. Turn control Power ON. NOTE: THE OVEN PROFILE SHALL RELOAD. HOWEVER, THE OVEN SHALL NOT GO TO THE READY STATE UNTIL THE OVEN TRANSPORT HAS COMPLETED A FULL REVOLUTION. Alarm Recovery Press ENTER to clear alarm Ensure the oven goes to the IDLE state. Investigate and correct existing problems. Power Loss Recovery Turn Control Power ON.



NOTE: THE OVEN PROFILE SHALL RELOAD. HOWEVER, THE OVEN SHALL NOT GO TO THE READY STATE UNTIL THE OVEN TRANSPORT HAS COMPLETED A FULL REVOLUTION. Load Profile and oven start procedure When the oven is turned on the MAIN MONITOR ensure the screen is displayed with the LOGIN dialog box.

LOGIN. LOAD PROFILE

Observe, that after selecting the Profile, back to the MAIN MONITOR is activated. Note that profile setpoints for zone temperatures, belt speed, etc. are displayed and the oven is in the IDLE state. Select and execute RUN.



NOTES: OVEN STATE SHALL CHANGE TO NOT READY. WHEN ALL ZONE TEMPERATURES, BELT SPEED, ETC. ARE WITHIN THEIR NORMAL OPERATING RANGES, THE DISPLAY SHALL INDICATE READY. IF THE OVEN HAS THE AUTORAIL OPTION INSTALLED, THE RAIL SHALL ADJUST ITSELF TO THE CORRECT WIDTH AS SPECIFIED IN THE PROFILE. IF THE OPTION IS NOT INSTALLED, OR IS DISABLED, THEN ADJUST THE RAIL WIDTH MANUALLY WITH THE RAIL SWITCH LOCATED ON THE OPERATOR'S CONTROL PANEL OF THE OVEN. Stop oven as required.



Reflow Soldering Process Management The following procedures shall be used to effect reflow soldering operations at POD: After turning machine on, logging on, and loading the required profile, observe the monitor displaying the temperatures in each zone as they change from ambient to the specified profile settings to indicate a ready condition.



Loading and unloading the conveyor For first article and production operations, load the conveyor as required.

NOTE: SPECIFIC THERMAL PROFILES ARE REQUIRED FOR PRECISE CONVEYOR SETUP AND LOADING. USE ONLY PROFILES PROVIDED BY ENGINEERING TO ENSURE REQUIRED THERMAL PERFORMANCE TO EFFECT ACCEPTABLE SOLDER JOINTS. Unload the conveyor when process terminates After first article production have quality assurance personnel inspect all solder joints and perform touch-up as required – in accordance with POD, POD-5145, Touch-up Procedures. When solder joints found acceptable, perform production operations. When solder joints found unacceptable, inform engineering so appropriate corrective action is taken to return processes to specified conditions. NOTES: ALL REQUIRED REWORK SHALL BE PERFORMED IN ACCORDANCE WITH IPC-7712. ALL REPAIR AND MODIFICATIONS SHALL BE PERFORMED IN ACCORDANCE WITH IPC-7721. ALL SOLDERING REQUIREMENTS SHALL CONFORM WITH ANSI/J-STD-001B.



8.0 APPLICABLE DOCUMENTATION POD Statement Of Work and Detailed Processes POD, PPM-2045, Electrostatic Discharge Procedures POD, PPM-2015, Material And Assembly Handling Procedures POD, QIPM-4030, Audit Of Processes And Procedures POD, PPM-2050, Safety Procedures Planning Documentation Lot Control Documentation Maintenance Requirements, Specifications And Procedures Compressed Air Test Results POD, QPM-3020, Equipment Calibration Procedures Equipment Calibration Logs POD Quality Assurance Inspection/Test/Analysis Logs POD Operator Operations, And Process Logs QQ-S-571 Solder Test Results MIL-F-14256 Flux For Assembly Operations Test Results MIL-P-55110 Printed Wiring For Electronic Equipment MIL-P-28809 Printed Wiring Assemblies MIL-STD-2000 Part/component Mounting For High Quality/Reliability Soldered Electronic Assemblies ANSI/IPC-A-610 Acceptability Of Printed Board Assemblies IPC-600C Acceptability Of Printed Boards IPC-700B Repair Of Printed Boards And Assemblies IPC-T-50 Terms And Definitions MIL-STD-275 Printed Wiring For Electronic Equipment POD Pre-operational, Operational, And Post Operational Checklists POD/TDC Operation and Maintenance Procedure



12.6 WAVE SOLDERING

MANUFACTURING PROCESS MANAGEMENT PROCEDURES

POD-5045-1 WAVE SOLDERING



1.0 PURPOSE AND SCOPE The purpose of these procedures is to provide detailed instructions concerning wave solder manufacturing process management at POD. This is done to ensure product quality consistently meeting or exceeding POD acceptance criteria. The scope of these procedures extends to all personnel responsible for ensuring effective wave solder process management at POD. RESPONSIBILITY AND AUTHORITY The following responsibilities shall be fulfilled to ensure wave solder manufacturing process management is properly effected to assure quality at POD: Manufacturing Engineer The Manufacturing Engineer is responsible and has authority to provide everything needed by manufacturing process managers to fulfill their responsibilities at POD. This includes procedures, training, equipment, tools, adequate and safe working conditions, ESD requirements, and all other required elements. Maintenance Technician The Maintenance Technician is responsible and has authority to ensure all operational elements (equipment, tools, etc.) are maintained and calibrated as specified. This assures all facilities, equipment, and tools are capable of being effectively and efficiently managed to assure product quality meeting specified requirements. Manufacturing Supervisor The Manufacturing Supervisor is responsible and has authority to provide proper direction to all manufacturing process managers at POD. This includes operational procedures, special instructions, schedules, product changes, drawings, and required materials and components. This also includes management directives, performance evaluations, and timely individual and team performance feedback. Manufacturing Operations Personnel Manufacturing Operations Personnel are responsible and have authority to assure manufacturing processes are managed in an effective, efficient manner. They are responsible for performing all manufacturing operations in accordance with current procedures, checklists, and supervisory direction. All personnel are responsible for effecting management policies and directives to assure quality meeting or exceeding specified POD requirements. Quality Assurance Inspection Personnel Quality Assurance Inspection Personnel are responsible and have authority to determine product quality does or does not meet specified POD acceptance criteria. They also are responsible for providing appropriate feedback concerning product quality to management and manufacturing process managers so corrective or continued manufacturing action may be effected.



3.0 Background Effective, efficient wave solder process management is required to produce acceptable solder joints and assemblies. The wave solder process is made up of several sub processes. Each process and sub process is supported by individual activities. It is at the activity level most impact is made on quality. This is because trained process managers consistently fulfill their responsibilities to assure quality. At POD, one of the most important products is a quality solder joint made right on time, the first time, every time. Only trained individuals fulfilling their responsibilities (Section 2.) can do this. To assure effective wave soldering process management, primary concern is focused on key process elements, parameters, and factors. Flux types, flux maintenance, preheat temperatures, conveyor speed, and flux activation and topside board temperature specifications all shall be met. Also, solder composition and purity, solder type, solder temperature, wave height, wave/board contact area, and wave/board contact dwell times must all meet specified requirements. Additionally, equipment shall be maintained and calibrated to ensure processes capable of producing specified quality. When everything is as specified, wave solder process management is effected. Then, process effects become apparent as solder joints meeting specified acceptance criteria. This is a highly interactive, interrelational, and manageable process. It has clearly defined cause and effect relationships (processes, sub processes, and activities managed instead of results as defect). All process management requirements are detailed in these procedures. This is done in conjunction with all other process considerations. Product acceptance is based on conformance to POD and appropriate industry acceptance specifications (IPC as an example). This is true of all components and materials comprising product. Soldering is a process in which two metal surfaces are metallurgically joined. A specified solder medium (metal filler with a melting point below 800 degrees F.) is used to “wet" and bond them. It is a process requiring both diffusion and intermetallic growth to effect an acceptable solder joint. This definition emphasizes the term "surfaces" (an object’s area having no depth) to clarify the distinction between soldering and welding, as an example. Welding is a process in which diffusion and intermetallic formations are effected to metallurgically join metals beyond their surfaces to a specified depth. This distinction also provides evidence that solder joining is a reversible process as it relies on heat to "undo" the solder joint. Welding requires complete joint destruction thus making repair and/or rework impossible at the component level, as an example. The term "wetting" requires a solid surface to be completely "coated" by a liquid. This means the liquid maintains intimate contact with all solder termination areas without resistance or the indication of dewetting ("pulling back” from the surfaces). In solder joining, the liquid is molten solder. What distinguishes "liquid" metal from some other liquid media is its change back to a solid when cooled below its melting point. When two metal surfaces are wetted, they may become joined upon solder medium solidification (often referred to as freezing). Again, this is done through effective process management.



Another important term is eutectic. Eutectic is defined as a combination of two metals (forming an alloy) that melts at a lower temperature than either individual metal. Also, eutectic is defined as alloys that change directly from liquid to solid, and the reverse, with no intermediate plastic states. Various solder types, their compositions, and melting points are found in ANSI/J-STD-006. Wave soldering and other machine dependent methods (reflow or vapor phase as examples) are not thought of as art forms. This often is the case with hand soldering. This is because hand soldering requires much more human intervention to effect acceptable joints. However, wave soldering uses the same objective principles as reflow or hand soldering. The primary difference is the less personal "touch" applied during this and the reflow process. Wave and reflow soldering processes rely less on personal process management as they are less "subjective.” This is because they are less sensitive to "feel" or touch. To effect (make) acceptable wave soldered joints, the process manager is trained to visualize the cause and effect relationships existing each time the process takes place. Time and temperature factors are primary elements required to assure effective process management. This means assuring correct conveyor speed over pre-heaters and the solder wave. When managed as specified, critical flux, board, and component temperature requirements are met. Considerations also are made concerning solder types, solder temperature, and solder wave/board contact time and area. Equally important are flux types and activity as well as where and how much is applied. During this process, the affects all the above factors have on solder joints are seen (see solder joint figures below). In all soldering processes and activities, surfaces shall be solderable. This requires PCB's and components to be free of contamination. Such contamination may consist of oxidation or other conditions (grease, fingerprints, dirt, etc.) deleterious to solder joint quality and reliability. However, all surfaces are contaminated to some extent. Simply, solder termination areas shall be "wettable" and excess contamination is a barrier to this. When mild contamination is present, flux is capable of removing (cleaning) it from the surfaces to be soldered. When excessive, nothing can be done to make acceptable solder joints. This makes it critical for operational personnel to be supplied only with highly solderable components and boards. In the wave solder process, all other factors are equally critical. Flux shall be applied, so mild contamination is removed. Preheating must raise the board temperature to a level capable of activating the flux so it works as specified. The solder temperature shall be capable of effecting an acceptable solder joint. If not high enough, colder solder joints or other unacceptable conditions shall be effected. If too hot, burnt joints, boards, and components are effected. Also, the conveyor speed shall be set to assure specified times are realized over the pre-heaters and wave. Plus, the board’s contact area on the wave shall be within specified limits. The wave solder process is similar to reflow soldering. The solder process mechanism used instead of hot air is molten solder applied to solder termination surfaces (component termination and PCB holes and pads). This is done from the board’s bottom surface as solder wetting is effected on it, and up through the holes and component leads. This is due to wave pressure and capillary action via wetting.



Flux is foamed, sprayed, or otherwise coated (ultrasonic application as an example) on the board’s bottom surface. It travels up through the holes and on component leads to the board’s surface coating all solder termination areas. The board travels over pre-heaters to precondition it and its components to prevent thermal shock upon contacting the wave. Also, this sub-process activates the flux at a specified temperature required to clean mild contamination from solder termination areas. Then, the assembly is conveyed over a solder wave where the solder joint is effected. The figure below is a graphic representation of a typical wave solder profile.

As I said in this book's Part 1, I have found no need to change reflow profiles for lead-free. Likewise, even though having less experience, I see no reason to change wave solder profiles or temperatures. I always use a wave solder profile matrix as a starting point for any job. I derived it many years ago while conducting experiments over long periods. Simply it requires using, or changing, varying conveyor speeds (primarily) and sometimes different preheat temperatures. However, the wave temperature remains constant at 500 degrees F. within a tolerance of 5 degrees up or down. The following is a crude example of a wave solder matrix I created, using a DOS based drawing software "package," and used over twenty years ago:



I turned this crude little thing into a spreadsheet that you all can do. It just depends on your needs as thermal mass, flux type, flux contact and application, conveyor speed (most important), preheat temperature, topside temperature, solder pot temperature, and wave/board area contact time. Please note the wave temperature, for any thermal mass, varies little. Also note, the conveyor speed is the primary vehicle to ensure acceptable solder joints are effected/made. This, of course, is dependent upon other variables as well. In these wave solder procedures you will see the venerable old Technical Devices "Nu Era" machine and how it is managed. I still like it best of all the machines with which I have worked. In the procedure, process managers use a simple yardstick, stop watch, IR pyrometer, and other "calibration" tools and requirements. I see no need to change any of this but for increased or decreased thermal mass. This includes using lead-free solder. I have proven, with this information (derived from countless "experiments"), it is possible to solder anything using almost any known solder medium. Also, bottom side board temperature has little value. What does is the top side temperature providing the ability to ensure complete flux activation and minimization of thermal shock from wave to board. After all, the delta between bottom side and top side is easily calculated no matter the thermal parameters. It becomes clear that the wave solder process and its sub-processes are highly dependent on individually performed activities. These consist of making decisions concerning all the foregoing requirements as the various settings indicated. For wave solder process managers to improve their "skills," they shall become proficient hand solder process managers. This provides a more intimate contact and visualization of what makes an acceptable solder joint. In wave soldering, everything must come together under effectively managed conditions to create solder joints equally reliable and acceptable as those effected during other soldering operations. These procedures detail all requirements to assure effective, efficient wave solder process management at POD. The following information provides detailed information concerning a typical wave soldering machine. It shows and explains its sub systems, sub processes, and personnel dependent activities to manage them effectively:



Single Wave Solder Pot And Pump Subsystem For Conventional Wave Soldering The solder wave generator is a major subsystem and process element. It consists of a heat insulated melting pot, electric heating elements, a pump, a combination pump housing, and a flow chamber. It also consists of a solder distribution duct, a direct current motor drive, a temperature controller, and an electrical control and distribution box. The pump element is a stainless steel propeller rotating at low speed (about 350 rpm). It moves a large volume of molten solder at low velocity. This produces a wave that is smooth, wide, and laminar in form. This pumping method also produces a smoother wave with less turbulence. There are no bearings submerged in the solder so overheating and excessive wear is eliminated. The solder flow is directed into a flow chamber to further reduce turbulence before it enters the solder discharge duct. The pump draws solder up from the bottom of the pot instead of drawing solder down from the top. This minimizes debris and other contaminate inclusions in the wave as dirt, components, steel, dross, etc. float to the top of the solder. A stainless steel duct shapes the waveform for optimum performance. This is done in conjunction with a four degree inclined conveyor. The duct is easily and quickly removed for cleaning while solder is molten. The D.C. motor drive provides effective wave height adjustment to 0.4" while remaining stable during operation. Cartridge type heating elements are encased within internal thermal tubes for maximum heating efficiency and heater replacement when the solder pot is cold. A solder drain valve is provided for easy emptying of the melting pot. Chip Wave (option) Dual Wave Subsystem For Surface Mount Devices (SMD) The dual pump, dual wave system is unique. The first solder wave is a series of solder columns, or jets, that scrub and wet the most isolated recesses of most surface mount assembly designs. The first wave is called "The Dancer" because it sometimes appears to do a "jitterbug" on the bottom side of the printed circuit board.



The second wave is smooth with laminar flow. This ensures defect free soldering for fine line printed circuitry. The solder pots are mounted on wheels and are retractable for access for maintenance to the assembly. The solder capacity of the melting pots is about 450 lbs. and a solder drain valve is provided for easy emptying of the melting pots. Foam Flux Unit Subsystem The foam flux unit tank and foam riser duct are constructed of linear polyethylene to resist attack by the most active fluxes and chlorinated cleaning solvents. A porous ceramic diffuser stone generates a 2.5" wide blanket of foamed flux. Pneumatic controls are panel mounted at the front of the machine adjacent to the flux unit. They consist of a snap action on/off switch for the air supply, a pressure regulator, a pressure gage, and a needle valve to control the foam height.

An air line filter and water trap prevent flux contamination. It shall be noted that an oil free air supply shall be used to prevent other serious flux contamination that could cause solder defects. The entire flux tank assembly is mounted on a stainless steel stand. It may be raised or lowered by a single lever to adjust the clearance under the printed circuitry as it passes over the flux duct. A drain hose is attached to the bottom of the tank. The flux capacity of the tank is approximately 1.5 - 2.0 gallons.



Pre-heater Subsystem The pre-heater subsystem features a variable width radiant preheating area. The heating area width is switched (in 1" increments) to conform to printed circuit width requirements.

Since the heated area is a flat plate, there are no hot spots. This allows the printed circuitry to absorb more heat at a much lower watt density per square inch than concentrated high surface temperature tubular heaters. The absence of these heater elements provides assurance that printed circuit boards are capable of being much closer to the heating area without damage. This significantly increases the efficiency of the pre-heater subsystem without hot spots. Again, this is because of the continuous flat plate heat radiation surface. The heated area surface temperature is closely maintained to specified requirements by a proportional, zero firing temperature controller. With the increased efficiency and extended length of this preheat subsystem, overhead heating may be unnecessary even for difficult to heat multilayer boards. However, if particular processes require overhead preheating, TDC supplies it as optional equipment. The extra long preheating area provides more soak time to heat printed circuitry at higher conveyor speeds.

Conveyor Subsystem The conveyor subsystem (moving pallet type) transports printed circuit boards over the foam fluxer, preheating, and wave soldering subsystems. The pallet is removable allowing several to be loaded with boards to be soldered before the process is initiated.



Each pallet has an adjustable mechanism whereby boards are fitted into “V” grooves, much as fingers, and firmly (but not too tightly) attached using locking knobs on top and at each end of the pallet. This feature eliminates the adjustable width finger type conveyor systems. The pallet is loaded into pre-positioned grooves in the transport mechanism. Then, the pallet is moved along it until it engages allowing boards to be fluxed, preheated, and soldered The conveyor transport has an infinitely variable speed range from 2 to 16 feet per minute. An SCR controlled permanent magnet motor drives it. Drive is effected through two synchronized universal joint shafts to eliminate the problems of linear sliding motion through keyed or splined drive bushings with their tendency to gum up and stick. Hood Enclosure Subsystem The hood enclosure subsystem encloses the work area for operator safety. It provides the capability to exhaust flux fumes and ensures effective removal of excess heat. It has a sliding safety glass window for easy and quick access to the machine. A vapor tight safety lamp illuminates the interior work area.

Instrumentation Subsystem A single in line instrument panel is located across the machine's front. It provides controls for the automatic wave soldering operation, its subsystems, and sub processes.

Solder Connection (Joint) Acceptability Acceptable solder connections often are bright and shiny (not always necessary) while clearly revealing solder termination area surface contours. They feather completely out to the joint's edge.



They are free of any residue or foreign matter. The joined surfaces are completely wetted showing no signs of being "cold.” They exhibit no evidence of dewetting, disturbance, or other unacceptable attributes. Based on the foregoing requirements, the first two figures show preferred and minimally acceptable solder joints while the third shows one that is unacceptable. POD requires solder joint quality conformance to IPC-A-610C, Class III requirements.

Solder joint reliability is another issue requiring careful determination. Though a solder joint exhibits visible quality, it may not have sufficient integrity, composition, or formation to ensure long term reliability. The reasons for this are many and this discussion is best left for more advanced study. However, visible quality is the primary starting point especially concerning its correlation to process management and capabilities. Root cause (process management and capabilities) and effect (solder joint quality) relationships are first established using visual quality verification methods. If process management is effected using proven process capabilities, solder joint quality shall be acceptable. Effecting An Acceptable Solder Joint Some of the most important requirements for effective wave soldering process management are clean solder surfaces, calibrated conveyor speeds, and controlled and verified temperature profiles. Also required are specified solder temperatures, specified solders and fluxes, calibrated wave contact areas and times, specified preheat temperatures and times, and specified top side board temperatures. All these requirements shall be met to ensure effective process management. Other equally important requirements are well trained operators, clearly defined procedures, and the attendant tools to promote process management. Solder Process Management The most important factor needed to effect process management is proper training. Each wave solder process manager shall be trained, evaluated, qualified, certified, and empowered to accept and fulfill responsibilities for ensuring solder process management is possible and effected. This shall be done to ensure acceptable solder joint quality. Each wave solder process manager must understand the following: Solder Termination Area Conditions Solder termination area (surfaces as PCB pads or component leads) shall be free of excessive contamination. Printed circuit board pads and/or component leads having excessive contamination (oxidation, grease, dirt, etc.) are not capable of being solder "wetted." It is not possible under any conditions to effect acceptable solder joints when excessive contaminates are present. No amount of heat, flux, or time shall help. Each solder process manager must determine that surfaces to be joined



are clean enough to be wetted and soldered so specified solder joint quality is assured and effected. If this determination cannot be made, the soldering process shall be stopped until corrective action is taken to return the process to a manageable state. Solder Termination Area Condition Examples To ensure solder process managers have solderable surfaces, only qualified suppliers, managing qualified processes, shall be selected to provide required PCB and component solder termination areas. This means that only "clean," solderable PCB's and components shall be purchased and introduced to soldering operations. The first figure is an example of a contaminated J-lead on a PLCC surface mount component. The second figure shows the results of a test using scanning electron microscopy (SEM) with energy disperssive X-Ray (EDX). It is a graphic clearly indicating excessive tin oxide contamination (18:1 oxide to surface metal ratio) on the J-Lead’s surface. This condition absolutely prevents solder wetting under any conditions. The third figure shows completely non-wetted SMT pads. They also prevent solder wetting under any conditions. The fourth figure shows effect as an unacceptable PLCC solder joint caused by its excessively oxidized J-Lead. However, the PCB surface (not having the condition shown in figure 12) soldered well as it exhibited complete wetting.

NOTE: AGAIN, THE FIRST FIGURE SHOWS J-LEAD CONTAMINATION AS OXIDATION (18:1 OXIDE TO SURFACE METAL RATIO). THIS CONDITION COULD EXIST ON THROUGH HOLE COMPONENTS, CHIP DEVICES, AND LEADED OR LEADLESS SMD’S. LOOK FOR THIS CONDITION AND THOSE ON PCB PADS. DO NOT ATTEMPT TO SOLDER UNDER THESE CONDITIONS. Wave Solder Thermal Management The wave solder process shall be managed using verified temperature profiles, as gradients, capable of first providing increasing heat to “ramp” the board temperature gradually. This is done so it is not “shocked.” because of the thermal change (delta T) when leaving the preheat zone and contacting the much higher temperature solder wave. This prevents damage to boards or components and promotes the specified top side board temperature to assure flux activation. Then, the process shall be managed to assure the solder wave is at the specified temperature to effect acceptable solder joints. The time required is not less than 2 nor more than 4 seconds within a specified contact area (contact time is a function of contact area and conveyor speed). Board and/or component overheating is prevented when times are correct. If overheating does occur, primary damage is done to the PCB as pad lifting (or rotation) from the board surface as in the first three figures. PCB damage also may be done as the cracked hole in the fourth figure. Component damage (cracking as an example) also may be effected due to excessive heat or thermal shock.




Solder Termination Area Surface Coating Types Solder termination area surface coating types often are electroplated or hot air solder leveled (HASL) tin/lead, or electrolessly deposited tin. Newer coatings are electroless gold, silver, palladium, “white” tin, and organics. They have been developed to overcome problems associated with the above types. Problems consist of non-wetted, uneven, and/or oxidized surfaces often with excessive intermetallic formations. All these plating or coating types are compatible with the solder medium to the extent deposited amounts do not “contaminate” the solder medium and joint. Contamination would be in excess of that specified in ANSI/J-STD-001B (Figure 5-1) during soldering operations. If the surface is coated or plated with other metals (electroplated or electrolessly deposited gold in excessive amounts, as an example), they shall be removed to assure solder compatibility or the solder medium shall be changed. Acceptable solder joints often have acceptable intermetallic growth effected as part of the joining process although some unacceptable joints are formed when wrong or excessive intermetallics form. Gold is an example of a metal (in excessive amounts) that is not compatible with tin/lead eutectic soldering. This metal causes embrittlement and subsequent solder joint failures over time - under mechanically induced stresses. NOTE: EXCESSIVE AMOUNTS MEANS GOLD, OR OTHER COATING, CONTAMINATING SOLDER JOINTS BEYOND THAT WHICH IS ACCEPTABLE TO ENSURE INITIAL QUALITY AND LONG TERM RELIABILITY. REFERENCE TABLE 5-1, ON PAGE 5, IN ANSI/J-STD-001B CONCERNING SOLDER LIMITS FOR TIN/LEAD ALLOYS. Flux Types Flux is composed of acid or caustic chemicals (high or low pH components [over 7 = alkaline, under 7 = acidic]). It is used to clean contaminates (mild oxidation, grease, or other residues) from solder termination areas. Fluxes become fluid at lower temperatures than solder. This means that when heated, flux flows onto solder termination areas first. As it does, it cleans and protects (when properly



activated) the heated metal surfaces until the solder becomes molten and flows onto and wets solder termination areas. Then, the solder solidifies (“freezes”) upon cooling to make the solder connection. Flux Requirements Flux is vital to most soldering processes. This is true though fluxless or no clean solutions are being sought as part of an ongoing effort to reduce environmental contamination produced during soldering and cleaning operations. The two flux types generally used are rosin flux or aqueous (water soluble acid) flux. After soldering operations, rosin flux shall be cleaned with isopropyl alcohol (one of its components). Aqueous flux shall be cleaned with water (a component in its binder). This is required because of the deleterious affects flux residues have when left on board, component, and soldered surfaces. They continue to act as a removal or cleaning mechanism. This causes damage and solder joint failures. Some flux residues are conductive providing paths for unwanted current flow capable of causing electrical shorts between surface conductors. Newer “no-clean” fluxes are composed of chemicals capable of removing contamination while needing little or no cleaning after reflow soldering. Their residue remains on or near the solder connection and provides none of the concerns stated in the above paragraph. However, rework or repair operation results often require localized cleaning to remove the then visibly exposed residue. NOTE: THE ONLY REASON METAL SURFACES ARE COVERED, COATED, OR PLATED IS TO PROTECT THEM FROM OXIDATION OR OTHER CONTAMINATION UNTIL THE SOLDER JOINT IS MADE. COPPER SURFACES (COMPRISING MOST PRINTED CIRCUIT CONDUCTORS) OXIDIZE ALMOST IMMEDIATELY UPON EXPOSURE TO AIR. SCRATCH A PENNY’S SURFACE AND SEE HOW LITTLE TIME IT TAKES FOR THE SHINY SCRATCHED AREA TO TURN DULL BECAUSE OF OXIDATION. Thermal Mass Considerations A single pad on a single sided circuit board involves relatively little thermal mass. A double-sided board with a plated through hole can double that mass. Multilayer boards (MLB’s), increased component leads, larger device types, different device types and MLB materials, terminals, connectors, and connecting wires further increase thermal mass. This means that temperature rise shall not be as rapid or as much when using a thermal profile designed for a board with less thermal mass. This means each board type and its unique thermal mass shall have a correspondingly unique thermal profile. There may be specific or unique profiles for single and simple double sided boards, for higher density four and simple six layer types, and those for eight to ten layers, and so on. Experiments (trials) shall be performed to determine which profile works for which board type. This is done using thermocouples mounted on PCB’s, “MOLES,” or other thermal profilometers that are run through the wave solder process. These setups provide precise thermal information at various stages in the soldering process along the conveyor’s path. Clear temperature readings are printed out, viewed, and/or graphed to make determinations concerning more effective thermal profile considerations so processes and solder joint quality is continuously improved. During experimentation, each board type is inspected and effects (acceptable or unacceptable solder joint quality) are correlated to cause. Cause is how well a process is managed relative to machine



and required sub process settings made in accordance with specifications and procedures. When effects are positive, cause is recognized as effective process management and processes may be effectively managed during production. When negative, experiments continue until positive effects are found and process settings are recorded and made available for use in production. Ongoing pre process audits and sample inspections promote continuous process improvement as part of statistical process control (SPC). As previously discussed, an important factor concerning thermal profile management is a solder termination area's surface condition. In addition to what was said earlier, oxides particularly act as thermal barriers to heat transfer. Even if a thermal profile provides the right properties for that board type, excessive oxidation always prevents enough heat reaching the solder termination areas to melt solder. Even if a specified flux type is used to clean mildly contaminated areas, excessive oxidation is a barrier to all solder process management efforts. Solder Joint Formation Time Requirements Time is a major factor affecting acceptable solder joint quality and preventing damage to boards, components, or finished assemblies. For wave soldering process management to be effective, the specified heat shall not be applied to solder termination areas for more that 4 seconds. Beyond this time, the board may be damaged (as in previous examples). If more time is required to wet solder termination areas, something is wrong. There may be too much thermal mass, the wrong thermal profile, too little heat input, or excessive oxidation. Corrective action shall be taken. The figure below shows a cross section of the perfect J-Lead solder joint effected in well managed solder processes.

NOTE: ACCEPTABLE SOLDER JOINTS ARE NOT AN ART FORM. THEY ARE NOT EFFECTED BY ARTISTS. ACCEPTABLE SOLDER JOINTS ARE OBJECTIVE EVIDENCE OF PROCESS MANAGERS USING THE RIGHT TOOLS WITH PROPER INSTRUCTIONS FOR THEIR USE TO ASSURE SPECIFIED QUALITY.



Unacceptable Solder Joints And Other Conditions As Cause For Rejection.






Disturbed Solder A disturbed solder joint has a crystalline appearance may be fractured or separated at the solder termination area junction. Overheated Solder An overheated solder connection appears dull and crystallized. Areas around overheated solder joints often appear discolored or burnt. Contaminated Solder A contaminated solder joint is unacceptable as it contains foreign matter such as insulation or other debris, etc.



Solder Bridging Solder bridging is a web or film of solder between adjacent vertical terminations (formed over the insulating PCB material). If extensive, it can be a web of solder between adjacent conductors. Some causes of bridging can be low solder temperature, insufficient flux, poor flux activation, or the presence of impurities in the molten solder. Other factors may involve the wetting angle, and the angle at which the board approaches and contacts the wave.

Icicling Icicling is solder extending out perpendicular from the PCB bottom side usually at the component leads. It is caused by a drainage restriction of molten solder from the board, lower than specified solder temperature, or faster than specified conveyor speed. Other causes may be wrong PCB angle over the wave, shorter than specified wave contact time, too little wave/board contact area, inadequate flux activity, and/or unacceptable solder purity. Blowholes And Voids Blowholes are voids having exited, or outgassed from within PCB plated holes or solder joints. Voids are small spherical cavities within the PCB plated hole wall in the first figure, or under/in a solder joint shown in the second figure. Causes of blowholes are excessive flux, flux residue left inside a solder joint, insufficient evaporation of the flux solvent before soldering, or moisture or organic plating residues having been entrapped in plated-through holes that “outgas” through the hole wall plating. Blowholes can be caused by PCB's not meeting supplier acceptance criteria such as minimum copper plating thickness. They and voids may also be caused by flux remaining in solder joints fighting contamination such as excessive oxidation.




Correction And Prevention Of Unacceptable Solder Connections. Action to correct and prevent unacceptable solder connections shall be taken by wave solder process managers. The action taken depends on the frequency and type of unacceptable connections found. When excessive or major defects are found, supervisors shall be notified so required correction can be made. When minor or minimal defects are found, the process managers shall correct the process to assure quality meeting specified requirements Repair, Modification, And Rework Repair, modification, and rework of unacceptable solder joints and/or assemblies shall be done using hand soldering with flux cored solder and temperature regulated soldering irons. Cleaning shall be done on the board after touch-up using the proper cleaning solution depending on the flux type used. NOTE: ALL TOUCH UP OPERATIONS AND ACTIVITIES SHALL BE PERFORMED IN ACCORDANCE WITH POD, POD-5055, REPAIR, MODIFICATION, AND REWORK PROCEDURES.



DEFINITIONS The following definitions are provided for all process managers to better visualize each process for which they are responsible: Operations Operations are defined as a series of processes required to provide product or services meeting certain requirements. Usually these requirements are based on customer needs, desires, or demands. POD employs many operations as management, engineering, marketing, sales, manufacturing, accounting, quality assurance, and others to ensure all its customers receive product meeting their requirements. Process A process is defined as a method or procedure. A process may be a single method or procedure, or may be made up of sub processes and activities. In a manufacturing operation, a process is employed to turn acceptable raw materials, components, and designs into acceptable product using various tool and equipment types. Sub Process A sub process may be part of a process. In the wave solder process, several sub processes are involved to effect acceptable solder joints. They are discussed in the foregoing section. Activity Processes and sub processes most often rely on individuals or teams performing activities to make product. In manufacturing, such activities may consist of moving or handling materials and components, changing machine or tool settings, turning equipment on or off, etc.. It is at the activity level most variability is introduced to manufacturing operations effecting varying degrees of quality. For this reason, it is vital process managers be well trained to fulfill their responsibilities by following procedures concerning specific process management requirements. Process Management Process management is the act of preventing defect by fulfilling individual responsibilities instead of reacting to it as the result of not fulfilling them. When process instead of results management is practiced, product quality is consistently acceptable. Process management differs from process control in that control means only consistent quality is produced. In a controlled instead of managed environment, that quality may be consistently good or bad. Process Capability Process capability is the measure of how well a process is being managed. Usually, a processes’ capability is expressed in statistical terms as a capability profile or Cpk. When a process is managed effectively, its Cpk shows how well while often providing an indication of what is needed to continuously improve. Continuous process improvement assures continuous quality improvement and that is what process managers focus on most. Solder Solder is defined as a metallic medium (as an alloy) that melts at temperatures below 800 degrees Fahrenheit to join metal surfaces having much higher melting points. Solder may be in different forms. It may be bar solder as used in wave solder machines, or it may be wire with a flux core used



to perform hand soldering. It may also be in the form of a paste composed of solder balls suspended in a binder with a flux component. None of these forms changes its definition. Solder Paste Solder paste is a metallic medium (as an alloy) formed into solder balls (ranging in diameter from about 4 to 40 microns). The balls are suspended in a binder (composed of flux and other chemicals). Solder paste, as all solder media, melts at temperatures below 800 degrees Fahrenheit to join metal surfaces having much higher melting points. The more spherical are the solder balls, the less surface area they have. This reduces their oxidation amount and rate at which they oxidize. This is important because more oxidation means less solderability. The solder paste composition has a high viscosity of approximately 900,000 centipoise. Higher viscosity aids in preventing solder paste spread on SMT pads. When too high, printing problems may occur relative to dispensing paste through stencil openings. Solder paste is applied to solder termination areas using a printing machine, squeegees, and stencils with openings of specified sizes, shapes, and aspect ratios. All this is done to assure a precise amount is printed where and in the condition required to effect acceptable solder joints. Wire/Core Solder Wire/Core solder is a solder medium composed of a eutectic alloy. Usually it is 60/40 tin-lead formed into a wire with a hollow flux filled core. Wire/Core solder is specified in varying diameters (typically from about .012” to .060”) for specific hand soldering activities. It provides a mechanism to apply flux from its core to the solder termination areas before solder melts, flows, and wets them to effect an acceptable solder joint. Flux Flux is defined as a chemically and physically active compound that when heated to specified temperatures it promotes base metal surface wetting by molten solder. It does this by removing minor surface oxidation, surface films, or other contamination. It then protects the surfaces from reoxidation during the soldering process. Various flux types (see POD Hand Soldering and Final Assembly Course) include: Rosin Rosin flux primarily is composed of natural resin extracted from oleoresin of pine trees and refined. Typically, these fluxes are made up of 60% solvent and 40% solids. Rosin flux (Type R) is an organic material distilled from pine tree sap. The active ingredients in this flux type primarily consist of abietic and pimaric acids. After rosin is extracted from pine trees, it is superficially processed to remove undesirable impurities while neutralizing the acid residues remaining from the extraction process. The purified material is called water-white rosin. It is used to manufacture rosin based flux. Some manufacturers hoping to overcome difficulties associated with obtaining and processing natural rosin, chemically synthesize substitute materials. These materials are called “resins.”



Pure rosin is a solid at room temperature and is chemically inactive while being insulative. Rosin melts at about 72 degrees C. (160 degrees F.) and the organic acids become active at around 108 degrees C. (225 degrees F.). This flux type’s peak capability is effected around 262 degrees C. (500 degrees F.). This is the temperature rosin begins decomposing into reducing gases. At temperatures above 346 degrees C. (650 degrees F.), the flux becomes inactive and polymerizes. This causes residue removal difficulties from board and solder joint surfaces. When solder surfaces require a more active flux, chemical compounds called activators are added to the rosin. The most commonly known rosin flux containing activators is called rosin, mildly activated or RMA. Activators are thermally reactive compounds (such as amine hydrochlorides) that break down at elevated temperatures. At these temperatures, hydrochloric acid is released to dissolve the surface oxides, tarnishes, and other contaminates. Mildly activated rosin flux (RMA) may contain a variety of activators in amounts less than 1%. Limits are placed on their electrical and chemical properties before and after soldering Rosin activated flux (RA) typically contains 1% - 5% activators. RA flux is used in applications when RMA is not strong enough. For military purposes, their use usually is limited to component tinning of sealed devices and solid wire. When warm, these fluxes can conduct electricity and can leave residues that can cause corrosion or shorting path formation between conductors. Organic Acid Flux Organic acid (OA) fluxes are types having active ingredients such as organic acids, organic hydrohalides, amines, and amides. These fluxes are water soluble since they contain no rosin. Good cleaning is critical with these flux types since the salt residues left by them are corrosive and conductive. OA fluxes also are referred to as water soluble fluxes (WSF’s). These fluxes are more aggressive. They generally are classified in J-STD-004 as types M or H. OA fluxes have active ingredients such as organic acids, organic hydrohalides, amines, and amides. All are corrosive activator materials. These fluxes are water soluble or water washable since they contain no rosin, or any low rosin or resin levels. Good cleaning is critical with these flux types as their residues are corrosive and electrically conductive. Resin Resin flux primarily is composed of natural resins other than rosin types and/or synthetic resins. Organic Organic elements are based on carbon atom structures. All life forms are organic. Organic fluxes are primarily composed of organic materials other than rosin or resin. Inorganic Inorganic elements are based on other than carbon atom structures. Inorganic fluxes are solutions composed of inorganic acids and/or salts.



LR, or No-Clean Fluxes Low residue (LR) fluxes usually have lower solids content (less than 5%) than traditional high-solids rosin fluxes. LR fluxes also are referred to as no-clean or “leave on” fluxes. Their residues are not intended for removal from assemblies so cleaning is not required. Their primary activator materials are weak organic acids (adipic or succinic acid). These materials are benign on a board surface and act as electrical insulators. LR fluxes may be higher solvent borne (usually isopropanol) or water borne in the case of volatile organic compound (VOC) free no clean fluxes. Low residue fluxes are not no-residue fluxes. Although benign, visible residues do remain on the assembly. For this reason, customers may require them to be cleaned. This often is requested for cosmetic rather than functionality reasons. If the flux residues have a significant thickness, they could interfere with electrical testing as “bed of nails” types. However, a different probe point, greater spring strength, or rotating probes often solve this problem. Low residue fluxes also might build up on test pins over time. This requires preventive maintenance as regular cleaning. Halides Halides are organic salts added to flux as activators. Halides are corrosive. Fluxing Activities And Classes A liquid flows freely over a surface only if in doing so the total free energy of the system is reduced. In soldering, the free energy of a clean surface is higher than a dirty one. Therefore, it is more likely to promote solder flow. With respect to this, fluxing activities are: Chemical Chemical fluxing activity reduces the oxides from the surface to be soldered and protects this surface from oxidation by covering it. Thermal Thermal fluxing activity assists transferring heat from the heat source to the material being soldered. Physical Physical activities allow the transportation of oxides and other reaction products away from the material surfaces being soldered. In consideration of these three fluxing activities, the following shall be noted: 1) There are two basic ways fluxes eliminate oxidation. They dissolve it into "solution" or they reduce it back to metal. If reduced, it clearly "disappears" and should not be re-deposited as an oxide (to be determined through supplier qualification). Some old flux types "dissolved" oxides by reacting a fatty acid (rosin) with the metal in the oxide. Then, it was “pushed aside” by solder flow and wetting action. In which mode a flux works, clearly depends on which flux is used. Some fluxes use both modes. 2) ANSI/J-STD-004 differentiates flux activities into three classes. They are Low (type L), Medium (type M), and High (type H). ANSI/J-STD-004 further classifies fluxes as to whether or not they contain halides. For example, a type L0 flux is a low activity, halide free flux. An L1 flux is a low activity flux containing some halide amount.



3) Numbers of industry and consortia studies have been conducted concerning low residue flux reliability. Type L fluxes have been shown relatively benign concerning corrosion and electrolytic failure mechanisms. For this reason, Section 4.2 allows the manufacturer to use a type L flux (L0 or L1) without going through the testing outlined in Appendix D. If the manufacturer chooses to use a more aggressive flux (types M and/or H), the potential exists for corrosive flux residues. If so, the manufacturer must go through the Appendix D testing to demonstrate adequate removal of potentially harmful flux residues. 4) It is highly recommended that the manufacturer not use a type H flux on printed wiring assemblies in any way – at any time. It is recommended that, if used at all, a type H flux be limited to component lead tinning. Even then, this may be done only when it can be demonstrated that the highly aggressive flux residues can be thoroughly removed. Electrochemical Migration Electrochemical migration is defined as the movement of metals across an intervening space between a cathode and anode. This movement is induced by the difference in electrical potential in the presence of fluid producing a micro-film of water on a substrate’s surface. Soldering Soldering is a process in which two metal surfaces are metallurgically joined, using a specified solder medium (metal filler with a melting point below 800 degrees F.). The process is effected by "wetting" the surfaces to be joined requiring diffusion and internetallic growth. The effect of this process is called a solder joint. Intermetallics In light of the previous definition (soldering), intermetallics always are formed when heated solder surfaces are brought into contact with solder melted upon them. As soldering requires diffusion and internetallic growth, each occurs as part of the soldering process. This is immediately so and time effects intermetallic growth as a continuous process. Intermetallic compounds have much different physical and mechanical properties than the metals comprising them. Typically, intermetallics are very brittle and have poor electrical conductivity. Also, when exposed to air, they oxidize very rapidly. Therefore, excessive intermetallics, formed either during the soldering process or over time, cause unreliable solder joints capable of failing under stressful conditions as thermal, or mechanical shock and/or vibration. Oxidation (oxide, oxidize) Oxidation is the act of burning. When oxygen is present in an atmosphere, it “burns” or oxidizes all material with which it comes in contact. When this happens, oxides are formed that resist thermal input as well as solder wetting. Some materials resist oxidation better than others. Most solder termination areas are copper (oxidizes very rapidly) covered with some protective coating to prevent further oxidation than that which was present before the coating’s application. In an inert atmosphere, oxidation is prevented (there is no oxygen or oxidizing agent). This means that if all processes relating to the use of materials capable of rapid oxidation were performed in an inert atmosphere, they would be more capable of solder wetting.



Inert Atmosphere Inert means inactive or static. An inert atmosphere is one without activity such as that containing oxygen which is one component in our life sustaining atmosphere surrounding earth. Nitrogen is an inert gas. When totally comprising an atmosphere (as inside a soldering machine), activity is eliminated concerning oxidation thereby providing protection to solder termination areas. This promotes or improves thermal input and solder wetting (solderability). This assures a higher rate of higher quality solder joints. Surface Surface is defined as an object’s area having no depth. Welding It shall be noted there is a distinction between soldering and welding. Welding is defined as a process in which diffusion and intermetallic formations are effected to metallurgically join metals beyond their surfaces to a specified depth. The welding process is effected at temperatures well above 800 degrees F.. This distinction also provides evidence that solder joining is a reversible process as it relies on heat to "undo" the solder joint. Welding requires complete joint destruction thus making repair and/or rework impossible at the component level, as an example. Solderability Solderability is defined as the ease with which solder adheres to a basis metal surface such as a component lead, PCB solder termination pad, or PCB conductor hole pad and wall. The presence of contamination (as oxides or residues) interferes with solderability. Acceptable solderability and solder joint formation, requires good solder wetting and a small contact angle. Wetting Wetting is defined as the formation of a relatively uniform, smooth, unbroken, and adherent solder film to a basis metal. Wetting requires a solid surface to be completely "coated" by a liquid. This means the liquid maintains intimate contact with all solder termination areas without resistance or any indication of "pulling" back from their surfaces. In solder joining, the liquid is molten solder. What distinguishes "liquid" metal from some other liquid media is its change back to a solid when cooled below its melting point. When two metal surfaces are wetted, they may become joined upon solder medium solidification (often referred to as freezing). This only is done under effectively process managed conditions. Contact Angle Contact angle is defined as the angle at which a solder fillet meets the basis metal. A small contact angle indicates good wetting whereas a large angle indicates poor wetting. Eutectic Eutectic is defined as a combination of two metals (forming an alloy) that melts at a lower temperature than either as individual metals. Also, eutectic is defined as alloys that change directly from liquid to solid, and the reverse, with no intermediate plastic states. Various solder types and their compositions and melting points are found in ANSI/J-STD-006.



Solder Joint A solder joint is effected in the soldering process. Under effectively managed conditions, solder joints exhibit acceptable attributes as smooth, usually shiny, clearly defined, well feathered, completely wetted metallic bonds between two metal surfaces. Aqueous Cleaning Aqueous cleaning is defined as process using water as the primary cleaning agent or solvent. It shall be noted that water is termed the “universal” solvent because it is capable of dissolving all material types to some extent over time. This type cleaning can mean using pure water, with detergent additives, or with a saponifier solution. Aqueous cleaning is done most often with water soluble fluxes, but can be used on rosin and low residue fluxes as well as with the appropriate additives. Aqueous cleaning generally is a multi-stage operation with most cleaning effected in the first wash stages with the dirtiest water while rinsing is done in later stages using the cleanest water. Manual Cleaning Manual cleaning is a process used to spot clean flux residues from assembly surfaces. It includes using a bristle brush with isopropyl alcohol as the cleaning agent or solvent. This process is not recommended for final cleaning. Saponification Saponification is defined as a cleaning process using a biodegradable rosin cleaner. In the process, the rosin is changed chemically to become water soluble. Wave Soldering Wave soldering requires intimate contact be made between molten solder and the assembly’s bottom side solder termination areas to effect solder joints. Conversely, reflow soldering is accomplished in a machine using air or an inert gas (nitrogen) as the solder reflow mechanism. Wave soldering requires attention to conveyor speed, flux action and activation, preheat and topside board temperatures, solder pot temperatures, wave contact times and areas, and solder purity. In reflow soldering, a hot gas envelopes the entire printed circuit assembly. In doing so, it activates the flux then melts the solder medium having been “printed” on the board’s surface onto which components have been attached. Upon melting, solder wets all termination areas. Upon cooling, the solder joint is made. In wave soldering, wave contact with solder termination areas wets them as wave pressure, and wetting and capillary action provides the mechanism for the solder to flow up holes and component leads to wet them to the board’s surface. The entire reflow process is completed in stages corresponding to increasing temperatures in several zones until the highest temperature is reached in what is called the liquidous zone. It is in this zone the solder melts (liquefies) and wets all solder termination areas. Wave soldering requires similar stages to ramp boards and components up to temperatures required to activate flux, and prevent thermal shock upon wave contact. Quality Quality is defined as conformance to clearly specified, understood, and accepted customer contract requirements.



Repair Repair is defined as the process required to restore the functional capability and/or performance characteristics of a defective article. This is done in a manner that precludes compliance of the article with applicable drawings or specifications. Modification Modification is defined as the process required to revise the functional capability or performance characteristics of a product to satisfy new acceptance criteria. Modifications usually are required to incorporate design changes that can be controlled by drawings, change orders, etc.. Modifications only shall be performed when specifically authorized and described in detail on controlled documentation. Rework Rework is defined as the act of reprocessing non-conforming or defective articles. This is done using original or equivalent processing to assure full conformance of the article with applicable drawings or specifications. Rework is doing something over that should have been done right the first time. Other Other terms are defined in IPC-T-50 and in specific guidelines, standards, and specifications indicated in Section 8. herein.



4.0 REQUIRED EQUIPMENT/TOOLS Specified Wave Soldering System Lev-Chek Wave Level Indicator Flux Density Hygrometer Infrared Pyrometer Solder Pot Thermometer Conveyor Speed Timer



5.0 PROCESS MANAGEMENT AND QUALITY SYSTEM REQUIREMENTS Process management and quality system requirements are steps required to maintain process management effectiveness to assure product quality meeting specified requirements. Traveler and drawings as required Component placement/insertion as required Safety, handling, and ESD as required Flux stone clean each shift (maximum) alcohol when not in use Flux air pressure as specified (15 - 30 p.s.i.) from clean, dry air supply Flux recycled every shift (maximum) and dependent on flux specific gravity measured each production lot (maximum) Read, understand, and use solder audit checklist before each run, lot, or different board type Flux density (specific gravity) as specified (approximately .9 for 2331 type at 76 degrees F.) Flux action and application as required (through PCB holes) Conveyor speed as specified (3 - 6 feet per minute per board type based on topside board temperature and wave contact area/time requirements). Temperature and wave solder contact area and time requirements, pre-heater (s) working, top side board temperature as specified per board and flux type (160 - 200 degrees F. typical – hotter if required to minimize SMD thermal shock). Wave contact time (1.5 - 3 seconds) and area (1-3 inches) with board parallel to wave depending on board type after wave inspection indicating specified soldering requirements



6.0 WAVE SOLDER PROCESS These procedures are used to ensure effective, efficient process management concerning wave soldering operations at POD. POD uses a TDC, NU/ERA wave soldering machine as a process capability to effect acceptable solder joints on printed circuit assemblies. This includes both through hole and surface mount devices.

Wave Solder Process Preparation Prepare all solder process elements for wave solder processes and proceed as follows while confirming all safety, material handling, setup, maintenance, calibration, and machine functions in accordance with these procedures. Ensure proper handling and ESD protection. The first figure indicates ESD protection required symbol. The second figure indicates ESD handling requirements shall be effected. The third figure shows the preferred method for handling Class III PCB assemblies. The fourth figure shows an acceptable handling method. In all cases it is required that ESD protection be provided all assemblies and all boards be handled so no damage, contamination, or other defect causing possibilities exist.



Ensure PCB date codes not older than six weeks. If so, ensure boards baked to remove moisture. Inspect boards to ensure all components seated properly and be sure component lead length does not exceed 0.10".



From left to right, in the figures below, turn on main power, hood lights, and melting pot (solder pot) heaters. NOTE: SOLDER HEAT UP TIME IS APPROXIMATELY TWO (2) HOURS AT 230 VAC TO REACH THE SPECIFIED TEMPERATURE OF 500 DEGREES F. (+ OR - 5 DEGREES). ALSO NOTE EMERGENCY STOP BUTTONS AT EACH END OF CONTROL PANEL.

Turn the conveyor on (in the fourth figure above) and set the speed control knob to the required position (in the figure below), for the specified board type, while observing the tachometer displaying the specified speed.



When the specified solder temperature is reached, clean dross as required, then turn on both wave solder pumps (if dual wave needed), or planar wave pump only when running through hole boards and/or those without chip device types. Determine and/or adjust specified solder wave height for printed circuit board thickness to be soldered. When necessary, use the LevChek device (first figure below) to set wave contact time, area, and parallelism.

As required, prepare fluxer for soldering operations. As required, add new flux as in second figure above. Measure specified flux density as required in first figure below (specific gravity). Also, use chemical titration as required. The second figure below shows a simple pre-process audit check list and a wave solder process manager taking a top side board temperature reading/



Turn air control "ON," then increase or decrease air supply as required. Adjust pallet finger width to the width of the printed circuit board and ensure boards properly secure. Also ensure enough finger to component clearance is provided.

Use PCB edge stiffeners as required (next to last figure above). Load printed circuit boards in pallets ensuring proper fit in “V” grooves. Once loaded into pallets, ensure components properly seated (last figure above).



Turn main pre-heater on (first figure below). Turn on individual heating elements as required (second figure below). Set pre-heater to the specified temperature setting. CAUTION: TURN ON ONLY THE NUMBER OF HEATERS INIDICATED NECESSARY BY THE WIDTH OF THE BOARD TO BE SOLDERED.

When required, determine top side board temperature is a specified (first figure below) to ensure specified flux activation and board warm up requirements are met. When required, measure or “calibrate” conveyor speed with stop watch while timing board/conveyor over yard stick placed along side machine (second figure below). NOTE: ALWAYS WEAR THERMAL GLOVES WHEN WORKING NEAR WAVE OR HEATED ELEMENTS. ALWAYS WEAR PROTECTIVE EYEWEAR WHEN WORKING AROUND OR NEAR THE WAVE SOLDER MACHINE. ALSO, USE THERMAL PROFILERS AS REQUIRED TO ENSURE SPECIFIED THERMAL REQUIREMENTS ARE MET FOR EACH ASSEMBLY.



Prepare all required elements to run first article. Run first article through wave solder process and perform a cursory inspection followed by the cleaning process. Provide first article to inspection for acceptability determination. If first article unacceptable, take corrective action to return process to required conditions or notify engineering so additional action may be taken as required. If acceptable prepare for production as in the following: Wave Soldering Operations Load pallets containing boards onto machine rails, and push them into position on conveyor rails to make contact with conveyor mechanism and engage it.

Observe the board traveling with the conveyor over the fluxer while adjusting specified foam height as needed. Observe proper flux action. Observe the board traveling on the conveyor, as it contacts and passes over the chip solder wave – when used, and as it contacts and passes over the planar wave.



Retrieve the soldered boards as they exit the machine on the conveyor.

Upon completion and cool down, inspect product quality in accordance with acceptance criteria as IPC-A-610C, Class III or specific criteria specified in the contract by POD, or other requirements. Perform corrective action as required. For wave soldering, this consists of informing engineering about defect and probable cause. Then, make required adjustments to assure production quality for all remaining assemblies. Move boards to cleaning process and perform cleaning operations.

Move boards to inspection area to determine quality, perform touch-up, and effect second operations. NOTES: ENGINEERING SHALL DETERMINE, AND MAKE REQUIRED ADJUSTMENTS IN ACCORDANCE WITH THESE PROCEDURES, AND WITH THE REQUIREMENTS OF THE PROCESS MATRIX. UTILIZATION SHALL BE MADE OF THE POD, MATERIAL, AND COMPONENT SPECIFICATIONS IN CONJUNCTION WITH POD, ASSEMBLY ACCEPTANCE SPECIFICATIONS, WHICH PRIMARILY CONCERN QUALITY OF ASSEMBLY ELEMENTS, AND FINAL ACCEPTANCE IN CLOSING THE QUALITY LOOP. SOLDERABILITY ACCEPTANCE SHALL BE CONSISTENT WHEN ALL REQUIRED ASSEMBLY ELEMENTS ARE OF THE SPECIFIED QUALITY. IF THIS IS NOT THE CASE DETERMINATION SHALL BE MADE OF INCONSISTENCIES, AND CORRECTIONS, AND ADJUSTMENTS SHALL BE MADE. ALL REQUIRED REWORK SHALL BE PERFORMED IN ACCORDANCE WITH IPC-7712. ALL REPAIR AND MODIFICATIONS SHALL BE PERFORMED IN ACCORDANCE WITH IPC-7721. ALL SOLDERING REQUIREMENTS SHALL CONFORM TO ANSI/J-STD-001B.



Process Summary For Wave Solder Process, Sub Processes, And Support Activities Place a stuffed PCB in the pallet fingers while ensuring all components are properly seated. Load the pallet onto the conveyor and push it into position to engage the drive mechanism. Observe the conveyor transporting the assembly over the foam fluxer where the underside of the board is coated with the specified flux while wetting the plated hole barrels through to the board's topside. Observe the conveyor continuing to transport the assembly over the pre-heater locations to evaporate the flux solvents, while activating the flux, and preconditioning the board to prevent thermal shock when the board reaches the wave. NOTE: IT IS AT THIS POINT THE SPECIFIED TOPSIDE BOARD TEMPERATURE IS MEASURED TO ASSURE PROCESS CONTROL AND DETERMINE THE EFFECTS OF PREHEATING. Observe the assembly being transported over the continuously circulating solder wave where solder joint formation occurs. NOTE: THIS IS WHEN AND WHERE THE MOLTEN SOLDER WETS THE BOARD'S BOTTOM SIDE, AND THROUGH HOLE BARRELS, BECAUSE OF WAVE PRESSURE, CAPILLARY ACTION, AND PROPER FLUX ACTIVATION. Observe the soldered assembly being transported gently off of the machine in preparation for operator inspection, touch up, and cleaning. Retrieve the soldered assembly as it is transported off the conveyor. At the end of each shift, shut down the process and machine in accordance with the procedures detailed in the POD/TDC Operations Manual. Move the assemblies to next operational area after process completion, and after signing appropriate logs/travelers.



8. 0 APPLICABLE DOCUMENTATION POD Statement Of Work and Detailed Processes POD, PPM-2045, Electrostatic Discharge Procedures POD, PPM-2015, Material And Assembly Handling Procedures POD, QIPM-4030, Audit Of Processes And Procedures POD, PPM-2050, Safety Procedures Planning Documentation Lot Control Documentation Maintenance Requirements, Specifications And Procedures Compressed Air Test Results POD, QPM-3020, Equipment Calibration Procedures Equipment Calibration Logs POD Quality Assurance Inspection/Test/Analysis Logs POD Operator Operations, And Process Logs QQ-S-571 Solder Test Results MIL-F-14256 Flux For Assembly Operations Test Results MIL-P-55110 Printed Wiring For Electronic Equipment MIL-P-28809 Printed Wiring Assemblies MIL-STD-2000 Part/component Mounting For High Quality/Reliability Soldered Electronic Assemblies ANSI/IPC-A-610 Acceptability Of Printed Board Assemblies IPC-600C Acceptability Of Printed Boards IPC-700B Repair Of Printed Boards And Assemblies IPC-T-50 Terms And Definitions MIL-STD-275 Printed Wiring For Electronic Equipment POD Pre-operational, Operational, And Post Operational Checklists POD/TDC Operation and Maintenance Procedure



9.0 MANUFACTURING OPERATIONS AUDIT CHECKLIST The following checklist shall be used before, during, and after wave soldering operations at POD. All pre-process (material handling, safety, ESD, etc.) requirements met PCB date codes not older than six weeks All components seated properly Component lead length does not exceed 0.10”. Pallet finger width properly adjusted Boards properly aligned for travel over wave Finger to component clearance as required Printed circuit boards in pallets with firm (not too tight) fit in “V” grooves. Machine and pre-heaters on Temperature Controller Adjustment as specified Specified Pre-heater Parameter Adjustment Conveyor on Pre-heater on Chip wave on Delta wave on Foam fluxer on Conveyor speed as specified Chip and Delta wave heights as specified Pallets containing boards loaded onto machine rails. Component seating properly effected. Pallets positioned on conveyor rails for start Proper flux action as it flows through holes to board top



Proper board contact over solder wave. Soldered boards retrieved as they exit the machine Product quality inspected in accordance with required acceptance criteria Corrective action performed as required Boards moved to cleaning process Boards moved to inspection area



12.7 HAND SOLDERING

MANUFACTURING OPERATIONS PROCEDURES

MOP-5050 HAND SOLDERING



1.0 PURPOSE AND SCOPE

The purpose of these procedures is to provide detailed instructions concerning hand soldering manufacturing operations at POD. This is done to ensure product quality consistently meeting or exceeding POD acceptance criteria. The scope of these procedures extends to all personnel responsible for ensuring effective hand soldering manufacturing operations at POD. 2.0 RESPONSIBILITY AND AUTHORITY The following responsibilities shall be fulfilled to ensure hand soldering manufacturing operations are properly effected to assure quality at POD: Manufacturing Engineer The Manufacturing Engineer is responsible and has authority to provide everything needed by manufacturing operations personnel to fulfill their responsibilities at POD. This includes procedures, training, equipment, tools, adequate and safe working conditions, ESD requirements, and all other required elements. Maintenance Technician The Maintenance Technician is responsible and has authority to ensure all operational elements (equipment, tools, etc.) are maintained and calibrated as specified. This assures all facilities, equipment, and tools are capable of being effectively and efficiently managed to assure product quality meeting specified requirements. Manufacturing Supervisor The Manufacturing Supervisor is responsible and has authority to provide proper direction to all manufacturing operations personnel at POD. This includes operational procedures, special instructions, schedules, product changes, drawings, and required materials and components. This also includes management directives, performance evaluations, and timely individual and team performance feedback. Manufacturing Operations Personnel Manufacturing Operations Personnel are responsible and have authority to assure manufacturing operations are carried out in an effective, efficient manner. They are responsible for performing all manufacturing operations in accordance with current procedures, checklists, and supervisory direction. All personnel are responsible for effecting management policies and directives to assure quality meeting or exceeding specified POD requirements. Quality Assurance Inspection Personnel Quality Assurance Inspection Personnel are responsible and have authority to determine product quality does or does not meet specified POD acceptance criteria. They also are responsible for providing appropriate feedback concerning product quality to management and manufacturing process managers so corrective or continued manufacturing action may be.



3.0 Background Effective, efficient hand solder process management is required to produce acceptable solder joints and assemblies. The hand solder process is made up of several sub processes. Each process and sub process is supported by individual activities. It is at the activity level most impact is made on quality. This is because trained process managers consistently fulfill their responsibilities to assure quality. At POD, one of the most important products is a quality solder joint made right on time, the first time, every time. Only trained individuals fulfilling their responsibilities can do this. To assure effective hand soldering process management, primary concern is focused on training and soldering proficiency. Additionally, all soldering irons shall be maintained and calibrated to ensure processes capable of producing specified quality. When everything is as specified, hand solder process management is effected. Then, process effects become apparent as solder joints meeting specified acceptance criteria. This is a highly interactive, interrelational, and manageable process. It has clearly defined cause and effect relationships (processes, sub processes, and activities managed instead of results as defect). All process management requirements are detailed in these procedures. This is done in conjunction with all other process considerations. Product acceptance is based on conformance to POD and appropriate industry acceptance specifications (IPC as an example). This is true of all components and materials comprising product. Soldering is a process in which two metal surfaces are metallurgically joined. A specified solder medium (metal filler with a melting point below 800 degrees F.) is used to “wet" and bond them. It is a process requiring both diffusion and intermetallic growth to effect an acceptable solder joint. This definition emphasizes the term "surfaces" (an object’s area having no depth) to clarify the distinction between soldering and welding, as an example. Welding is a process in which diffusion and intermetallic formations are effected to metallurgically join metals beyond their surfaces to a specified depth. This distinction also provides evidence that solder joining is a reversible process as it relies on heat to "undo" the solder joint. Welding requires complete joint destruction thus making repair and/or rework impossible at the component level, as an example. The term "wetting" requires a solid surface to be completely "coated" by a liquid. This means the liquid maintains intimate contact with all solder termination areas without resistance or the indication of dewetting ("pulling back” from the surfaces). In solder joining, the liquid is molten solder. What distinguishes "liquid" metal from some other liquid media is its change back to a solid when cooled below its melting point. When two metal surfaces are wetted, they may become joined upon solder medium solidification (often referred to as freezing). Again, this is done through effective process management. Another important term is eutectic. Eutectic is defined as a combination of two metals (forming an alloy) that melts at a lower temperature than either individual metal. Also, eutectic is defined as alloys



that change directly from liquid to solid, and the reverse, with no intermediate plastic states. Various solder types, their compositions, and melting points are found in ANSI/J-STD-006. Wave soldering and other machine dependent methods (reflow or vapor phase as examples) are not thought of as art forms. This often is the case with hand soldering. This is because hand soldering requires much more human intervention to effect acceptable joints. However, hand soldering uses the same objective principles as reflow or wave soldering. The primary difference is more personal "touch" applied during this process. Wave and reflow soldering processes rely less on personal process management as they are less "subjective.” This is because they are less sensitive to "feel" or touch. To effect (make) acceptable hand soldered joints, the process manager is trained to visualize the cause and effect relationships existing each time the process takes place. Time and temperature factors are primary elements required to assure effective process management. For wave and reflow soldering, this means assuring correct conveyor speed. When managed as specified, critical flux, board, and component temperature requirements are met. Considerations also are made concerning solder types, solder temperature, and solder wave/board contact time and area. Equally important are flux types and activity as well as where and how much is applied. This is manually done in hand soldering. For hand soldering, operator training and ability is most important. This means training and the ability to understand exactly what happens a hand soldering process manager effects an acceptable solder joint. As in wave and reflow soldering, hand soldering requires a knowledge of solder wetting, soldering iron contact time, flux activation, and an understanding of a board's thermal characteristics so as not to violate these factors. During this process, the affects all the above factors have on solder joints are seen (see solder joint figures below). In all soldering processes and activities, surfaces shall be solderable. This requires PCB's and components to be free of contamination. Such contamination may consist of oxidation or other conditions (grease, fingerprints, dirt, etc.) deleterious to solder joint quality and reliability. However, all surfaces are contaminated to some extent. Simply, solder termination areas shall be "wettable" and excess contamination is a barrier to this. When mild contamination is present, flux is capable of removing (cleaning) it from the surfaces to be soldered. When excessive, nothing can be done to make acceptable solder joints. This makes it critical for operational personnel to be supplied only with highly solderable components and boards. In the hand solder process, all other factors are equally critical. Flux shall be applied, so mild contamination is removed. Heating must raise the solder termination are temperature to a level capable of activating the flux so it works as specified. The solder temperature shall be capable of effecting an acceptable solder joint. If not high enough, colder solder joints or other unacceptable conditions shall be effected. If too hot, burnt joints, boards, and components are effected. The hand solder process is similar to wave and reflow soldering. The solder process mechanism used instead of hot air or wave soldering is a highly trained and skilled person manually using a soldering iron and wire solder, with fluxed contained therein, to effect acceptable solder joints with many of the same time, temperature, and cleanliness factors required.



In wave soldering, flux is foamed, sprayed, or otherwise coated (ultrasonic application as an example) on the board’s bottom surface. It travels up through the holes and on component leads to the board’s surface coating all solder termination areas. The board travels over pre-heaters to precondition it and its components to prevent thermal shock upon contacting the wave. Also, this sub-process activates the flux at a specified temperature required to clean mild contamination from solder termination areas. Then, the assembly is conveyed over a solder wave where the solder joint is effected. The figure below is a graphic representation of a typical wave solder profile.

In hand soldering operations, no such profiles formally exist. Such "profiles" are in the minds of the hand soldering process managers and depend on their training and skills. They must use "personal" techniques to ensure high quality solder joints are effected - without benefit of automated fluxing or thermal profiles. It becomes clear that the hand solder process and its sub-processes are highly dependent on individually performed activities. These consist of making decisions concerning all the foregoing requirements as the various settings indicated. For hand solder process managers to improve their "skills," they shall become proficient hand solder process managers. This provides a more intimate contact and visualization of what makes an acceptable solder joint. For hand soldering people, they shall be made aware of factors and elements required to effect acceptable solder joints using wave and reflow soldering processes. In wave soldering, everything must come together under effectively managed conditions to create solder joints equally reliable and acceptable as those effected during other soldering operations. These procedures detail all requirements to assure effective, efficient hand solder process management at POD.



Solder Connection (Joint) Acceptability Acceptable solder connections often are bright and shiny (not always necessary) while clearly revealing solder termination area surface contours. They feather completely out to the joint's edge. They are free of any residue or foreign matter. The joined surfaces are completely wetted showing no signs of being "cold.” They exhibit no evidence of dewetting, disturbance, or other unacceptable attributes. Based on the foregoing requirements, the first two figures show preferred and minimally acceptable solder joints while the third shows one that is unacceptable. POD requires solder joint quality conformance to IPC-A-610C, Class III requirements.

Solder joint reliability is another issue requiring careful determination. Though a solder joint exhibits visible quality, it may not have sufficient integrity, composition, or formation to ensure long term reliability. The reasons for this are many and this discussion is best left for more advanced study. However, visible quality is the primary starting point especially concerning its correlation to process management and capabilities. Root cause (good or bad process management and capabilities) and effect (solder joint quality) relationships are first established using visual quality verification methods. If good process management is effected, using proven process capabilities, solder joint quality shall be acceptable. If not, they shall not. Effecting An Acceptable Solder Joint Some of the most important requirements for effective wave soldering process management are clean solder surfaces, calibrated conveyor speeds, and controlled and verified temperature profiles. Also required are specified solder temperatures, specified solders and fluxes, calibrated wave contact areas and times, specified preheat temperatures and times, and specified top side board temperatures. All these requirements shall be met to ensure effective process management. Other equally important requirements are well trained operators, clearly defined procedures, and the attendant tools to promote process management. Solder Process Management The most important factor needed to effect process management is proper training. Each wave solder process manager shall be trained, evaluated, qualified, certified, and empowered to accept and fulfill responsibilities for ensuring solder process management is possible and effected. This shall be done to ensure acceptable solder joint quality. Each wave solder process manager must understand the following:



Solder Termination Area Conditions Solder termination area (surfaces as PCB pads or component leads) shall be free of excessive contamination. Printed circuit board pads and/or component leads having excessive contamination (oxidation, grease, dirt, etc.) are not capable of being solder "wetted." It is not possible under any conditions to effect acceptable solder joints when excessive contaminates are present. No amount of heat, flux, or time shall help. Each solder process manager must determine that surfaces to be joined are clean enough to be wetted and soldered so specified solder joint quality is assured and effected. If this determination cannot be made, the soldering process shall be stopped until corrective action is taken to return the process to a manageable state. Solder Termination Area Condition Examples To ensure solder process managers have solderable surfaces, only qualified suppliers, managing qualified processes, shall be selected to provide required PCB and component solder termination areas. This means that only "clean," solderable PCB's and components shall be purchased and introduced to soldering operations. The first figure is an example of a contaminated J-lead on a PLCC surface mount component. The second figure shows the results of a test using scanning electron microscopy (SEM) with energy disperssive X-Ray (EDX). It is a graphic clearly indicating excessive tin oxide contamination (18:1 oxide to surface metal ratio) on the J-Lead’s surface. This condition absolutely prevents solder wetting under any conditions. The third figure shows completely non-wetted SMT pads. They also prevent solder wetting under any conditions. The fourth figure shows effect as an unacceptable PLCC solder joint caused by its excessively oxidized J-Lead. However, the PCB surface (not having the condition shown in figure 12) soldered well as it exhibited complete wetting.

NOTE: AGAIN, THE FIRST FIGURE SHOWS J-LEAD CONTAMINATION AS OXIDATION (18:1 OXIDE TO SURFACE METAL RATIO). THIS CONDITION COULD EXIST ON THROUGH HOLE COMPONENTS, CHIP DEVICES, AND LEADED OR LEADLESS SMD’S. LOOK FOR THIS CONDITION AND THOSE ON PCB PADS. DO NOT ATTEMPT TO SOLDER UNDER THESE CONDITIONS. Wave And Hand Solder Thermal Management The wave solder process shall be managed using verified temperature profiles, as gradients, capable of first providing increasing heat to “ramp” the board temperature gradually. This is done so it is not “shocked.” because of the thermal change (delta T) when leaving the preheat zone and contacting the much higher temperature solder wave. This prevents damage to boards or components and promotes the specified top side board temperature to assure flux activation. Then, the process shall be managed to assure the solder wave is at the specified temperature to effect acceptable solder



joints. The time required is not less than 2 nor more than 4 seconds (THIS IS A KEY FACTOR REQUIRED FOR SUCCESSFUL HAND SOLDERING ACTIVITIES EFFECTING ACCEPTABLE SOLDER JOINTS) within a specified contact area (contact time is a function of contact area and conveyor speed). Board and/or component overheating is prevented when times are correct. If overheating does occur, primary damage is done to the PCB as pad lifting (or rotation) from the board surface as in the first three figures. PCB damage also may be done as the cracked hole in the fourth figure. Component damage (cracking as an example) also may be effected due to excessive heat or thermal shock.


Solder Termination Area Surface Coating Types Solder termination area surface coating types often are electroplated or hot air solder leveled (HASL) tin/lead, or electrolessly deposited tin. Newer coatings are electroless gold, silver, palladium, “white” tin, and organics. They have been developed to overcome problems associated with the above types. Problems consist of non-wetted, uneven, and/or oxidized surfaces often with excessive intermetallic formations. All these plating or coating types are compatible with the solder medium to the extent deposited amounts do not “contaminate” the solder medium and joint. Contamination would be in excess of that specified in ANSI/J-STD-001B (Figure 5-1) during soldering operations. If the surface is coated or plated with other metals (electroplated or electrolessly deposited gold in excessive amounts, as an example), they shall be removed to assure solder compatibility or the solder medium shall be changed. Acceptable solder joints often have acceptable intermetallic growth effected as part of the joining process although some unacceptable joints are formed when wrong or excessive intermetallics form. Gold is an example of a metal (in excessive amounts) that is not compatible with tin/lead eutectic soldering. This metal causes embrittlement and subsequent solder joint failures over time - under mechanically induced stresses. NOTE: EXCESSIVE AMOUNTS MEANS GOLD, OR OTHER COATING, CONTAMINATING SOLDER JOINTS BEYOND THAT WHICH IS ACCEPTABLE TO ENSURE INITIAL QUALITY AND



LONG TERM RELIABILITY. REFERENCE TABLE 5-1, ON PAGE 5, IN ANSI/J-STD-001B CONCERNING SOLDER LIMITS FOR TIN/LEAD ALLOYS. Flux Types Flux is composed of acid or caustic chemicals (high or low pH components [over 7 = alkaline, under 7 = acidic]). It is used to clean contaminates (mild oxidation, grease, or other residues) from solder termination areas. Fluxes become fluid at lower temperatures than solder. This means that when heated, flux flows onto solder termination areas first. As it does, it cleans and protects (when properly activated) the heated metal surfaces until the solder becomes molten and flows onto and wets solder termination areas. Then, the solder solidifies (“freezes”) upon cooling to make the solder connection. Flux Requirements Flux is vital to most soldering processes. This is true though fluxless or no clean solutions are being sought as part of an ongoing effort to reduce environmental contamination produced during soldering and cleaning operations. The two flux types generally used are rosin flux or aqueous (water soluble acid) flux. After soldering operations, rosin flux shall be cleaned with isopropyl alcohol (one of its components). Aqueous flux shall be cleaned with water (a component in its binder). This is required because of the deleterious affects flux residues have when left on board, component, and soldered surfaces. They continue to act as a removal or cleaning mechanism. This causes damage and solder joint failures. Some flux residues are conductive providing paths for unwanted current flow capable of causing electrical shorts between surface conductors. Newer “no-clean” fluxes are composed of chemicals capable of removing contamination while needing little or no cleaning after reflow soldering. Their residue remains on or near the solder connection and provides none of the concerns stated in the above paragraph. However, rework or repair operation results often require localized cleaning to remove the then visibly exposed residue. NOTE: THE ONLY REASON METAL SURFACES ARE COVERED, COATED, OR PLATED IS TO PROTECT THEM FROM OXIDATION OR OTHER CONTAMINATION UNTIL THE SOLDER JOINT IS MADE. COPPER SURFACES (COMPRISING MOST PRINTED CIRCUIT CONDUCTORS) OXIDIZE ALMOST IMMEDIATELY UPON EXPOSURE TO AIR. SCRATCH A PENNY’S SURFACE AND SEE HOW LITTLE TIME IT TAKES FOR THE SHINY SCRATCHED AREA TO TURN DULL BECAUSE OF OXIDATION. Thermal Mass Considerations A single pad on a single sided circuit board involves relatively little thermal mass. A double-sided board with a plated through hole can double that mass. Multilayer boards (MLB’s), increased component leads, larger device types, different device types and MLB materials, terminals, connectors, and connecting wires further increase thermal mass. This means that temperature rise shall not be as rapid or as much when using a thermal profile designed for a board with less thermal mass. This means each board type and its unique thermal mass shall have a correspondingly unique thermal profile. There may be specific or unique profiles for single and simple double sided boards, for higher density four and simple six layer types, and those for eight to ten layers, and so on.



Experiments (trials) shall be performed to determine which profile works for which board type. This is done using thermocouples mounted on PCB’s, “MOLES,” or other thermal profilometers that are run through the wave solder process. These setups provide precise thermal information at various stages in the soldering process along the conveyor’s path. Clear temperature readings are printed out, viewed, and/or graphed to make determinations concerning more effective thermal profile considerations so processes and solder joint quality is continuously improved. During experimentation, each board type is inspected and effects (acceptable or unacceptable solder joint quality) are correlated to cause. Cause is how well a process is managed relative to machine and required sub process settings made in accordance with specifications and procedures. When effects are positive, cause is recognized as effective process management and processes may be effectively managed during production. When negative, experiments continue until positive effects are found and process settings are recorded and made available for use in production. Ongoing pre process audits and sample inspections promote continuous process improvement as part of statistical process control (SPC). As previously discussed, an important factor concerning thermal profile management is a solder termination area's surface condition. In addition to what was said earlier, oxides particularly act as thermal barriers to heat transfer. Even if a thermal profile provides the right properties for that board type, excessive oxidation always prevents enough heat reaching the solder termination areas to melt solder. Even if a specified flux type is used to clean mildly contaminated areas, excessive oxidation is a barrier to all solder process management efforts. Solder Joint Formation Time Requirements Time is a major factor affecting acceptable solder joint quality and preventing damage to boards, components, or finished assemblies. For wave soldering process management to be effective, the specified heat shall not be applied to solder termination areas for more that 4 seconds. Beyond this time, the board may be damaged (as in previous examples). If more time is required to wet solder termination areas, something is wrong. There may be too much thermal mass, the wrong thermal profile, too little heat input, or excessive oxidation. Corrective action shall be taken. The figure below shows a cross section of the perfect J-Lead solder joint effected in well managed solder processes.

NOTE: ACCEPTABLE SOLDER JOINTS ARE NOT AN ART FORM. THEY ARE NOT EFFECTED BY ARTISTS. ACCEPTABLE SOLDER JOINTS ARE OBJECTIVE EVIDENCE OF PROCESS MANAGERS USING THE RIGHT TOOLS WITH PROPER INSTRUCTIONS FOR THEIR USE TO ASSURE SPECIFIED QUALITY.



Unacceptable Solder Joints And Other Conditions As Cause For Rejection.






Disturbed Solder A disturbed solder joint has a crystalline appearance may be fractured or separated at the solder termination area junction. Overheated Solder An overheated solder connection appears dull and crystallized. Areas around overheated solder joints often appear discolored or burnt.



Contaminated Solder A contaminated solder joint is unacceptable as it contains foreign matter such as insulation or other debris, etc. Solder Bridging Solder bridging is a web or film of solder between adjacent vertical terminations (formed over the insulating PCB material). If extensive, it can be a web of solder between adjacent conductors. Some causes of bridging can be low solder temperature, insufficient flux, poor flux activation, or the presence of impurities in the molten solder. Other factors may involve the wetting angle, and the angle at which the board approaches and contacts the wave.

Icicling Icicling is solder extending out perpendicular from the PCB bottom side usually at the component leads. It is caused by a drainage restriction of molten solder from the board, lower than specified solder temperature, or faster than specified conveyor speed. Other causes may be wrong PCB angle over the wave, shorter than specified wave contact time, too little wave/board contact area, inadequate flux activity, and/or unacceptable solder purity.



Blowholes And Voids Blowholes are voids having exited, or outgassed from within PCB plated holes or solder joints. Voids are small spherical cavities within the PCB plated hole wall in the first figure, or under/in a solder joint shown in the second figure. Causes of blowholes are excessive flux, flux residue left inside a solder joint, insufficient evaporation of the flux solvent before soldering, or moisture or organic plating residues having been entrapped in plated-through holes that “outgas” through the hole wall plating. Blowholes can be caused by PCB's not meeting supplier acceptance criteria such as minimum copper plating thickness. They and voids may also be caused by flux remaining in solder joints fighting contamination such as excessive oxidation.




Correction And Prevention Of Unacceptable Solder Connections. Action to correct and prevent unacceptable solder connections shall be taken by wave solder process managers. The action taken depends on the frequency and type of unacceptable connections found. When excessive or major defects are found, supervisors shall be notified so required correction can be made. When minor or minimal defects are found, the process managers shall correct the process to assure quality meeting specified requirements Repair, Modification, And Rework Repair, modification, and rework of unacceptable solder joints and/or assemblies shall be done using hand soldering with flux cored solder and temperature regulated soldering irons. Cleaning shall be done on the board after touch-up using the proper cleaning solution depending on the flux type used. NOTE: ALL TOUCH UP OPERATIONS AND ACTIVITIES SHALL BE PERFORMED IN ACCORDANCE WITH POD, POD-5055, REPAIR, MODIFICATION, AND REWORK PROCEDURES.



4.0 DEFINITIONS The following definitions are provided for all process managers to better visualize each process for which they are responsible: Operations Operations are defined as a series of processes required to provide product or services meeting certain requirements. Usually these requirements are based on customer needs, desires, or demands. POD employs many operations as management, engineering, marketing, sales, manufacturing, accounting, quality assurance, and others to ensure all its customers receive product meeting their requirements. Process A process is defined as a method or procedure. A process may be a single method or procedure, or may be made up of sub processes and activities. In a manufacturing operation, a process is employed to turn acceptable raw materials, components, and designs into acceptable product using various tool and equipment types. Sub Process A sub process may be part of a process. In the wave solder process, several sub processes are involved to effect acceptable solder joints. They are discussed in the foregoing section. Activity Processes and sub processes most often rely on individuals or teams performing activities to make product. In manufacturing, such activities may consist of moving or handling materials and components, changing machine or tool settings, turning equipment on or off, etc.. It is at the activity level most variability is introduced to manufacturing operations effecting varying degrees of quality. For this reason, it is vital process managers be well trained to fulfill their responsibilities by following procedures concerning specific process management requirements. Process Management Process management is the act of preventing defect by fulfilling individual responsibilities instead of reacting to it as the result of not fulfilling them. When process instead of results management is practiced, product quality is consistently acceptable. Process management differs from process control in that control means only consistent quality is produced. In a controlled instead of managed environment, that quality may be consistently good or bad. Process Capability Process capability is the measure of how well a process is being managed. Usually, a processes’ capability is expressed in statistical terms as a capability profile or Cpk. When a process is managed effectively, its Cpk shows how well while often providing an indication of what is needed to continuously improve. Continuous process improvement assures continuous quality improvement and that is what process managers focus on most. Solder Solder is defined as a metallic medium (as an alloy) that melts at temperatures below 800 degrees Fahrenheit to join metal surfaces having much higher melting points. Solder may be in different forms. It may be bar solder as used in wave solder machines, or it may be wire with a flux core used



to perform hand soldering. It may also be in the form of a paste composed of solder balls suspended in a binder with a flux component. None of these forms changes its definition. Solder Paste Solder paste is a metallic medium (as an alloy) formed into solder balls (ranging in diameter from about 4 to 40 microns). The balls are suspended in a binder (composed of flux and other chemicals). Solder paste, as all solder media, melts at temperatures below 800 degrees Fahrenheit to join metal surfaces having much higher melting points. The more spherical are the solder balls, the less surface area they have. This reduces their oxidation amount and rate at which they oxidize. This is important because more oxidation means less solderability. The solder paste composition has a high viscosity of approximately 900,000 centipoise. Higher viscosity aids in preventing solder paste spread on SMT pads. When too high, printing problems may occur relative to dispensing paste through stencil openings. Solder paste is applied to solder termination areas using a printing machine, squeegees, and stencils with openings of specified sizes, shapes, and aspect ratios. All this is done to assure a precise amount is printed where and in the condition required to effect acceptable solder joints. Wire/Core Solder Wire/Core solder is a solder medium composed of a eutectic alloy. Usually it is 60/40 tin-lead formed into a wire with a hollow flux filled core. Wire/Core solder is specified in varying diameters (typically from about .012” to .060”) for specific hand soldering activities. It provides a mechanism to apply flux from its core to the solder termination areas before solder melts, flows, and wets them to effect an acceptable solder joint. Flux Flux is defined as a chemically and physically active compound that when heated to specified temperatures it promotes base metal surface wetting by molten solder. It does this by removing minor surface oxidation, surface films, or other contamination. It then protects the surfaces from reoxidation during the soldering process. Various flux types (see POD Hand Soldering and Final Assembly Course) include: Rosin Rosin flux primarily is composed of natural resin extracted from oleoresin of pine trees and refined. Typically, these fluxes are made up of 60% solvent and 40% solids. Rosin flux (Type R) is an organic material distilled from pine tree sap. The active ingredients in this flux type primarily consist of abietic and pimaric acids. After rosin is extracted from pine trees, it is superficially processed to remove undesirable impurities while neutralizing the acid residues remaining from the extraction process. The purified material is called water-white rosin. It is used to manufacture rosin based flux. Some manufacturers hoping to overcome difficulties associated with obtaining and processing natural rosin, chemically synthesize substitute materials. These materials are called “resins.”



Pure rosin is a solid at room temperature and is chemically inactive while being insulative. Rosin melts at about 72 degrees C. (160 degrees F.) and the organic acids become active at around 108 degrees C. (225 degrees F.). This flux type’s peak capability is effected around 262 degrees C. (500 degrees F.). This is the temperature rosin begins decomposing into reducing gases. At temperatures above 346 degrees C. (650 degrees F.), the flux becomes inactive and polymerizes. This causes residue removal difficulties from board and solder joint surfaces. When solder surfaces require a more active flux, chemical compounds called activators are added to the rosin. The most commonly known rosin flux containing activators is called rosin, mildly activated or RMA. Activators are thermally reactive compounds (such as amine hydrochlorides) that break down at elevated temperatures. At these temperatures, hydrochloric acid is released to dissolve the surface oxides, tarnishes, and other contaminates. Mildly activated rosin flux (RMA) may contain a variety of activators in amounts less than 1%. Limits are placed on their electrical and chemical properties before and after soldering Rosin activated flux (RA) typically contains 1% - 5% activators. RA flux is used in applications when RMA is not strong enough. For military purposes, their use usually is limited to component tinning of sealed devices and solid wire. When warm, these fluxes can conduct electricity and can leave residues that can cause corrosion or shorting path formation between conductors. Organic Acid Flux Organic acid (OA) fluxes are types having active ingredients such as organic acids, organic hydrohalides, amines, and amides. These fluxes are water soluble since they contain no rosin. Good cleaning is critical with these flux types since the salt residues left by them are corrosive and conductive. OA fluxes also are referred to as water soluble fluxes (WSF’s). These fluxes are more aggressive. They generally are classified in J-STD-004 as types M or H. OA fluxes have active ingredients such as organic acids, organic hydrohalides, amines, and amides. All are corrosive activator materials. These fluxes are water soluble or water washable since they contain no rosin, or any low rosin or resin levels. Good cleaning is critical with these flux types as their residues are corrosive and electrically conductive. Resin Resin flux primarily is composed of natural resins other than rosin types and/or synthetic resins. Organic Organic elements are based on carbon atom structures. All life forms are organic. Organic fluxes are primarily composed of organic materials other than rosin or resin. Inorganic Inorganic elements are based on other than carbon atom structures. Inorganic fluxes are solutions composed of inorganic acids and/or salts.



LR, or No-Clean Fluxes Low residue (LR) fluxes usually have lower solids content (less than 5%) than traditional high-solids rosin fluxes. LR fluxes also are referred to as no-clean or “leave on” fluxes. Their residues are not intended for removal from assemblies so cleaning is not required. Their primary activator materials are weak organic acids (adipic or succinic acid). These materials are benign on a board surface and act as electrical insulators. LR fluxes may be higher solvent borne (usually isopropanol) or water borne in the case of volatile organic compound (VOC) free no clean fluxes. Low residue fluxes are not no-residue fluxes. Although benign, visible residues do remain on the assembly. For this reason, customers may require them to be cleaned. This often is requested for cosmetic rather than functionality reasons. If the flux residues have a significant thickness, they could interfere with electrical testing as “bed of nails” types. However, a different probe point, greater spring strength, or rotating probes often solve this problem. Low residue fluxes also might build up on test pins over time. This requires preventive maintenance as regular cleaning. Halides Halides are organic salts added to flux as activators. Halides are corrosive. Fluxing Activities And Classes A liquid flows freely over a surface only if in doing so the total free energy of the system is reduced. In soldering, the free energy of a clean surface is higher than a dirty one. Therefore, it is more likely to promote solder flow. With respect to this, fluxing activities are: Chemical Chemical fluxing activity reduces the oxides from the surface to be soldered and protects this surface from oxidation by covering it. Thermal Thermal fluxing activity assists transferring heat from the heat source to the material being soldered. Physical Physical activities allow the transportation of oxides and other reaction products away from the material surfaces being soldered. In consideration of these three fluxing activities, the following shall be noted: 1) There are two basic ways fluxes eliminate oxidation. They dissolve it into "solution" or they reduce it back to metal. If reduced, it clearly "disappears" and should not be re-deposited as an oxide (to be determined through supplier qualification). Some old flux types "dissolved" oxides by reacting a fatty acid (rosin) with the metal in the oxide. Then, it was “pushed aside” by solder flow and wetting action. In which mode a flux works, clearly depends on which flux is used. Some fluxes use both modes. 2) ANSI/J-STD-004 differentiates flux activities into three classes. They are Low (type L), Medium (type M), and High (type H). ANSI/J-STD-004 further classifies fluxes as to whether or not they contain halides. For example, a type L0 flux is a low activity, halide free flux. An L1 flux is a low activity flux containing some halide amount.



3) Numbers of industry and consortia studies have been conducted concerning low residue flux reliability. Type L fluxes have been shown relatively benign concerning corrosion and electrolytic failure mechanisms. For this reason, Section 4.2 allows the manufacturer to use a type L flux (L0 or L1) without going through the testing outlined in Appendix D. If the manufacturer chooses to use a more aggressive flux (types M and/or H), the potential exists for corrosive flux residues. If so, the manufacturer must go through the Appendix D testing to demonstrate adequate removal of potentially harmful flux residues. 4) It is highly recommended that the manufacturer not use a type H flux on printed wiring assemblies in any way – at any time. It is recommended that, if used at all, a type H flux be limited to component lead tinning. Even then, this may be done only when it can be demonstrated that the highly aggressive flux residues can be thoroughly removed. Electrochemical Migration Electrochemical migration is defined as the movement of metals across an intervening space between a cathode and anode. This movement is induced by the difference in electrical potential in the presence of fluid producing a micro-film of water on a substrate’s surface. Soldering Soldering is a process in which two metal surfaces are metallurgically joined, using a specified solder medium (metal filler with a melting point below 800 degrees F.). The process is effected by "wetting" the surfaces to be joined requiring diffusion and internetallic growth. The effect of this process is called a solder joint. Intermetallics In light of the previous definition (soldering), intermetallics always are formed when heated solder surfaces are brought into contact with solder melted upon them. As soldering requires diffusion and internetallic growth, each occurs as part of the soldering process. This is immediately so and time effects intermetallic growth as a continuous process. Intermetallic compounds have much different physical and mechanical properties than the metals comprising them. Typically, intermetallics are very brittle and have poor electrical conductivity. Also, when exposed to air, they oxidize very rapidly. Therefore, excessive intermetallics, formed either during the soldering process or over time, cause unreliable solder joints capable of failing under stressful conditions as thermal, or mechanical shock and/or vibration. Oxidation (oxide, oxidize) Oxidation is the act of burning. When oxygen is present in an atmosphere, it “burns” or oxidizes all material with which it comes in contact. When this happens, oxides are formed that resist thermal input as well as solder wetting. Some materials resist oxidation better than others. Most solder termination areas are copper (oxidizes very rapidly) covered with some protective coating to prevent further oxidation than that which was present before the coating’s application. In an inert atmosphere, oxidation is prevented (there is no oxygen or oxidizing agent). This means that if all processes relating to the use of materials capable of rapid oxidation were performed in an inert atmosphere, they would be more capable of solder wetting.



Inert Atmosphere Inert means inactive or static. An inert atmosphere is one without activity such as that containing oxygen which is one component in our life sustaining atmosphere surrounding earth. Nitrogen is an inert gas. When totally comprising an atmosphere (as inside a soldering machine), activity is eliminated concerning oxidation thereby providing protection to solder termination areas. This promotes or improves thermal input and solder wetting (solderability). This assures a higher rate of higher quality solder joints. Surface Surface is defined as an object’s area having no depth. Welding It shall be noted there is a distinction between soldering and welding. Welding is defined as a process in which diffusion and intermetallic formations are effected to metallurgically join metals beyond their surfaces to a specified depth. The welding process is effected at temperatures well above 800 degrees F.. This distinction also provides evidence that solder joining is a reversible process as it relies on heat to "undo" the solder joint. Welding requires complete joint destruction thus making repair and/or rework impossible at the component level, as an example. Solderability Solderability is defined as the ease with which solder adheres to a basis metal surface such as a component lead, PCB solder termination pad, or PCB conductor hole pad and wall. The presence of contamination (as oxides or residues) interferes with solderability. Acceptable solderability and solder joint formation, requires good solder wetting and a small contact angle. Wetting Wetting is defined as the formation of a relatively uniform, smooth, unbroken, and adherent solder film to a basis metal. Wetting requires a solid surface to be completely "coated" by a liquid. This means the liquid maintains intimate contact with all solder termination areas without resistance or any indication of "pulling" back from their surfaces. In solder joining, the liquid is molten solder. What distinguishes "liquid" metal from some other liquid media is its change back to a solid when cooled below its melting point. When two metal surfaces are wetted, they may become joined upon solder medium solidification (often referred to as freezing). This only is done under effectively process managed conditions. Contact Angle Contact angle is defined as the angle at which a solder fillet meets the basis metal. A small contact angle indicates good wetting whereas a large angle indicates poor wetting. Eutectic Eutectic is defined as a combination of two metals (forming an alloy) that melts at a lower temperature than either as individual metals. Also, eutectic is defined as alloys that change directly from liquid to solid, and the reverse, with no intermediate plastic states. Various solder types and their compositions and melting points are found in ANSI/J-STD-006.



Solder Joint A solder joint is effected in the soldering process. Under effectively managed conditions, solder joints exhibit acceptable attributes as smooth, usually shiny, clearly defined, well feathered, completely wetted metallic bonds between two metal surfaces. Aqueous Cleaning Aqueous cleaning is defined as process using water as the primary cleaning agent or solvent. It shall be noted that water is termed the “universal” solvent because it is capable of dissolving all material types to some extent over time. This type cleaning can mean using pure water, with detergent additives, or with a saponifier solution. Aqueous cleaning is done most often with water soluble fluxes, but can be used on rosin and low residue fluxes as well as with the appropriate additives. Aqueous cleaning generally is a multi-stage operation with most cleaning effected in the first wash stages with the dirtiest water while rinsing is done in later stages using the cleanest water. Manual Cleaning Manual cleaning is a process used to spot clean flux residues from assembly surfaces. It includes using a bristle brush with isopropyl alcohol as the cleaning agent or solvent. This process is not recommended for final cleaning. Saponification Saponification is defined as a cleaning process using a biodegradable rosin cleaner. In the process, the rosin is changed chemically to become water soluble. Wave Soldering Wave soldering requires intimate contact be made between molten solder and the assembly’s bottom side solder termination areas to effect solder joints. Conversely, reflow soldering is accomplished in a machine using air or an inert gas (nitrogen) as the solder reflow mechanism. Wave soldering requires attention to conveyor speed, flux action and activation, preheat and topside board temperatures, solder pot temperatures, wave contact times and areas, and solder purity. In reflow soldering, a hot gas envelopes the entire printed circuit assembly. In doing so, it activates the flux then melts the solder medium having been “printed” on the board’s surface onto which components have been attached. Upon melting, solder wets all termination areas. Upon cooling, the solder joint is made. In wave soldering, wave contact with solder termination areas wets them as wave pressure, and wetting and capillary action provides the mechanism for the solder to flow up holes and component leads to wet them to the board’s surface. The entire reflow process is completed in stages corresponding to increasing temperatures in several zones until the highest temperature is reached in what is called the liquidous zone. It is in this zone the solder melts (liquefies) and wets all solder termination areas. Wave soldering requires similar stages to ramp boards and components up to temperatures required to activate flux, and prevent thermal shock upon wave contact. Quality Quality is defined as conformance to clearly specified, understood, and accepted customer contract requirements.



Repair Repair is defined as the process required to restore the functional capability and/or performance characteristics of a defective article. This is done in a manner that precludes compliance of the article with applicable drawings or specifications. Modification Modification is defined as the process required to revise the functional capability or performance characteristics of a product to satisfy new acceptance criteria. Modifications usually are required to incorporate design changes that can be controlled by drawings, change orders, etc.. Modifications only shall be performed when specifically authorized and described in detail on controlled documentation. Rework Rework is defined as the act of reprocessing non-conforming or defective articles. This is done using original or equivalent processing to assure full conformance of the article with applicable drawings or specifications. Rework is doing something over that should have been done right the first time. Other Other terms are defined in IPC-T-50 and in specific guidelines, standards, and specifications indicated in Section 8. herein.



5.0 REQUIRED EQUIPMENT/TOOLS Specified Hand Soldering Irons, Tips, Handles, And Controllers Solder Iron Tip Temperature Thermocouples Solder Iron Tip Cleaning Sponges Specified Wire Solder With Specified Flux



6.0 OPERATIONAL AND QUALITY SYSTEM REQUIREMENTS Operational and quality system requirements are steps required to maintain process management effectiveness to assure product quality meeting specified requirements. Traveler and drawings as required Components as indicated on assembly drawing and bills of material Safety, handling, and ESD as required Solder Iron Tip Cleaning Sponge Cleaned and Wetted Regularly Solder as specified Flux As Specified Read, understand, and use solder audit checklist before each run, lot, or different board type



7.0 HAND SOLDERING OPERATIONS These procedures are used to ensure effective, efficient process management concerning hand soldering operations at POD. POD uses specified and approved soldering tools to effect acceptable solder joints on printed circuit assemblies. This includes both through hole and surface mount devices. Ensure proper handling and ESD protection. The first figure below indicates ESD protection required symbol. The second figure indicates ESD handling requirements shall be effected. The third figure shows the preferred method for handling Class III PCB assemblies. The fourth figure shows an acceptable handling method. In all cases it is required that ESD protection be provided all assemblies and all boards be handled so no damage, contamination, or other defect causing possibilities exist.



Select and ensure the soldering iron tip is as specified for the operation to be performed while securely setting it within the handle’s receptacle. Set the soldering iron tip temperature for the specified setting to perform the required soldering operation. Ensure soldering iron tip is properly tinned with the specified solder. NOTE: SOLDERING IRON TIPS ARE MADE FROM COPPER WIRE PLATED WITH .001" OF IRON SO AS TO MINIMIZE SOLDER JOINT CONTAMINATION. IF TIPS REVEAL COPPER, THEY MUST BE REPLACED.

Ensure soldering iron tip cleaning sponge clean and damp throughout all soldering operations. The first figure below shows a sponge in an unacceptable condition as worn and dirty. The second figure below shows a clean, damp sponge in good condition, and one not yet dampened for tip cleaning.



Lightly wipe tip on damp sponge and ensure soldering iron tip properly cleaned before soldering operations. DO NOT LEAVE TIPS ON SPONGE TOO LONG AS THERMAL DEGRADATION OCCURS.

Apply the soldering iron tip to the maximum mass points of the solder termination areas (component and board surfaces simultaneously) while applying specified wire solder to the maximum contact solder termination area (usually the PCB pad) to be soldered. This is shown in the following figures. Observe the solder flowing onto and wetting the PCB pad and component termination areas.

NOTE: NEVER APPLY SOLDER TO THE SOLDERING IRON TIP TO MAKE A SOLDER JOINT.



Remove the soldering iron tip from the solder termination areas and observe the solder joint forming as it solidifies (freezes). Do not apply the soldering iron tip to the solder termination areas longer than three seconds. Pad lifting or destruction shall be effected if this time is exceeded as shown in the first two figures below.

Ensure the solder joint meets all POD acceptance criteria as an IPC Class III solder joint with smooth, shiny (preferably), well feathered, totally wetted features as shown in the last two figures above, and clearly visible solder termination area outlines and contours. If not, notify supervisor. NOTE: AGAIN, SOLDER SHALL NOT BE MELTED AGAINST THE IRON TIP AND ALLOWED TO FLOW ONTO THE WORK. SOLDER APPLIED TO A CLEANED, FLUXED, AND PROPERLY HEATED SURFACE shall MELT AND FLOW WITHOUT DIRECT CONTACT WITH THE HEAT SOURCE, AND shall PROVIDE A SMOOTH, EVEN SURFACE FILLETING OUT TO A DESIRABLE THIN EDGE. Immediately after effecting each solder joint, gently wipe the soldering iron tip on the clean, damp sponge. Then, re-tin the tip surface and wipe it again immediately before restarting soldering operations. Replace the soldering iron in its holder being sure not to allow the tip to rest or be used in a way causing it stress. While ensuring the tip is well tinned, turn off the controller and allow the iron to cool. Inspect all solder joints and perform touch-up as required – in accordance with POD, POD-5145, Touch-up Procedures.



NOTES: ALL REQUIRED REWORK SHALL BE PERFORMED IN ACCORDANCE WITH IPC-7712. ALL REPAIR AND MODIFICATIONS SHALL BE PERFORMED IN ACCORDANCE WITH IPC-7721. ALL SOLDERING REQUIREMENTS SHALL CONFORM WITH ANSI/J-STD-001B. Replace soldering iron tips, controllers, and other required tools in accordance with POD Operation and Maintenance Procedures.



8.0 APPLICABLE DOCUMENTATION POD Statement Of Work and Detailed Processes POD, PPM-2045, Electrostatic Discharge Procedures POD, PPM-2015, Material And Assembly Handling Procedures POD, QIPM-4030, Audit Of Processes And Procedures POD, PPM-2050, Safety Procedures Planning Documentation Lot Control Documentation Maintenance Requirements, Specifications And Procedures Compressed Air Test Results POD, QPM-3020, Equipment Calibration Procedures Equipment Calibration Logs POD Quality Assurance Inspection/Test/Analysis Logs POD Operator Operations, And Process Logs QQ-S-571 Solder Test Results MIL-F-14256 Flux For Assembly Operations Test Results MIL-P-55110 Printed Wiring For Electronic Equipment MIL-P-28809 Printed Wiring Assemblies POD, POD-5135, Hand Soldering Procedures ANSI/J-STD-001B Requirements For Soldered Electrical And electronic Assemblies ANSI/IPC-A-610 Acceptability Of Printed Board Assemblies IPC-600C Acceptability Of Printed Boards IPC-7721 Repair And Modification Of Printed Boards And Electronic Assemblies IPC-7711 Rework Of Electronic Assemblies IPC-TM-650 Test Methods Manual IPC-T-50 Terms And Definitions IPC-D-275 Printed Wiring For Electronic Equipment POD Pre-operational, Operational, And Post Operational Checklists POD Operation and Maintenance Procedures For Tools And Equipment Used To Train Personnel To Manage Repair, Modification, And Rework Processes



12.8 WINESCO REPAIR/REWORK

WENESCO/PCI CONNECTOR REPLACE PROCESS

MACHINE

POWER PANEL CONTROLS

PROCESS CONTROL PANEL

MINI WAVE CONTROL PANEL

SYSTEM AIR PRESSURE SETTING



ASSEMBLY TO BE REPAIRED - KIT BOARD AND PCI CONNECTORS

CONNECTOR TO BE REPLACED MATCHING CONNECTOR TO SITE

TAPING CONNECTOR REPLACEMENT SITE TAPING CONNECTOR REPLACEMENT SITE



CONNECTOR REPLACEMENT SITE TAPED CONNECTOR REPLACEMENT SITE TAPED

PLACING BOARD TO BE REPAIRED INTO OVEN FOR THERMAL PRECONDITIONING

BOARD IN OVEN SET AT 100 DEGREES C. FOR MINIMUM TWO HOURS

SETTING UP BOARD FIXTURE FOR DESOLDERING OPERATION

BOARD IN FIXTURE AND IN MACHINE FOR FIRST FIT LOOK



REMOVING PREVIOUSLY USED SOLDER WELL REMOVING PREVIOUSLY USED SOLDER WELL

CLEANING PREVIOUSLY USED SOLDER WELL

REMOVING DROSS FROM SOLDER POT BEFORE NEW SOLDER WELL INSTALLATION

INSTALLING CORRECT SOLDER WELL FOR PCI CONNECTOR REPAIR

PCI SOLDER WELL INSTALLED



SWITCH ON OVERARM ALIGNMENT LIGHT ALIGN OVERARM LIGHT WITH CENTER OF

SELECTED SOLDER WELL

SET BOTTOM SIDE PRE-HEATER AS REQUIRED SET PREHEAT TIMER AS REQUIRED

ENABLE SOLDER POT FOOT PEDAL AS REQUIRED

TEST FOOT PEDAL AND SOLDER WAVE TO ASSURE CORRECT ACTION



OBSERVE SOLDER WELL FLOW AT REQUIRED HEIGHT AND VOLUME

REMOVE NOW THERMALLY PRECONDITIONED BOARD FROM OVEN

REFIT BOARD TO SOLDER FIXTURE REFIT FIXTURE TO SOLDER MACHINE

VERIFY BOARD AND CONNECTOR POSITION RELATIVE TO SOLDER WELL

REASSURE BOARD TO SOLDER WELL CLEARANCE AS .1”



ANOTHER VIEW OF CONNECTOR ALIGNMENT AND CLEARANCE REMOVE BOARD AND FIXTURE

SELECT AND ASSURE SPECIFIED FLUX FOR SPECIFIED SOLDERING OPERATION

APPLY FLUX TO BOTTOM SIDE BOARD AREA FOR CONNECTOR REMOVAL

REINSTALL AND REALIGN BOARD/FIXTURE TO SOLDER WELL

CONFIRM ALIGNMENT WITH OVERARM LIGHT AS CENTERED ON CONNECTOR



BOARD POSITIONED FOR CONNECTOR REMOVAL

DEPRESS SOLDER WAVE FOOT PEDAL UNDER SIDE VIEW SHOWING SOLDER WAVE

MAKING REQUIRED BOARD CONTACT

MANUALLY GRASP CONNECTOR FOR REMOVAL UPON SEEING SOLDER WETTING

REMOVE CONNECTOR FROM SITE AND RELEASE FOOT PEDAL TO STOP WAVE

BOARD POSITIONED FOR CONNECTOR REMOVAL



INSPECT REMOVED CONNECTOR FLUX TOP SIDE BOARD SITE FOR CONNECTOR INSERTION AND SOLDERING

WHILE DEPRESSING FOOT PEDDLE, WAIT FOR SOLDER WETTING TO INSERT

CONNECTOR DEPRESSING FOOT PEDAL

INSERT AND ASSURE CONNECTOR SEATED PROPERLY IN REQUIRED SITE

RELEASE FOOT PEDDLE, AWAIT SOLDER SOLIDIFICATION AND INSPECT SITE



WENESCO/MEG-ARRAY CONNECTOR REPLACEMENT

PROCEED REPLACING THESE CONNECTORS USING THE SAME PROCEDURES AS BEFORE



12.9 SRM4 REPAIR/REWORK

POD

MICROPAX REPLACEMENT PROCEDURES

USING THE AIR-VAC SRM4 REPAIR MACHINE



1.0 PURPOSE AND SCOPE The purpose of these procedures is to provide detailed operational instructions required to effectively manage repair and/or rework processes using the Air-Vac, SRM4 rework/repair machine.

The scope of these procedures extends to all those operating or requiring repair/rework operations for various leaded device types as components and connectors.

2.0 INTRODUCTION The Berg Micropax connector requires special attention for several reasons. One is through hole pin fragility. Another is the very tight clearances and tolerances of the connector pins and the holes into which they shall be inserted. Another is thermal consideration both of boards and connectors. For these reasons, and others, Micropax connector replacement requires using the SRM4 as detailed in the following procedures:

3.0 TERMS & DEFINITIONS To be developed as required and process specific.



4.0 SAFETY

Operational safety, when using the SRM4, shall consist of the following requirements:

EQUIPMENT

Per POD and Air-Vac requirements.

PERSONNEL

Per POD and Air-Vac requirements.



ADDITIONAL SAFETY, HANDLING, ESD, AND MOISTURE SENSITIVITY REQUIREMENTS

NOTE: REFERENCE APPROPRIATE POD SAFETY, ESD, MATERIAL HANDLING, AND MOISTURE SENSITIVE DEVICE PROCEDURES TO ENSURE ALL REQUIREMENTS UNDERSTOOD AND MET BEFORE BEGINNING ANY PROCESS MANAGEMENT EFFORTS.



5.0 STARTUP After connecting the machine to specified power and air sources (MACHINE POWER ON), all machine and operational startup requirements shall be met in accordance with these procedures, the SRM4 operations manual, and the following: SYSTEM CONROLS AND FUNCTIONS Use POD SOPxxx to manage the SRM4 soldering process to replace the Micropax connector. INITIAL AND ONGOING SYSTEM SETUP Use POD SOPxxx to manage the SRM4 soldering process to replace the Micropax connector.



6.0 OPERATIONAL PROCEDURES This procedure provides detailed information concerning operational requirements for the Air-Vac, SRM4 desoldering and resoldering equipment. USING THE SRM4 The following procedures shall be used to perform desoldering and resoldering operations as required to repair or rework Micropax connectors. NOTE: THESE PROCEDURES CONSIST PRIMARILY OF GRAPHIC INFORMATION INSTEAD OF TEXT. Board Setup Process Management

SETUP AND ALIGN BOARD FOR REQUIRED PROCESS

PERFORM BOARD THERMAL PRECONDITIONING ON TOP OF SOLDER POT

MEASURE TOP SIDE BOARD TEMPERATURE DURING THERMAL PRECONDITIONING CYCLE

FOR THIS BOARD, TOP SIDE TEMPERATURE MAXED OUT ACCEPTABLY AS INDICATED



BOARD RAISE/LOWER CONTROL BOARD BOTTOM SIDE .050" - .100" ABOVE

SOLDER WELL

AS IN SETUP PROCEDURES, ENSURE AIR BOOT ALIGNS WITH SOLDER WELL

WITH BOARD IN PLACE, LOWER WELL OVER SITE/DEVICE AND BEGIN ALIGNMENT PROCESS

WHILE VIEWING FROM FRONT AND SIDES, ALIGN BOARD/SITE WITH AIR BOOT

COMPLETE BOARD/SITE/COMPONENT ALIGNMENT PROCESS



CONTINUALLY ENSURE SOLDER FLOW AS SPECIFIED

CONTINUALLY ENSURE WELL FLOW SOLDER TEMPERATURE AS SPECIFIED



Connector Removal Process Management

THERMALLY PRECONDITION BOARD ON TOP OF SOLDER POT AND WELL, WHEN POSSIBLE

ENSURE TOP SIDE BOARD TEMPERATURE, AFTER PRECONDITIONING, AS SPECIFIED

USE OVEN TO THERMALLY PRECONDITION BOARDS, AS SPECIFIED AND REQUIRED

ENSURE OVEN "SEALED" DURING THERMAL PRECONDITIONING PROCESS

ENSURE FLOW TIME AND % AS SPECIFIED FOR BOARD TO BE PROCESSED

SELECT AND TEST VARIOUS ADJUST MENU SETTINGS AND SWITCH TO MAIN MENU



IN MAIN MENU, SWITCH TO RUN AND PREPARE TO ACTIVATE WELL FLOW

WHEN READY TO PROCESS BOARD, SELECT CYCLE TO MANUALLY ACTIVATE PROCESS

USE SPECIFIED FLUX TYPE FOR BOARD TO BE PROCESSED

ENSURE SITE TO BE SOLDERED PROPERLY FLUXED

AFTER ACTIVATING CYCLE, OBSERVE TIME COUNT DOWN TO ZERO

WHEN TIME AT ZERO, OBSERVE COMPONENT LIGHT ILLUMINATION



WITH COMPONENT LIGHT ILUMINATED, USE APPROPRIATE TOOL TO BEGIN COMPONENT

REMOVAL PROCESS

CONTINUE REMOVAL PROCESS UNTIL DEVICE FREE OF HOLES



Hole Cleaning Process Management

IMMEDIATELY UPON CONNECTOR REMOVAL, HOLE CLEAN BOOT LOWERED AND

SWITCHED ON, WAVE DROPS, SOLDER REMOVED

VISUALLY ENSURE ENOUGH SOLDER REMOVED TO EFFECT NEW CONNECTOR INSERTION



Connector Pin Straightness Assurance

NOTE: FOR MICROPAX CONNECTORS, IT IS ESSENTIAL THAT PIN STRAIGHTNESS IS CAPABLE OF INSERTION INTO BOARD SITE - THE FIRST TIME AS ONLY THREE REPAIR SEQUENCES ALLOWED.

MICROPAX CONNECTOR OFTEN REQUIRING ADDITIONAL PIN STRAIGHTNESS

DETERMINATION

MICROPAX CONNECTOR INSERTION INTO GAGE TO DETERMINE PIN STRAIGHTNESS



Connector Insertion Process Management

FOR MICROPAX CONNECTORS, ALL CONNECTOR PINS STARTED, TO AT LEAST

10% DEPTH, OR FULLY PLACED (PREFERRED) INTO HOLES BEFORE SOLDERING

CONNECTOR FULLY INSERTED BEFORE REFLOW OR VERY GENTLY TAPPED INTO HOLES AND MOLTEN SOLDER DURING

PROCESS



Connector Soldering Process Management

AS IN SETUP PROCESS, ENSURE SOLDER WAVE NOT EXCESSIVE BUT SET AS SPECIFIED

FOR TIME AND % FLOW WHILE ENSURING PROPER BOTTOM SIDE BOARD CONTACT

AS IN SETUP PROCESS, ENSURE SPECIFIED SOLDER WELL TO BOARD CLEARANCE

ENSURE ALL SETTINGS AS SPECIFIED ENSURE SOLDER TEMPARATURE AS

SPECIFIED

MOMENTARILY DEPRESS CYCLE SWITCH TO ACTIVATE SOLDER WAVE

OBSERVE TOP SIDE SOLDER FLOW AND WETTING AFTER SPECIFIED PERIOD



CONNECTOR SOLDERED INTO PLACE EXHIBITING GOOD TOP SIED WETTING

CONNECTOR SOLDERED INTO PLACE EXHIBITING GOOD BOTTOM SIDE WETTING



Attendant And Optional Processes

SHUTDOWN Return equipment to operators if production warrants or follow shut down procedures listed in procedures.

THERMAL SOLDER TIP "DRILL" FOR FINAL HOLE CLEANING TOUCH UP - AS NEEDED



QUALITY

Reference SOP2571: POD Quality Policy.

OPERATOR MAINTENANCE

Return all tools, containers, and fixturing to proper storage areas.



12.10 BGA REPAIR/REWORK (SRT-1000) 1.0 PURPOSE AND SCOPE The purpose of these procedures is to detail operational requirements for the Summit 1000 Surface Mount rework and repair machine. The scope of these procedures extends to all manufacturing operations personnel, and process managers responsible for effecting specified rework and repair operations concerning ball grid array (BGA) and fine pitch leaded devices on printed circuit assemblies at POD. 2.0 INTRODUCTION AND DEFINITIONS At POD it is vital, from time to time, to rework or repair SMT electronic assemblies using fine pitch and BGA device types. To do this, POD uses the Sierra Research and Technology, Inc (SRT) Summit 1000 rework and repair machine. The SRT 1000 machine (figure 1) is capable of removing and replacing required devices with programmable accuracy and precise thermal profiles required for reflow soldering processes. It is particularly suited for BGA’s (figure 2) and very fine pitch leaded components as quad flat packs (QFP’s as in figure 3). It also can be used for first time placement and reflow operations concerning these device types. To match the “bumps” on a component’s bottom side with the corresponding PCB solder termination pads, a prismatic viewing system, with an integral illumination capability, is used. This creates two separate images in the field of view (figure 4) allowing the operator to accurately align components with PCB footprints. SRT’s advanced vision system allows the operator to generate “on screen” fiducial marks making alignment very easy.

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2.1 MACHINE AND CAPABILITIES DESCRIPTION SRT assembles a finely painted 14 gauge steel cabinet between two precision crafted T-weldment frames to provide a rigid construction. The cabinet divides into the pneumatic compartment (left) and power/electronics compartment (right). AC power feeds into the right end of the cabinet below the main power switch. Compressed air or gas feeds into the cabinet’s left side. The system, when placed on its work stand, is 74.5” high. Its estimated shipping weight is 550 lbs. It shall be noted the system requires a minimum of three feet of workspace on its right side and behind the machine. Also required is a minimum of six inches on the left side for servicing. The machine is shown in figure 5. An easily accessible Emergency Stop (E-Stop) button is highly visible on the cabinet’s right cabinet face (figure 6) above the reset button. The top heater flow meter, primary bottom heater flow meter, and secondary heater flow meter air controls are above the air supply regulator and pressure gauge on the panel facing the operator’s left side (figure 7). A high resolution, 17” monitor (also in figure 5) sits above the cabinet and provides the operator with Windows based program selections on a conveniently positioned trackball (figure 8). A computer shelf houses the personal computer below on the work stand. The linear bearing X-Y table tracks on two paired Thomson bars providing X movement (left/right) and Y (front/back) movement (figure 9) to accommodate a standard board size up to 18” by 16” and optional board size up to 22” by 18” (figure 10). Bottom heaters, air, and a thermocouple provides controlled heat to the board’s underside. Figure 9 also shows the thermocouple as the yellow wire on the right.

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A component carrier positions the component for pickup (figure 2 on page 6). The pickup Z-motor drives a lead screw positioner (figure 11) that moves along a vertical grooved slide track (figure 12) for an approximate 8” run or travel. During operation, the motor drives the pickup down (figure 13). The pickup has a breakaway feature when a component is sensed. Vacuum lifts a component with a pickup tube and after alignment the pickup tube places the component on the board (figure 14). The top heater includes an air feed and a thermocouple to provide controlled heat through the array nozzle (also figure 14). This heater assembly also moves up and down, but movement is provided by a pneumatic cylinder. A ventilation manifold draws of the hot air, fumes, and vapors.

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A video camera and microscope assembly is mounted on an arm/elbow arrangement calibrated to pre-set alignment positions (figures 15 and 16). The low lux camera peers through a Leica optics equipped microscope with magnification ranges. The microscope optics has a reticle network for alignment and registration. A prism shuttle provides precise placement by viewing through at both the component bottom and the board top as a visual overlay (figure 17). The computer program displays calibrated gram force selections for placement and removal (figure 18). It regulates the top and bottom heater temperature selections, and provides full control of all processes. This sophisticated program provides simplicity of operation for this semi-automatic system that performs rework, repair, or prototyping of SMT assemblies using BGA or very fine pitch device types.

2.2 GENERAL MACHINE CHARACTERISTICS The SRT 1000 offers the following outstanding characteristics: 2.2.1 MS Windows based software 2.2.2 Superior video incorporating Leica optics and SRT’s patented split imaging capability 2.2.3 Shuttled prism viewing with integral illumination

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2.2.4 Advanced vision system (AVS) using a single monitor of highest available resolution for computer and vision 2.2.5 Programmable removal and placement force 2.2.6 High resolution linear bearing S-Y table 2.2.7 Independent X (left/right) and Y (forward/back) axis movement and theta controls 2.2.8 Full computer control of all process parameters 2.2.9 On screen profiling for thermal studies 2.3 GENERAL SPECIFICATIONS As indicated in the foregoing with the following additions: 2.3.1 Component Sizes The system is capable of handling bare die and packaged components ranging in size from .25” square to 1.9” square and up to .6” thick. 2.3.2 Board Clamping And Sizes The board is held in an industrial grade adjustable holder that supports it on 3 sides as it is clamped on 2 sides. The holder includes a series of horizontal stainless steel rods providing bottom board support. The rods are easily removable in the event they interfere with components mounted on the board’s bottom side. Optional board edge clamps are available that reduce the maximum board size to 15 X 18”or 21 X 18” in the X direction plus an increment for leaded component pickup. Fine adjust controls are provided for final alignment. 2.3.3 Component Pickup The pickup handles component movement in the Z and Theta axes. The pickup has four positions consisting of HOME, PICK, NEAR-PLACE, AND PLACE. The combination of moving the table in the X, Y, and theta axes allows precise alignment of component to board. Components are automatically presented to the pickup by the component shuttle. Centering the component to the pickup is accomplished using a nest attached to the component shuttle. If leaded components are used, a component tray (mounted to the board holder) is used. All forces applied during PLACE and REMOVAL operations are programmable. 2.3.4 Topside Board And Component Heating Board and component topside heating is achieved with a hot gas heater and array nozzle (optional perimeter nozzles may be supplied to heat only the outside of a device’s perimeter) sized to suit the component. These are available for components from .5” square to those 2” square. Minimum array nozzle size is .6” X .9”. Maximum top heater temperature capacity is 450 degrees C.



2.3.5 Bottom Side Heating Bottom side heating is available in one of the following forms: 1) Upwardly directed 750 W hot gas heater providing localized heating to an area approximately 1.5” diameter. Maximum recommended heater temperature is 350 degrees C. 2) Large area radiant heater consisting of a temperature controlled hotplate beneath the board holder. Maximum recommended heater temperature is 300 degrees C. 3) Large area plenum hot gas heater beneath the board holder consisting of a plenum furnished with an array of orifices through which temperature controlled hot gas is blown. The heated area is mechanically programmable by blocking off selected orifices. Maximum recommended heater temperature is 200 degrees C. NOTE: BOTTOM HEATING IS PROVIDED TO HELP MAINTAIN BOARD FLATNESS, TO REDUCE TEMPERATURE DIFFERENCE BETWEEN TOP AND BOTTOM SIDES, AND TO MINIMIZE THERMAL SHOCK TO A BOARD OR ASSEMBLY DURING A SINGLE SITE SOLDERING PROCESS. THE BOTTOM HEATER IS NOT INTENDED AS A REPLACEMENT FOR TOP-SIDE HEATING AND THE EXTENT OF HEATING, OR THE TEMPERATURE SETTING OF THE BOTTOM HEATER IS NOT INTENDED FOR THE PURPOSE OF SIGNIFICANTLY INCREASING OR DECREASING THE TIME/TEMPERATURE CYCLE DURING THE SOLDERING PROCESS. 2.3.6 Component To Board Alignment Component to board alignment is achieved by means of a multi-element optics system. This includes a 50 mm prism providing concurrent “look up/down” viewing of the component bumps/balls/leads and corresponding mounting pads on the PCB. 2.3.7 Component and Board Views Component (up) and board (down) views are illuminated separately in a way that lighting intensity can be adjusted independently to suit different reflectivity levels and prevent image washout. 2.3.8 Optics The system uses Leica MC3 optics with a 5 step magnification changer (6.4X, 10X, 25X, and 40X), a 63X video coupler, and a low lux CCD video camera with approximately a 768 by 494 line resolution. 2.3.9 Field Of View The field of view represents the entire angular expanse as displayed on the monitor for that particular magnification range at that time. Table 1-1 lists the ball grid array field of view as seen with the standard .63 video couplers for the five magnification steps. The field units are expressed in inches.



Table 1-1) BGA FIELD OF VIEW (1 of 2) STANDARD VIDEO COUPLER (UNITS = INCHES)

MAGNIFICATION STEP FIELD OF VIEW - X FIELD OF VIEW - Y

6.4 1.58 1.17 10 1.01 .76 16 .61 .46 25 .37 .28 40 .24 .18

Table 1-2) BGA FIELD OF VIEW (2 of 2) .63 VIDEO COUPLER (UNITS = INCHES)

MAGNIFICATION STEP FIELD OF VIEW – X FIELD OF VIEW – Y

6.4 2.15 1.90 10 1.62 1.22 16 .98 .74 25 .60 .45 40 .38 .28

2.3.10 Video Output The system uses “S” video and provides digitized imaging of video signals permitting storage of these images in files for future use. A single high resolution monitor is used for simultaneous video and SierraMate software viewing. 2.3.11 Diagnostics For diagnostic purposes, windows screens are provided to allow verification and correct functioning of all system inputs, outputs, and sensors. Figures 19 shows on screen while figure 20 focuses more clearly on thermocouple readings in ambient.

2.4 SOFTWARE Software for the SRT is provided to ensure effective, efficient process management. The following descriptions are offered to indicate software capabilities and use requirements:

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2.4.1 General The system is controlled with SierraMate for Windows software that includes the Advanced Vision System. Different access levels are available. The first is for easy operator use. Second and third levels provide the ability to create and modify programs, sequences and configurations, perform diagnostics, etc. At the first level (operator), the operating procedure only requires BOARD, COMPONENT, and SEQUENCE selections (figure 21). The available choices shall have been previously programmed at the second level thus limiting the operator choices to those relevant to the procedure being performed. Prompts are provided for the operator to verify correct system setup and processing parameters (figure 22).

All processing parameters are fully programmable by the responsible engineer or technician. Access to these parameters, and other data at the second and third levels, are password protectable. 2.4.2 Thermal Cycles Thermal cycles consist of PREHEAT followed by REFLOW. The times and temperatures of these portions of a cycle are independently adjustable using slide bars on the process screen. Ramp rates, up to specified preheat and reflow temperatures, are adjustable to suit the product being processed. All thermal cycle parameters selected for a particular product are saved for that specific board and site. Operator selection of a specific board and site automatically selects the already stored thermal cycle. 2.4.3 Forces PLACE and REMOVAL forces are programmable to suit a particular product by using slide bars on the process screen. Once chosen, these parameters are saved for that specific board and site. Operator product selection (substrate/component combination) automatically selects the appropriate forces to be applied, depending on the sequence selected.

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2.4.4 Temperature Control Temperatures are sensed at the heaters by k-type thermocouples to effect specified control. Three mode controls (PID-Proportional, Integral, and Derivative) maintain heater temperatures to within + or – 5 degrees C. of set-point. 2.4.5 Advanced Vision System (AVS) AVS provides electronically generated fiducial marks as cross hairs, boxes, or other shapes to assist component alignment with the substrate on which they are to be mounted. It also permits using fiducials to aid component to substrate alignment. 2.4.6 Data Logging Six thermocouple inputs are provided to allow thermal profiles to be logged. Inputs 1 and 2 are reserved for top and bottom heaters. Inputs 3,4,5, and 6 are available for external thermocouples that can be attached to the site/assembly to show real time temperatures, thermal separation, etc. During data logging, a choice is provided to either observe the profiles on the video screen or to hide them from view. Each thermocouple is represented on the screen by a different color. Thermal profile data are stored in ASCII format with the ability to be viewed graphically, numerically, or print. 2.4.7 Event Logging All events occurring on the system are logged and retained in an ASCII file. Logged information includes date and time, board designation, component designation, sequence, site location, cycle duration, and data log file (if applicable). 2.5 OPERATIONAL SEQUENCE The system provides integrated component centering for area array components by means of the component nest. Leaded components are centered using a separate rotatable component tray that is attached to the X-Y table. 2.5.1 Removal Sequence The following outlines the removal Sequence: 1) CHOOSE BOARD, SITE, AND SEQUENCE 2) CLICK GO TO START CYCLE. - PRISM SHUTTLE TRANSPORTS PRISM ABOVE COMPONENT. 3) ILLUMINATION ON. COMPONENT IS CENTERED IN NOZZLE BY ADJUSTING BOARD IN X AND Y AXIS 4) PRISM SHUTTLE RETRACTS. - ILLUMINATION OFF. 5) HEATER IS LOWERED TO BOARD - REFLOW CYCLE IS STARTED 6) AS REFLOW CYCLE ENDS, PICKUP TUBE DESCENDS, TOUCHES COMPONENT, VACUUM IS ACTIVATED, AND PICKUP IS RASED TO NEAR PLACE POSITION – REMOVING COMPONENT FROM BOARD. 7) HEATER IS RAISED. - PICKUP ASCENDS TO HOME POSITION. 8) COMPONENT SHUTTLE TRANSPORTS COMPONENT NEST UNDER COMPONENT. 9) PICKUP TUBE DESCENDS TO PICK POISITON - VACUUM IS DEACTIVATED. COMPONENT IS RELEASED INTO NEST. 10) PICKUP TUBE ASCENDS TO HOME POSITION.



2.5.2 Placement Sequence The following outlines the placement Sequence: 1) CHOOSE BOARD, SITE, AND SEQUENCE 2) CLICK GO TO START CYCLE.- SHUTTLE TRANPORTS COMPONENT AND PRISM UNDERNEATH VACUUM PICKUP TUBE. 3) PICKUP TUBE DESCENDS FROM HOME TO PICK POSITION, TOUCHES COMPONENT, VACUUM ACTIVATES, AND COMPONENT IS PICKED AND RAISED TO HOME POSITION. 4) COMPONENT SHUTTLE RETRACTS. ILLUMINATION ON. 5) OPERATOR PROMPTED TO BRING SITE INTO VIEW UNDER PRISM AND TO CLICK GO. 6) PART LOWERED TO ALIGNMENT HEIGHT. 7) IMAGE ALIGNMENT PERFORMED BY ADJUSTING BOARD IN X AND Y AXES, AND COMPONENT IN THETA. 8) PRISM SHUTTLE RETRACTS - ILLUMINATION OFF. 9) PICKUP TUBE DESCENDS TO NEAR PLACE - THEN PLACE POSITIONS. 10) VACUUM DEACTIVATED AND PUCKUP TUBE ASCENDS TO HOME POSITION. 11) IF APPROPRIATE, PLACEMENT IS FOLLOWED BY REFLOW CYCLE 2.5.3 Options Besides alternative bottom side heaters, the following options are available: 1) Extended Y Rails - allows an 18” by 22” board to be handled by the substrate holder. 2) Split Mirror – providing an enhanced capability to handle large, fine pitch perimeter packages or devices as fine pitch QFP’s. Also allows opposite component corner viewing with high magnification. By reducing the field of view, large components can be magnified sufficiently for easy and accurate alignment of fine pitch leaded components or peripherally bumped area array components. 3) Tool Kit – providing a comprehensive collection of tools needed to align and maintain the system. 4) Spare Parts Package – provides a part selection allowing repair of critical items and reduce down time. 5) Workstand – provides replacement for a work bench that conveniently houses the computer and to provide a free standing capability. 6) Monitor Arm Assembly – attached to the system right T – weldment frame providing convenient monitor placement 47” above floor level. 7) Earthquake Protection Assembly – consisting of floor anchors and equipment restraints. 2.6 UTILITIES See operations manual for power and gas requirements as well as physical dimensions (1-13) 2.7 SAFETY AND ESD Consists primarily of issues concerning heat, burns, breathing heated vapors, etc. (1-13 and throughout operations manual). All safety and ESD requirements are presented in Section 7.0. 2.8 WARRANTY Standard information (1-13)



2.9 SYSTEM INTEGRATION AND CONTROL SYSTEMS The system integrates electrical, pneumatic, optical/video, mechanical, and computer technologies together under SierraMate for Windows software control in a menu driven format. Sierra Mate controls all process parameters for components, board in process, and sequence being performed. The system, under the computer’s direction, controls the I/O function that controls movement positioning, heat application, and measured force. The menu selection allows software instruction executing to make the computer control the intended function. When the SRT is powered on and the START/RESET is pressed, the SierraMate for Windows program automatically starts with the board, component, and sequence last processed. At this point, the operator can simply click on the GO button to begin the operation, or click on the change buttons to select a different board, part and/or sequence - then click GO. NOTE: THE PROCESS PARAMETERS FOR ALL THE BOARDS AND COMPONENTS/SITES, FROM WHICH THE OPERATOR CHOOSES, SHOULD HAVE BEEN PREVIOUSLY SETUP. When the operator clicks on the GO button to begin the sequence, a video window appears with prompting instructions. Operations are controlled by the operator using the mouse/trackball, or by system sequence. The keyboard is needed only to setup the process parameters, or to do machine setup/maintenance. 2.10 MENUS The following menus are an integral part of the SierraMate, Windows software. They are used to manage all machine processes. 2.10.1 Board Menu The board menu is provided to create new boards. Click on Board, or New Board and a dialogue box appears. The title bar indicates NEW BOARD, MODIFY BOARD, or DELETE BOARD - depending on the required action. Enter board name to be created as any name up to 20 characters – including spaces. Select the type board to be created by clicking on one of the board types shown in the list. When a board type is selected, Board Weight Index and Board Thickness changes accordingly. SierraMate uses the Board Weight Index to calculate the default times and temperatures used to process this board. The Board Thickness, along with the component height, is used to calculate the default Near Place Height and Alignment Height. If the board type required is not displayed in the list shown, select one most closely matching the board to be created. Then, modify the Board Weight Index and/or Board Thickness scroll bars accordingly. When finished, click on the OK button. SierraMate automatically adds a default component for this board. This may be changed later as explained in the Component Menu section. 2.10.2 Retrieve Click on Board then Retrieve. This selection allows retrieval of a board that was previously created. Type in the name of the board to be retrieved or double click on the name shown in the list. To create a new board, in lieu of selecting an existing board, click on the Create New Board button. This has the same effect as selecting the New Board menu selection.



2.10.3 Modify Click on Board then Modify. This is done to modify a board that was previously created. A dialogue box appears displaying current board name and values. The board name, thickness, and/or weight index may be modified. NOTE: ANY CHANGES MADE TO BOARD THICKNESS CAUSES ALIGNMENT HEIGHT TO BE UPDATED ACCORDINGLY. ALSO, ANY CHANGES TO BOARD WEIGHT INDEX CAUSES TIMES AND TEMPERATURE SETTINGS TO CHANGE TO THE DEFAULTS FOR THE SELECTED WEIGHT INDEX. 2.10.4 Copy Click on Board then Copy. This menu choice allows copying the current board to another board name. 2.10.5 Delete Click on Board then Delete. Select this item to delete a board previously created. A window appears allowing the user to type in the board name, or to double click on the board to delete it. 2.10.6 Edit List Of Board Types Click on Board then Edit List of Board Types. This entry allows editing the list of standard board types located in a file entitled BOARDS.INI. This file contains the list of standard board types, associated weight indices, and thicknesses. Board types may be modified, added, or deleted as required. Up to 100 board types may be defined. The windows NotePad program is used to edit this file. The board type name is shown in square brackets. This is the name appearing in the list of board types when creating a new board. The associated information should follow the format as the other types shown. Any changes take effect upon exiting NotePad and returning to SierraMate. 2.10.7 Exit This menu selection provides the means to quit SierraMate. If the current process settings are not saved, a save or not message is displayed before exiting. 2.10.8 Component Menu It shall be noted the terms component, part, or site all are identical references. 2.10.9 Add Component To Board This menu selection allows the ability to add a component to a board. A dialogue box appears allowing the selection from a list of Standard Part Types by clicking on the down arrow, or by defining a part by clicking on the Custom Part button. Standard parts are defined in a file that may be modified by using the Edit List of Part Type – from the Component Menu. When clicking the Custom Part button, another dialogue box appears. Enter the name for the custom part. This may be any name up to 20 characters long- including spaces, but cannot be the same name as a Standard Part Type. Use the scroll bars to input part dimensions. The height dimension is used by SierraMate to calculate the Alignment Height for the chosen component. click on the OK button to save the information.



Modify the features by using the scroll bars. The Square Part check box allows specifying whether X and Y dimensions are the same. When this box is checked, X and Y scroll bars always shall have the same value. Moving the X or Y scroll bar makes the other move the same amount. When done, click on OK to save the values. 2.10.10 Delete Component From Board Select this menu item to delete a component from a board. This item is not available if only one component exists on the current board (it is disabled in this event). A dialogue box appears. Select from the component/sites list currently on the board by clicking on the down arrow. Then, click on the OK button. SierraMate prompts to verify desired component deletion. 2.10.11 Modify Current Component Use this menu selection to modify the current component dimensions. This menu selection only is available if the current component is a custom part (not a part selected from the list of Standard Part Types). Modify part features using the scroll bars. The Square Part check box provides the ability to specify if the X and Y dimensions are to be the same. When this box is checked, the X and Y scroll bars always have the same value. Moving the X or Y scroll bar makes the other move the same amount. When done, click on OK to save the values. NOTE: AFTER CHANGING A COMPONENT’S HEIGHT DIMENSION, THE SOFTWARE UPDATES THE ALIGNMENT HEIGHT SETTING TO ITS NEW VALUE. 2.10.12 Fiducial Setup NOTE: HEATER/PART BOX FIDUCIAL SETUP ONLY IS AVAILABLE IF CURRENTLY SELECTED ACTION/SEQUENCE USES A HEATER/PART BOX FIDUCIAL. Select this menu item to modify the size and location of the part box fiducial. This box may be used by the operator to center the part in the video before picking it. Refer to Section 8 for more details concerning using sequence commands. This fiducial may be implemented in sequences by using the commands SHOW PART BOX and HIDE PART BOX. When this menu item is selected, a screen appears. Use the scroll bars to change the box size. The box position may be modified by grabbing the box with the trackball and dragging it to the desired location. When satisfied with the box size and location, click on the Save button. This saves the information to the board file for the currently selected component. 2.10.13 Edit List of Part Types This entry allows editing the list of standard part types located in a file entitled PARTS.INI. This is the file containing the list of part types and associated dimensions. Part types may be modified, added, or deleted. Up to 100 part types may be defined. The NotePad program is used to edit this file. The part type name is shown in square brackets. The associated information should follow the same format as all other types shown. Any changes take effect when the file is saved and NotePad is exited. 2.10.14 Process Menu



All process settings discussed in this section are set by SierraMate software to default values based on information entered by the user for the particular board and part that is currently selected. Then, these can be modified if needed as described below. When selecting any process menu item, the right side of the screen shown shall be similar in all cases. The top right shows the current board, component, and sequence selected. To change any of these, simply click on the item to be changed. To run the selection shown, click on the Run button. This is the same as clicking on the GO button on the main screen. Use the save button to save the current settings to disk. This saves all settings. 2.10.15 Times And Temperatures NOTE: TIME AND TEMPERATURE SCREEN APPEARS ONLY IF CURRENT SEQUENCE USES HEATING. CLICK ON A SEQUENCE ON RIGHT OF PROCESS TO PAUSE WHEN NECESSARY. Selecting this menu item displays a screen showing heater set-points and heating times. Default values for these settings are based on the Board Weight Index specified when the board first was created. These values then may be changed on this screen. For Preheat and Reflow settings, use the scroll bars to change the values. NOTE: IF THE HEATER RAMP OPTION IS ON (I.E. HEATER RAMP OPTION = 1 IN THE CONFIGURATION FILE), RAMP PARAMETERS ALSO shall BE SHOWN. THIS ALLOWS THE TOP HEATER TO BE RAMPED UP TO THE SPECIFIED PREHEAT OR REFLOW SET-POINT. THIS RAMPING OCCURS BEFORE THE PREHEAT TIME FOR PREHEAT RAMP, AND BEFORE REFLOW TIME FOR REFLOW. 2.10.16 Ramps The Preheat Ramp starts at a 25 degree C. default setting and the set-point ramps at the rate entered until the ramp set-point is equal to the Preheat Set-point at which time the Preheat time starts. The Reflow ramp starts at the Preheat Set-point and ramps until the ramp set-point is equal to the Reflow Set-point at which time the Reflow time starts. Example: Settings for Preheat Ramp = 2 degrees C every second Preheat top heater set-point = 175 degrees C. Preheat dwell time = 30 seconds Settings for Preheat Ramp = 2 degrees C every second Reflow top heater set-point = 270 degrees C. Reflow dwell time = 30 seconds When heating cycle starts, set-point for the top heater at time 0 shall be 25 degrees C. After one second, the set-point shall be 27 degrees C., after two seconds it shall be 29 degrees C, etc., until



the Preheat set-point is attained. The Preheat dwell begins and remains at the Preheat Set-point for the entire dwell time (30 seconds). When the Reflow part of the cycle begins (time 0 for reflow), the set-point is 175 degrees C., and after one second it is 177 degrees C., etc. Once Reflow set-point is reached, the Reflow dwell begins and remains at Reflow Set-point for the entire dwell time (30 seconds). Total cycle time is the time required to ramp to Preheat Set-point (75 seconds), the Preheat dwell (30 seconds), the time to ram to Reflow Set-point (48 seconds), and the Reflow dwell (30 seconds). The values shown below the Reflow box also may be modified. These are time values for additional heating and solidification occurring after the Reflow part of the sequence is completed. To change these values, click on the up or down arrows next to the appropriate setting. Note that not all settings are used in all sequences. The following is an explanation of these time settings: Additional Reflow Time: Occurs in Place-Reflow, Reflow-Place, Reflow sequences to allow proper solder to pad wetting . Also occurs in Remove Sequence to level the solder on the pads after removing a part. Post Placement Time: Occurs in Reflow-Place sequence to allow required solder wetting after part placement. Solidification Time: Occurs in Place-Reflow and Reflow-Place sequences allowing the solder to solidify before releasing the part. The following summarizes when they occur in each sequence: Remove Sequence . . Preheat Reflow (part lifted to Near Place height) Additional Reflow Time (heaters turned off; heaters and pickup raised) . . Reflow Sequence . . Preheat Reflow Additional Reflow Time (heaters turned off and raised) Solidification Time (pickup raised)



. . Place-Reflow Sequence . . (part is placed) Preheat Reflow Additional Reflow Time (heaters turned off and raised) Solidification Time (vacuum turned off and pickup raised . . Reflow-Place Sequence . . (part is held at Near Place height) Preheat Reflow Additional Reflow Time (part is placed) Post Placement Time (heater turned off and raised) Solidification Time (vacuum turned off and pickup raised) . . 2.10.17 Alignment Height This is the height at which the component is held during the part/site alignment part of a sequence. When a component initially is added to a board, the software calculates the default Alignment Height as a function of the component height and board thickness. 2.10.18 Force Settings This screen indicates the amount of force to be used when placing or removing a component. Current settings are default when adding a new part. To change these values, use the scroll bars shown. The minimum and maximum forces are specified in the FORCE section of the SRTWIN.INI configuration file. 2.10.19 Datalog Menu The Datalog entering feature of SierraMate software allows up to 6 thermocouple inputs to be logged at once. The data are stored in an ASCII file and may be viewed later using the SierraMate Graph Utilities program (described later) or imported into a spreadsheet program. Use this menu to setup datalog entry. A dialogue box appears.



Datalog Type Select one of the 3 choices shown for datalog type by clicking on it. No Datalogging Turns off datalog entry Datalogging in Background Causes the data to be stored to file but no graph appears when running a sequence. Datalogging with Live Viewing Stores data to file but allows data to be viewed as plotted on a graph 2.10.20 Datalog Name After electing to datalog (either in background or with live viewing), a file name shall be entered to store the data. This name shall be a valid DOS name consisting of from one to eight characters. SierraMate prompts to re-enter the name if not valid. The default extension is LOG. A different datalog file may be created for each sequence run by entering digits for the last 1, 2, or 3 characters of the filename. This causes the file name to increment each time a sequence is run. For example, entering a file name dlog00 causes up to 100 datalog files to be created (dlog00 through dlog99). If no digits are entered as described above, the datalog file shall be overwritten each time a sequence is run. 2.10.21 Datalog Thermocouples Select thermocouples to be logged by clicking on the appropriate check boxes in the TC’s To Be Logged panel. Note that TC 1 and TC 2 are the Top and Bottom Heater thermocouples respectively. Thermocouple jacks are provided for TC 3 through TC 6. Datalog entry of thermocouples are supplied by the user. When satisfactory selections have been made, click on the OK button. If Datalogging with Live Viewing selected, a graph icon appears to the left of the video window when a sequence is started. To view the graph, click on this icon. The graph may be moved by dragging it with the trackball/mouse. Use any part of the graph border to grab it with the trackball. The graph also may be reduced in size by clicking on the Size button. This provides a less obstructed view of the video window when wishing to view the graph and video simultaneously. The data shall be shown on the graph as lines and as numbers in the upper left part of the graph. The numbers appear in order of TC numbers so TC 1 data is the first number shown, TC 2 data next, etc. These numbers appear in different colors and correspond to the color of the line being plotted for that TC. If the TC was not selected to be graphed in the Datalog Setup, its corresponding numerical value is shown as “---“. The graph data are updated every second during the sequence. The graph automatically scrolls when the plot reaches the right side of the graph (figure 27). Up to 10 minutes of data may be collected.



2.10.22 View Last Graph When a sequence ends, the datalogging graph automatically is closed. To view it again, select View Last Graph from the menu. The graph re-appears with data on it. If the amount of data has exceeded the viewable length of the graph, a scroll bar is visible at the top of the graph. This may be used to scroll the data on the graph forward or backward. The scroll bar appears only if the amount of data has exceeded the viewable length of the graph. To view a numeric display of the temperature at any point on the graph, point with the cursor to the place needed to see the display and click on it. This moves the time line to that point on the graph. Both time and temperature is displayed. The time line also may be dragged across the graph. Click on the Close button when finished viewing the graph. NOTE: THIS MENU SELECTION ONLY ALLOWS VIEWING DATA JUST ACQUIRED. TO VIEW ANY DATA PREVIOUSLY COLLECTED, USE THE SIERRAMATE GRAPH UTILITIES PROGRAM (DESCRIBED IN A LATER SECTION). 2.10.23 Learn Menu Learn sequence allows the software to Learn the time needed for a board to reach reflow temperature. This Reflow time then is displayed with option to save its value. NOTE: LEARN MAY BE ACCOMPLISHED IN ONE OF THE TWO WAYS EXPLAINED BELOW 2.10.24 Use Vacuum Sensing Only This method uses the Pickup Vacuum sensor to determine when a component has reached reflow temperature. This is done by repeatedly trying to pick a soldered component from the board during the Reflow portion of the Remove process and checking the Pickup Vacuum sensor to determine if the part has been removed. When the software detects that the component has been removed, it stores the reflow time that was required and updates the Reflow Settings accordingly. To begin, select Use Vacuum Sensing Only. A dialogue box appears. Enter the maximum number of pickup tries to be attempted by clicking on the up or down arrows. Click on the OK button to start the learn sequence. The Remove sequence then shall be run. The pickup starts trying to pick the component at 19 seconds before the end of the Reflow time specified in the Reflow settings and then continues trying for the number of tries specified. The

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interval between tries is approximately 5 seconds. If the maximum number of attempts is reached before the component is removed, the sequence aborts. To repeat the learn mode, a change in process temperature or increase in the number of tries shall be considered. 2.10.25 Use Temperature And Vacuum Sensing This type Learn requires that a thermocouple probe, or board instrumented with a thermocouple, be used. It shall be plugged into TC jack 3 of the machine. This TC shall be located at the pad/lead solder joint to measure the temperature at this location. To begin this type Learn sequence, select Use Temperature and Vacuum Sensing from the Learn menu. A dialogue box appears. Use the scroll bar to enter the required temperature for the Learn TC to reach before the Pickup attempts to remove the component. Next, enter the maximum number of tries the Pickup shall make to remove the part. If the component is not to be removed, specify 0 for the number of tries (Selecting 0 for the number of tries shall learn the time to selected temperature). Click on the OK button to begin the Learn sequence. If 0 Pickup tries selected, the Reflow sequence is run. Otherwise, the Remove sequence is run. 2.10.26 View Event Log This menu item brings up a dialog box representing the system Event Log containing a sequential record of all operations performed on the system (figure 28). It is an ASCII file that may be imported into other applications as spreadsheet programs, etc. The maximum Event Log size is approximately 3,000 events. The system prompts to save (copy to a different file name), then delete the Event Log when required. The Event Log’s file name is EVENTLOG.TXT.

1) Copying Text To copy portions of the Event Log to the Windows Clipboard, select Copy Selected Text to Clipboard from the File menu. Once copied, the text can be pasted into other applications using the paste feature. 2) Searching For Text To search for particular Event Log text, select Find from the Search menu. Enter the required text and click on the Find Next button. It is possible to specify the starting point’s search by clicking on any line in the Event Log.

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2.10.27 Delete Event Log Select this menu item to delete the Event Log. This is necessary when the Event Log reaches its maximum size. Password protection is in place. 2.10.28 Setup Menu The following procedures are required to use the Setup Menu: 1) I/O Diagnostics This menu item brings up a dialog box. From this window, it is possible to actuate all SRT 1000 outputs and to read all inputs. This is useful for checking machine functionality and to perform trouble-shooting. 2) Sequences SierraMate software is installed on the SRT 1000 with standard sequences to attach and remove components. These sequences do not normally need to be modified. However, there may be instances when this needs to be done. 3) Configuration This menu allows changing various system parameters as passwords, delays, etc. that are stored in the configuration file SRTWIN.INI. Use the Windows NotePad program to edit this file even though parameters rarely need changing. 4) Force The SRT 1000 is capable of applying pre-programmed forces on components during placement and/or removal. Se Force Settings in the Settings menu section for more information about how to specify required forces for specific components. 2.10.29 Video Menu Use the following procedures for the Video Menu: 1) Color This menu item allows switching the video from color to black and white, or the reverse. When color is selected, a check mark appears next to this menu item. This is the default setting when Sierra Mate boots up. To change to black and white, select this menu item. The check mark disappears and the video is in black and white. Select this menu item again to change back to color. 2) Open/Close Video This menu item allows opening or closing the video window. If the video window is open (visible), selecting this menu item closes it. If the video window is closed (not visible), selecting this menu item opens it to maximum size. Located to the right of the video window is a Control Box window. This box does not appear when running a sequence, but it can be accessed if needed by double clicking on the Video Window drag bar (video area above black horizontal line). The Control Box contains groups of buttons controlling commonly used functions:



3) Video Take SnapShot – Click on this button item to capture the image in the video window to a file. The image is saved to a file named SNAP.BMP. This is a bitmap file (.BMP extension) that can be edited using various paint programs and/or imported into word processing or other documents. To view the SnapShot, use the View ShapShot menu selection described below. It shall be noted that each time a SnapShot is taken, the previous file is overwritten unless the file is saved as a different name. When renaming a file, a .BMP extension shall be provided. 4) View ShapShot Use this menu item to view a bitmap file previously captured using the Take SnapShot button. When this menu item is selected, a window containing the SnapShot appears. From this window, other .BMP files may be viewed or saved using new file names. To view a different bitmap file, select Open from the file menu of the View SnapShot window and an Open file dialog box appears. Select the file to be viewed and click OK. The file then appears in the View SnapShot window. At this point, save the file to a different name by selecting Save from the file menu. Again, the file shall have a .BMP extension. View a different file by selecting Load from the File menu. It is not possible to access another software feature while in this window. The menu shall be closed to continue. 5) Heater Up-Down – Use this button to raise and lower the top heater. Clicking on the Heater Down button lowers the heater while the button reads Heater Up. Clicking again raises the heater with the button reading Heater Down. 6) Pick-Up NOTE: DO NOT LOWER BOARD UNLESS A BOARD IS IN THE BOARD HOLDER. 7) Vacuum Clicking on the Vacuum On causes the PickUp vacuum to turn on or off depending on current state. 8) Home Click on this button to send the PickUp to its home (fully raised) position. 9) Near – Place Click on this button to send the Pickup from Home to Near Place and to toggle the position of the Pickup between Near Place and Place. 10) Force Amount of force applied by pickup in place position. Change as required using scroll bar. If pickup is in place position, it shall be brought to near place, then place again for a new force value to be effected.



NOTE: DOUBLE CLICKING IN THE PICKUP BOX BRINGS UP JOG BUTTONS FOR PICKUP. 11) Prism In-Out – Clicking on this button makes the Prism to move to View or Home position. The Pickup always is homed before the Prism is moved in. If the Heater is down, this button is disabled. Part Lighting – Click on this button to toggle the lamps that illuminate the component - on/off. Board Lighting – Click on this button to toggle the lamps that illuminate the board – on/off. 12) Resizing Video Window To resize the video window, use the plus and minus buttons located at the video window’s top right side. Clicking on the minus button decreases window’s size by a factor of two each time it is clicked. Clicking on the plus button increases it by a factor of two each time it is clicked. Four sizes are available as full, one half, one quarter, and one eighth size. 13) Moving The Video Window To move the video window, use the mouse/trackball to grab the bar at the window’s top. Move the window by moving the mouse/trackball. This is similar to moving any window in Microsoft Windows except for concerning where it may be moved (function of the frame grabber card). 2.10.30 Help Menu Use this menu to obtain help. 1) Help Use this menu selection to receive complete on-line SRT 1000 help from SierraMate software. 2) About Use this menu item to obtain information concerning the currently installed software’s revision level. 3) System Information Use this menu selection to obtain information regarding current computer configuration. 2.11 RUNNING SEQUENCES A sequence may be run from either the Main window by clicking on the GO button, or from the Process windows by clicking on the Run button. The Run button typically is used when setting up a process for a particular board/component. This allows running a sequence without having to close the Process window to access the GO button. Different boards, components, or sequences may be selected while in the Process window by clicking on the board, component, and/or sequence name shown on the process window’s upper right position.



2.12.1 Verifying Machine Settings After initiating a sequence, the video window appears with a message display window below it. A prompt appears to perform some task. Once this is done, click on the GO button to continue. Additional instructions now are provided on the message display window. 2.12.2 Mouse/Trackball Arrow Location Note that during the sequence, the mouse/trackball arrow automatically is moved to the next most logical location on the screen. This allows the ability to click on the mouse/trackball button without having to move the arrow manually. 2.12.3 Accessing Control Box Window During a sequence, it is possible to access the Control Box window by double clicking on the Video Window drag bar. The controls in this box allow controlling the Pickup, Prism, and Heater position. It also allows taking Snapshots of the Video window. To make this box appear, double click on the Drag Bar at the Video window’s top position. Double clicking again causes the Control Box to disappear. NOTE: DURING A SEQUENCE, IT IS POSSIBLE TO TAKE SNAPSHOTS BUT NOT TO VIEW THEM AS THE VIEW SHAPSHOT BUTTON IS NOT ACCESSIBLE. 2.12.4 Aborting a Sequence A sequence may be aborted at any time by clicking on the Stop button. If a component is being held on the Pickup, a prompt is provided to move the table to a discard location to deposit the component. A sequence also automatically aborts for the following reasons: 1) Low air flow to the Top and/or Bottom heater 2) Top or Bottom heater thermocouples are over maximum temperature or open (450 degrees C. is the default maximum temperature) 3) E-Stop button depressed NOTE: WHEN ABORTING FOR ANY OF THE ABOVE REASONS, A MESSAGE APPEARS IN THE MESSAGE DISPLAY WINDOW INDICATING WHY THE SEQUENCE WAS ABORTED. 2.12 GRAPH UTILITIES PROGRAM The Graph Utilities program is a separate program from SierraMate. It allows viewing, printing, and creating image files of datalog files created using SierraMate datalogging. 2.12.1 Running Program To run this program, access the Program Manager screen and double click on the Graph Utilities icon in the SierraMate group. 2.12.2 Viewing A Graph To view a file, select Open from the File menu. This brings up a file dialog box. All SierraMate datalog files are saved s the name entered in the Datalog Setup plus the extension .LOG. the files are located in the same directory as SierraMate (C:\SRTWIN).



Click on the file to be viewed and click on the OK button. A graph of the file appears. The graph displays the data for each thermocouple selected for logging when the graph was created. Open additional graphs as needed by using the Open menu. If more than one graph is being viewed, use the Windows menu (tile, etc.) to arrange the graph windows. 2.12.3 Changing The Graph Title The default graph title displayed is the DOS file name. The graph’s title may be changed before printing or creating a picture file. This may be done by selecting Graph Title from the Edit menu. Enter the new title and click on the OK button. The new graph title appears. Note that this new title applies only to the graph and does not change the datalog file name. 2.12.4 Printing A Graph To print a graph, select Print from the File menu. It shall be noted that a user printer must properly be setup before it is possible to use the printing process. 1) Graph Color A prompt is provided to select whether a graph shall be printed in color or black and white. When printed in black and white, symbols shall be printed in lieu of colors indicating each of the graph’s data sets. Printing in color on a black and white printer yields gray scale images. This makes it difficult to distinguish data and information. 2) Graph Size The printed graph’s size is dependent on the size of the graph’s appearance on screen. The obtain the largest size graph, do the following: From Windows Print Manager, select Landscape as the Orientation and exit Print Manager. Return to the graph to be printed, click on the Maximize button, and select FILE/PRINT to begin the printing process. 2.12.5 Image Files To aid incorporation of displayed graphs into other documents, use the Graph Utilities program to create an image file of the graph. From the required program, retrieve the image file as needed. To create an image file, select Create Image File from the File menu and select either Bitmap or Metafile. Bitmap files may not be scalable in a particular program but may be edited/re-sized in paint programs to fit as required. Metafiles may be scaled but cannot be modified by some paint programs. The files created shall have the same name as the datalog files except for their DOS extensions as .BMP or .WMF. Other programs are available and capable of reading ASCII data al .LOG files. It is then possible to create graphs from them. 2.12.6 Video Board Demo Program The Video Board Demo Program is provided by the manufacturer of the frame grabber video board. Its icon is located in the SierraMate for Windows group of the Program Manager. This program allows capturing of color images as well as some image processing features as zooming, sharpening, and blurring. See the file README.WIN in the directory C:\ivc\win for more information.



NOTE: THIS PROGRAM AND THE SIERRAMATE PROGRAM SHOULD NOT BE RUN AT THE SAME TIME SINCE THEY BOTH ACCESS THE FRAME GRABBER VIDEO BOARD. ONLY ONE PROGRAM IS ALLOWED ACCESS TO THE BOARD AT A TIME. EXIT SIERRAMATE BEFORE RUNNING THE PROGRAM AND VICE-VERSA. 2.13 TERMS AND DEFINITIONS The following definitions are provided for all process managers to better visualize each process for which they are responsible: 2.13.1 Operations Operations are defined as a series of processes required to provide products or services meeting certain requirements. Usually these requirements are based on customer needs, desires, or demands. POD employs many operations as management, engineering, marketing, sales, manufacturing, accounting, quality assurance, and others to ensure all its customers receive product meeting their requirements. 2.13.2 Process A process is defined as a method or procedure. A process may be a single method or procedure, or may be made up of sub processes and activities. In a manufacturing operation, a process is employed to turn acceptable raw materials, components, and designs into acceptable product using various tool and equipment types. 2.13.3 Sub Process A sub process may be part of a process. In the stencil printing process, several sub processes are involved to effect acceptable solder paste application. They are discussed in the foregoing section. 2.13.4 Activity Processes and sub processes most often rely on individuals or teams performing activities to make product. In manufacturing, such activities may consist of moving or handling materials and components, changing machine or tool settings, turning equipment on or off, etc.. It is at the activity level most variability is introduced to manufacturing operations effecting varying degrees of quality. For this reason, it is vital process managers be well trained to fulfill their responsibilities by following procedures concerning specific operational and process management requirements. 2.13.5 Process Management Process management is the act of preventing defect by fulfilling individual responsibilities instead of reacting to it as the result of not fulfilling them. When process instead of results management is practiced, product quality is consistently acceptable. Process management differs from process control in that control means only consistent quality is produced. In a controlled instead of managed environment, that quality may be consistently good or bad. 2.13.6 Process Capability Process capability is the measure of how well a process is being managed. Usually, a process’s capability is expressed in statistical terms as a capability profile or Cpk. When a process is managed effectively, its Cpk shows how well while often providing an indication of what is needed to continuously improve. Continuous process improvement assures continuous quality improvement and that is what process managers always focus on most.



2.13.7 Solder Solder is defined as a metallic medium (as an alloy) that melts at temperatures below 800 degrees Fahrenheit to join metal surfaces having much higher melting points. Solder may be in different forms. It may be bar solder as used in wave solder machines, or it may be wire with a flux core used to perform hand soldering. It may also be in the form of a paste composed of solder balls suspended in a binder with a flux component. None of these forms changes its definition. 2.13.8 Solder Paste Solder paste is a metallic medium (as an alloy) formed into solder balls (ranging in diameter from about 4 to 40 microns). The balls are suspended in a binder (composed of flux and other chemicals). Solder paste, as all solder media, melts at temperatures below 800 degrees Fahrenheit to join metal surfaces having much higher melting points. The more spherical are the solder balls, the less surface area they have. This reduces their oxidation amount and rate at which they oxidize. This is important because more oxidation means less solderability. Figure 29 shows solder balls removed from their binder. Figure 30 shows solder balls that have “settled out” in an alcohol solution. The larger balls have moved to the bottom of the jars.

The solder paste composition has a high viscosity of approximately 900,000 centipoise. Higher viscosity aids in preventing solder paste spread on SMT pads. When too high, printing problems may occur relative to dispensing paste through stencil openings. Solder paste is applied to solder termination areas using a printing machine, squeegees, and stencils with openings of specified sizes, shapes, and aspect ratios. All this is done to assure a precise amount is printed where and in the condition required to effect acceptable solder joints. 2.13.9 Wire/Core Solder Wire/Core solder is a solder medium composed of a eutectic alloy. Usually it is 60/40 tin-lead formed into a wire with a hollow flux filled core. Wire/Core solder is specified in varying diameters (typically from about .012” to .060”) for specific hand soldering activities. It provides a mechanism

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to apply flux from its core to the solder termination areas before solder melts, flows, and wets them to effect an acceptable solder joint. 2.13.10 Flux Flux is defined as a chemically and physically active compound that when heated to specified temperatures it promotes base metal surface wetting by molten solder. It does this by removing minor surface oxidation, surface films, or other contamination. It then protects the surfaces from re-oxidation during the soldering process. Various flux types (see POD Hand Soldering and Final Assembly Course) include: 2.13.11 Rosin Rosin flux primarily is composed of natural resin extracted from oleoresin of pine trees and refined. Typically, these fluxes are made up of 60% solvent and 40% solids. Rosin flux (Type R) is an organic material distilled from pine tree sap. The active ingredients in this flux type primarily consist of abietic and pimaric acids. After rosin is extracted from pine trees, it is superficially processed to remove undesirable impurities while neutralizing the acid residues remaining from the extraction process. The purified material is called water-white rosin. It is used to manufacture rosin based flux. Some manufacturers hoping to overcome difficulties associated with obtaining and processing natural rosin, chemically synthesize substitute materials. These materials are called “resins.” Pure rosin is a solid at room temperature and is chemically inactive while being insulative. Rosin melts at about 72 degrees C. (160 degrees F.) and the organic acids become active at around 108 degrees C. (225 degrees F.). This flux type’s peak capability is effected around 262 degrees C. (500 degrees F.). This is the temperature rosin begins decomposing into reducing gases. At temperatures above 346 degrees C. (650 degrees F.), the flux becomes inactive and polymerizes. This causes residue removal difficulties from board and solder joint surfaces. When solder surfaces require a more active flux, chemical compounds called activators are added to the rosin. The most commonly known rosin flux containing activators is called rosin, mildly activated or RMA. Activators are thermally reactive compounds (such as amine hydrochlorides) that break down at elevated temperatures. At these temperatures, hydrochloric acid is released to dissolve the surface oxides, tarnishes, and other contaminates. Mildly activated rosin flux (RMA) may contain a variety of activators in amounts less than 1%. Limits are placed on their electrical and chemical properties before and after soldering Rosin activated flux (RA) typically contains 1% - 5% activators. RA flux is used in applications when RMA is not strong enough. For military purposes, their use usually is limited to component tinning of sealed devices and solid wire. When warm, these fluxes can conduct electricity and can leave residues that can cause corrosion or shorting path formation between conductors.



2.13.12 Organic Acid Flux Organic acid (OA) fluxes are types having active ingredients such as organic acids, organic hydrohalides, amines, and amides. These fluxes are water soluble since they contain no rosin. Good cleaning is critical with these flux types since the salt residues left by them are corrosive and conductive. OA fluxes also are referred to as water soluble fluxes (WSF’s). These fluxes are more aggressive. They generally are classified in J-STD-004 as types M or H. OA fluxes have active ingredients such as organic acids, organic hydrohalides, amines, and amides. All are corrosive activator materials. These fluxes are water soluble or water washable since they contain no rosin, or any low rosin or resin levels. Good cleaning is critical with these flux types as their residues are corrosive and electrically conductive. 2.13.13 Resin Resin flux primarily is composed of natural resins other than rosin types and/or synthetic resins. 2.13.14 Organic Organic elements are based on carbon atom structures. All life forms are organic. Organic fluxes are primarily composed of organic materials other than rosin or resin. 2.13.15 Inorganic Inorganic elements are based on other than carbon atom structures. Inorganic fluxes are solutions composed of inorganic acids and/or salts. 2.13.16 LR, or No-Clean Fluxes Low residue (LR) fluxes usually have lower solids content (less than 5%) than traditional high-solids rosin fluxes. LR fluxes also are referred to as no-clean or “leave on” fluxes. Their residues are not intended for removal from assemblies so cleaning is not required. Their primary activator materials are weak organic acids (adipic or succinic acid). These materials are benign on a board surface and act as electrical insulators. LR fluxes may be higher solvent borne (isopropanol) or water borne in the case of volatile organic compound (VOC) free no clean fluxes. Low residue fluxes are not no-residue fluxes. Although benign, visible residues do remain on the assembly. For this reason, customers may require them to be cleaned. This often is requested for cosmetic rather than functionality reasons. If the flux residues have a significant thickness, they could interfere with electrical testing as “bed of nails” types. However, a different probe point, greater spring strength, or rotating probes often solve this problem. Low residue fluxes also might build up on test pins over time. This requires preventive maintenance as regular cleaning. 2.13.17 Halides Halides are organic salts added to flux as activators. Halides are corrosive. 2.13.18 Fluxing Activities And Classes A liquid flows freely over a surface only if in doing so the total free energy of the system is reduced. In soldering, the free energy of a clean surface is higher than a dirty one. Therefore, it is more likely to promote solder flow. With respect to this, fluxing activities are:



1) Chemical Chemical fluxing activity reduces the oxides from the surface to be soldered and protects this surface from oxidation by covering it. 2) Thermal Thermal fluxing activity assists transferring heat from the heat source to the material being soldered. 3) Physical Physical activities allow the transportation of oxides and other reaction products away from the material surfaces being soldered. In consideration of these three fluxing activities, the following shall be noted: There are two basic ways fluxes eliminate oxidation. They dissolve it into “solution” or they reduce it back to metal. If reduced, it clearly “disappears” and should not be re-deposited as an oxide (to be determined through supplier qualification). Some old flux types “dissolved” oxides by reacting as a fatty acid (rosin) with the metal in the oxide. Then, it was “pushed aside” by solder flow and wetting action. In which mode a flux works, clearly depends on which flux is used. Some fluxes use both modes. ANSI/J-STD-004 differentiates flux activities into three classes. They are Low (type L), Medium (type M), and High (type H). ANSI/J-STD-004 further classifies fluxes as to whether or not they contain halides. For example, a type L0 flux is a low activity, halide free flux. An L1 flux is a low activity flux containing some halide amount. Numbers of industry and consortia studies have been conducted concerning low residue flux reliability. Type L fluxes have been shown relatively benign concerning corrosion and electrolytic failure mechanisms. For this reason, Section 4.2 allows the manufacturer to use a type L flux (L0 or L1) without going through the testing outlined in Appendix D. If the manufacturer chooses to use a more aggressive flux (types M and/or H), the potential exists for corrosive flux residues. If so, the manufacturer must go through the Appendix D testing to demonstrate adequate removal of potentially harmful flux residues. It is highly recommended that the manufacturer not use a type H flux on printed wiring assemblies in any way at any time. It is recommended that, if used at all, a type H flux be limited to component lead tinning. Even then, this may be done only when it can be demonstrated that the highly aggressive flux residues may be thoroughly removed. 2.13.19 Electrochemical Migration Electrochemical migration is defined as the movement of metals across an intervening space between a cathode and anode. This movement is induced by the difference in electrical potential in the presence of fluid producing a micro-film of water on a substrate’s surface. 2.13.20 Soldering Soldering is a process in which two metal surfaces are metallurgically joined, using a specified solder medium (metal filler with a melting point below 800 degrees F.). The process is effected by



“wetting” the surfaces to be joined requiring diffusion and intermetallic growth. The effect of this process is called a solder joint. 2.13.21 Intermetallics In light of the previous definition (soldering), intermetallics always are formed when heated solder surfaces are brought into contact with solder melted upon them. As soldering requires diffusion and internetallic growth, each occurs as part of the soldering process. This is immediately so and time effects intermetallic growth as a continuous process. Intermetallic compounds (IMC's) have much different physical and mechanical properties than the metals comprising them. Typically, intermetallics are very brittle and have poor electrical conductivity. Also, when exposed to air, they oxidize very rapidly. Therefore, excessive intermetallics, formed either during the soldering process or over time, cause unreliable solder joints capable of failing under stressful conditions as thermal, or mechanical shock and/or vibration. 2.13.22 Oxidation (oxide, oxidize) Oxidation is the act of burning. When oxygen is present in an atmosphere, it “burns” or oxidizes all material with which it comes in contact. When this happens, oxides are formed that resist thermal input as well as solder wetting. Some materials resist oxidation better than others. Solder termination areas are copper (oxidizes very rapidly) covered with some protective coating to prevent further oxidation than that which was present before the coating’s application. In an inert atmosphere, oxidation is prevented (there is no oxygen or oxidizing agent). This means that if all processes relating to the use of materials capable of rapid oxidation were performed in an inert atmosphere, they would be more capable of solder wetting. 2.13.23 Inert Atmosphere Inert means inactive or static. An inert atmosphere is one without activity such as that containing no oxygen - one component in our life sustaining atmosphere surrounding earth. Nitrogen is an inert gas. When totally comprising an atmosphere (as inside a soldering machine), activity is eliminated concerning oxidation thereby providing protection to solder termination areas. This promotes or improves thermal input and solder wetting (solderability). This assures a higher rate of higher quality solder joints. 2.13.24 Surface Surface is defined as an object’s area having no depth. 2.13.25 Welding It shall be noted there is a distinction between soldering and welding. Welding is defined as a process in which diffusion and intermetallic formations are effected to metallurgically join metals beyond their surfaces to a specified depth. The welding process is effected at temperatures well above 800 degrees F.. This distinction also provides evidence that solder joining is a reversible process as it relies on heat to “undo” the solder joint. Welding requires complete joint destruction thus making repair and/or rework impossible at the component level, as an example. 2.13.26 Solderability



Solderability is defined as the ease with which solder adheres to a basis metal surface such as a component lead, PCB solder termination pad, or PCB conductor hole pad and wall. The presence of contamination (as oxides or residues) interferes with solderability. Acceptable solderability and solder joint formation, requires good solder wetting and a small contact angle. 2.13.27 Wetting Wetting is defined as the formation of a relatively uniform, smooth, unbroken, and adherent solder film to a basis metal. Wetting requires a solid surface to be completely “coated” by a liquid. This means the liquid maintains intimate contact with all solder termination areas without resistance or any indication of “pulling” back from their surfaces. In solder joining, the liquid is molten solder. What distinguishes “liquid” metal from some other liquid media is its change back to a solid when cooled below its melting point. When two metal surfaces are wetted, they may become joined upon solder medium solidification (often referred to as freezing). This only is done under effectively process managed conditions. Figures 31 and 32 clearly show unacceptable wetting conditions on bare board surfaces. Figure 33 shows an unacceptable solder joint because of J-Lead oxidation.

2.13.28 Contact Angle Contact angle is defined as the angle at which a solder fillet meets the basis metal. A small contact angle indicates good wetting whereas a large angle indicates poor wetting. 2.13.29 Eutectic Eutectic is defined as a combination of two metals (forming an alloy) that melts at a lower temperature than either as individual metals. Also, eutectic is defined as alloys that change directly from liquid to solid, and the reverse, with no intermediate plastic states. Various solder types and their compositions and melting points are found in ANSI/J-STD-006. 2.13.30 Solder Joint A solder joint is effected in the soldering process. Under effectively managed conditions, solder joints exhibit acceptable attributes as smooth, usually shiny, clearly defined, well feathered, completely wetted metallic bonds between two metal surfaces. Figure 34 shows the “perfect” solder joint in cross section.

31 32 33



2.13.31 Aqueous Cleaning Aqueous cleaning is defined as process using water as the primary cleaning agent or solvent. It shall be noted that water is termed the “universal” solvent because it is capable of dissolving all material types to some extent over time. This type cleaning can mean using pure water, with detergent additives, or with a saponifier solution. Aqueous cleaning is done most often with water soluble fluxes, but can be used on rosin and low residue fluxes as well as with the appropriate additives. Aqueous cleaning generally is a multi-stage operation with most cleaning effected in the first wash stages with the dirtiest water while rinsing is done in later stages using the cleanest water. 2.13.32 Manual Cleaning Manual cleaning is a process used to spot clean flux residues from assembly surfaces. It includes using a bristle brush with isopropyl alcohol as the cleaning agent or solvent. This process is not recommended for final cleaning. 2.13.33 Saponification Saponification is defined as a cleaning process using a biodegradable rosin cleaner. In the process, the rosin is changed chemically to become water soluble. 2.13.34 Stencil A stencil is a metal mask (other types are becoming available as polyimide film as an example) with holes (clearly described openings) either etched (chemically milled) or laser cut in a precise pattern across and through it. It is attached to a metal frame capable of being precisely mounted in a stencil printing machine. A stencil printing machine moves a squeegee across it to print, dispense, or apply solder paste onto PCB solder termination areas. This is done to provide the medium needed to effect solder joints when components are adequately placed and reflow soldered. 2.13.35 Stencil Printing Machine A stencil printing machine is equipment required to move a squeegee across a stencil and its openings to print, dispense, or apply solder paste onto PCB solder termination areas. This is done so solder reflow processes may be managed to effect acceptable solder joints.

34



2.13.36 Squeegee A squeegee is a device attached to a stencil printing machine. The machine moves the squeegee across a stencil’s surface and openings with a specified pressure and speed required to print, dispense, or apply solder paste onto PCB solder termination areas. This is done so solder reflow processes may be managed to effect acceptable solder joints. 2.13.37 Reflow Soldering Reflow soldering is accomplished in a machine using air or an inert gas (nitrogen) as the solder reflow mechanism. Conversely, wave soldering requires intimate contact between molten solder and the assembly’s bottom side solder termination areas to effect solder joints. In reflow soldering, a hot gas envelops the entire printed circuit assembly. In doing so, it activates the flux then melts the solder medium having been “printed” on the board’s surface onto which components have been attached. Upon melting, solder wets all termination areas. Upon cooling, the solder joint is made. The entire process is completed in stages corresponding to increasing temperatures in several zones until the highest temperature is reached in what is called the liquidous zone. It is in this zone the solder melts (liquefies) and wets all solder termination areas. Figure 36 shows a typical reflow profile for a particular solder paste manufacturer’s recommendation.

2.13.38 Quality Quality is defined as conformance to clearly specified, understood, and accepted customer contract requirements. 2.13.39 Repair Repair is defined as the process required to restore the functional capability and/or performance characteristics of a defective article. This is done in a manner that precludes compliance of the article with applicable drawings or specifications. 2.13.40 Modification Modification is defined as the process required to revise the functional capability or performance characteristics of a product to satisfy new acceptance criteria. Modifications usually are required to

36



incorporate design changes that can be controlled by drawings, change orders, etc.. Modifications only shall be performed when specifically authorized and described in detail on controlled documentation. 2.13.41 Rework Rework is defined as the act of reprocessing non-conforming or defective articles. This is done using original or equivalent processing to assure full conformance of the article with applicable drawings or specifications. Rework is doing something over that should have been done right the first time. 2.13.42 Other Other terms are defined in IPC-T-50 and in specific guidelines, standards, and specifications indicated in Section 5. herein. 2.13.43 SRT Specific Terminology The following terminology is defined to make it possible to create a new board. The list is composed of terms used when creating or modifying boards, components, or processes: 1) Area Array Heater (AAH) An assembly comprised of a heater and plenum nozzle. Nozzles are part specific and are designed to heat the entire component area. 2) Board Weight Index An index number acting as a pointer to a file that has default process parameter for preheat and reflow. This file can be modified if required (SETTINGS.INI). 3) Core Assembly consisting of the pickup and heater mechanisms mounted to front of top cabinet. Reference generally made to Upper and Lower Cores. Upper core: Assembly composed of the bearings, cylinders, and/or motors for pickup theta and Z motions and heater Z motion Lower core: Assembly composed of the top heater and any others items associated with it. In the case of AAH of PAH, there is a plenum for attachment of this nozzle type. For VPH’s there is the mechanism for sizing the heater, including motors and lead screws. 4) Dialogue Box This is an MS-Windows term for the box or window appearing for entering information of answering a question. Dialogue boxes can become nested (having one within another). Only the last dialogue box shall accept input. To get to the previous dialogue box without entering or changing information in the last dialogue box, use the CLOSE or CANCEL button. 5) Perimeter Array Heater (PAH) An assembly consisting of a heater and multi-tube nozzle. Nozzles are component specific and are designed to heat the perimeter leads of the component. Two styles of the PAH are available. One has a through the middle viewing PAH and one is for use on the AAH plenum (PAAH).



6) Process Variables The following terms describe process variables associated with SRT operation: Ramp: Incrementing heater set-point temperature in time intervals. See Process Settings in creating a new board. Preheat: Time and temperature settings for the initial heating of a component. Reflow: Time and temperature settings for reflow of a component. Post Removal/Additional Reflow Time: Additional heating time after reflow time has elapsed. In a removal sequence, this time begins after component is lifted to near place position. Post Placement Time: Additional heating time after reflow time and Additional Reflow Time (if used) has elapsed. Typically used with a Reflow/Place sequence to allow proper wetting of leads to pads after placement. Solidification Time: Additional time with heat off allowed for solder solidification. Used in any reflow sequence attaching a component to a site. Sequence: A series of events effecting a complete process. SierraMate software has sequences appropriate for the customer’s system requirement. Up to 20 sequences may be resident in the Sequence selection box Sequences are simple ASCII files that are user definable. 2.13.44 Ball Grid Array (BGA) A BGA is a device (component) having solder “balls” or spheres attached to its underside. These balls take the place of leads on leaded devices as the means providing input and output from the component to the board and reverse. There are several BGA types. The most common may be the plastic BGA or PBGA. Another type is the ceramic BGA or CBGA. There are metal packaged BGA’s and micro-BGA’s. All are designed to minimize spacing requirements on the board to which they are assembled. As an example, a quad flat pack (QFP) often requires twice the spacing between devices as that of a similarly design BGA. Figures 37, 38, and 39 show various BGA types.

2.13.45 POD Acronyms A-side The top side of a PC board. Artwork date code Used to verify that stencil and PC board artwork match

37 38 39



B-side The bottom side of a PC board Bank A multi feeder unit used to hold feeders in the IPII machine. Bar Code A set of parallel bars used for inventory purposes, i.e. batch tracking Batch A set of images to be processed in a single programmed run. Blueline The assembly drawing of a PC board BTU The name of the reflow oven. CAD-DLS Computer aided design data link system CCD level The brightness of the camera on FUJI equipment CERT Acronym for chemical emergency response team Cimbridge Drawing A scaled drawing describing a surface mount assembly Conceptronic A chemical based stencil cleaner CP-2 A high speed FUJI SM placement machine with 100 feeder capability. CP-3 A high speed FUJI SM placement machine with 140 feeder capability. CP-4 A super high speed SM placement machine with 140 feeder capability CR Enter Key on machine Customer's parts Parts furnished by the customer for a prototype build. Cut code Refer to the way components are prepped for surface mount handload. Dek An automatic stencil printing machine used to stencil, solder paste on pcbs DFMS Design for manufacturability sheets. (Found in the Traveler) Used for noting external problems found during proto build E-stop Emergency stop switch; stops all machine actions ESD Electro-static discharge Fiducial A reference point on used to align production equipment Fine Pitch Part with .025 center of lead to center of lead spacing GAL Gate Array Logic (Programmed PLCC) GL-2 A FUJI glue dispensing machine. GSP 1 A manual FUJI stencil printing machine used to stencil solder paste on PC boards GSP 2 A semiautomatic FUJI stencil printing machine used to stencil solder paste on PC boards Head Nozzle holders on the IPII machine. Also, the printhead (top section) of Dek Image A single printed circuit assembly. IP-2 A surface mount placement machine that places larger parts at a slower rate of speed than the CP machines Kwiky Proto order that shall be shipped within 5 days. Loop A large setup and a large tear down of the CP placement machines Main Screen The first screen started allows menu selections from on computer controlled equipment (auto screen) Manlink Manufacturing link (software for generating programs)



MCS The terminal that is used to download programs to the machine MERT Acronym for medical emergency response team MFU Refers to multi feeder unit used to hold feeders in the IPII machine (bank) MSDS Material safety data sheets - give chemical information NGS A scaled drawing describing a surface mount assembly PCB Printed Circuit Board P.D. Part Data - Information used to describe the shape of parts to the Fuji machine P&P or PnP Pick and Place (includes stencil to reflow processes) PAL Programmable Array Logic (Programmed PLCC) Panel A term to describe a sheet of printed circuit boards PDA Process Development Assistant PFS Process flow sheet (also called router) PIM Process information management (support group that generates programs for PnP) Pipeline Work in process on conveyors PLCC Plastic body chip carrier; A square part with J leaded legs on 4 sides Polarity An identification mark showing direction for correct placement of part according to documentation Proto Prototype assembly Raw board number A number assigned to an image before any components are placed Recipe A program for assembling a printed circuit assembly Router Process flow sheet Screen Screen is what the DEK calls a stencil SMHL Surface Mount Handload SMQ62 A solder paste with water soluble resin SMT 1 The process where solder paste and components are placed on the A side of the panel and reflowed SMT 2 The process where solder paste and components are placed on the B side then reflow and A side then reflowed SMT 4 The process where solder paste and components are placed on the A side and reflowed, then glue and components are placed on B side and the glue cured. B-side parts are wave soldered SMT 5 The process where solder paste, glue and components are placed on A side then reflowed SMT 6 The process where solder paste, glue and components are placed on the B side and reflowed, then solder paste and components are placed on the A side and reflowed. Limited to "chips" on "B" side SMT 9A or B A process that does not follow the normal rules. It's spelled out on the Router step-by-step. 9A=A side 1st 9B=B side 1st SMT Surface mount technology SMT Carrier Carriers to protect the panels and Bottom side components from damage during reflow in BTU oven or Vitronics process.



Smart Sonic A stencil cleaner (using sound to loosen paste) SOPT List Setup optimization list SOPT Setup optimization SPC Statistical process control Solder Ball Balls of solder on pcboard post BTU >5 mil Solder Bead Small solder balls <5 mil Standoffs Hardware that supports a panel while being processed in the FUJI equipment. Stiffeners Support rails attached to side of panels before BTU process. TAT Turn around time Proto Packet Prototype documentation package Waffle Tower A tray feeder for the IP-2 XFP Extra Fine Pitch, (.020 lead to lead spacing)



3.0 RESPONSIBILITY AND AUTHORITY The following responsibilities shall be fulfilled to ensure stencil printing manufacturing operations are properly effected to assure quality at POD: 3.1 MANUFACTURING ENGINEER The Manufacturing Engineer is responsible and has authority to provide everything needed by manufacturing operations personnel to fulfill their responsibilities at POD. This includes procedures, training, equipment, tools, adequate and safe working conditions, ESD requirements, and all other required elements. 3.2 MAINTENANCE TECHNICIAN The Maintenance Technician is responsible and has authority to ensure all operational elements (equipment, tools, etc.) are maintained and calibrated as specified. This assures all facilities, equipment, and tools are capable of being effectively and efficiently managed to assure product quality meeting specified requirements. 3.3 MANUFACTURING SUPERVISOR The Manufacturing Supervisor is responsible and has authority to provide proper direction to all manufacturing operations personnel at POD. This includes operational procedures, special instructions, schedules, product changes, drawings, and required materials and components. This also includes management directives, performance evaluations, and timely individual and team performance feedback. 3.4 MANUFACTURING OPERATIONS PERSONNEL Manufacturing Operations Personnel are responsible and have authority to assure manufacturing operations are carried out in an effective, efficient manner. They are responsible for performing all manufacturing operations in accordance with current procedures, checklists, and supervisory direction. All personnel are responsible for effecting management policies and directives to assure quality meeting or exceeding specified POD requirements. 3.5 QUALITY ASSURANCE INSPECTION PERSONNEL Quality Assurance Inspection Personnel are responsible and have authority to determine product quality does or does not meet specified POD acceptance criteria. They also are responsible for providing appropriate feedback concerning product quality to management and manufacturing process managers so corrective or continued manufacturing action may be effected.



4.0 OPERATIONS AND QUALITY SYSTEM REQUIREMENTS POD, as an ISO 9000 registered company, bases its quality system on twenty requirements to ensure a firm foundation is established for continuous process improvement and total quality management. Primary to this system is the policy and philosophy that processes shall be managed instead of results as defect. This ensures defect is prevented as early as possible and that quality is effected and assured the first time, on time, every time, at the lowest cost. The following requirements form POD’s quality system foundation to ensure effective, efficient operational and quality system performance: 4.1 MANAGEMENT RESPONSIBILITY 4.2 QUALITY SYSTEM 4.3 CONTRACT REVIEW 4.4 DESIGN CONTROL 4.5 DOCUMENTATION AND DOCUMENT CONTROL 4.6 PURCHASING 4.7 CUSTOMER SUPPLIED PRODUCT 4.8 PRODUCT IDENTIFICATION AND TRACEABILITY 4.9 PROCESS CONTROL 4.10 INSPECTION AND TESTING 4.11 MEASURING AND TEST EQUIPMENT 4.12 INSPECTION AND TEST STATUS 4.13 NON-CONFORMING PRODUCT 4.14 CORRECTIVE AND PREVENTIVE ACTION 4.15 HANDLING, STORAGE, PACKAGING, PRESERVATION, AND DELIVERY 4.16 QUALITY RECORDS 4.17 INTERNAL AND EXTERNAL QUALITY AUDITS 4.18 QUALITY TRAINING 4.19 SERVICING



4.20 STATISTICAL TECHNIQUES Other requirements, starting with 4.21, shall pertain specifically to manufacturing assembly operations. These requirements shall be clearly understood and effected by all manufacturing assembly operations personnel.



5.0 REQUIRED OPERATIONS AND QUALITY SYSTEM ELEMENTS The following elements are required for efficient, effective manufacturing and quality system operations: 5.1 DOCUMENTATION The following documentation shall be available for all management, supervisory, quality, engineering, and operational personnel: 5.1.1 POD, PPM-2050, Safety Procedures 5.1.2 POD, PPM-2045, Electrostatic Discharge Procedures 5.1.3 POD, PPM-2015, Material And Assembly Handling Procedures 5.1.4 POD, QIPM-4030, Audit Of Processes And Procedures 5.1.5 POD Planning Documentation 5.1.6 POD Lot Control Documentation 5.1.7 POD Maintenance Requirements, Specifications And Procedures 5.1.8 POD, QPM-3020, Equipment Calibration Procedures And Logs 5.1.9 POD Quality Assurance Inspection/Test/Analysis Procedures And Logs 5.1.10 POD Operator Operations, And Process Logs 5.1.11 QQ-S-571 Solder Test Results 5.1.12 MIL-F-14256 Flux For Assembly Operations Test Results 5.1.13 MIL-P-55110 Printed Wiring For Electronic Equipment 5.1.14 MIL-P-28809 Printed Wiring Assemblies 5.1.15 POD, POD-5030, Stencil Printing Process Procedures 5.1.16 ANSI/J-STD-001B Requirements For Soldered Electrical And Electronic Assemblies 5.1.17 ANSI/IPC-A-610B Acceptability Of Printed Board Assemblies 5.1.18 IPC-A-600C Acceptability Of Printed Boards 5.1.19 IPC-7721 Repair And Modification Of Printed Boards And Electronic Assemblies 5.1.20 IPC-7711 Rework Of Electronic Assemblies



5.1.21 IPC-TM-650 Test Methods Manual 5.1.22 IPC-T-50 Terms And Definitions 5.1.23 IPC-D-275 Printed Wiring For Electronic Equipment 5.1.24 POD Pre-operational, Operational, And Post Operational Checklists 5.2 FACILITIES, EQUIPMENT, TOOLS 5.2.1 The SRT Summit 1000 machine 5.2.2 The SRT nozzle appropriate for a part w/ 3050-0229 bent at a 90 degree angle to act as a spacer at each corner of the nozzle 5.2.3 The SRT nest appropriate for selected part 5.2.4 The SRT support box sized for the component being reworked 5.2 .5 Detachable edge supports and point supports for the SRT 5.2.6 Leather gloves for handling hot boards 5.2.7 Metron mirrors for inspecting the finished product



6.0 OPERATIONS AND QUALITY SYSTEM ELEMENT EVALUATION AND QUALIFICATION All operation and quality system elements shall be evaluated and qualified before introduction to or use in process managed capabilities at POD. 6.1 ROUTER AND DRAWINGS 6.2 SAFETY, HANDLING, AND ESD 6.3 OPERATIONAL AND WORK SPECIFIC INSTRUCTIONS 6.4 QUALITY SYSTEM DOCUMENTATION 6.5 REPAIR AND REWORK PROCESS MANAGEMENT REQUIREMENTS The repair and rework process manager shall ensure the following requirements are met before beginning production: 1) Tools and equipment are properly prepared before production 2) Printed circuit boards properly cleaned and baked 3) Solder paste as specified 4) Equipment properly maintained, calibrated, and in good working order 5) All safety requirements in place and being met 6) All ESD requirements in place and being met 7) All material handling requirements in place and being met 8) Work area in clean and orderly condition 9) All support elements, tools, and personnel available 10) Work order or traveler correct and available for job 11) Supervisory direction and work instructions available and being used 12) Fiducials bright, shiny, and clearly visible.



7.0 OPERATIONS USING THE SRT REPAIR/REWORK MACHINE These procedures are used to ensure effective, efficient BGA and fine pitch device repair and rework operations at POD. POD operations personnel use specified and approved repair and rework equipment, tools, and attendant process management elements to effect and assure quality repair and rework operations. This is done to assure acceptable solder joint and product quality. 7.1 MACHINE OVERVIEW Figure 40 shows the machine in an operational setting at POD. Figure 41 provides a view of the machine’s internal mechanisms.

40 41



7.2 PRE OPERATIONAL REQUIREMENTS The following requirements shall be met before beginning repair/rework operations: 7.2.1 Handling And ESD Requirements Ensure proper handling and ESD protection. Figure 42 indicates ESD protection required symbol. Figure 43 indicates ESD handling requirements shall be effected. Figure 44 shows the preferred method for handling Class III PCB assemblies. Figure 45 shows an acceptable handling method. In all cases it is required that ESD protection be provided all assemblies and all boards be handled so no damage, contamination, or other defect causing possibilities exist.

NOTE: SPECIAL CARE SHALL BE TAKEN TO AVOID CONTAMINATING SOLDER TERMINATION SURFACE AREAS WITH FINGER PRINTS, GREASE, DIRT, OR OTHER ELEMENTS THAT WOULD CAUSE SOLDERABILITY PROBLEMS OR UNACCEPTABLE SOLDER JOINT FORMATION. 7.2.2 System Operational Steps (Overview) The following discussion provides information concerning basic SRT repair/rework operational steps:

42 43

44 45



1) Power On The operator turns on machine power as well as air/gas and depresses the START button (right front panel below E-STOP button as in figures 46 and 47).

2) Computer On The system computer turns on and boots the following: • Windows • SierraMate for Windows software • Software initialization displaying each segment 3) Operation Once system initialization completed, the system is ready for operation. The main menu is displayed on the monitor screen. It lists the last board processes in (1) Board Box. In the screen’s center, is (2) the component/site, and on the right is (3) the sequence/action. The GO button is very prominent, as it is located in the screen’s center below (2). This screen is shown in figure 48.

46 47

48 49



The trackball/mouse (figure 49) is used to position the screen’s cursor to initiate action as required. Action may be effected to select an appropriate box, as described above, make selections or changes within them or various other Windows locations and menus. After all required settings and selections are made, activating GO is the primary objective to effect rework or repair operations. Depending upon sequences selected, other requirements as boards, components, flux, etc. may need to be specified before effecting operations. Once GO is initiated, an entire sequence is executed. It shall be understood this is dependent entirely on effective operator/machine interaction. NOTE: IT ALWAYS IS POSSIBLE TO CANCEL ANY SEQUENCE OR OPERATION. THIS SHALL BE DONE IF ANY DISCREPANCY IS OBSERVED THAT MIGHT AFFECT SAFETY, PERFORMANCE, AND QUALITY OR ANYTHING ELSE DELETERIOUS TO OPERATIONAL EFFECTIVENESS.



7.3 PRE-OPERATIONAL SAFETY REQUIREMENTS At this time, inspect inside and around the machine (figure 50) for articles or substances that might cause damage, or other process problems, and remove or correct them as necessary to effect safe operations. Figure 51 shows two of the warning labels, found on various machine part locations, that shall be observed for safe operation.

7.3.1 Important Terms And Definitions The following terms, definitions, and information shall be understood and used by all personnel working with or around the SRT repair/rework machine: 1) DANGER is defined as an imminently hazardous circumstance in which death or serious injury may result if adequate precautions are not taken. 2) WARNING is defined as a potentially hazardous circumstance in which death or serious injury may result if adequate precautions are not taken. 3) CAUTION is defined as a potentially hazardous circumstance in which minor injury or damage to equipment or parts may result if adequate precautions are not taken 7.3.2 SRT Equipment Safety Information SRT repair and rework equipment operates at high temperatures capable of causing personal burn injuries. This WARNING is provided indicating it is dangerous for anyone to come in contact with any surfaces labeled HOT or HOT air. No one must ever breathe HOT air. An exhaust vent provides a route for heat dissipation and vapor/fume escape – with proper connection. Another WARNING is provided indicating the hazardous condition existing when pneumatic mechanisms are activated for various activities and sequences. Additionally, a WARNING is provided indicating voltages within the cabinet are capable of causing personal injury or loss of life. DANGER, WARNING, CAUTION: ALWAYS ALLOW THE SYSTEM TO COOL TO A SAFE LEVEL BEFORE PERFORMING MAINTENANCE OR ADJUSTMENTS.

50 51



The machine’s cabinet is designed to protect operating personnel from internal hazards as voltages, high temperatures, and pinch points. Only qualified, trained personnel are allowed to operate equipment with cabinet covers removed. Also, only qualified, trained personnel are allowed access to internal parts and mechanisms while cabinet covers are removed. CAUTION: ALWAYS WEAR SAFETY GLASSES AND PROTECTIVE GLOVES WHEN WORKING WITH OR NEAR EQUIPMENT. ALL PERSONNEL MUST ENSURE ALL WARNING AND SAFETY LABELS, SIGNS, OR OTHER INDICATIONS ARE OBSERVED TO AVOID ACCIDENTS AND PERSONAL INJURY. THIS PROCESS MAY USE A BOARD WITH WET SOLDER PASTE ON ITS SURFACE. SOLDER PASTE CONTAINS LEAD. WEAR LATEX GLOVES DURING THE SETUP OF THE BOARD ON THE MACHINE IF WET PASTE HAS BEEN APPLIED. WASH HANDS AFTER WORKING IN THE AREA, EVEN IF GLOVES WERE WORN. DO NOT EAT, DRINK, OR SMOKE PRIOR TO WASHING HANDS.



7.3.3 Machine And System Readiness Ensure all system settings and elements are as specified. This includes determining system element air pressure (figures 52 and 53), and other requirements such as camera and split mirror locations relative to calibration markers (figures 54 and 55).

52 53

54 55



7.4 PREPARATION The following procedures shall be used to prepare all required elements before beginning repair or rework operations: 7.4.1 Before Performing Any Work Before performing any work, ensure the printed circuit board (PCB/PCBA) to be processed is baked to remove any moisture in the components and PCB substrate. This is necessary to prevent any visible or microscopic popcorning (semi-explosive release of steam from components making them defective) of other parts on the board during the heating cycle. Follow the times and temperatures specified for this baking cycle on the oven and oven documentation. NOTE: TYPICALLY, THE PCB BAKE PROCESS IS DONE OVERNIGHT AT A TEMPERATURE OF 250 DEGREES F. FOR 3 HOURS. FOR MOISTURE SENSITIVE COMPONENTS/DEVICES (MSD's), SEE MSD AND SEALING PROCESSES, HEREIN, STARTING ON PAGE 350. Inspect the board requiring rework. If the part requiring rework has a heatsink on it, refer to the product documentation to determine how to remove the heatsink. Usually it is popped off with a small flat-blade screwdriver. Also, determine all components are in good condition. BGA balls shall be inspected to ensure they all are present and leaded devices shall be checked to ensure their leads are straight and properly aligned (figures 56 and 57). It is easily seen that neither of these parts are acceptable.

NOTE: IF THE HEATSINK REMAINS ON DURING REWORK, IT IS MUCH MORE DIFFICULT, IF NOT IMPOSSIBLE, TO PROCESS (INCREASED THERMAL MASS AND THICKNESS). THE HEATSINK ALSO SHALL INTERFERE WITH THE PICK-UP TUBE. Also check to see if sufficient access around the part to be reworked is available. It may be necessary to remove some topside components to provide enough room. Use a metal ruler to determine if any components are within .200" of the BGA body. If so, remove and set them aside for later re-assembly. A good technique is to place them on top of a clear ESD folder page with the board’s reference designator drawing inside. After removal, place each part on its designated spot

56 57



on the drawing. If any parts are damaged during removal, replace them with like parts for the subsequent attachment process. 7.4.2 Board Flatness (Coplanarity) The board shall be flat and rigidly held during all rework operations performed using this machine. This is one of the repair/rework processes’ most important requirements. If boards and tools are not flat, solder defects result. Inspect all boards to determine their flatness or coplanarity (figure 58).

NOTE: WHEN ADDING A COMPONENT TO A BOARD, SOLDER PASTE SHALL BE PRINTED ON THE BOARD’S SPECIFIED SOLDER TERMINATION AREAS (PADS). IN THIS CASE, BE SURE LATEX OR HEAT-RESISTANT GLOVES ARE WORN DURING SETUP AND WHILE MOUNTING THE BOARD IN THE MACHINE. Select the correct nest (figure 59) for the part to be removed or replaced. It must fit closely around the part’s body so it cannot move while the shuttle moves the part tray to the pick-up tube. Place the nest over the two tooling pins located on the part shuttle. Do this with the raised end to the right. 7.4.3 Heating Nozzles And Support Boxes Heating nozzles deliver hot air from the heating element to the part and board. They provide the mechanism to ensure required top-side board heating is assured, and that specified reflow and acceptable solder joints are effected. Support boxes provide additional printed circuit board support. They also provide additional localized heating directly under the part to be mounted.

58 59



1) Nozzle Selection Select the required heating nozzle for the part to be repaired/reworked. Use calipers (from the toolbox) to measure the part’s length and the width. The correct nozzle’s inner wall is .110" greater than the component’s outer wall (all around). When a rectangular part is required, compare both its length and width dimensions to the length and width dimensions inside the nozzle to ensure the same size relationship exists as before (figure 60). Also, as previously indicated, ensure .200” spacing exists between the placement area and peripheral components to assure clearance for the heating nozzle (figure 61).

2) Nozzle Mounting Mount the nozzle under the two screws on each side of the pick-up tube. Lift and twist the nozzle with a clockwise motion to fit it over the screws and onto the machine. If there is difficulty getting the new nozzle over the spring-loaded screw head, press down lightly on the top of the screw head (arrow in figure 63) and twist the nozzle into place. To reach the screw, curl a finger up and over the plate directly above the nozzle.

62 63

60 61



To remove a nozzle, use gloves or a tool to grasp its lower section and rotate the nozzle counter clock-wise, when viewed from the top. Use a counter clockwise motion to remove the heating nozzle. Rotate the nozzle until it snaps free. Then, slowly pull it downward while taking care not to damage the pickup tube. Figures 62 and 63 show the nozzle mounting process as described. Figure 64 provides a view looking up at the pickup tube (center with red grommet attached), and the two nozzle attachment screws. CAUTION: IF THE NOZZLE WAS JUST USED FOR HEATING A PART, IT IS VERY HOT. USE LEATHER OR THERMAL GLOVES TO REMOVE IT FROM THE MACHINE 3) Support Box (Lower Heater “Chimney”) Selection And Mounting – When Required Select is the SRT support box for the board to be processed. Ideally, the support box shall have the same inner wall dimension as the inner wall dimension of the heating nozzle. Turn the board upside down and test fit it on the opposite side of the board from the BGA to be reworked. Ensure it does not interfere with components on the board’s bottom side. Using its via pattern, center it around the BGA but on the opposite side of the board as shown in figures 65 and 66. The half circle vent holes shall be next to the board (opposite those shown).

65 66

64



Use two pieces of Kapton tape to secure it to the bottom of the board. Avoid covering the vent holes in the support box with the Kapton tape (figures 67 and 68). 7.4.4 Board Mounting Turn the board over and mount it into the machine’s moveable X-Y table edge guides. Boards having many massive parts act as a heatsink. When and where possible, place them toward the machine’s front as it gets hotter than the rear. If overhanging connectors are in the way, mount detachable edge supports onto the table’s frame. Adjust the support locations so they hold the board as rigidly as possible. Place magnetic supports under the board to keep it flat. Follow this by mounting the board in the detachable edge supports by clamping them in place. Adjust all positions so the area under the part being reworked has plenty of under-side air flow for heating (figures 69 and 70). Figure 71 shows the mounted board with the underside board support (chimney).

67 68

69 70



After mounting, the board shall be stiff and flat. If it sags or is floppy when pressed down upon with a finger, use additional supports, or rearrange the ones already being used to eliminate the problem. 7.5 SYSTEM OPERATIONS OVERVIEW When an operator turns on the SRT 1000 system and presses the START/RESET button, it boots directly into Windows. Then, it opens SierraMate software. As the software comes up, progress is displayed as each item is initialized. Once the software has completed initializing, the system is read for operation. On the main screen, the last board processed is displayed in the Board (1) box. In the middle is the box for Component/Site (2), and to the right is a box displaying Sequence/Action (3). In the middle of the screen below (2), the GO button is displayed. A typical operation is carried out by (1) selecting Board, (2) selecting Site, (3) selecting Sequence, then GO. Selection of different board/site/sequence is conducted by clicking the CHANGE button within the respective box (figure 72).

Depending on the sequence selected, other items as board, component, flux, etc. may need to be made available before processing is begun. Once GO has been initiated by clicking, an entire sequence is executed. Sequences require operator/machine interaction.

72

71



7.5.1 Board Board is placed into board holder and rests on support bars, support pins, and/or clamped into holder. Area Array nozzles contact the board in normal operation. Board is placed to provide support under site to be worked on. 7.5.2 Component The SRT 1000 accommodates either area array or leaded components. The system features automatic centering for area array components with a component shuttle and component specific nests. When using area array components, fit appropriate nest to locating pins on part tray. Components are placed into nest before sequence is begun if it requires a new component. Leaded components are accommodated by a component tray fixed to the right rail of board holder and do not use nests above (figures 73 and 74). A different set of sequences is used for leaded components.

7.5.3 Sequence Select the appropriate sequence. As the sequence is being executed, prompts for operator interaction are displayed at the bottom of the screen. When the sequence is complete, provision is made to repeat the same sequence. If this is not needed, click the STOP button and the software returns to the main screen. Sequences for leaded components use the prism to align a component to a nozzle, but picks component from the component tray versus component shuttle. These sequences do not normally appear as available sequences. They are available after related files are renamed. The following provides information concerning renaming sequence files for leaded devices: 1) Exit SierraMate for Windows software 2) Open Windows File Manager 3) In the SRTWIN Directory, locate file with extension LD (leaded device). 4) Change all LD extensions to an ACT extension.

73 74



5) Restart the software Sequences for leaded devices are now available and are designated “L.” NOTE: THE REMOVAL SEQUENCE FOR LEADED COMPONENTS USUALLY IS THE SAME AS AREA ARRAY DEVICES. THEREFORE, NO NEST SHALL BE ON THE PART SHUTTLE IN A REMOVAL SEQUENCE WHEN DOING A LEADED COMPONENT. 7.5.4 Top Heating Nozzles (As In Section 7.4) Nozzles are component specific and shall be installed before a sequence is started. 7.6 CREATING BOARDS, COMPONENT/SITES, AND PROCESSES Programming boards and processes requires accessing the main menu. The menu is displayed across the top of the main screen after double clicking in the dark gray box surrounding the 1, 2, 3, and GO boxes on the screen. The main menu may be password protected. If the system arrives with this menu password protected, the password shall be SYSTEM without being case sensitive. The password may be removed or changed. 7.6.1 Boards Board files are comprised of components/sites. All boards must contain at least one component/site and a default component/site is included when a new board is created. This may be deleted after other components/sites are added to Board. 7.6.2 Components/Sites Unique part location that shall have a specific process assigned to it. Designations usually are component names or site designations. 7.6.3 Variables All variables needed to carry out a sequence on a particular component/site as preheat and reflow time temperatures, alignment, height, place/removal force, etc. Variables used depend on the sequence being performed. 7.6.4 Creating/Modifying a Board All boards must contain at least one component/site. Because of this, a default component is assigned to a board. A default process is assigned for all components based upon the board weight index. Once other components are added to the board, the default component can be deleted. The default process



7.7 OPERATIONS - GENERAL Use the following procedures to effect process management concerning BGA and fine pitch repair and rework operations: 7.7.1 Machine Setup If the machine is off, turn it on by moving the bright yellow and red lever (on the machine’s right side) to the ON position (figure 75). Turn on circuit breakers 1, 2, and 3 to activate control system, and top and bottom heater circuits. Once this is done, the machine automatically boots to the SRT software to run the machine. Figure 76 shows the screen displayed when system turned on.

7.7.2 Screen Display Steps The screen shows 3 steps that shall be specified for the board to be reworked. 1) Assembly Number Determine the assembly number for the selected board. If it is not already displayed in the white box for the 'Board' in item #1, move the cursor to the 'Change' box and click on it. The list of all the boards that have been programmed for the machine appears. If the assembly number is not on the list, contact the engineer or technician for the machine to have it added. Select the assembly number for the board and click on it so it is highlighted. Hit 'OK'. The required board number now appears in the white box. 2) Reference Designator Move to the 'Component/Site' box in item #2. If the reference designator for the part requiring repair is not shown in the box, move the cursor to the 'Change' box and click on it. Use the pull down arrow button to display the other reference designators. Select the appropriate reference designator from the list and hit 'OK'. The correct reference designator is now be visible in the white box. If the reference designator is not on the list, contact the engineer or technician for the machine to have it added. 3) Sequence The third step is to select the sequence for the machine to perform. The choices used for production rework include:

75 76



• 'Machine Warm-up' - Heats machine’s plenum and heating nozzle. Provides more uniform heating during the first part of the day. NOTE: THIS PROCESS STEP NOT USED UNLESS SPECIFIED BY ENGINEERING • 'Remove' - Heats part, automatically lifts it off the board, then allows the machine to cool before discarding the part. • 'Manual Remove' - Heats part, and lifts the heating nozzle so the operator can remove the part with tweezers while the solder is still molten. NOTE: THIS PROCESS STEP NOT USED UNLESS SPECIFIED BY ENGINEERING

• 'Place only' - Places component onto board. • 'Reflow only' - Heats part and allows machine to cool before lifting the heating nozzle out of the way.

• 'Place and Reflow' - Places component onto board, heats part, and allows machine to cool before lifting the heating nozzle out of the way.

• 'Squareness Check' - Calibrates pick-up tube vertical alignment to X-Y axis. NOTE: THIS PROCESS STEP USED ONLY BY ENGINEERING If required sequence not displayed in white box, move cursor to 'Change' box and click on it. Use the down arrow to display other sequences. Select appropriate sequence from list and hit 'Go'. Now it is displayed in box. 7.7.3 Begin Sequence With correct items shown for #1, #2, and #3 begin sequence by hitting GO. Refer to specific instructions for each sequence as described in the next section. 7.8 MACHINE WARM-UP (ONLY USED WHEN SPECIFIED BY ENGINEERING) This sequence is used to warm up the machine at the beginning of use. It helps provide consistent and more even heating for the first rework cycle of the day. 7.8.2 Sample Board Place a scrap blank sample board in the machine and clamp it in place as in figure 78. 7.8.3 GO Hit the "GO" button on the screen by clicking on it with the cursor. The prism moves into position over the heating nozzle and pick-up tube.



7.8.4 Move Board Into Position The machine prompts the user to move the board into position so the nozzle is completely over the scrap board. When in position, hit "GO". 7.8.5 Warm Up The heating nozzle moves down into position to go through a 4-minute warm-up cycle (figure 79). Use this sequence before repair/rework operations – only when specified.

7.9 REMOVE PART The following procedures are used to remove parts from the board: NOTE: GRAPHIC EXAMPLES FOR THIS AND OTHER PROCESSES ARE PROVIDED IN FIGURES 80 THROUGH 99 STARTING ON PAGE 95. 7.9.1 Standard BGA Removal To remove a standard BGA part from the board, select assembly number, reference designator, and 'Remove' sequence from the main screen. NOTE: IF THE PART TO BE REMOVED IS A SOCKET WITH AN OPEN MIDDLE, OR A PART THAT HAS AN IRREGULAR TOP, IT MAY BE NECESSARY TO USE THE 'MANUAL REMOVE' SEQUENCE. The 'Remove' sequence automatically lifts the part off the board and allows the machine to cool before discarding the part. This is preferred over the 'Manual Remove' since there is less likelihood for serious board warpage to occur. 7.9.2 GO If ready, hit the 'Go' button on the screen by clicking on it with the cursor. The prism moves into position over the heating nozzle and pick-up tube. 7.9.3 Move Board Into Position The machine prompts the user to move the board into position so the part to be reworked is under the heating nozzle. Place a red arrow near the part to be reworked so it is easy to find on the video display screen. Do not place the red arrow over the middle of the part because the pick-up tube

78 79



shall have trouble making a seal to the part when trying to lift it off the board. Push the X-Y table to position so the part is under the machine’s prism box. The part shall be visible in the screen. 7.9.4 Fine Adjustment Use the fine adjusting X and Y knobs to center the part over the heating nozzle. The nozzle may be rotated slightly. If so, split the distance between the nozzle to part gap on the part’s left and right. Repeat this process for the top and bottom gap. Ideally, the same gap shall be visible for the tightest areas on all 4 sides of the part. When everything is centered, hit the 'Go' button on the screen. 7.9.5 Preheat, Soak, And Reflow Cycles The machine begins preheating, soaking, and reflowing the solder paste to effect the solder joint. During the 'Remove' sequence, it uses the pick-up tube to lift the part from the melted solder. If the vacuum sensor detects the part was picked up, it turns off the heaters and waits for the machine to cool down before lifting the heating nozzle up and discarding the part. If the vacuum sensor does not detect the part was picked up, it shall re-try as many times as has been programmed. Then, it shall wait for an indication whether to stop trying. Select 'Retry' or 'Cancel' - as appropriate. 7.9.6 Repeat Sequence The software allows repeating the same sequence again after hitting 'Go' or to stop and go back to the main menu by hitting 'Stop'. Use the cursor to indicate the decision. 7.10 ADD NEW PART The following procedures are used to add a new part to an assembly: NOTE: GRAPHIC EXAMPLES FOR THIS AND OTHER PROCESSES ARE PROVIDED IN FIGURES 82 THROUGH 99 STARTING ON PAGE 95. 7.10.1 Place And Reflow Sequence When adding a new part, use 'Place and Reflow' sequence to perform the operation. This sequence is a combination of 'Place Only' and the 'Reflow Only' sequences linked together. Refer to section 10.4 for the specifics about how to place the component. 1) Placement After the alignment process, hit 'Go' and the pick-up tube lowers the part to just above the paste. Next, the heating nozzle drops over the part and touches the board. Then, the pick-up tube gently places the part into the paste. 2) Reflow Do not use the "Place Only' and 'Reflow Only' as substitutes for this combined sequence. If done, the heating nozzle lowers over the part already having been placed onto the board by the pick-up tube. It is much better to allow the heating nozzle to rest against the board and let the pick-up tube place the part into the paste. This does not cause the board to bounce disturbing the part resting in the paste. This effect is believed to be a primary cause of bridging.



7.11 PICK AND PLACE PART The following procedures are used to pick and place a part on the specified board: NOTE: GRAPHIC EXAMPLES FOR THIS AND OTHER PROCESSES ARE PROVIDED IN FIGURES 82 THROUGH 99 STARTING ON PAGE 95. 7.12.1 Placement Requirements To place a new part onto the board and reflow it, only use the 'Place and Reflow' sequence. To place a part onto the board, use the 'Place only' sequence. Once having determined the required sequence, verify it is shown in the 'Sequence' box in item #3 on the main menu. Select the applicable assembly number and reference designator, for the board to be processed, and make sure they are present in the 'Board' and 'Component/Site' box. 7.12.2 Component Requirements At this point, the board with the BGA site pasted has been mounted into the machine. Locate a new part from the stock area. The BGA should have been stored in a sealed container or dry storage box. If not, it shall need to be baked prior to rework. Look at the bottom of the package to verify there are no missing balls. Also double check the stock room issued the correct component, and it is the size and pin configuration required for the board to be processed. 7.12.3 Begin Cycle Hit 'Go' to start the cycle. The machine prompts component placement into the nest. Orient the component so its polarity matches the board’s as currently mounted in the machine. Use the drawing and silk-screen graphics to verify board polarity. Component and board polarity indicators MUST match. If not, rework time shall have been wasted and the board is scrapped. When the part is correctly in the nest, hit 'Go'. To provide one other opportunity to verify polarity, the machine prompts to re-check it. After verification, hit 'Go'. 7.12.4 Site Centering The machine prompts to roughly center site in video window. To do this, push or pull the table to position it so the BGA site pads are visible in the middle of the screen. Rotate the microscope’s magnification knob as needed to view the entire BGA site. This step is provided to achieve only coarse positioning. Precise positioning doesn't matter yet, so don't dwell on this step other than assuring the correct reference designator is in view. To encourage this, the machine only turns on the board lighting. When the BGA's pads are roughly in the middle of the screen, hit 'Go'. 7.12.6 Part Lighting And Precise Alignment The machine now turns on the part lighting together with board lighting. Precise alignment follows. 1) Fine adjustment knobs Use the adjustment knobs on the upper left and lower right side of the table to adjust the board position to make the pads overlap the position of the BGA balls. It is advantageous first to focus on one row of balls and pads - then position them first.



2) Part rotation adjustment Use the silver knob on the upper left side of the shroud (over the heating core and pick-up system) to adjust part rotation. Focusing on one row of balls and pads at a time helps make this adjustment. 3) Part and board lighting adjustment Use the part lighting and board lighting adjustment knobs to change the light intensity on each item in view. These knobs are located on the vertical panel on the right front of the machine. By turning the lights up and down, verification is made concerning what is being viewed on the screen are really the BGA balls, or pads on the board. By concentrating on one corner at a time, watch the pad disappear and the ball reappear in the same spot. This provides assurance the two precisely overlap. 4) BGA pattern If the BGA has only 4 rows of balls, around the package’s perimeter, a pattern of only 4 rows of round objects on each side shall be seen. If more than 4 rows are seen, adjust in left/right, or up/down to make all pads overlap. 5) Continue adjustment Continue adjusting left/right, up/down, rotation, and lighting knobs until a perfect overlap appears. A way to check this is to slightly shift one of the knobs to one side or the other. This makes it possible to observe the overlapped pad and ball move apart. Return the board to the original position and they overlap again. 6) More precise alignment To make a more precise alignment, increase microscopic magnification and turn the knob on the split mirror - at the front of the prism. While continue turning, the lower left corner of the pads and balls are seen moving toward the screen’s center. The upper right pads and balls do the same. Adjust the magnification until the part’s corners (now superimposed upon each other) completely fill the screen. 7) Corner ball alignment Perform the same fine adjustment with left/right, up/down, rotation, and lighting knobs until the corner balls perfectly overlap the corner pads. When satisfied with the part’s position, relative to the board, return the split mirror and magnification to their original positions. 8) Confirm alignment and/or repeat With improved alignment, it still is possible to see the appropriate number of rows on each side of the BGA. If not, a row of pads was skipped. Repeat the steps above to adjust as needed. 7.12.7 Part Placement When everything appears as required, hit 'Go' and the machine places the part. If the 'Place only' sequence was run, the machine shall have placed the part into the paste. Visually determine how well this was done. If the 'Place and Reflow' sequence was used, the machine shall have lowered the part, lowered the heating nozzle to the board, placed the part, and reflowed it.



7.12 REFLOWING PART Use the following procedures to effectively manage reflow operations: NOTE: GRAPHIC EXAMPLES FOR THIS AND OTHER PROCESSES ARE PROVIDED IN FIGURES 82 THROUGH 99 STARTING ON PAGE 95. 7.12.1 Reflow After Component Placement To reflow a part already placed on the board, select the assembly number, reference designator, and 'Reflow only' sequence from the main screen. If the part to be reflowed has a heatsink on top, remove it first. 7.12.2 Reflow Only The 'Reflow only' sequence heats only the board area under the heating nozzle. It does not allow part removal or placement. Primarily, it is used for parts already having been placed and reflowed, and when the paste did not fully flow. Another use is with a BGA socket where the solder joints have been cracked. The reflowing action of this sequence allows the joint’s solder to flow again to “heal” the crack. This sequence also may be used to eliminate an open under a BGA if enough of the solder ball is present. Liquid flux shall be applied and allowed to run down between the rows of the BGA to help its balls reflow and wet to the pad. NOTE: THIS SEQUENCE SHOULD NOT BE USED IN AN ATTEMPT TO REMOVE A BRIDGE FROM A BGA. THE ADDITIONAL REFLOW shall DO NOTHING TO REMOVE AN EXISTING BRIDGE. Hit the 'Go' button. The prism moves into position over the heating nozzle and pick-up tube. 7.12.3 Coarse Positioning Board For Preheating The machine prompts the user to move the board into position so the part to be preheated is under the heating nozzle. Always place a red arrow near the part needing to be reheated so it is easy to find on the video screen. Push the X-Y table to position the part under the prism box of the machine. The part shall be visible in the screen. 7.12.4 Fine Adjusting Board For Preheating Use the fine adjusting X and Y knobs to center the part over the heating nozzle. The nozzle may be rotated slightly from the part. If so, split the distance between the nozzle to part gap on the part’s left and right side. Repeat the same process for the top and bottom gap. Ideally, the same gap shall be visible for the tightest areas on all 4 sides of the part. When everything is centered, hit the 'Go' button on the screen. 7.12.5 Pheheating, Soaking, And Reflow Sequence The machine begins preheating, soaking, and reflowing the part’s solder joints. After completing reflow, the sequence allows the machine and board to cool before the heating nozzle is lifted off the board. 7.12.6 Repeat Sequence The software allows repeating the same sequence by hitting 'Go', or to stop and go back to the main menu by hitting 'Stop'. Use the cursor to indicate what is required.



NOTE: FOR THOSE PROCESSES REQUIRING SOLDER PASTE APPLICATION, ENSURE PAD SURFACES ARE CLEAN, FREE OF DEBRIS OR EXCESS SOLDER, AND ARE FLAT (FIGURE 80) SO PLACEMENT AND REFLOW IS PROPERLY EFFECTED. FOR PLACE AND REFLOW PROCESSES, NOT REQUIRING SOLDER PASTE, APPLY SPECIFIED FLUX ONTO SPECIFIED PAD AREAS (FIGURE 81).

Figure 80) Ensure part mounting site clean, smooth, and solderable.

Figure 81) Apply specified flux to part mounting site as required to assure



NOTE: THE FOLLOWING IMAGES SHOW VARIOUS STEPS REQUIRED TO REMOVE, PICK AND PLACE, REFLOW, PLACE A NEW PART, AND FOR SOLDER PASTE APPLICATION:

Figure 82) Select requirement from boxes 1, 2, and 3 as required.

Figure 83) Mount board (underside chimney too), as specified, and move it

Figure 84) Use Y axis knob for fine adjustment

Figure 85) Use X axis knob for fine adjustment.

Figure 86) Use Theta axis knob for fine adjustment.

Figure 87) View fine adjustment effects on screen assuring part centered within



Figure 88) Closely watch heater nozzle descend and position over/around part

Figure 89) Monitor display as graph shows heating effects to ensure

Figure 90) When picking and placing, center part within heating nozzle.

Figure 91) When picking and placing, use split mirror to accurately align

Figure 92) Observe pickup tube descending and placing part precisely

Figure 93) Observe heating nozzle descend over and precisely around part



NOTE: THE NEXT TWO IMAGES SHOW SOMETHING OF THE SOLDER PASTE

STENCIL PRINTING PROCESS. FOR THE REWORK OPERATION, THIS SELDOM IS REQUIRED, NOR IS IT PREFERRED. BETTER REFLOW PERFORMANCE,

QUALITY, AND RELIABILITY IS ACHIEVED WITHOUT THIS PROCESS STEP WHEN

USING A PASTE FLUX ONLY.

NOTE: IF IN SOME INSTANCES SOLDER PASTE APPLICATION IS REQUIRED, THE

NEXT PROCESS STEPS SHALL BE EFFECTED. THERE NOW ARE BETTER STENCILS AVAILABLE AND THE TOOL SHOWN NO LONGER IS REQUIRED AS

FLAT STENCILS, THAT CAN BE TAPED TO THE REWORK SITE'S SURFACE, ARE

PREFERRED - AS SHOWN IN THIS BOOK'S PART TWO, 11.4.

7.13 SQUARENESS CHECK (PERFORMED ONLY BY ENGINEERING) Use the following procedures to run the squareness check program: 7.13.1 Program Elements And Requirements The squareness check program is used to square the pick-up tube to the X-Y table where the board is held. The SRT suitcase is needed. It contains a rectangular plate and a square for this process. It is stored by technicians - in the spare parts area. 7.13.2 Mount Rectangular Plate Remove the detachable edge supports from the X-Y table. Mount the rectangular plate in the edge guides with the beveled edge facing up (figure 100).

Figure 94) Visually inspect part to determine accurate alignment with PCB

Figure 95) When visually accepted, have part/PCB X-Rayed to ensure

Figure 96) Select required micro-stencil for solder paste printing when reqhired.

Figure 97) Apply solder paste using micro-stencil and squeegee ensuring



7.13.3 Bring Up Squareness Check Sequence Bring up the "Squareness Check" sequence on the Main Screen and hit "GO". 7.13.4 Perform Squareness Measurement The pick-up tube comes down to its near place position. Use the square to check squareness from front to back and left to right (figure 101).

7.13.5 Perform Squaring Process Bend the pick-up tube slightly to improve its squareness. If severely out of square, consult with the technician to remove the tube and have it straightened. 7.14 WORK INSPECTION When a BGA part has been added to the board, quality is inspected to verify successful rework. Board Test & X-Ray is used to verify the process. As a preliminary step, do the following part inspection before taking the board to these other areas. 7.14.1 Visual Component To Board Alignment (Squareness) Check the part squareness relative to the silk-screen or traces on the board (figure 102). A part having been fully reflowed is very square to the board. If rotated (skewed relative to the reference line or lifted as in figure 103), this is a common sign the part has not fully reflowed.

100 101

102 103



7.14.2 Visually Aided Reflow And Solder Joint Quality Verification Visually inspect, or use a microscope and/or Metron Mirror to look at the 4 sides of the BGA (figure 104). First, check there was total reflow on all 4 sides, and the part collapsed towards the board into the solder. If any residual solder paste bricks are seen, complete reflow was not effected. If complete reflow was not effected, consult with the engineer to have the profile changed. 7.14.3 Bridging Verification Once good solder reflow is verified, verify there are no bridges. X-Ray is used exclusively for this determination as in figure 105 on previous page. 7.14.4 Repeat Process And X-Ray Or Board Test Repeat the same process for the part’s other direction. If both sides look good, take the board to X-Ray or Board Test for verification that there are no opens or other electrical problems (figures 106 and 107). Each BGA that passes X-Ray shall be marked "X-Rayed". Each BGA that does not pass X-Ray shall be marked with a red arrow. All boards shall be returned to the BGA rework center following the X-Ray process.

106 107

104 105



NOTE: BEFORE, DURING, AND AFTER PROCESS COMPLETION, ENTER REQUIRED INFORMATION AND NOTES IN THE MANUAL LOG (FIGURE 107). REFER TO THE DATALOGGER FILE MENU (FIGURE 108) FOR DETAILED INFORMATION CONCERNING TIME, DATE, AND SEQUENCE.

7.15 TURN MACHINE OFF Upon having completed or stopped the last sequence and when ready to turn the machine off, flip the bright yellow and red lever on the right side of the machine to the 'Off' position.

107 108



7.16 MEASURING AND GRAPHING TEMPERATURE PROFILES (ENGINEERING ONLY) There are 6 thermocouples on the machine that are used to profile boards and sense the current temperatures. The first two are built into the machine and are used to measure the top heater and bottom heater temperatures. The other 4 are located on the left side of the machine. These can be positioned on a board or in and around the heating nozzle by tacking them down with Kapton tape (109). The most accurate measurements are made using scrap boards and drilling holes in them to mount thermocouples in part site corners so tips are in very close proximity to areas to become solder joints (figure 110). To show real time temperature measurements, use the cursor to click on the graph icon near the upper left corner of the screen. A graph appears showing what is being measured. Hit the 'Close' button to hide the graph or the 'Size' button to reduce the size of it on the screen. Figure 111 shows the beginning of thermal profiling process. Figure 112 shows acceptable profile for a particular part and board.

7.17 PROCESS CONTROLS AND MONITORS The following requirements shall be met to ensure effective, efficient process control and monitor: 7.17.1 Stencil Storage Store the minimicro stencils in their appropriate storage trays on the rework station. Verify they are clean before using. Inspect the solder paste bricks per the inspection criteria before going on to the next phase of BGA repair.

Figure 109) One method used to measure temperature profiles on

Figure 110) The preferred method used to measure temperature profiles on

Figure 111) Display showing beginning of temperature profiling process

Figure 112) Final graph showing acceptable thermal profile for particular



7.17.2 Troubleshooting Tips

PROBLEM POSSIBLE SOLUTIONS The board number or component reference designator are not in the list of possible parts.

Get the engineer or technician to set up the correct files for this new board and/or part.

Part placement is offset. Check for squareness on the pick-up tube, using the square from the SRT tool kit and the "Squareness Check" sequence. Consult the technician or engineer to help check this. Try a dry run of the "Place only" sequence onto a non-pasted board. See if the placement aligns to the pads.

Balls of the BGA do not line up directly over the pads on the board. (Part appears to be a different size in the video screen during alignment.

Check the alignment offset in the SRT configuration file. It is accessible by choosing Setup, Configuration, Prism, and finally Alignment Height. Check that the board thickness and part thickness are entered correctly on the board and component/site specification screens.

The video screen is not displaying what is expected. Check that the magnification on the microscope is not caught between settings. Check that the split mirror is reset to its original position and not overlapping images.

There is a gap between the heating nozzle and the board on one or more sides.

The board is not flat. Verify the support box was used and add more underside support pins. This condition shall probably cause bridges. One of the underside support pins may be resting on a bottom side component or a through-hole lead. Support pins for the Mini-Micro stencil are being used in place of the SRT pins. The wrong pins shall lift the board too high and make it bow upward. The nozzle is resting on a component within the .200" keepout area. The part shall need to be removed before rework can proceed.

The board is not flat in the machine. Support pins and/or the support box are not being used to support the board. The support pins for the Mini-Micro stencil are being used in place of the SRT pins. The wrong pins shall lift the board too high and make it bow upward. The support box or support pins are resting on bottom side components or through hole leads.

Nozzle is stuck in the down position against the board. The board may not be flat. Push up gently on the left side of the heater core to allow the machine to lift it up out of the way. Re-adjust the board supports on the assembly. The air or nitrogen line may have been detached from the machine.



PROBLEM POSSIBLE SOLUTIONS Nozzle is stuck in the up position. Grab the nozzle on the machine and push on it slightly.

It shall sometimes stick in this position if the machine hasn't been used in awhile.

Can't pick up the part off of the board during "Remove" sequence. A red arrow or label is on the part and the pick-up tube can not get a good vacuum seal to it. Remove or shift the label. The heatsink was not removed from the BGA prior to rework. The profile is not getting the board hot enough to melt the solder joints of the part. Try using the "Manual Remove" sequence and lift the part off with tweezers. If the part is still stuck, consult with the engineer or technician to modify the profile.

All the solder paste didn't melt when the part was added on. The wrong profile was used to heat the board during the reflow cycle. The incorrect profile applied too little heat to the board and part such that the solder in the paste did not melt. If upon verification, the correct profile was used, consult with the engineer or technician. A longer reflow time or higher temperature at reflow may be needed.

A small number of solder bridges formed under the part. There was too much paste from the mini stenciling process. The board was not flat during the reflow cycle. Check that a support box was used under the part and additional SRT point supports were used in other areas. A gap may be visible between the nozzle and the board surface on one side. The part may have been out of the dry packaging and storage environment. This caused the package to warp. The part may be too heavy and it needs high lead corner balls to act as a stand-off. Consult with the engineer on this problem.

A large number of solder bridges formed under the part. The wrong profile was used to heat the board during the reflow cycle. The incorrect profile applied too much heat such that the part collapsed too close to the board surface. If upon verification, the correct profile was used, consult with the engineer or technician. There was too much paste from the mini stenciling process.

The part being removed has stuck to the nozzle. A label on the part may have melted and attached itself to the pick-up tube. Get a technician or engineer to clean out the tube. Consult with the material engineer.



PROBLEM POSSIBLE SOLUTIONS Open joints were detected at X-ray or board test. The part may have been out of the dry packaging and

storage environment. This caused the package to warp. The replacement package may have been missing a ball. The board may not be flat. Adjust the under side support pins to assure flatness. Verify the support pins being used are only the SRT type.

"Cone-head" shaped joints were detected at X-ray. The solder did not fully flow during heating. Consult with the engineer or technician to modify the profile. Solder mask has been flaking off around the pads. Use micro-taping to cover these areas if it is severe.

The SRT software doesn’t come up when the machine is turned on. Consult with the engineer or technician to determine what type of software problem or computer hardware problem is occurring.

7.18 MAINTENANCE AND CALIBRATION The following procedures shall be used to perform maintenance and calibration processes: 7.18.1 Squareness Check (Engineering Only) Once a week, and whenever the machine is placing components with an offset from the pads, the pick-up tube shall be squared. Mount the metal plate from the technician's alignment kit onto the edge guides of the X-Y table. Select and run the "Squareness Check" sequence from the Main Menu. Use the square from the kit to see if it is square to the plate. Check it from front to back and from side to side. Push gently on it to bring it into position. If it does not cooperate, the technician may need to remove it and straighten it. 7.18.2 Setting Up New Profiles (Engineering Only) The engineer or technician shall need to set up all new profiles for parts not already in the system. The rework process is designed to try and mimic the original assembly process as closely as possible. To do that, a preheat, a soak, a reflow, and a cool down cycle are all part of the reflow profile to correspond to the same cycles in the reflow ovens. 1) To successfully set-up a reflow profile, a little bit of know-how, a little bit of luck, and a lot of trial-and-error is needed. This usually is done on a prototype board that a customer wants to use. For this reason, usually is best to start on the cool end of the spectrum increasing temperatures and times as needed. 2) Sequences are all set up to follow the same preheat, soak, and cool down cycle. The machine's reflow temperature and duration are specified by the engineer or technician in the "Times and Temperatures" pull-down menu. Access this by double-clicking the mouse inside the grey box on the screen. Type in the password and access is gained to all the maintenance and set-up menus. The standard profile is shown in figure. 3) From "Times and Temperatures" screen, select the required board number and reference designator. The sequence also can be selected, but it does not seem relevant for SRT's software.



Modify the top header reflow temperature, time and additional reflow time as required. Other variables may be modified but, as the sequences are written, they do not affect the profile. 4) To set up a new board, go into the board and component/site pull-down menus to add them to the lists. Go into the "Times and Temperatures" and estimate the peak temperature and the time settings. Some general rules of thumb are: • For boards with 8 layers or less, start a peak temperature between 250 degrees C and 290 degrees C. • For boards with more than 8 layers and lots of ground planes, start with a peak temperature between 290 degrees C and 340 degrees C. • Metal heat sinks on the top of the part seem to help evenly distribute the heat. This tends to reduce the peak temperature needed to reflow the part. • Generally, adding a part onto the board takes more heat than removing it (up to 50% more). • The sides and corners of the part tend to reflow last. If the sides have complete reflow, the interior balls shall have complete reflow. • Different reference designators of the same part on the same board may require different profiles. • The nearer the part to the board center or to heat-sinking parts, the more heat shall be needed to reflow it. 5) An effective, non-destructive way to thermocouple a new part is to tape the thermocouples to the board’s surface at the 4 corners of the part. Do this to a board where the part needs to be removed. Avoid thermocoupling a part in wet solder paste. 6) Run the removal sequence with initial time and temperature settings. Ideally, all 4 thermocouples shall indicate a minimum of 210 degrees C for at least 30 seconds, and a peak temperature no more than 250 degrees C. Since the back of the part is much cooler than its front, due to the machine's air flow, pay close attention to the bounds on this recommendation. It also is a good idea to not allow the solder to be molten at any place on the part for more than 2 1/2 minutes. 7) After first attempting part removal, much knowledge may be applied concerning future time and temperature relationships, as well as peak temperature requirements.



8.0 QUALITY SYSTEM AND OPERATIONS AUDIT CHECKLIST The following checklist shall be used by all repair/rework process managers to ensure effective, efficient repair/rework process management. The checklist shall be used before, during, and after operations. 8.1 PRE PROCESS START REQUIREMENTS AND SAFETY INSPECTION

� INSPECT AROUND AND IN MACHINE FOR ANY SAFETY VIOLATIONS OR ANY OBJECTS THAT MIGHT CAUSE PERSONAL INJURYU OR MACHINE DAMAGE

� MACHINE SETUP – POWER ON

� COMPUTER BOOT – PROPER DISPLAY SCREEN

� SCREEN DISPLAY STEPS - SHOWS 3 STEPS FOR BOARD TO BE REWORKED � 1 - ASSEMBLY NUMBER FOR BOARD - CHANGE - SELECT � 2 - COMPONENT/SITE – CHANGE – SELECT – REFERENCE DESIGNATOR � 3 - SELECT SEQUENCE � REMOVE � PLACE ONLY � PLACE AND REFLOW

� IF REQUIRED SEQUENCE NOT DISPLAYED - CHANGE BOX – SELECT

� BEGIN SEQUENCE - WITH CORRECT ITEMS SHOWN FOR #1, #2, AND #3 - BEGIN SEQUENCE (GO) - NEXT SECTION 8.2 MACHINE WARM-UP (ONLY WHEN SPECIFIED)

� SAMPLE BOARD - CLAMP IN PLACE

� MOVE BOARD INTO POSITION - MACHINE PROMPTS TO MOVE BOARD INTO POSITION - NOZZLE COMPLETELY OVER SCRAP BOARD - WHEN IN POSITION - GO

� WARM UP HEATING NOZZLE - MOVES INTO POSITION – 4 MINUTE WARM-UP CYCLE 8.3 PART REMOVAL

� STANDARD BGA REMOVAL - SELECT ASSEMBLY NUMBER - REFERENCE DESIGNATOR - REMOVE SEQUENCE FROM MAIN SCREEN



NOTE: IF PART TO BE REMOVED IS A SOCKET WITH AN OPEN MIDDLE, OR A PART THAT HAS AN IRREGULAR TOP, IT MAY BE NECESSARY TO USE 'MANUAL REMOVE' SEQUENCE

� REMOVE SEQUENCE - AUTOMATICALLY LIFTS PART OFF BOARD - ALLOWS MACHINE TO COOL BEFORE DISCARDING PART NOTE: PREFERRED OVER 'MANUAL REMOVE' - LESS SERIOUS BOARD WARPAGE

� GO - PRISM MOVES INTO POSITION OVER HEATING NOZZLE AND PICK-UP TUBE

� MOVE BOARD INTO POSITION - MACHINE PROMPTS TO MOVE BOARD INTO POSITION SO PART TO BE REWORKED IS UNDER HEATING NOZZLE NOTE: PLACE RED ARROW NEAR PART TO BE REWORKED SO IT IS EASY TO FIND ON VIDEO DISPLAY SCREEN. DO NOT PLACE OVER MIDDLE OF THE PART - PICK-UP TUBE SHALL HAVE TROUBLE MAKING A SEAL TO PART WHEN IT TRIES LIFTING IT OFF

� PUSH X-Y TABLE TO POSITION PART UNDER MACHINE’S PRISM BOX - PART VISIBLE ON SCREEN

� FINE ADJUSTMENT - FINE ADJUST X AND Y KNOBS - CENTER PART OVER HEATING NOZZLE - NOZZLE MAY BE ROTATED SLIGHTLY - IF SO, SPLIT DISTANCE BETWEEN NOZZLE TO PART GAP ON PART’S THE LEFT AND RIGHT - REPEAT PROCESS FOR TOP AND BOTTOM GAP NOTE: IDEALLY, SAME GAP VISIBLE FOR TIGHTEST AREAS ON ALL 4 SIDES OF PART.

� WHEN EVERYTHING CENTERED - GO

� PREHEAT, SOAK, AND REFLOW CYCLES - MACHINE NOW PREHEATS, SOAKS, AND REFLOWS SOLDER PASTE TO EFFECT SOLDER JOINT NOTE: DURING REMOVE SEQUENCE IT SHALL USE THE PICK-UP TUBE TO LIFT PART FROM MELTED SOLDER. IF VACUUM SENSOR DETECTS PART PICKED UP, IT SHALL TURN OFF HEATERS AND WAIT FOR MACHINE TO COOL DOWN BEFORE LIFTING HEATING NOZZLE UP AND DISCARDING PART. IF VACUUM SENSOR DOES NOT DETECT PART PICKED UP, IT RETRIES - TIMES PROGRAMMED - WAITS FOR INDICATION TO STOP TRYING. RETRY OR 'CANCEL - AS APPROPRIATE

� REPEAT SEQUENCE - SOFTWARE REPEATS SAME SEQUENCE - GO OR STOP 8.4 ADD NEW PART � PLACE AND REFLOW SEQUENCE - SEQUENCE IS COMBINATION - PLACE ONLY/REFLOW ONLY SEQUENCES LINKED



� USE SPECIFIED PART NUMBER WITH SPECIFIED BOARD WITH SPECIFIED HEATING NOZZLE (PART PERIMETER INSIDE HEATING NOZZLE WITH .110” CLEARANCE ALL AROUND). � USE SPECIFIED BOARD SUPPORT AS REQUIRED � FLUX SITE WITH SPECIFIED FLUX (TYPE, SHELF LIFE, ETC.) AT SPECIFIED LOCATION AND ENSURE NOT ON SITE LONGER THAN ½ HOUR NOTE: BE SURE TO INSPECT PART FOR MISSING BALLS (BGA’S) OR BENT LEADS (LEADED DEVICES). � ALIGN PART USING VISION CAMERA AND SPLIT MIRROR ENSURING ALL BALL OR LEAD ROWS ALIGN PROPERLY WHILE ENSURING ALL PADS ARE COVERED WITH CORRESPONDING BALLS OR LEADS � PLACEMENT AFTER ALIGNMENT – GO - PICK-UP TUBE LOWERS PART TO JUST ABOVE PASTE (WHEN SPECIFIED) - HEATING NOZZLE DROPS OVER PART - TOUCHES BOARD - PICK-UP TUBE GENTLY PLACES PART INTO PASTE � REFLOW - DO NOT TO USE PLACE ONLY/REFLOW ONLY AS SUBSTITUTES FOR THIS COMBINED SEQUENCE AS HEATING NOZZLE LOWERS OVER PART ALREADY PLACED BY PICK-UP TUBE - ALLOW HEATING NOZZLE TO REST AGAINST BOARD AND LET PICK-UP TUBE PLACE PART INTO PASTE NOTE: THIS DOES NOT ALLOW BOARD TO BOUNCE TO DISTURB PART RESTING IN PASTE. THIS EFFECT IS BELIEVED TO BE A PRIMARY CAUSE OF BRIDGING CAUTION: OPERATORS ONLY REFLOW ONCE. IF UNSUCCESSFUL, CONTACT ENGINEERING TO CHANGE PROFILE AS ONLY THREE REWORK CYCLES ARE PERMITTED THEN BOARD SHALL BE SCRAPPED. ALSO, DO NOT ROTATE OR MOVE BOARD FROM POSITIONS SHOWN IN FOLLOWING PHOTOS AS ENGINEERING HAS PROFILED FROM PRECISE LOCATIONS. 8.5 PICK AND PLACE PART � PLACE NEW PART ON BOARD AND REFLOW - ONLY USE PLACE AND REFLOW SEQUENCE. VERIFY SHOWN IN THE 'SEQUENCE' BOX (ITEM 3) ON MAIN MENU -SELECT APPLICABLE ASSEMBLY NUMBER AND REFERENCE DESIGNATOR, FOR BOARD TO BE PROCESSED - SURE PRESENT IN BOARD AND COMPONENT/SITE BOX � BOARD WITH REQUIRED BGA SITE PASTED (AS REQUIRED) � BOARD MOUNTED ONTO MACHINE WITH REQUIRED “HEAT CHIMNEY” AND PERIPHERAL SUPPORTS � NEW PART FROM STOCK



NOTE: THE BGA SHALL HAVE BEEN STORED IN A SEALED CONTAINER OR DRY STORAGE BOX. IF NOT, IT SHALL NEED TO BE BAKED PRIOR TO REWORK. LOOK AT THE BOTTOM OF THE PACKAGE TO VERIFY THERE ARE NO MISSING BALLS. ALSO DOUBLE CHECK THE STOCK ROOM ISSUED THE CORRECT COMPONENT AND IT IS THE SIZE AND PIN CONFIGURATION REQUIRED FOR THE BOARD TO BE PROCESSED. � BEGIN CYCLE - GO - MACHINE PROMPTS - PLACE PART INTO NEST. ORIENT PART’S POLARITY - MATCH BOARD MOUNTED IN MACHINE. NOTE: USE DRAWING AND SILK-SCREEN GRAPHICS TO VERIFY BOARD POLARITY. COMPONENT AND BOARD POLARITY INDICATORS MUST MATCH. IF NOT, REWORK TIME WASTED AND BOARD SCRAPPED. � WHEN PART CORRECTLY IN NEST - GO - MACHINE PROMPTS TO CHECK POLARITY AGAIN - GO � MACHINE PROMPTS - COARSE CENTER SITE IN VIDEO WINDOW - PUSH OR PULL TABLE AROUND TO POSITION - BGA SITE PADS VISIBLE IN MIDDLE OF SCREEN. ROTATE MICROSCOPE MAGNIFICATION KNOB TO VIEW ENTIRE BGA SITE AT ONE TIME. NOTE: THIS STEP PROVIDED ONLY TO ACHIEVE COARSE POSITIONING. PRECISE POSITIONING NOT NOW IMPORTANT - ASSURE ONLY CORRECT REFERENCE DESIGNATOR VIEWABLE. TO ENCOURAGE THIS, MACHINE ONLY TURNS ON BOARD LIGHTING. WHEN BGA PADS ROUGHLY IN MIDDLE OF THE SCREEN � GO � MACHINE TURNS ON PART AND BOARD LIGHTING. PRECISE ALIGNMENT FOLLOWS: � USE ADJUSTMENT KNOBS ON UPPER LEFT AND LOWER RIGHT SIDE OF TABLE TO ADJUST BOARD POSITION MAKING PADS OVERLAP BGA BALL POSITIONS. FOCUS ON ONE ROW OF BALLS AND PADS - POSITION FIRST � USE SILVER KNOB ON UPPER LEFT SIDE OF SHROUD OVER HEATING CORE AND PICK-UP SYSTEM TO ADJUST PART ROTATION. FOCUS ON ONE ROW OF BALLS AND PADS AT A TIME TO ADJUST � USE PART AND BOARD LIGHTING ADJUSTMENT KNOBS TO CHANGE LIGHT INTENSITY ON EACH ITEM IN VIEW. NOTE: BY TURNING LIGHTS UP AND DOWN, VERIFICATION MADE ABOUT WHAT IS SEEN ON SCREEN ARE BALLS OR PADS ON BOARD. CONCENTRATE ON ONE CORNER AT A TIME - WATCH PAD DISAPPEAR AND BALL REAPPEAR IN SAME EXACT SPOT. THIS HELPS ASSURE PRECISE OVERLAP. IF BGA HAS ONLY 4 ROWS OF BALLS ALL AROUND PERIMETER, THERE ONLY SHALL BE SEEN 4 ROWS OF ROUND OBJECTS ON EACH SIDE. IF MORE THAN 4 ROWS SEEN, ADJUST IN LEFT/RIGHT, OR UP/DOWN TO GET ALL PADS TO OVERLAP



� PART PLACEMENT - GO - MACHINE PLACES PART. IF PLACE ONLY SEQUENCE RAN - MACHINE PLACES PART INTO PASTE - VISUALLY OBSERVE PLACEMENT RESULTS. IF PLACE AND REFLOW SEQUENCE USED, MACHINE LOWERS PART, LOWERS HEATING NOZZLE TO BOARD, PLACES PART, AND REFLOWS IT. 8.6 REFLOW OPERATIONS REFLOW PART PLACED ON BOARD � SELECT ASSEMBLY NUMBER, REFERENCE DESIGNATOR, AND REFLOW ONLY SEQUENCE FROM MAIN SCREEN. � COMPONENT SITE FLUXED AS SPECIFIED AND LOWER SUPPORT “HEAT CHIMNEY” IN PLACE WITH SPECIFIED BOARD EDGE SUPPORTS. NOTE: IF PART TO BE REFLOWED HAS A HEATSINK ON TOP, REMOVE IT FIRST. REFLOW ONLY SEQUENCE ONLY HEATS BOARD AREA UNDER HEATING NOZZLE. IT DOES NOT ALLOW PART REMOVAL OR PLACEMENT. ALSO, THIS SEQUENCE SHOULD NOT BE USED TO TRY AND REMOVE A BRIDGE FROM A BGA. THE ADDITIONAL REFLOW SHALL DO NOTHING TO REMOVE AN EXISTING BRIDGE � GO - PRISM MOVES INTO POSITION OVER HEATING NOZZLE AND PICK-UP TUBE � MACHINE PROMPTS USER TO MOVE BOARD INTO POSITION SO PART TO BE PREHEATED IS UNDER HEATING NOZZLE. NOTE: PLACE A RED ARROW NEAR PART TO BE REHEATED SO IT IS EASY TO FIND ON VIDEO SCREEN. PUSH X-Y TABLE TO POSITION PART UNDER MACHINE’S PRISM BOX. THE PART SHALL BE VISIBLE IN THE SCREEN � FINE ADJUST BOARD FOR PREHEATING � MACHINE BEGINS PREHEAT, SOAK, AND REFLOW SEQUENCE. AFTER REFLOW COMPLETE, SEQUENCE ALLOWS MACHINE AND BOARD TO COOL DOWN BEFORE HEATING NOZZLE LIFTED OFF BOARD � SOFTWARE ALLOWS SAME SEQUENCE REPEAT – GO - OR TO STOP AND GO BACK TO MAIN MENU BY HITTING STOP. 8.7 SQUARENESS CHECK PROGRAM (ENGINEERING ONLY)

� USE SQUARENESS CHECK PROGRAM TO SQUARE PICK-UP TUBE TO X-Y TABLE WHERE BOARD IS HELD

� REMOVE THE DETACHABLE EDGE SUPPORTS FROM X-Y TABLE. MOUNT RECTANGULAR PLATE THE EDGE GUIDES WITH BEVELED EDGE UP



� BRING UP THE "SQUARENESS CHECK" SEQUENCE ON THE MAIN SCREEN

� GO

� PICK-UP TUBE COMES DOWN TO ITS NEAR PLACE POSITION. USE SQUARE TO CHECK SQUARENESS - FRONT TO BACK - LEFT TO RIGHT

� BEND PICK-UP TUBE SLIGHTLY TO IMPROVE ITS SQUARENESS. IF SEVERELY OUT OF SQUARE, CONSULT WITH TECHNICIAN TO REMOVE TUBE AND HAVE IT STRAIGHTENED 8.8 WORK INSPECTION (CHECKLIST UNDER CONSTRUCTION) AFTER BGA PART ADDED TO BOARD - QUALITY INSPECTED TO VERIFY SUCCESSFUL REWORK. BOARD TEST & X-RAY IS USED TO VERIFY THE PROCESS. AS A PRELIMINARY STEP, DO THE FOLLOWING PART INSPECTION BEFORE TAKING THE BOARD TO THESE OTHER AREAS: COMPARE PART SQUARENESS TO BOARD’S SILK-SCREEN OR TRACES. A PART THAT HAS FULLY REFLOWED IS VERY SQUARE TO THE BOARD. IF IT IS ROTATED, THE PART HAS NOT FULLY REFLOWED � USE A METRON MIRROR TO LOOK AT THE 4 SIDES OF THE BGA. FIRST, CHECK THAT THERE WAS TOTAL REFLOW ON ALL 4 SIDES, AND THE PART COLLAPSED TOWARDS THE BOARD INTO THE SOLDER. IF ANY RESIDUAL SOLDER PASTE BRICKS ARE SEEN, COMPLETE REFLOW WAS NOT EFFECTED. IF COMPLETE REFLOW WAS NOT EFFECTED, USE THE "REFLOW ONLY" PROFILE TO TRY AGAIN. BEFORE RUNNING THE SEQUENCE, ROTATE THE BOARD 180 DEGREES IN THE MACHINE. IF THIS DOESN'T TAKE CARE OF THE COMPLETE REFLOW PROBLEM, CONSULT WITH THE ENGINEER OR TECHNICIAN TO GET THE PROFILE CHANGED � ONCE A GOOD SOLDER REFLOW IS VERIFIED, VERIFY THERE ARE NO BRIDGES. TO DO THIS, USE A LONG, RECTANGULAR BGA METRON MIRROR AND A FIBER OPTIC LIGHT SOURCE TO INSPECT DOWN THE ROWS OF THE BGA. POSITION THE FIBER OPTIC LIGHT SOURCE DIRECTLY IN FRONT. PLACE IT CLOSE TO THE BALLS OF THE BGA. PLACE THE BGA IN FRONT OF THE LIGHT. PLACE THE MIRROR AGAINST THE BOARD SURFACE AT ABOUT A 45 DEGREE ANGLE NOTE: WITH THE LIGHT AND MIRROR POSITIONED CORRECTLY, BRIGHT HOURGLASS BEAMS OF LIGHT SHALL BE SEEN COMING THROUGH THE ROWS OF THE BGA. REPOSITION TO SEE THE OTHER END OF THE PART � REPEAT PROCESS AND X-RAY OR BOARD TEST REPEAT THE SAME PROCESS FOR THE PART’S OTHER DIRECTION. IF BOTH SIDES LOOK GOOD, TAKE THE BOARD TO X-RAY OR BOARD TEST FOR VERIFICATION THAT THERE ARE NO OPENS OR OTHER ELECTRICAL PROBLEMS. (SEE FIG. 6). EACH BGA THAT PASSES X-RAY SHALL BE



MARKED "X-RAYED". EACH BGA THAT DOES NOT PASS X-RAY SHALL BE MARKED WITH A RED ARROW. ALL BOARDS SHALL BE RETURNED TO THE BGA REWORK CENTER FOLLOWING THE X-RAY PROCESS 8.9 TURN MACHINE OFF (ONLY WHEN REQUIRED) � TURNING OFF THE MACHINE UPON HAVING COMPLETED OR STOPPED THE LAST SEQUENCE AND WHEN READY TO TURN THE MACHINE OFF, FLIP THE BRIGHT YELLOW AND RED LEVER ON THE RIGHT SIDE OF THE MACHINE TO THE 'OFF' POSITION � GRAPHING THE TEMPERATURE PROFILE W/ THERMOCOUPLES THERE ARE 6 THERMOCOUPLES ON THE MACHINE THAT ARE USED TO PROFILE BOARDS AND SENSE THE CURRENT TEMPERATURES. THE FIRST TWO ARE BUILT INTO THE MACHINE AND ARE USED TO MEASURE THE TOP HEATER AND BOTTOM HEATER TEMPERATURES. THE OTHER 4 ARE LOCATED ON THE LEFT SIDE OF THE MACHINE. THESE CAN BE POSITIONED ON A BOARD OR IN AND AROUND THE HEATING NOZZLE BY TACKING THEM DOWN WITH KAPTON TAPE. TO SHOW WHAT IS BEING MEASURED BY THEM, USE THE CURSOR TO CLICK ON THE GRAPH ICON NEAR THE UPPER LEFT CORNER OF THE SCREEN. A GRAPH SHALL APPEAR AND SHOW WHAT IS BEING MEASURED. HIT THE 'CLOSE' BUTTON TO HIDE THE GRAPH OR THE 'SIZE' BUTTON TO REDUCE THE SIZE OF IT ON THE SCREEN � PERFORM MAINTENANCE AND CALIBRATION 8.10 ABREVIATED AUDIT CHECKLIST – SYSTEM OPERATIONS SEQUENCE

� CHOOSE BOARD, SITE, AND SEQUENCE

� CLICK GO TO START CYCLE. - PRISM SHUTTLE TRANSPORTS PRISM ABOVE COMPONENT.

� ILLUMINATION ON. COMPONENT IS CENTERED IN NOZZLE BY ADJUSTING BOARD IN X AND Y AXIS

� PRISM SHUTTLE RETRACTS. - ILLUMINATION OFF.

� HEATER IS LOWERED TO BOARD - REFLOW CYCLE IS STARTED

� AS REFLOW CYCLE ENDS, PICKUP TUBE DESCENDS, TOUCHES COMPONENT, VACUUM IS ACTIVATED, AND PICKUP IS RASED TO NEAR PLACE POSITION – REMOVING COMPONENT FROM BOARD.

� HEATER IS RAISED. - PICKUP ASCENDS TO HOME POSITION.

� COMPONENT SHUTTLE TRANSPORTS COMPONENT NEST UNDER COMPONENT.

� PICKUP TUBE DESCENDS TO PICK POISITON - VACUUM IS DEACTIVATED. COMPONENT IS RELEASED INTO NEST.

� PICKUP TUBE ASCENDS TO HOME POSITION PLACEMENT SEQUENCE

� CHOOSE BOARD, SITE, AND SEQUENCE



� CLICK GO TO START CYCLE.- SHUTTLE TRANPORTS COMPONENT AND PRISM UNDERNEATH VACUUM PICKUP TUBE.

� PICKUP TUBE DESCENDS FROM HOME TO PICK POSITION, TOUCHES COMPONENT, VACUUM ACTIVATES, AND COMPONENT IS PICKED AND RAISED TO HOME POSITION.

� COMPONENT SHUTTLE RETRACTS. ILLUMINATION ON.

� OPERATOR PROMPTED TO BRING SITE INTO VIEW UNDER PRISM AND TO CLICK GO.

� PART LOWERED TO ALIGNMENT HEIGHT.

� IMAGE ALIGNMENT PERFORMED BY ADJUSTING BOARD IN X AND Y AXIS, AND COMPONENT IN THETA.

� PRISM SHUTTLE RETRACTS - ILLUMINATION OFF.

� PICKUP TUBE DESCENDS TO NEAR PLACE - THEN PLACE POSITIONS.

� VACUUM DEACTIVATED AND PUCKUP TUBE ASCENDS TO HOME POSITION.

� IF APPROPRIATE, PLACEMENT IS FOLLOWED BY REFLOW CYCLE



12.11 MSD AND VACUUM SEALING PROCEDURES 1.0 PURPOSE The purpose of these procedures is to provide standardized sensitivity classifications and handling procedures to avoid damage to moisture sensitive devices. 2.0 SCOPE This scope of these procedures applies to all integrated circuits in packages which, because of absorbed moisture, could be sensitive to damage during solder reflow. 3.0 DEFINITIONS/ACRONYMS

• Moisture Sensitive Device (MSD) - Any component that may have its reliability degraded by reflow soldering due to the moisture content inside the component. • RH – Relative Humidity • Desiccator – Humidity controlled environmental space (may also be referred to as Dry Box). • Critical Moisture Limit - The maximum safe moisture content a part can have for reflow soldering. • Humidity Controlled Space - A storage chamber that can maintain a maximum relative humidity level of 20% at building ambient temperature. These are dry boxes, nitrogen chambers and desiccators. • Moisture Barrier Bag - A bag that is stamped with DRY PACK or has a sticker stating there are moisture sensitive devices inside. MIL-STD-81075 TYPE I. • Desiccant - A moisture absorbing material in a bag form meeting MIL-D-3464, TYPE II • Humidity Indicator Card - A card with % humidity markings having instruction about reading the humidity. • Dry Pack - A moisture barrier bag with desiccant and humidity indicator card inside. • Exposure Limit - The maximum time a component can be out of a humidity-controlled environment, or out of a dry pack. • Dry box – Container (chamber or dry environmental storage unit) used to store moisture sensitive devices for short periods. • Level 2 - Allows component to be out of a humidity-controlled environment for one year at <30°C/60% RH. • Level 3 - Allows component to be out of a humidity-controlled environment for a maximum of 168 hours <30°C/60% RH. • Level 4 - Allows component to be out of a humidity-controlled environment for a maximum of 72 hours <30°C/60% RH. • Level 5 - Allows component to be out of a humidity-controlled environment for 24 to 48 hours <30°C/60% RH. • Level 6 – Component always shall be baked before use and once baked shall be reflowed within the time limit specified on the label. NOTE: DUE TO A GEOGRAPHICAL AREA'S LOW HUMIDITY AND HIGH PARTS TURN OVER IT MAY BE POSSIBLE ONLY TO BE CONCERNED WITH LEVEL 3 AND ABOVE. LEVELS 1 & 2 SHALL BE TREATED AS NON-SENSITIVE PARTS.



4.0 ELECTROSTATIC DISCHARGE (ESD) PROTECTION The relatively low humidity of the baking environment requires that ESD precautions shall be observed in the handling of components. Use standard ESD handling during entire procedures. Consult the packaging materials specification before reusing packaging media such as trays. 5.0 BAKING CONDITIONS (REQUIREMENTS OR SHALL BE's) When baking components, the part number shall be logged as well as the date and time components are placed in the oven. Also, the date and time components shall be removed from the oven, and actual removal, shall be logged. Components shall be placed in a dry pack after removal from the bake oven. Baking temperature shall be determined by verifying what temperature the shipping media has marked on it. Unless otherwise specified by the manufacturer, bake components shipped in high temperature shipping media for 12 hours at 125°C (+10°C/-10°C). Electronic Assembly Development Center recommends a 12-hour bake instead of the 24-hour bake specified by IPC. Components packed in shipping media which shall not withstand the 125° C temperature shall be baked at 40°C (+5°C/-0°C) for 168 hours at <5% RH. Electronic Assembly Development Center recommends a 168-hour bake instead of the 192-hour bake recommended by IPC. 6.0 MOISTURE SENSITIVE DEVICE IDENTIFCATION. Moisture sensitive device level 1 through level 6 shall be clearly identified and designated by the manufacturer. Moisture sensitive devices shall be packaged in DRY PACK’S or shall be stored in humidity controlled environments. DRY PACK’S containing parts labeled as level 3 through level 6 shall be considered moisture sensitive devices. 7.0 OPENING DRY PACKS AND VERIFYING MOISTURE CONTENT DRY PACKS shall be opened by carefully cutting straight across the package near the heat seal with a pair of scissors. Remove the humidity indicator card and ensure the humidity level has not exceeded 20%. If the humidity indicator card reads 20% or less, proceed with normal, specified operations.



If the 20% RH dot has turned pink and the 30% RH dot is not blue, components have been exposed to a level of moisture beyond that recommended, and the usable “dry” pack life has expired. These components shall be baked prior to reflow as specified herein. Carefully inspect moisture barrier bags for holes or tears. If any bag is damaged, discard it immediately and use an undamaged bag. Place all components, fresh desiccant, and humidity indicator card into the DRY PACK. Reseal bag with vacuum heat sealer with nitrogen purge as clearly indicated in these procedures.

8.0 LEVEL 3 THROUGH LEVEL 6 MOISTURE SENSITIVE DEVICE EXPOSURE TIME TRACKING AND TRACEABILITY. Component packaging shall have bar code labels with Hewlett-Packard part number, moisture sensitivity level, date, and exposure limit label affixed to packaging. Personnel applying blank exposure limit labels are responsible for the following: Place the Exposure limit label on the component package, on the same side as the part number label. If components are new or if they just came out of the drying oven, fill in the Previous Exposure Time with a 0 (zero). If components are not new and all the lines on the previous Exposure limit label were filled in, enter the cumulative time from the old label in the Previous Exposure Time on the new Exposure limit label. General guidelines for filling out “Time Open and Time Sealed” data on Exposure Limit labels. a) Fill in the current date & time when opening a dry pack and loading components on a machine. b) Time exposed shall be written in tenths of an hour.

Humidity reading

greater than 20 %

Humidity reading 20% or less



c) Personnel unloading components upon job completion are responsible for bag sealing, and entering the date, and time on the Exposure Limit label. d) Determine how long components were most recently exposed and add this to the # of hours a reel was previously exposed. This provides the Cumulative Exposure Time. e) Components now shall be in a dry pack and resealed.

Maximum hours 168 Prev. Exposure time 0

Time Open Time Sealed Cumulative

Date Time Date Time Exposure Time

2/5/98 7:30 AM 2/5/98 10:45 AM 3.3

4/3/98 8:44 AM 4//98 11:12 AM 5.8

0-6 minutes .1 31-36 minutes .6




25-30 minutes .5 55-60 minutes 1

9.0 REACTIVATING DESICCANT BAGS Determine if bag can be reactivated by baking. If bag cannot be reactivated discard the bag in the normal trash (not hazardous waste). Bags shall be marked with reactivation instructions. Example, REACTIVATION TIME IN BAG 16 HOURS AT 245° F (+ 10°F /- 10°F). Verify that bags are in good condition, before and after the bake cycle. Bake bags per instruction marked on the bag. Store desiccant in a moisture proof container (original container).

Reactivation information



10.0 CORRECT PACKAGING FOR MOISTURE SENSITIVE PARTS Select proper size moisture-barrier bag. Look inside bag towards light, to check for holes. If the bag has holes throw the bag in the trash, and select a new bag. Insert fresh desiccant pack and one humidity indicator card in a moisture barrier bag. The indicator shall change colors with the Relative Humidity level of its environment. Place moisture sensitive parts inside prepared bag. Seal bag using vacuum/heat sealer. Part number and Moisture Sensitivity Caution Label shall be on outside of bag. 11.0 REFERENCE DOCUMENTS IPC-SM-786A Procedures for Characterizing and handling of MSD's Reflow Sensitive ICs MIL-STD-81075 TYPE I Barrier materials Flexible. Electrostatic-free Heat sealable MIL-D-3464 TYPE II Desiccant, Activated, bagged, Packaging use and Static Dehumidification A-5951-1589-1 Hewlett Packard document ESD 5961-7344 May 26, 1995 Plastic BGA Project

Notebook 12.0 EQUIPMENT

NAME DESCRIPTION

Oven Used to bake components at low temperature.

Oven Used to bake components at high temperature. And reactivate

desiccant bags.

Desiccator Used to store components in when not in Dry packs

Vacuum heat sealer Used to vacuum seal component in moisture proof bags

13.0 Primary Stock Receiving Receive components into primary stock. Check moisture sensitivity level on Moisture sensitive caution label. If moisture level is not indicated, either by level number or maximum exposure time, contact materials engineering to obtain correct information.



Enter part number in database and compare moisture sensitive level in database with moisture sensitive level on caution label. If two levels match, proceed to next step. If levels do not match, contact materials engineering to verify which is correct. If part number is not found in database, enter it as required. If packaging is sealed and in good condition, proceed as required. If bag is not sealed or is damaged, re-bake and/or reseal in new bag as required. Components shall be baked to remove moisture, as required. Place used desiccant bag in storage container for bags needing reactivation. Enter date and time bag is resealed on the exposure limit label. Reseal excess components, fresh desiccant bag, and humidity indicator card in a moisture barrier bag. Place dry pack in the specified stock location. 14.0 Primary Stock Issue Parts Pull components to be issued from stock location. Open package by cutting along heat seal to allow bag reuse. Remove components, desiccant bag, and humidity indicator card. Place desiccant bag in storage container for bags needing reactivation. Enter date and time bag opened on exposure limit label. Determine if the humidity indicator card indicates humidity is above 20% the components shall be baked. If the humidity is 20% or lower, proceed to next step. Components shall be baked to remove moisture, as required. Place used desiccant bag in storage container for bags needing reactivation. Separate issue quantity components from total quantity of component on hand. Enter date and time bags are resealed on exposure limit labels. Reseal excess components, fresh desiccant bags, and humidity indicator cards in moisture barrier bags. Ship components issued to customer. Return excess components to specified stock location. 15.0 Secondary Stock Returned parts Read cumulative exposure time label to determine if exposed time is within specified sensitivity level limits. If exposed time is within sensitivity level limits, proceed. If exposed time is over specified sensitivity level limits, perform baking process. If bag is sealed and in good condition, proceed with next step. Components shall be baked to remove moisture when required. Place desiccant bag in storage container for bags needing reactivation.



Place components in moisture barrier bag with a fresh desiccant bag and humidity indicator card. Reseal bag using vacuum heat sealer. Return components to specified stock location. 16.0 Secondary Stock Parts Issue Verify quantity issued is the same as part quantity contained in the package received. If so, proceed to next step. If quantity is different, notify stock and correct. Open package by cutting along heat seal to allow bag reuse. Remove components, desiccant bag, and humidity indicator card. Place desiccant bag in storage container for those needing reactivation. Enter date and time the bag opened on exposure limit label. Determine if the humidity card indicates humidity is higher than 20%. If so, rebake. If the humidity is 20% or lower then proceed. Components shall be baked to remove moisture, as required. Separate component issue quantity from total component quantity. Enter date and time bags are resealed on exposure limit labels. Reseal excess components, fresh desiccant bags, and humidity indicator cards in moisture barrier bags. For correctly issued components, proceed. Notify stock when excess components are found. Place a date label on package if missing. Ship components to customer. Return excess components to primary stock. 17.0 Recycle Desiccant Bags Inspect bags assuring bags are marked with baking instructions for bag reactivation. Example: Reactivation time in bag 16 hours at 245°°°° F (+ 10°°°°F /- 10°°°°F). Discard bags in specified trash containers if they have no reactivation instructions. Visually inspect bag to determine the condition of the bags before baking. If bag condition unacceptable, discard bags in specified trash containers. When baking required, place bags in oven, set temperature to 245° F. and bake bags for sixteen hours before removing from the oven. Visually inspect bags after baking to determine bag condition. If bag condition unacceptable, discard bags in specified trash containers. If bag condition acceptable, proceed.



Reactivated bags shall be stored in original shipping containers. 18.0 Pick and Place Receive parts from stock and immediately verify part number on bag matches part number ordered. Open package by cutting along heat seal allowing bag reuse. Record date and time bag was opened as indicated on exposure limit label. If parts are new but with no exposure limit label, the operator shall attach an exposure limit label to component package. Determine if humidity indicator card in bag indicates humidity higher than 20%. If so, components shall be sent back to secondary stock to be baked. If humidity is 20% or lower, proceed to next step. Load components on feeder, complete machine setup, and proceed. If production is interrupted, remove feeders with moisture sensitive devices for proper disposition. If not, proceed to next step. Store moisture sensitive devices on feeders in dry box until the assembly line is ready to complete operation within specified time required for moisture sensitive devices. When assembly line is ready to resume the production run, remove feeders with moisture sensitive devices from dry box, and proceed. Run assemblies until production is complete. When the production run is complete, the operator shall tear down the set up, remove moisture sensitive devices from the feeders, and proceed to next step. Record date and time on exposure limit label. Determine if cumulative exposure time is within sensitivity level limits. If exposed time is within sensitivity level limits, proceed to next step. If exposed time is over the sensitivity level limits, rebake. After rebake, place components in moisture barrier bag with a fresh desiccant bag and humidity indicator card. Reseal bag using the vacuum heat sealer. Return remaining components to secondary stockroom. 19.0 Programming Receive parts from stock for programming, and verify whether components are moisture sensitive parts.



Open bags as describe in section 7.0 of this document. If bags never opened and/or there is no exposure limit label, add it/them. Record date and time bag was opened on the exposure limit label. Determine if the humidity indicator card in bag indicates humidity is higher than 20%. If so, components shall be baked. Program components as specified for individual part numbers and proceed. NOTE: NON-PROGRAMMED PARTS SHALL BE RETURNED TO PRIMARY STOCK. Record date and time that the moisture barrier bag is closed on the exposure limit label. Determine if cumulative exposure time is within sensitivity level limits. If exposed time is within sensitivity level limits, proceed to next step. If exposed time is over sensitivity level limits, rebake. Place components in moisture barrier bag with a fresh desiccant bag and humidity indicator card. Reseal the bag using the vacuum heat sealer. Ship programmed parts to the customer. Return all non-programmed parts to the Primary stock. 20.0 Rework Determine if printed circuit board to be assembled has any moisture sensitive parts. For boards without moisture sensitive parts, proceed. Boards with moisture sensitive parts must be assembled only as specified in this procedure. Determine whether any moisture sensitive parts, required on the printed circuit board, are near a rework area. If the moisture sensitive parts are not in rework area, move them to the required location. When moisture sensitive parts are in rework area, proceed and exercise caution as in next step. If moisture sensitive parts are to be heated to a point that could cause damage, proceed to next step with caution while ensuring all requirements in this procedure are followed. If the moisture sensitive parts are not be heated enough to cause any possible damage, proceed. Confirm all the components required for board assembly or rework and can be heated to 125° C. Remove any components from any board that can not be heated to 125° C. Bake the printed circuit board for 12 hours at 125° C (See 5.0). Remove baked board from oven and proceed. Rework boards, as required exactly following specific rework procedures.



VACUUM SEALING MOISTURE SENSITIVE DEVICES 1.0 PURPOSE The purpose of this document is to provide basic instruction to Vacuum Seal components using the Accu-Seal Model 35 vacuum heat sealing equipment. 2.0 SCOPE This procedure covers the Vacuum Sealing of components as required by IPC for moisture sensitive parts handling. 3.0 DEFINITIONS Moisture Sensitive Devices (MSD) – Any device thats reliability is degraded by reflow soldering due to the moisture content the component has absorbed. Moisture Barrier Bag – A bag that is stamped with dry Pack or has a sticker stating that there are moisture sensitive devices inside. All shall meet MIL-STD-81075-TYPE I requirements. Foot pedal – the part of the vacuum sealing equipment that starts the vacuum sealing process 4.0 REFERENCE DOCUMENTS Accu-seal Operating Instructions A-5951-1589-1 - ESD 5.0 SAFETY This unit uses a quick “Heat-Up” strip element protected by a Teflon strip. Do not touch this surface. THIS IS A BURN HAZARD. Ensure hands and fingers are not underneath either of the sealing jaws when in operation. This is a pinch point. 6.0 MAINTENANCE Daily Operators maintenance Wipe down all surfaces on workstation and the Accu-Seal to remove any dust. Only use a specified ESD topical cleaner on workstation surfaces. If a “hot spot” occurs (noticeable by overheating and bag melting at any point on the seal) the heating element may need replacement. Contact maintenance for any necessary repairs.



7.0 MACHINE LAYOUT

Main Power Switch

Gas Pressure Regulator

Operating Mode Switch Vacuum gauge Heat Timer

Cool Timer

Vacuum Sealing Jaws

Heat Sealing Jaws

Vacuum Timer

Gas Timer

Support

Tray

Heat strip with Teflon cover on both top and bottom of opening

Plastic tubing for sealing bag during vacuum operation



8.0 EQUIPMENT SET-UP Machine settings: If seal on the MBB is not adequate to hold vacuum, contact engineering. Air pressure – 3cfm @ 70 PSI Min., Max air pressure 100 PSI. Nitrogen – Gas pressure may be regulated as indicated by pressure gauge on top panel (factory set at 30 PSI). Heat Timer – Set heat timer to position # 3. Cool Timer – Set the cool timer to position # 5.

Vacuum timer – Set Vacuum timer to position # 4. Gas Timer - Set gas timer to position # 4.



9.0 MACHINE OPERATION Turn sealers Main Power switch to “ON” indicated by green lamp.

Verify that settings of the Cool Timer, Heat Timer, Vacuum Timer, and Gas Timer are set as required. Operating Mode Switch - Push switch to the amber side. The amber lamp shall be on and the blue lamp shall be off.

Practice process by leaving heat timer set on 0 seconds and by operating machine in vacuum mode. This allows the operator to become familiar with the vacuum process without wasting bags. Locate product in the bag being sealed as close to the nozzle as is possible without interfering with the front (Heat) sealing jaw closing. The product thickness helps prevent the bag from collapsing over the vacuum nozzle. If the product is cylindrical, position it farther away from the sealing jaw to prevent creases in the sealing area.

Orange lamp on switch in

down

Blue lamp off This side of switch in up position



Position the bag over the vacuum nozzle. The above views are from the vacuum sealer's backside showing nozzle in bag opening. Hold the bag at an angle as shown in the second figure below. This shall help to prevent the bag from collapsing over the vacuum nozzle opening during operation.

KEEP FINGERS AWAY FROM SEALING JAW. Tap foot switch and the vacuum jaws close until the end of the cooling cycle. Simultaneously, as the vacuum jaws close, gently pull the bag back

Back of Vacuum nozzle

Keep bag from covering the opening vacuum operation

Bag unacceptably collapsed over the Vacuum nozzle



and up away from the nozzle. Otherwise the bag can collapse in front of the vacuum nozzle, preventing further evacuation.

NOTE: THE SEALING CYCLE MAY BE ABORTED AT ANY TIME BY TURNING “OFF” THE MAIN POWER SWITCH. The Heat sealing jaw closes as the heat time lamp illuminates. Both jaws shall be closed during the remainder of the cycle. NOTE: TAPPING THE FOOT SWITCH A SECOND TIME SHALL OVERRIDE THE GAS TIMER AND START THE SEALING CYCLE. Jaws shall open upon the completion the cooling cycle. Remove the vacuum-sealed bag from the machine and inspect bag seal. NOTE: THE SEAL SHALL NOT HAVE ANY LARGE CREASES ALLOWING AIR BACK INTO THE VACUUM-SEALED BAG. The seal shall have a uniform heat seal across the width of the bag. The operator may seal the bag a second time if the first seal was not adequate, or there are any concerns about the bag being sealed as required.

Heat sealing jaws in open position Vacuum and Heat sealing jaws both in closed position



The bag shall be pulled tightly around the item showing the outline of bag contents including desiccant bags.

Crease in seal not acceptable

Two desiccant bags clearly visible



12.12 LIQUID SOLDER MASKING PROCEDURES

CAMALOT MODEL 1818 "AUTO MASK" LIQUID DISPENSING MACHINE

NOTE: H-P SPOKANE (NOW AGILENT TECHNOLOGIES) USED MASK INSTEAD OF SELECTIVE WAVE SOLDERING PALLETS FOR A LONG TIME. THE ONLY PROBLEM I SEE NOW IS THE PREVALENCE OF NO-CLEAN OPERATIONS. IT JUST WORKED WELL AND WAS VERY CHEAP COMPARED TO SELECTIVE WAVE SOLDER PALLETS.

1.0 PURPOSE The purpose of this document is to provide operators within the Pre-Wave process area with the safety and machine operating instructions for the SMTC Auto Mask process utilizing the Camalot Model #1818 liquid dispenser. The Model 1818 dispenser has many operating features. This document assumes that all operators of this piece of equipment have under gone one-on-one training with a skilled trainer, technician, or engineer and have read this document in its entirety before operating this piece of equipment. An operator is deemed qualified after he/she has been signed off by a designated trainer (reference the section on Camalot Model 1818 in the Operator Training Checklist.). 2.0 DEFINITIONS & ACRONYMS Pre-Wave: A process cell within SMTC's assembly area that comes directly after the Pick and Place process and prior to the Post-Wave process. Activities such as panel racking, masking, riveting, and through hole assembly take place within the Pre-Wave process area/ Camalot #1818: An automated liquid dispensing system used to apply water soluble mask to SMTC standard 1/3 and 1/2 size sub-panels. 3.0 THEORY OF OPERATION The SMTC automatic mask dispensing process is based on the use of the Camalot Model #1818 Liquid Dispenser. This machine is designed to dispense water soluble mask on populated printed circuit assemblies that are located within the constraints of the corporate 1/3 and 1/2 size sub-panel, while registered in SMTC's 17" x 20" wave solder rack. Mask is dispensed on those areas of the printed circuit assembly where solder wetting is undesirable or prohibited.



The Camalot 1818 utilizes an automatic fiducial correction vision system that is used to align the printed circuit assembly to the mechanics of the dispensing head. In addition, the model 1818 has new technology dispensing features such as automatic height detection capability via a touch probe sensor, XYZ automatic needle calibration, and a dual valve toggle dispensing head for both coarse and fine mask applications. 4.0 SAFETY - GENERAL All personnel shall note the location of the nearest fire extinguisher and be familiar with the evacuation procedure for their area (consult with the safety coordinator for the area) Required Safety Clothing and Equipment: Safety glasses shall be worn at all times when running this piece of equipment. ESD heel straps or approved ESD shoes shall be worn when in the production area. ESD cords shall be worn when running this piece of equipment. Emergency Procedures In case of an Emergency (Medical, Chemical, or Fire) CALL EXTENSION 2222. Report the type of emergency and its location. In the event of an evacuation, remain calm, and follow the evacuation route for the area. Do not stop to turn-off equipment or to collect personal items. 5.0 CAMALOT MACHINE SAFETY The Camalot Liquid Dispenser, like any other automated machine can cause serious injury if the appropriate safeguards are ignored or when inappropriate or unsafe practices are followed. Emergency Stop - There is one Emergency stop on the front panel of the Camalot Masker. The Emergency Stop switch is a large red push/pull palm button that is located on the front panel of the machine. When depressed, the entire machine is shut down. To restart the machine, after the reason for the Emergency Stop has been cleared, the Emergency Stop Button shall be pulled out, the Machine Reset button pressed, and the machine "ON" button pressed to re-start the machine; Safety Interlocks - The Camalot masker is equipped with two safety interlocks 1) Low Pressure Interlock - In the event of low air supply pressure to the machine, the machine will shut down automatically. Maintenance shall be called to resolve the condition for the low pressure shut down. Once resolved, the Machine Reset button shall be pressed, and the Machine "ON" button pressed to re-start the machine. 2) Door Interlocks - With the front doors of the masker closed, the doors will automatically lock when a program is requested to "RUN". If the doors are open and a program is requested to



"RUN", the machine will run at 50% of its normal dispense speed. The machine shall never be operated with the doors open. Machine Safety Enclosure - The Camalot Masker is equipped with a safety enclosure which covers the top and sides of the machine. The front of the machine has two access doors for panel loading and unloading and for machine maintenance and calibration access. 6.0 CONSUMABLE MATERIALS Water Soluble Mask:

WonderMask "WA" w/glycerin (blue) 6250 +/- 250 cP @#6, 20rpm HP Part Number 8500-4442

Dispensing Needles 18 gauge needle used for valve #1 Camalot P/N 9591 22 gauge needle used for valve #2 Camalot P/N 9594

Ordering Info: Camalot Systems Inc.

145 Ward Hill Ave. Haverhill, Mass. 01835

(508) 521-730

MACHINE OPERATING INSTRUCTIONS Before Operating Masker Ensure the daily and/or weekly maintenance has been performed as defined in "Operator Maintenance" section of this document before operating this equipment. Ensure the pressure gauge located on the top of the pressure pot is set to: Masker A/B 38 psi Masker C: 38 psi - Do not change tank pressures. System Start-Up Ensure the Emergency Stop button has been released and the machine access doors are closed. Press the "RESET" button on the machines front panel and then press the green "ON" button to turn-on the machine. NOTE: THE CAMERA LIGHT WILL ILLUMINATE IMMEDIATELY, THE GREEN "ON" BUTTON WILL ILLUMINATE IN APPROXIMATELY 10 SECONDS AND THE MONITOR DISPLAY WILL BEGIN BOOTING UP. THE ENTIRE MACHINE STARTUP TAKES APPROXIMATELY 1 MINUTE. THE SCREEN WILL PROMPT TO SELECT EITHER 1) PRODUCTION MODE OR 2) DEVELOPMENT MODE. SELECT 1) PRODUCTION MODE.



Selecting a File Using the track ball select the "FILE OPERATIONS" icon in the upper left corner of the display by placing the trackball pointer on the icon and by pressing the left button. Note the left trackball button is used for all commands other than specific editing commands or when prompted by the machine. The file naming convention is as follows. File names are a total of 8 characters long and are derived by using the last 3 digits of the board prefix, the last 3 digits of the boards suffix, and 2 digits of the panel revision. Example: Board Number E4400-63003 Panel Revision B-122294 Resulting Masker file Name = 40000312 Select the "PRODUCT" directory and locate the directory corresponding to the assembly prefix (first five numbers of the assembly number). Within that directory, locate the specific board file to be dispensed. First click on the board file and then on the "LOAD" command. The system will prompt whether or not to over-write the file currently in memory - or it simply will load the selected file. Close the "FILE OPERATIONS" window by placing the trackball pointer on the bar in the upper left corner of the menu and by pressing the left button. A pattern now is ready to be dispensed. File Operating Mode The Camalot Masker has 3 file operating Modes 1) Edit Mode - this mode is used for editing a file. In this mode power to the system axis motors is terminated. The axis motors cannot and will not move while in Edit Mode. Gantry can move without warning when leaving the diagnostics mode. 2) Trace Mode - this mode is used for dispensing a pattern. In this mode material is actually dispensed on the product. This is the normal operator "RUN" mode. 3) Camera Mode - this mode is used for board programming, real time editing, and for program verification. In this mode the machine operates just as if in Trace mode but from the position of the camera. An image of the camera position is displayed on the screen at all times while in this mode. Running (dispensing) a program After selecting a program that shall be dispensed, the program is ready to be run. 1) Open the machine access doors. If the doors are locked, place the trackball pointer on the padlock icon and press the left button. Note the padlock icon now indicates an "unlocked" condition. 2) Most assemblies use the two panel tooling holes as reference points for aligning the panel to the camera. If there is any plating around these tooling holes, use a black pen to blacken the area around the tooling holes. This will prevent an error in the vision system.



3) Place the racked panel, with the bottom bar to the left (unless otherwise specified) and the circuit side up, onto the guide rails in the machine. Gently slide the rack forward until it comes to a complete stop against the rack locating pin. Close the machine access doors (They will automatically lock when the Camalot is requested to "RUN"). NOTE: IF THE MACHINE ACCESS DOORS ARE NOT CLOSED AND A PROGRAM IS REQUESTED TO "RUN", THE MACHINE WILL RUN AT 50% OF ITS NORMAL SPEED. THE MACHINE SHALL NEVER BE RUN WITH THE MACHINE ACCESS DOORS OPEN. 4) Ensure the dispensing head is either at the "HOME" position (at the extreme right rear corner of the machine above the purge cups) or at the "PARK" position (at the extreme left rear corner of the machine where the needles are emerged in the water cup) before dispensing a pattern. 5) To move the machine to the "HOME" position, place the trackball pointer on the "HOME" icon and press the left button. Note the machine shall be in either "TRACE" or "CAMERA" mode in order for the machine to move to the "HOME" position. 6) To move the machine to the "PARK" position, place the trackball pointer on the "PARK" icon (lower right corner of the display) and press the left button. Note the machine shall be in "TRACE" mode in order for the machine to move to the "PARK" position. 7) With the machine in Trace mode, position the trackball pointer on the "RUN" icon (bottom right corner of the display) and press the left button. The machine will begin executing the program. If the vision system does not locate the reference points, refer to the troubleshooting section at the end of this document. 8) If for any reason the stop a dispense pattern is paused, hit any of the three buttons on the trackball. After dispensing the remaining line commands still in the machines memory buffer, the machine will stop. Then, the display prompts to " Abort Dispense", to "Continue Dispense", to "Go Back One Command", or to "Unlock Doors". If it is decided to unlock the doors and view the dispensed product, the doors shall be locked before the "Continue Dispense" command is selected or the machine will run at half speed through the remainder of the program. 9) When a dispense pattern has finished running, the machine will automatically return to the "PARK" position and the doors will unlock to allow the removal of the finished product. 10) If additional panels are to be run that have the same file name, simply load the racked panel into the machine (as described in paragraph 6.5.3) and activate the "RUN" icon. 11) If a new program shall be selected, see "Selecting a File" above.



Verify Mask Program 1) If board to be masked has a "Verify Mask Program" step on router, follow steps in Selecting a File. 2) If the filename is in the Product Directory and documentation is in the cabinet, operator may follow normal masking procedure (operator/trainer shall initial "Verify Mask Program" step on router and notify FYI PIM programmer to steps taken). 3) If filename is not in the Product Directory, place the boards on-hold and notify PIM Programmer of a mask program to be verified. CAUTION: OPERATION OF PRESSURE TANK - DANGER FAILING TO FOLLOW INSTRUCTIONS TO DEPRESSURIZE TANK PRIOR TO OPENING COULD RESULT IN SERIOUS INJURY. ALWAYS ENSURE THAT TANK IS FULLY DEPRESSURIZED BEFORE OPENING. NOTE: PRESSURE SETTING FOR ALL MASK TANKS SHALL BE SET AT 38LBS. Checking Mask Level in Tank It is not necessary to open the tank to check the mask level. The tank rests on a scale constantly weighing the tank and its contents. The low-level weight is 100 lbs. Add mask according to the instructions in this document if the mask level falls below this level. The high level weight is 160 lbs. Do not allow weight to go above 160 lbs. Do not make any changes to the scale indicator unit. AUTOMATIC NEEDLE CALIBRATION The Camalot dispensing system uses an automatic needle calibration process to align the dispensing needle to the XY and Z axes of the machine. Through this calibration process the machine performs a mechanical offset to all three axis to compensate for the variability between needles. The needle calibration process is used when a needle is changed, if an needle is bent, if the dispense height of the needle is in question (dispensing to high or to low) or if there is an obvious offset between the mask being dispensed and the PCB geometry to the point that it is affecting product quality. The offset information from the needle calibration is saved in the machines memory until the next needle calibration is run. During the needle calibration process, the dispensing head goes through a calibration routine (for the specified needle) where the Z axis travels downward until the dispensing needle strikes a spring loaded cylindrical piston which calculates the length of the dispensing needle. The needle then travels to a calibration plate where a Z axis touch probe extends to calibrate the height of the surface to be dispensed. The needle then dispenses three purge dots and then a final dot that is looked at by the camera system. The camera is then calibrated to the final dot and the offset information is saved in the machine's memory.



A needle calibration shall be performed when: 1) A needle is changed 2) If a needle is bent 3) If the dispense height of the needle is in question (dispensing too high or too low) 4) If there is an obvious offset between the mask being dispensed and the PCB geometry to the point that it is effecting product quality. Needle Calibration 1) From the Product directory select and load the file "NEEDLE.CAM". "NEEDLE.CAM" can be loaded as a subpattern if another file is already loaded in memory. 2) Open the machine doors and with finger while ensuring the Z-axis plunger is operating smoothly. If necessary, use a cotton swab with isopropyl alcohol and clean in and around the plunger to allow it to move freely. 3) Ensure the calibration pad (where mask is dispensed during the needle calibration process) is clean of mask. Wipe mask away with a damp sponge if necessary. Wring excess water out of sponge before wiping. 4) Select the "HOME" icon and if not already in "TRACE" mode, select the "TRACE" mode icon. The machine will home accordingly. NOTE: THE MACHINE SHALL BE IN TRACE MODE IN ORDER TO RUN THE NEEDLE CALIBRATION ROUTINE. 5) Select the Needle Calibration icon (icon has picture of a needle with "xy" in the bottom left hand corner). 6) Select which valve shall be calibrated (i.e. valve 1 or valve 2). The machine will automatically run the calibration routine as required. 7) After running the calibration routine, the camera will align over the final dispensed dot and the following message will be displayed: LEFT BUTTON FOR LIGHT MATERIAL, CENTER BUTTON FOR DARK MATERIAL, RIGHT BUTTON TO CANCEL NOTES: IF A POORLY DISPENSED DOT (LACKING MASK MATERIAL OR HAS A POORLY DEFINED CIRCUMFERENCE) IS PRESENTED TO THE CAMERA PRESS CANCEL AND RESTART THE NEEDLE CALIBRATION.



IF A WELL DEFINED DOT IS PRESENTED TO THE CAMERA SELECT THE LEFT BUTTON. THE CAMERA CROSS HAIRS ON THE DISPLAY WILL IMMEDIATELY ALIGN OVER THE DISPENSED POINT AND THE FOLLOWING MESSAGE WILL BE DISPLAYED IMAGE FOUND DISPLAYED - HIT LEFT BUTTON TO CONTINUE 8) Hit left button and with the trackball pointer close the window. Closing the window finalizes the calibration and the dispensing head will automatically move to the HOME position. 9) Clean plunger and platform with a clean sponge (ensure all excess water has been wrung from sponge). Clean immediately to prevent mask from drying and becoming difficult to remove. 10) If necessary select the next needle to be calibrated, otherwise the needle calibration process is complete. RUN MASK COUPONS Mask Coupons are 4" x 5" FR4 panels that are used to run a program to determine the amount of mask being dispensed at any given time. This program will dispense mask in an area about 2" x 3" on each of the coupons. When the valves are dispensing the correct volume of mask, then the mask on each coupon shall weigh between 3.5 grams and 4.1 grams. Mask Coupons shall be run: At the beginning of each shift (daily) When a valve has been rebuilt or adjusted 1) Locate the copper-clad panel with thick tape on top divided into six equal sections. This panel shall be stored in a SMTC Solder Rack by the workstation for the maskers. 2) Slide racked panel into masker. 3) Close all windows on the electronic balance (the scale located on masker workstation) 4) Turn the scale 'ON' or if it is already 'ON' press "RE-ZERO' 5) The display shall view "o 0.000" (indicates the scale is stable and level) If the display does not indicate the scale is level: 1) Adjust the feet of the scale so the bubble towards the front of scale on the left side is centered between the lines 2) Press "RE-ZERO" again 3) Gently slide the left window open



4) Place one of the 4" x 5" FR4 mask coupon panels inside on the tray 5) Close the window 6) Record the weight on the "MASK COUPONS" spreadsheet for "SAMPLE 1" in the "COUPON TEAR WEIGHT" column. 7) Place the coupon in the first compartment of the copper clad panel located in the masker (see diagram on masker window) 8) Repeat for "SAMPLE" and "SAMPLE 3" Load mask coupon program 1) Using the track ball select the "FILE OPERATIONS" icon located in the upper left corner of the display. 2) Select the "PRODUCT" directory. 3) Load "COUP6X.CAM" 4) For File Operating Mode, select "TRACE" Mode 5) Click "RUN" Weight mask coupons Upon completion of "COUP6X.CAM, the operator shall weigh mask coupons. To obtain an accurate weight reading of the mask, the coupons shall be weighed within a 5 minute period - upon completion of the dispense program. 1) Remove the first coupon from the masker. 2) Gently slide the left window open 3) Place the masked coupon on tray 4) Record the weight on the "MASK COUPONS" spread sheet for "SAMPLE 1" in the "WET WEIGHT" column 5) Repeat for "SAMPLE 2" AND "SAMPLE 3". 6) Subtract "COUPON TEAR WEIGHT" from "WET WEIGHT" for "MASK WEIGHT". 7) Record coupon information on mask coupon spread sheet each time the function is performed until mask weight is within he desired parameters.



8) If mask does not weigh within the acceptable parameters - Depending on the amount of mask that was dispensed; Too much mask - using 1/2" flare-nut wrench over pneumatic fitting - turn valve clockwise. Not enough mask - using 1/2" flare-nut wrench over pneumatic fitting - turn valve counter-clockwise. NOTE: BECAUSE OF THE CONSISTENCY OF THE MASK, RUN SEVERAL COUPONS (3 AT LEAST) AFTER THE FINAL ADJUSTMENT TO THE VALVE TO OBTAIN AN ACCURATE WEIGHT MEASUREMENT. 9) Perform until dispensed mask weight is within acceptable parameters. 10) Wash coupons in the sink and place on work station next to scale. 11) Remove racked copper clad coupon panel from masker and set next to work station. Skipping Bad Images It is not unusual for a panel to have one or more bad or "X-OUT" images in a subpanel. These images are considered scrap and shall not be assembled or in this case masked as it provides no value. The Camalot software allows the skipping of these images prior to running a dispense pattern. 1) With the program containing the bad image loaded on the display, determine which image needs to be skipped by referencing the " Camalot Masker SubPanel Programming Sequence" diagram (Appendix "A"). 2) After determining which image needs to be skipped, select "Edit" mode at the bottom of the screen. Using the trackball, place the caret before the first line number to be skipped and press the left button. 3) With the trackball move the pointer to the last line number to be skipped and press the right button. All lines to be skipped will now be highlighted. 4) With the trackball select the "ENABLE/DISABLE" icon (top left of display, 2nd row of icons, 4th icon from left... green with series of yellow dots) and press the left button. All highlighted lines will now turn lower case. 5) All upper case lines in the program will be dispense, all lower case lines will be ignored. 6) To reverse this command and to reactivate the skipped images, select the commands in lower case and again select the "ENABLE/DISABLE" icon. 7) The highlighted lines will now turn upper case and will be included in the dispense program.



System Shut Down 1) Select the "PARK" icon from the lower right hand corner of the display, then select "TRACE" mode. The dispensing head will move to the left rear of the machine and the Z axis will move downward into the water cups and submerge the needles. 2) Open the access doors and remove all articles in and around the dispensing area. If not already done, remove the racked panel from the dispensing area. 3) Close the access doors. Note that once the access doors are closed and power to the machine is turned off, the doors can not be reopened without turning on the machine. 4) Press the "OFF" button on the front of the machine. This will turn-off the Camalot system and its computer. Valve/Needle Purging Needle purging is required any time a needle has been exposed to the air for a prolonged period of time (15 minutes or greater) without fluid being dispensed or after needles have been in the park position water cups for greater than and hour. As a rule, needles shall be purged at the start of a new shift, after break periods, or when the material at the needle tip begins to skin and dry thus restricting fluid flow. It is better to error on purging more frequently than less. For valve 2, it is especially important to purge frequently. Performing a Needle Purge 1) A needle purge shall be performed when the dispensing head is at the machines HOME position. 2) There are two cups located under each valve when the dispensing head is located at the Camalot's home position. When purged, each valve shall dispense material into these cups. 3) On the front control panel of the machine, locate the purge selector switch for V1 and V2. Select the valve to be purged. 4) Press the black PURGE button and observe material flowing from the selected valve. Hold the button for 10 to 30 seconds or as required to get a uniform flow of material from the valve. 5) Pushing the PURGE button several times for very short periods may be effective for dislodging dried material from the dispensing needle. 6) After the Purge is complete it may be necessary to use a damp sponge to wipe the tip of the needle. USE EXTREME CAUTION when wiping the needle. If a needle is bent during wiping, a needle calibration shall be performed.



DAILY OPERATOR MAINTENANCE At the Beginning of each Shift 1) HOME the machine and remove the water cups from the PARK position cup holder. Empty and refill the cups with fresh water. Install the cups in the holder being careful not to spill water in the dispensing area. Replace the cups with new ones when necessary. 2) With 409 cleaner and a soft paper towel, wipe the inside and out side of the machine access doors to improve visibility. 3) Remove the copper clad panel used to catch dripping mask from under the panel dispense area. After wiping down the panel dispense area with a damp sponge to remove all mask, replace the dirty copper clad panel with a clean one and send the dirty copper clad panel through the in-line washer and store for reuse. Alternatively, the panel may be cleaned and dried at the sink in the process area. 4) Stir mask in pressure tanks 20-30 turns. 5) From the "PRODUCT" directory select and load the file "NEEDLE.CAM". 6) At the End of each Shift 7) Clean and organize work area for the next shift. 8) With a damp sponge, wipe down the inside of the machine. Be sure to wipe mask from the slide rails of the rack fixture and all machine surfaces. Weekly Maintenance Adding mask - add mask when scale reads 100 lbs. or below. 1) When adding mask: add mask from sealed containers only! DO NOT add mask from partially full containers. 2) Release pressure in tank by opening the back valve so the arrow points toward the vacuum pump. Allow tank to fully depressurize before opening. 3) Open the cap on top of the material entry tube. 4) Place funnel inside the material entry tube. 5) Add mask until the scale reads about 160 lbs., the high mask limit. Carefully clean the threads of the tube and replace cap.



6) De-gas 10-15 minutes. To de-gas, keep back valve pointed towards the vacuum pump (the depressurization setting), and open the front valve so the arrow points toward the vacuum pump. The vacuum will de-gas the mask material, removing any air bubbles in the mask. 7) To stop the de-gassing process, close the front valve (valve head shall be at a right angle to the air line). 8) Repressurize tank by turning back valve so arrow points toward regulator. Stirrer - This tank has a blue handle at the top which, when turned, stirs the mask. Mask shall be stirred once per shift. Stir mask 20-30 turns. Needle Purge At the beginning of the graveyard shift each Sunday evening operators shall purge both needles (Valve 1 & Valve 2) in each machine. The purge shall be run after the mask has been stirred, before any production is run. 1) With the valves parked in the water cups, remove the two drip cups from the "HOME" position and replace them with two 8 ounce Styrofoam cups. 2) From the Product directory load "NEEDLE1.CAM" 3) Press "RUN" 4) The gantry will move close to the doors and "PAUSE" 5) Open the doors and remove both needles (Valve 1 & Valve 2). If there is a noticeable bend in the needle, any damage in the tip of needle or if the there is any questionable feature about a needle then dispose of it immediately. 6) Wash the needle in the sonic cleaner located on the masker work station. 7) Inspect any needles already in the cleaner, blow them out with the air hose located next to the sink and set them in the packet with the other needles. 8) “HOME" the gantry 9) Click on the I/O icon (located on top row of the screen toward the right side) 10) Move the pointer to the "SET OUTPUTS" section of screen and click on "1". This will purge valve 1. 11) Set the timer located in the plastic tray next to the monitor for 8 minutes. When the timer sounds, click on "1" again. This will shut the valve off.



12) Move the pointer to the "SET OUTPUTS" section of screen and click on "2". This will purge valve 2. 13) Set the timer located in the plastic tray next to the monitor for 8 minutes. When the timer sounds, click on "2" again. This will shut the valve off. 14) Close the doors and "PARK" the gantry. 15) Replace the Styrofoam cups with the 4 ounce plastic drip cups. Click on the upper left corner box to close the "I/O" window.

16) Replace the needles: 51112.3.23.1. Run "NEEDLE1.CAM" 51112.3.23.2. Install new needles for Valve 1 and Valve 2. Gently push up on the needle as it is threaded it into the valve. CAUTION: THE BLACK PLASTIC COLLAR ON THE TIP OF THE VALVE WILL STRIP IF TOO MUCH PRESSURE IS EXERTED WHILE INSTALLING NEEDLE. Machine Clean-Up With a 409 cleaner and a soft paper towel, clean all external surfaces of the machine including the top Plexiglas cover. Note that dust will accumulate on the top of the cover and will affect the lighting inside the equipment if not cleaned. TROUBLESHOOTING Vision System Does Not Accept Reference Points 1) The reference points are the most important part of the program. If the vision system does not align the reference points correctly, the mask will not be dispensed in the correct locations. 2) If the vision system fails to find the reference points, ensure the tooling holes are not plated. If they are, blacken them with a black marker, and run program again. 3) Only as a last resort, re-teach the reference points. When the vision system does not accept the reference points, the monitor will prompt to re-teach the reference points. Click on the XY coordinates of the point to make the trackball active in moving the camera. Manually align the cross hairs into the center of the tooling hole. It is extremely important to center as closely as possible. Accept the position, and align the second reference point in the same way.



PRODUCTION QUALITY REQUIREMENT - CAMALOT MASKERS Mask Thickness: Mask thickness shall be less than or equal to 0.020" measured dry. Coverage 1) Ground Plane Areas: No exposed (shiny) areas greater than 0.010" wide. 2) Ground Plane Areas attached to through holes which shall be soldered: mask must maintain clearance of at least 0.060" but no more than 0.080". 3) Plated Holes: Inside of barrel shall be covered. Complete hole fill is not necessary. 4) Material shall be dispensed around 5-pin RF connectors with sufficient setback from plated thru-holes. The material does not flow onto the plated thru-hole at any point. 5) 0603 components (pepper chips): Mask must make contact with the board on any 2 opposite sides of the part. 6) 3-Dimensional Parts: On components that are masked on ends without leads, mask must make a seal between the part and the board to prevent solder from getting underneath the part. For components that are masked on leads, the leads shall have, as a minimum, a thin coating of mask. 7) Leads may be visible through mask, as long as they are not exposed (shiny). Holes between adjacent leads are acceptable as long as the leads are not exposed. 8) Threaded standoffs: Threads shall have, as a minimum, a thin coating of mask. Threads may be visible through mask, as long as they are not exposed (shiny). Process Control 1) Do not touch-up anything that meets quality criteria. 2) If quality requirements are not met as described above, verify process setup (pressures, amount of mask in tank, etc.) per documentation. If more than 5 touch-ups are required per panel (not to exceed 1 minute per panel), stop the process and contact PIM or Process Engineering.



CAMALOT MODEL 1818 OPERATOR TRAINING CHECKLIST

Operator Name: ______________________ Trainer Name: ____________________ Begin training date: ______________________ End training date:__________________ Machine overview Difference between the Camalot masker and the Creative Automation masker � Two valves with 2 needle sizes - V1 = 18 gauge, V2 = 22 gauge � Touch probe height sensor for panel warpage compensation � Masking panels while they are in the wave solder rack � Auto fiducial recognition � Needle height set by program, not by operator Overview of machine safety features � System safety enclosure/light tower/buzzer � Door interlocks � Low air pressure shut-down � Location of emergency stop button Pressure Pot - differences between new pressure pot and Creative Automation pot � Vacuum purging of pressure pot (why and how often) � Pressure settings of pots (Masker A/B = 38 lbs., Masker C = 38 lbs.) � Location of mask feed lines and "off/on" valve � Pressurizing/depressurizing pot



Machine Start-up Overview of the Camalot 1818 front panel � Location and purpose of machine reset and "on/off" buttons � Location and purpose of emergency stop button Turn machine on � Approximate 1 minute wait period during machine turn-on Machine Operating Modes � Complete tour of machine software (do's and don'ts) � Review machine operating modes (edit, trace, and camera) � Review "HOME" and "PARK" positions - how and when they are used � Demonstrate use of trackball Door Lock/Unlock � Review door lock and unlock modes - relationship with audio and visual alarms � Unlocking door during program interruption Needle Purging � Review needle purging (purpose, frequency) and importance of water well � Valve 2 especially sensitive to clogging if not purged often � Locate purge select knob on front panel and demonstrate File Selection � Review directory structure (production, assembly prefix) � Demonstrate program selection and loading files



Changing Needles � Change whenever severe damage or bending has occurred (more than 5 degrees) � CAMERA-TO-NEEDLE Offset shall be performed anytime a new needle is installed or if there

is an obvious offset between the mask being dispensed and the PCB geometry to the point that it is affecting product quality.

� How to change a needle - demonstrate removal and replacement NOTE: NEEDLE CALIBRATION SHALL BE DONE ANYTIME A NEW NEEDLE IS INSTALLED OR IF A NEEDLE IS BENT. Run Mask Coupons � If there is a discrepancy determining the amount of mask being dispensed. � Anytime the operator/trainer has adjusted the knurl-knob thumb screw on top of the valve. � At the beginning of the work week (approximately 3 or 4 hours into the first shift) � Go to the File Operations screen, in Product directory � Load COUPON6X.CAM � Locate copper-clad panel with tape dividing it into 6 equal sections � Weight three clean 4" x 5" FR4 coupons � Record the weight of each, and place in the first three partitions of the panel � Run COUPON6X.CAM Upon completion, weight each coupon � Subtract tear weight of coupon from masked coupon for mask weight (mask weight shall be

between 3.5 - 4.1 grams) Needle Calibration � After replacing a needle � If the needle dispense height is in question (dispensed and the PCB geometry to the point that

it affects product quality).



Needle calibration for both valves � Ensure z axis plunger is working smoothly-clean with clean sponge with all excess water

wrung from sponge. � Load needle.cam from product directory in trace mode � Wipe away the dispensed material immediately after each needle is calibrated. Skipping Bad Images � Highlight items with the right and left trackball keys � Show relationship of highlighted item and use of enable/disable icon � Review image numbering convention Running a Program � Have trainee select file "testpan.cam" from the Product directory and dispense the program on

a blank copper clad panel. � Have trainee skip the second image and dispense again. � While the panel is dispensing, have the trainee demonstrate interrupting the program. Mask Quality � When is hand touch-up allowed: No more than 1 minute per panel - any areas that consistently

have skips or voids in the mask shall be brought to the attention of the programmer so they can be changed.

� When shall a programmer be called or a product placed on-hold because of mask quality

issues? If all troubleshooting procedures have been studied, including calibrating needle and weighing mask coupon, without resolving the problem, contact programmer or Maintenance Technician.

Machine "A" Acceptable Mask Weight: 3.5 - 4.1 grams

SAMPLE 1 SAMPLE 2 SAMPLE 3

MACHINE

VALVE

WET WEIGHT COUPON MASK WET WEIGHT COUPON MASK WET WEIGHT COUPON

A W/IN 10 MIN TEAR WEIGHT WEIGHT W/IN 10 MIN TEAR WEIGHT WEIGHT W/IN 10 MIN TEAR WEIGHT



12.13 PANELIZATION AND DE-PANELIZING This sub-section is about de-panelization. Though seemingly not a very exciting subject, I find nearly as many questions asked about it as most others. Not only that, most all designers with whom I've worked nearly always ask questions, or make wrong assumptions, about panelizing during the design phase. This is interesting because there are so many other complex and much more important questions that should be asked - or are there? Of course, before one can de-panelize, one must panelize. The biggest problem in this relatively simple step is to work concurrently with board suppliers and assemblers. The issue becomes who to work with first - the board shop or the assembly house? The answer is very simple. You work with both starting with the board shop. However, at nearly the same time (just after receiving the fabricator's input), you work concurrently with the assembly house to compare notes, so to speak. Each has its panelization and de-panelization requirements - most often for different reasons not always understood or communicated - one to the other. Very often, the two capabilities do not talk concurrently with one another. Therefore, the designer needs to get them together or, at the very least, make objective decisions based on input from each. Board shops need, so they meet your ever-increasing need for lower cost product, to place as many boards up on, say, an 18" x 24" panel as possible. Assembly capabilities must have distinct requirements met as being able to use panels that fit their PnP and other processes. What to do? Just do it, but do it right! Because everyone has a point of view and distinct needs, this becomes another important compromise issue. Again, compromise is what's all about. Making the right decisions at the design level, using DFM/CE, ensures most negative compromise effects are minimized and acceptable product is assured. This whole book is about compromise concerning what goes into very complicated processes and process management effects. I mean we've discussed hole to pad relationships, component to edge relationships, solder and soldering requirements, and about a zillion other things affecting a design choices and product quality/reliability. Panelization is no different. When consulting with PCB design "experts," I mostly find very talented, well-educated folks never having set foot in a board shop or even an assembly capability. Therefore, many are left to make assumptions - something any good engineer never does. So, let's eliminate assumption making and the problems attendant to it. Besides, even though it is a benefit, design types needn't visit such capabilities as long as they have the ability to communicate effectively with experts in their fields - using DFM/CE principles as set forth in this book. A good designer, working within a well-managed business organization, has most all tools required to design PCB's. Though it's a never-ending struggle to keep up with all design tool upgrades, the important tools must be justified and brought on-board. Another important DFM/CE tool, used to better manage processes, is a good CAM package.



Valor procedures are detailed in this book's Part 1. Another good package is Innoveda's CAM 350. Each has very good panelization capabilities. One just costs one hell of a lot more, but does one hell of a lot more. The following image shows the panelization menu, among others:

Just as most designers have learned they cannot rely totally on their CAD software's auto-route capability, most understand they simply cannot panelize by just doing it. They must work concurrently with their suppliers to do it right. As for the de-paneling process, it is important to understand available options and compromises. These options and compromises are very important. I have reduced many to ONE for MLB's supporting complex SMT assemblies. As I've said many times before, I cannot tolerate pizza cutters when used, on MY MLB's, with fine pitch or numerous chip devices - especially close to board edges. Too much damage occurs with "V" scoring and breaking apart panels with this process. This is true of any such crude attempts to excise, or singulate, individual boards from the panels to which they once belonged. I have no de-paneling procedures or process photos here, but there is much evidence supporting my position and I have worked with several process developers concerning this process. Also, I've witnessed many hours, over several years, of this type de-paneling process and have observed not one single failure - when the process is properly managed. Simply, buy or find a contract manufacturer having routing capabilities if you are faced with such a situation. Most everyone is, of course. If assembling only small quantities, use designs with pre-routed slots and obtain an under or over table router capable of finishing the job. Sears even sells them but remember proper tooling, setup, router-bit selection, installation, and care to change bits when even slightly worn. This certainly includes drills as well.



Keep in mind, with routing, there are no second operations required as hand operations to clean up rough edges left by the pizza cutter or snap a-part activities in the de-panelizing process. There are no filing or other routing operations required. Most importantly, there are no second operations required to repair, rework, or otherwise correct busted devices and solder joint terminations - notwithstanding possible expensive damage to MLB structures. These factors alone are enough to chill one's blood and make a believer out of everyone ever having experienced this garbage. Routing, with vacuum cleaning and ESD capabilities, is a very smooth operation, as I have demonstrated and used many times before. This depends on how well the process is managed. This means what equipment is used, how well it is maintained, and how well the router bits are managed. You all know what multiple-up panels look like. The following two images show them (note the small "starter" slot (in the blue circle) used to facilitate final PCBA routing. The third image is from IPC-2221 depicting fiducial location requirements concurrent with panelization design. Following them is an image depicting "V" groove dimensional and physical requirements. However, this image cannot be duplicated as manufacturable because no router-bit can configure such grooves (only variations) - NO DFM/CE HERE. Discuss concurrently with your qualified board shop for master drawing and note requirements. After that are photos of typical routing machines suitable for use in an assembly environment but without required enclosures. Laser routers also are available but I have no experience with them.



X-OUTS We cannot forget this important facet. X-Outs always are a factor in PCB fabrication and assembly. They affect profitability for both. They also may be process indicators concerning PCB fabrication capabilities. After all, yields for both fab and assembly are adversely affected when too many are found. The first image in the foregoing series shows only one. However, it is part of a four-up panel. One in four isn't that good. What is? Try one in twenty or fifty depending on board density and complexity. Fortunately, the image shown was representative of only one in about forty. With this company, we demanded high first pass yields from our suppliers and our assembly operations. Some folks don't get it, as CE is a very important factor in this equation. It starts with DFM and the supplier evaluation and qualification processes. It all ends up at PnP, etc. SUMMARY There is little mechanical shock involved in the routing process provided, again, the process is well managed. There is much, no matter conditions, associated with snapping or pizza cutting panels. That's all I have to say about that.



12.14 FINAL ASSEMBLY (SYSTEM OR "BOX" BUILD) This is where it all comes together as a final assembly or sub-assembly going into a total system package. The term box build originated many years ago. For me, in the commercial world, it was in the mid-1980's. At that time, many contract manufacturers were just catching on to what they could offer their customers beyond simply placing components on boards. Commercial contract types really were just starting to figure it all out, they thought. They also thought, at that time, SMT was the saving grace and many such folks just didn't see the BIG picture and how they could add "value" for their customers as they were looking almost desperately for a niche (what's changed?). Customers didn't get it either as most large OEM's remained vertically integrated - from design through test. That would all change, but not for a time. Hewlett-Packard, as one example, had their board shops, assembly operations, and plastics manufacturing capabilities. It was pervasive, expansive, and expensive. H-P even used their sheet metal and machine shops to the exclusion of outsourcing - as much as possible. Every "big" organization, providing "final" product, was vertically integrated. In 1992, that all started rapidly changing. IBM was on the brink of disaster as they still were mainframe manufacturers with little PC experience of the type needed to be competitive. Others were equally in trouble, as it was becoming a "cheap" world demanding better product quality and significantly reduced prices (sound familiar?). There were headlines in most major business and trade magazines to that effect. There had to be an answer. It was callout out-sourcing, partnering, and a host of other terms meaning the end to archaic vertical design and manufacturing practices. At first, this didn't work well as there were problems with the emerging systems. There were but a few large contract manufacturers. SCI, Solectron, Flextronics, and but a few others were on the scene. None understood, had, or offered what was needed in terms of total production capabilities - to the final assembly, nor did they know how to practice "partnering" on such a huge scale. No one had a sufficient quality system with which to do so. DFM/CE was not practiced or understood, in this arena, at that time. A combination of things started happening. Solectron's top brass folks (Winston Chin and Les Nishimura), with whom I worked, were mostly ex-IBMers. They got together with their former employers and put together some plans to relieve the situation. Also, IBM had a pretty good quality system that trickled down, or was forced upon, their suppliers before the revolution (it was IBM's way or the highway). The same thing was going on with other companies and the race was on for major corporations to rid themselves of non-value added operations, and for contract manufacturers to take over whatever they could. Just look over the past ten or so years at what's happened to the CEM world. There are so many, spawned usually from their former associations, it's hard to count them all. Then you have folks like Sanmina, once a lowly board manufacturer with a bad reputation, taking over so many other board shops and assembly operations. They last gobbled up SCI, that at one time was the largest CEM on the block if not planet.



Anyway, without getting to carried away on a complex subject, there simply now are no successful large OEM's building everything in-house. Out-sourcing is in, just as has been in the military and aerospace complex for years. One big difference exists, as the latter folks did it much better though not able to do so now with such restrictive cost demands placed on all manufacturing operations. DFM/CE is needed now more than ever. This especially true when dealing with off-shore manufacturing suppliers. This is a time of huge adjustments for us all, but that never changes. In truth, this type assembly has been around forever, of course. Mostly, box builds were always part of the electro-mechanical design and assembly world. OEM's mostly did this and "passed" product along to higher "tier" manufacturers as in automobile manufacturing. In the military/aerospace community, the first suppliers were those providing raw materials. Then, sub-contractors were suppliers. They supplied product to others of their type until the major sub-assemblies were installed in final production for major contractors. In-turn, they supplied to whatever government agency or military complex, or to aircraft manufacturers. This is when and where the term supply chain management (SCM) took on serious meaning. A simplified graphic illustrates how SCM works.

Being a complete contract manufacturer (CM) means understanding, completely, DFM/CE and SCM. Without this knowledge, all is lost - as history has proven so many times. The same is true for quality programs housing all factors and elements required as part of DFM/CE and SCM. Having been involved with many military and aerospace contract negotiations, as an engineer and board shop owner, I understand what is required to be successful. In this book's Section 14.0 concerning quality and reliability, I discuss how many quality program requirements were developed, implemented, and used over the years. I talk about how, in my early career days, I was exposed to military quality requirements. These were MIL-I-45208 inspection requirements as part or independent of MIL-Q-9858A quality program requirements. I emphasize the "A" revision for 9858 because it hasn't changed one bit from its



inception in the early 1960's. This requirement, ISO admittedly, evolved into ISO 9000 as its primary foundation element. H-50 served well as the quality program audit instrument. What's most fascinating about this is how I used to negotiate with purchasing agents, with government contractors, and come away with an order from time to time. It was too easy once proven capable of qualifying and conforming to these early quality program requirements. For me, in the PCB industry, qualification and conformance to such requirements as MIL-P-55110, 50884, and 28809 also was essential. What's funny though, as I later found out, was the purchasing people loved playing jokes - in a sense. They honestly enjoyed seeing "rookie" folks like me self-destruct. Sure, I got the first order based on our qualification and conformance, but there was much more to the equation. I/we now had to meet customer specified quality requirements - no matter how good we thought we looked. I go into this more in the aforementioned quality and reliability section following this sub-section. For now, naivete prevails, as it will - always. I remember having a meeting with a relatively young Sanmina's Milan Mandarec and Jure Sola. They asked me if this SMT thing ever was going to become something. This was in the mid-80's and I had just come in from the cold, cruel military SMT world (I dearly loved) so I said, "of course." They weren't sure at first, but much later they became believers, as did we all. They also asked whether there was a future producing sub and final assemblies. I again said yes and they took this a bit more to heart and started their first press fit back-plane operations. Look at Jure now. He's the CEO of Sanmina-SCI. When I first met him, he'd just come off Milan's soccer fields in Yugoslavia to become Sanmina's sales manager. He made sales alright. He made tons of them using whatever means it took, but shipments almost always were late and returns were many and often. I take no credit in their success. I was fought by them most of the way, especially when it came to quality through process management instead of constantly reacting to defective results - as often was the case with them and many others at this time. I even gave them several very objective presentations during which they chided (more like warned me) me that I was disrupting their operation by apparently criticizing that which to everyone was obvious. I did battle with many others of the day. Where are they now? They went bye-bye. The handwriting clearly was on every wall everywhere. The image atop the next page (one of many) was provided by a major customer for many suppliers at the time. A Memorex engineer contacted me asking what happened. I told him that wrong material choices were subjected to poorly managed lamination processes. Many meetings followed. None were fruitful as Sanmina and many others kept on keeping on with used car sales rhetoric and obscene sales tactics (let me make you a deal you can't refuse). Jure and I remained friends, as we both were likable folks though not sharing common ground upon which to stand or walk.



I remember also seeking PCB fabricators that could produce boards finer than 50 mil pitch SMT designs. Some of that time's best said this never could be done let alone assembling the things and making them work in boxes. Sales, for many at that time, were the dominating factor - not shipments, quality, or reliability. Times have changed somewhat, but most folks still think mostly SALES and CHEAP. Why else would we be in China? Why, because have real problems allowing our companies to stay in business - for many reasons including such a high tax burden. Sure, they have low labor rates, but that really is only part of the equation (% gross profit - not the whole enchilada). We just don't have it anymore nor do off shore suppliers due to lack of, WHATELSE but DFM/CE, and the urgency to just get it out the door. This is where and when DFM/CE is most important. If the major contractor doesn't have it right, it's most often because it did not consult concurrently with all its sub-contractors. This is why traceability became, and is, so important. This means knowing exactly what element or component went into what assembly and that element or component was/is capable of being traced back to its origin for cause and effect determination. Of course, we aren't even talking about commercial off the shelf (COTS) and the negative impact it's having on product. Examples of this include aircraft accidents or incidents (there is no such thing as either, by the way, as everything has cause and is preventable) and the investigations that follow. If a plane crashed/crashes, it is essential to establish cause and hopefully prevent its recurrence. However, this is getting much more difficult with current quality and reliability issues being more difficult to resolve with COTS, as one example. COTS has generated a whole new world of concern and increased burden on buyers and users. Most high reliability suppliers now must do their in house quality evaluations and reliability studies. This was not the case some time ago when "special" product was manufactured (actually culled out of normal production runs) and certified to certain specifications for use in hi-rel assemblies. I have worked in many situations where other's designs or mine may have been cause. More than this, I have worked on fabrication and assembly projects wherein designs were not acceptable for our process capabilities but, because of contract requirements and a lack of good DFM/CE, we were required to continue.



There were occasions when, because of this or certain material types were unavailable, our processes rendered what ultimately caused serious problems. This was/is unfortunate and totally unacceptable mostly because we were in contract situations wherein little reliability data or information was yet available. No matter, the government agency required us to proceed. These decisions lost lives. I can cite many examples regarding stupid commercial design and production tricks - as can you all. Most effected only business failures without threatening or endangering lives. Some cost lives. I won't go into them all, but I will tell of four occasions. One was about a year ago. The others go back over the last twenty years. 1) "CONBOX" I was consulting as a DFM/CE, manufacturing, process, component, and quality engineer for this company. I was there for about fourteen months at a reasonable rate, considering recent conditions in this country. From day one, I received little respect. It wasn't for some time I found the reason. This simply came down to this company's total lack of design, manufacturing, quality, reliability, test, and cost understanding. I've always enjoyed a challenge, but this? I walked into this place and immediately was asked, no grilled, about what I could do to make things right. I offered my standard rhetoric concerning DFM/CE and extolled all its benefits. The three folks in charge looked at me slightly askew as if to say, "what is this all about?" It turns out these very nice, well educated (two PhD and one Masters types) were total rookies having set out to make product they "designed" for their only Asian client/customer - who paid all the bills. Unknowingly at the time - this was the big reason I was there. One of the first images in this book's Part 1 (you know, the "C" clamp) turned out to be their first serious, or not, endeavor into high technology aside from creating some pretty neat software. They just figured, I guess to them, this whole product design and manufacturing thing was no big deal. This turned out to be the case so their Asian partner forced them to hire me, or someone like me (not possible, of course).



Over the contract period, I fixed many problems including the one above. They included all the problems associated with PCB fabrication and assembly. Things, into the first six or so months, went pretty well with a lot of high fives and "ataboys" as product started working without benefit of clamps. We went from near 0% yields to 99% within three months. Then things changed drastically. These folks, now numbering about forty highly educated and talented but un-cohesive individuals, had taken on an additional challenge. They were about to design and build a commercial system (a box) for use all over Asia. This is because that part of the world does not have the cable and other communication infrastructures we enjoy in this country. They were/are starting to do it by satellite. That's another story but for the box that was designed to sell millions as product connected by satellite link. The box was/shall be sold to companies and individuals without thought of environmental affects and consequences, or any other reliability concerns. It was to be housed in a simple injection molded plastic case - open to the elements (via cooling slots, etc.). This all was being done by a company not even having a rudimentary quality system, let alone a notion of what DFM/CE was about but for the little I provided to keep them in business. The assembly I named the "CONBOX" is somewhat of a sarcastic acronym for a product I'll not divulge but for the associated design, manufacturing, and reliability issues inherent in it. One of the "big three" company hierarchy types hired a very talented project manager who obviously had not managed a project until this time. However, I use the term "managed" loosely as this thing was anything but well managed. This individual had the highest "management" respect. He was given complete authority for the box design and production though not close to being hardware oriented. The PCB/PCBA part of the equation worked well enough alone - in a relatively "sterile" environment. The box into which it went was another story. The box was to be a two piece injection molded part (top and bottom) that encased the guts as the board, power supply, and exhaust fan vented directly to whatever environment. The problem simply was the box, and all in it, could not survive in the harsh environmental conditions to which it was to be subjected. Actually, I doubted/doubt it would survive anywhere for long or short periods. Initially this was proven using simple thermal cycling accomplished by placing the assembly in a heat chamber. There wasn't even humidity applied, let alone mechanical stress or shock. This was a debacle or MCF, if you prefer. Many failures resulted as no true understanding of reliability principles was even remotely apparent. Other relatively minor issues prevailed. One, as an example, was the plastic injection molded housing design. First, the board was designed using my rules but they were violated. One example excluded requirements for tooling/test holes versus mounting holes. These fine folks just made the holes all the same size - .250" as I recall. The board fabricator couldn't work with these just as could not the assembly house. The board had to go back to the original design I specified. This meant redesigning the boards with both tooling and mounting holes. That meant retooling the box



at a very high cost. Then, at least, the thing became manufacturable though not even close to being proven reliable. This really gets back to quality and reliability issues surrounding any design without benefit of DFM/CE. Because of cost and schedule constraints (what's new), the project manager listened to nothing I, or anyone else, had to say or present concerning the best design requirements for manufacturability, cost, quality, servicing, and reliability. He just forged ahead and it got exciting. I hardly blame him for needing a paycheck in extremely declining economic times but jeez! I only blame management for not applying or practicing the DFM/CE principles and requirements I set forth. I can't even tell you how many products were returned and continue to be returned. I cannot even tell you how pissed off is the customer. I can't begin to imagine what such a bright group (in no way a team) of INDIVIDUALS are now doing with their lives. China, maybe! 2) DIGITAL ENGINE CONTROL PROGRAM In the early days of 1980, or so, everything was going digital. At least attempts were being made to do so. The F-16 would become the first combat, or any other type aircraft, to "fly by wire." First there had to be digital systems capable of this concept. One of the first and most important were digital jet engine control systems housed in a box capable of surviving, and providing survivability for the stuff in it, enormous stresses and shock encountered in daily operational use. Pratt and Whitney, under Navy contract, was assigned to produce evolutionary jet engine technology for military aircraft. Included in these efforts were digital jet engine controls. This was to be a box capable of being computer controlled with input from the pilot via the throttle mechanism using 0's and 1's instead of hard cables. Just as with the F-16, polyimide PCB's and wiring systems were to be used. They were, but not without incident and serious consequences. Flight failures occurred and were traced back to the material choices. In the F-16, polyimide insulated wiring harnesses were cause as they began deteriorating causing them to short against other wires in the harness bundles and to the plane's fuselage. This would be fixed in time as would the rigid MLB's in the jet engine control systems. Neither was an easy fix. For the jet engine control MLB's, the Navy's Lab in Indianapolis (now EMPF or ACI in Philadelphia, I think) determined cause as designing and fabricating polyimide boards taken to full cure. This meant the boards were relaminated with a 270 degree C. Tg as was typical at that time. I worked with Jerry Kirschenbaum, at Trace Labs in CA as somewhat of an observer. He provided information that would forever change polyimide lamination cycles. It was determined that innerlaminar and foil bond strengths were diminished very rapidly after thermal cycling. Factually, findings were shocking. After but a few cycles, foil bond strengths were reduced from a normal 5-7 pounds to less than 1 pound.



This finding had laminate material and board suppliers changing profiles. Typically, relamination profiles forced Tg reductions from 270 to 250 degrees C. This dramatically increased reliability and resolved most issues relating to the digital engine control systems and the boxes in which they reside. This example shows that no box design or product can be made reliable without DFM/CE. Digital engine controls and most all fly by wire applications work just fine now but for some in railroad applications. That's another story but very interesting. I won't take time here to discuss much of this but to say, as a semi-frequent train traveler, most maintenance people despise the systems. I didn't like them much when having to change locomotives several times on several journeys though I did have more peaceful meals without train motion. 3) MX MISSILE PROGRAM This is a REAL box build story. Where else could one find such a story with so much at stake - but for the highly successful Trident missile program - using very "conventional" interconnect technologies? This program was doomed from the outset. We're talking multiple nuclear warheads independently guided by navigational boxes within each. Unlike the Trident missile program, the MX went all the way with supposedly high reliability rigid/flex interconnect systems. Originally, there were 79 layers of the stuff in each box. Initially, this was the way to go. Conventional wiring was not acceptable as it added much bulk and weight to the boxes. The problems were simple. Rigid/flex circuitry, as all circuit types, had/has limitations. Exceeding 11 layers was the problem with this design and its unsuccessful production and flight. Each guidance system's main board was comprised of 22 rigid and flexible circuit layers. It was found, through many studies and one in particular, that exceeding 11 layers created many non-resolvable problems. One was related to processing especially after lamination and drilling wherein circuitry had to go through dry film lamination to allow imaging. During the dry film lamination process, heat and pressure is applied to the circuitry to assure adhesion. When layer count is higher than 11, due to the rigid/flex circuit nature, electroless plating often "collapses" preventing electroplating, as shown again in the next image:



This appears as delamination. It is and isn't. Actually, the electrolessly "plated" hole walls collapsed during dry film lamination as the material is very "soft," for lack of a better term. It compresses very easily and prevents through-hole electrical continuity. Additionally, the adhesive materials used in the MLB constructions has a very low Tg. This, in itself, eliminates the ability to laminate very high layer count rigid/flex circuitry. Not only does the material "cold-flow" at room temperatures, it is very hygroscopic so moisture issues are constant threats to reliability. These factors contribute to delamination in operational product. This places a great deal of emphasis on how to design the boxes into which these circuits must reside and survive. Though this type hardware need only fly once, it faces the widest ranges of mechanical thermal stress and shock possible in addition to extreme environmental challenges. Hence, box designers and builders must use all possible DFM/CE tools available. 4) COMMERCIAL CHEMICAL CLEANING ASSEMBLY PROJECT Once I worked with a pretty nifty contract manufacturer in South Dakota (great place but for tornadoes). They produced, or attempted production of many sophisticated commercial electronics and electro-mechanical designs. Most production was successfully accomplished though some rendered less than desirable quality, reliability, and PROFIT. There were several reasons for this. Among them was a lack of knowledge or ability negotiating concurrent contracts without benefit of DFM/CE or SOW's. It was a dart throwing debacle. When prototypes were assembled, little cost or other important data was collected or properly used. One of the projects was total system box build for a major commercial and industrial cleaning product. It entailed procuring all electronic and mechanical elements. Then, the product was assembled. The "boxes" within the "big box" were comprised of PCB's, PCBA's, sheet metal, plastics, tubing, O-Rings, machined parts and all manner of other things electro-mechanical. In the end, the customer demanded lower prices while the supplier sought increased revenues. Neither understood the other and this situation became a standoff with the box in limbo. Fortunately or unfortunately, it was and always will be this way when living on the cutting edge where the envelope constantly is being pushed. Usually, this is where "breakthrough" technology is employed - instead of that being evolutionary.

I’m too cool and know how to get it done right – the first time! It's just

part of my heredity and evolution.

Patience my ass! I’m going

to kill something,

even if it’s the design. This is revolutionary for me and my

kind.



SUMMARY You can't design and build the box without knowing and preparing for what goes into it and what will affect it all. The few examples presented clearly are an indicator of this. Despite, the sometime negative effects, revolutionary efforts often lead to great advances very quickly though reliability information may be delayed for some time. Simply, as I said before in this book's Part 1, evolutionary is preferred for most DFM/CE requirements but revolutionary efforts are required in others. No matter, the box must be designed for what's inside it, how it is to perform - under what conditions, and what initial quality and long-term reliability requirements are.



12.15 CLEANING AND CLEANLINESS Cleaning is a dead issue, right? Wrong, of course. Even with no-clean fluxes, issues still exist. One of which is cleaning no-clean flux residues after touchup. Another pertains to some high reliability applications require more conventional fluxes are required to effect acceptable solder joints. Yet another are applications, especially those with through hole components in very thick MLB's, requiring very active fluxes. One more are applications with uniquely plated or coated component surfaces, as RF filters (using "German Silver," or?) requiring very active fluxes. This story, as does the one for lead-free soldering, also has no ending. It would be very nice if "one size fits all," but that isn't possible. So, what to do? Nostalgia - just a bit more! Back in the good/bad old days, when SMT was a gleam in everyone's eyes, solder paste formulation gurus mixed brews with many different fluxes and tin/lead variations. We were cautioned to use only pastes with spherical solder balls as more rapid oxidation rates would become a bit of a factor with solder shapes other than round. We, trying to assemble and clean our product, could not always determine what to do. Many types of equipment, wash capabilities, machines, and chemistries were used. Do you remember this monster? Technical Devices made and sold this fourteen-foot long machine. At H-P we scavenged the magnahelic gauges and used them in out BTU ovens to determine how clogged up the vents were due to escaping flux gases and resulting residues. I know not what happened to the machine as we changed over to no-clean and hardly every looked back. The machine used several separate chambers to do the job and many times with saponificants added. As is typical, the first chamber used the dirty water while the second was clean and the final was a rinse. In the early days, high pressure was attempted with fine pitch devices (less than 50 mils) to "blast" out the crud from underneath these devices.

Nothing really worked well in the beginning. The recipe just wasn't available then and flux entrapment nearly always was apparent effecting real problems with solder joint reliability over time. Just as now, DI water was used in addition to other mixes. You may remember MIL-P-28809 being our guide for resistivity of solvent extract (ROSE) testing requirements as primary. We used/use de-ionizing tanks with resin beds, to ensure the water was capable of meeting board cleanliness requirements (I think it was 2 megohms/cm). Is that right? That meant, the water had to have much higher resistivity readings coming out of the tanks - something on the order of 6 plus megohms.



When lower than 4 the tanks were replaced. This became a very expensive but seemingly necessary proposition.

You also remember using the Omega-Meter. I apologize for the following image as it got a bit degraded over the last twenty or so years. This test method involved using 70% alcohol and 30% DI water, as mixed in the cone shaped glass apparatus. Then the board was rinsed in this mixture and the meter was used to determine resistance.

With all this there was a severe problem. The solder paste chemical types didn't talk to the cleaning chemical types. This left us in a lurch, if you will. We just didn't know what was in the solder paste binder. Therefore, it was difficult and often impossible to assure cleanliness requirements were being met. With fine pitch devices, and some others, water molecules alone could not get under the devices and clean. Visual flux evidence often was apparent driving us up walls. Saponification and high-pressure (sometimes 40-80 psi) processes worked to some extent but you should have seen all the little chip components at the cleaning machine's sump bottom when its cleaning time was upon us. CLEANLINESS NOW BUT THE DEBATE CONTINUES Now cleanliness has taken on newer meaning. It also uses more and better, than ROSE, to test cleanliness though ROSE often is used as a process indicator and the first step leading to better testing and analysis. The following comments were taken from the IPC Technet some time ago:



Sender: TechNet <[email protected]> From: Tegehall Per-Erik <[email protected]> Subject: Re: Ionograph measurements Content-Type: text/plain; charset="ISO-8859-1" Even if you could find a method to scientifically measure cleanliness of an assembly (which I doubt will ever happen since flux residues are absorbed into the epoxy resin) you would also need to be able to tell how the concentration of the various contaminants varies over the surface of the assembly in order to assess the impact on reliability. This means that you also must be able to transform contamination levels into reliability figures. You must then know which of the contaminants that are hygroscopic and which are hydrophobic, which are ionic and which are non-ionic, but also which contaminants that cause synergistic effects when mixed. Therefore, I think, a scientific approach for verifying quality ought to focus on methods for assessing the impact on reliability instead of methods for measuring the cleanliness. Surface Insulation Resistance (SIR) measurement is such a method (described in Appendix B in J-STD-001C) but, as it is used today, its scientific base including acceptance criterion is not what it ought to be. Per-Erik Sender: TechNet <[email protected]> From: Mel Parrish <[email protected]> Subject: Re: Ionograph measurements X-To: Tegehall Per-Erik <[email protected]> In-Reply-To: <[email protected]> Content-Type: text/plain; charset="iso-8859-1" Good input! From an historical perspective, Ionograph testing was intended to support rosin base fluxes closely controlled by flux qualification specifications which is certainly not the case today. Given the consistent contamination resource as well as cleaning chemistries the correlation to cleanliness to performance was a valid consideration. Good application for the time and common processes allowed. Today we must rely more heavily upon SIR/MIR types of testing however IC testing resources can add a degree of confidence as it can identify and quantify the contamination type. Unfortunately these tests are not inline process tests as were the quick and simple Ionic tests when life was simpler. Mel Parrish Director, Training Materials Resources Soldering Technology International 102 Tribble Drive Madison, AL 35758 256 705 5530 256 705 5538 Fax [email protected] www.solderingtech.com Date: Wed, 2 Oct 2002 08:18:36 -0400 Reply-To: [email protected] Sender: TechNet <[email protected]> From: joyce <[email protected]> Subject: Re: Ionograph measurements X-To: Tegehall Per-Erik <[email protected]>



In-Reply-To: <[email protected]> Content-Type: text/plain; charset="iso-8859-1" guys, I am bit confused here. Are we talking about process development or process control at assembly level? (1) all the cleanliness establishment shall be done at development stage. Ionograph is not a good tool. Liquid chromatography might be the better way to go to define what is the compatibility problem and what kind of contamination is on the board. If you get the right personnel, you might be able to pin point what is the root cause if you exceeding the spec. (2) Ionograph is good for process control after you defined your "process". It give a lump sum of ionic reading without differentiate where it come from and what it is. If you got 6 sigma control of everything, you should not see any difference between your process development stage and control. If you change vendor, as long as you know what to look for, you should be fine after vendor qual. (3) sure you can use Ionograph machine as cleaner (did that before)...provide you know what are you doing and have enough money to replace some of the parts in the Ionograph machine...(depend upon who is going to do the replacement, if it is you, you most likely will have second thought). In theory, if the process development were done properly, the chances for the exceeding spec is very very slim. Normally, when it is start to drift towards the limit, someone should start walk on the floor to play detectives. However, that does not give you any glory status of "problem solver" or "team player". jk Date: Thu, 3 Oct 2002 10:59:54 +0100 Reply-To: [email protected] Sender: TechNet <[email protected]> From: Mike Fenner <[email protected]> Subject: Re: Ionograph measurements In-Reply-To: <[email protected]> Content-Type: text/plain; charset="iso-8859-1" Its probably worth recalling that the original Mil 28809 actually required the ionics on a board to be extracted manually in a "classic lab" manner by a someone in a white coat. The Ionograph, Omegameter and so on were developed as means to simplify this process and make it possible for non-chemists to carry out testing without a lab. This they did with varying degrees of efficiency and that's where the equivalence numbers come from. We need to keep in mind that there is a high degree of empiricism in them and they are only quantitative - an amount. Qualitative aspects were looked after by defining quite closely the flux type they were valid for. Also keep in mind this was decades ago. Current technology fluxes may or may not have the same relationship of quantity of extractable ionics to reliability that was assumed in the MIL. Today the Ionograph is just a dirt meter for ionics. It produces a number which goes up and down same as a volt meter does for electricity. The



numbers it produces can be used as an approximate measure of process control. Clearly a high number is bad, but how bad should preferably be related to something more application specific founded on reliability testing. Regards Mike Fenner Applications Engineer, European Operations Indium Corporation T: + 44 1908 580 400 Date: Thu, 3 Oct 2002 08:59:06 -0500 Reply-To: "TechNet E-Mail Forum." <[email protected]>, [email protected] Sender: TechNet <[email protected]> From: [email protected] Subject: Re: Ionograph measurements X-To: [email protected] Content-type: text/plain; charset=iso-8859-1 Per-Erik, The ROSE/SEC tests were originally developed for process control. Unfortunately, it worked so well (at the time) that it became the measure for "clean" for electronic assemblies for weapons specification WS-6536E and later MIL-STD-2000 as a product acceptance measure. It later migrated into J-STD-001, also as a product acceptance measure. It has remained in the J-STD-001 specification because no one has, as yet, come up with a better way to measure that is easily and cheaply accessible to all. Most assemblers have a ROSE/SEC tester handy and most figure that even flawed data is better than no data. Doug Pauls Rockwell Collins Date: Thu, 3 Oct 2002 16:46:42 +0200 Reply-To: "TechNet E-Mail Forum." <[email protected]>, "d. terstegge" <[email protected]> Sender: TechNet <[email protected]> From: "d. terstegge" <[email protected]> Subject: Re: Ionograph measurements Content-Type: text/plain; charset=US-ASCII Content-Disposition: inline The original question (mine) referred to the situation where a customer doesn't agree with the contmination-limit that's used for process control with the Ionograph. Qualification of this process was mainly based on SIR-measurements. Date: Sat, 5 Oct 2002 17:55:05 +0100 Reply-To: "TechNet E-Mail Forum." <[email protected]>, Graham Naisbitt <[email protected]> Sender: TechNet <[email protected]>



From: Graham Naisbitt <[email protected]> Subject: Re: Ionograph measurements X-To: Per-Erik Tegehall <[email protected]> In-Reply-To: <[email protected]> Content-type: text/plain; charset="US-ASCII" > Joyce, > > As I understood the orignal question, the Ionograph measurements were used > for a sort of product (assembly) qualification per J-STD-001C, i.e. neither > process development nor process control. > > Per-Erik Techies, As I am writing this in Finland and unable to get a connection before I leave, this might seem somewhat tardy but... Per-Erik and others have made many comments regarding the history, methodology and future practices for reliable production. If I might just add my Pennorth: Jack Brouse of Alfa Metals informed an IPC committee discussing circuit cleanliness that: "ionic extract cleanliness testing was only EVER intended as a process MONITOR". Unfortunately, the US Military picked up on the method, and selected a pass/fail criteria that was modified to several ever lower levels until 1.5 microgrammes/centimeter/squared of NaCl EQUIVALENCE was achieved. This was most misleading - particularly when folks began to produce fine-line, fine-pitch circuits. This is NOT a test method and as Per-Erik pointed out so correctly, it is virtually impossible to determine how clean is clean. Furthermore, it also states that it is acceptable to leave UP TO 1.5 microgrammes of salt on every square centimetre of your assembly - OH REALLY?? In modern miniature circuitry - I don't think so! That is why so many employ their own (empirical) pass/fail - I prefer "Go / No Go" levels, in my experience typically less than 0.2 microgrammes. The method: Involves MEASURING the resistivity of a test solution comprising alcohol and de-ionised water. This is a good method - except that it NEVER zero's back to the same start level. The "empirical" bit, is the individual vendors math's package that converts this MEASUREMENT into an EQUIVALENCY of sodium chloride, and has to compute the volume of test liquid that is used - and that certainly varies from machine to machine - PLUS - other factors involving the filter and resistivity sensor etc.. Speaking of Equivalency Factors - I promised to send a number of you the US Navy document - and I will, just as soon as I get into the office and find it! Please stay with me on this.... Now, as to methods to determine end product reliability - as Per-Erik said, this is a good one, but no specification is yet available. Well, yes it is now - at least in draft form - because yours truly just



finished writing it and presented it to the IEC committee here in Helsinki yesterday - and it was accepted. I have already sent a draft to Jack Crawford to circulate to the various committee chairmen at IPC, and will be in New Orleans to discuss this in November. If anyone wants this latest draft, let me know. Just bear-in-mind that it is a draft with no formal accreditation at this time. Finally, just let me say that we are trying to develop a process method using BOTH our SIR and ionic test machines. Watch this space..... � Regards, Graham Naisbitt [email protected] Mobile: +44 (0)79 6858 2121 Date: Tue, 15 Oct 2002 16:03:22 +0100 Reply-To: [email protected] Sender: TechNet <[email protected]> From: Mike Fenner <[email protected]> Subject: Re: Ionograph measurements X-To: "Dieselberg, Ron" <[email protected]> In-Reply-To: <96217FF0807CF446B7701FDF27F654B2195867@ohcinceex2.ohcinele.cinele.com> Content-Type: multipart/alternative; RE: [TN] Ionograph measurementsYou can down load MIL specs etc from http://assist2.daps.dla.mil/quicksearch/ Regards Mike Fenner Date: Tue, 22 Oct 2002 17:38:41 -0500 Reply-To: "TechNet E-Mail Forum." <[email protected]>, Jack Crawford <[email protected]> Sender: TechNet <[email protected]> From: Jack Crawford <[email protected]> Subject: Re: Cleanliness Testing - When is it clean enough? X-To: [email protected] Content-Type: text/plain; charset="us-ascii" This is a reminder that Doug has made available a set of informative papers and articles with general discussion on cleaning. I've zipped them all together into a single file (>4MB) that you can download using a web browser. In the address line put: http://216.203.210.37 and that will open in our public FTP site. You'll see a folder called "CleaningBoards"; the download file is inside. I think I remember that all the papers are in .pdf. Some of the reports have had a birthday or two but there's good info available to the determined reader.



Thanks again to Doug for sharing. Jack Crawford Director, Professional Development and Assembly Technology [email protected] 847-790-5393 fax 847-504-2393 D(S)UMMARY And the beat goes on just as with lead-free soldering and no-clean solder paste. I think you all get the idea.



12.16 INSPECTION AND TEST I have much to say here. However, I'm running out of room and time for this book's revision. In another revision, I will present more detail. No matter, this subject and section requires special care and attention to DFM/CE principles and requirements. INSPECTION To begin, I don't believe in inspection at all. In fact, in my opinion (not at all humble) - based on objective evidence all around us. All inspection processes and activities waste time. Of course, I live in the tiny world of DFM/CE wherein everything is "perfect," right? No way - but inspection of any type too often is used for the wrong primary purposes. Final inspection, or any inspection for that matter, should and must be done on a random basis only to collect statistical data and information to ensure continuous process improvement is practiced. This only can be done within a well-managed business with a very good process (not quality) management program. It also requires using DFM/CE within Lean Manufacturing operations where JIT is practiced. All this requires ensuring, first, everything and everyone within the organization practices what it preaches, and requires from outside suppliers. All internal suppliers must practice these processes and procedures before ever "assaulting" the outside world. Otherwise, the whole thing becomes a totally futile exercise. Do you see why? JIT and Lean aren't exactly new terms or concepts. Many have practiced it for years, though some better than others. Just look at Toyota and the fact they now are the number one car maker in the world. THEIR CARS ARE GREAT AND JUST DON'T BREAK. In a Lean system, very little inspection is required because supplier evaluation and qualification processes are very well established and practiced. This means incoming inspection, for example, is nearly eliminated but for ongoing supplier quality evaluations. This means only supplier process management data and information is collected and continually analyzed with real time feedback provided to that supplier so they continually make process management improvements. This book is about designing for manufacturability using vital tools like concurrent engineering. When everyone practices business and process management efficiently and effectively, defect is reduced or eliminated - during all production phases. ISO and QS 9000, along with other specific quality program requirements, lend much to the process management equation. When properly practiced, these programs, along with the ones aforementioned, virtually assure quality is effected through process, instead of quality, management. Look at the following information, while noting its total waste, derived from some procedures I wrote many years ago: 7.0 PROCEDURES - PCB FABRICATION The following procedures, at a minimum, shall be used for final inspections and testing.



7.1 RECEIVE LOT CONTROL DOCUMENTATION, and lots to be inspected. 7.2 INSPECT DOCUMENTATION for completeness, accuracy, and required inspection, and operator stamps and signatures. 7.3 SAMPLE SIZE Determine sample sizes for sample inspections to be performed. Generate and assign random numbers to parts within the lots. 7.4 INSPECTION Inspect sample lots in accordance with the requirements of POD, PCB Acceptance Specifications. 7.5 ACCEPTANCE AND IDENTIFICATION Accepted lots shall be identified, and the lot traveler documentation shall be stamped accepted, and the lots shall be moved into shipping, or into reliability, or laboratory test, holding sites. 7.6 REJECTION Rejected lots shall require that attendant lot control documentation be stamped rejected. Rejected lots shall then be returned to production for rescreening, or 100% inspection. Lots having been rejected three times shall be scrapped. 7.7 RESCREENING Upon rescreening, lots shall be reinspected, and upon acceptance an acceptance stamp shall be superimposed over the previous rejection stamp. 7.8 LABORATORY AND RELIABILITY TESTING Lots requiring reliability, or laboratory testing, shall be tested in accordance with appropriate procedures, and specifications. 7.9 REINSPECTION Lots shall not be reinspected more than three times. 7.10 AUDITS Quality process audits shall be performed separately, but in concert with In Process Inspection that shall be performed in accordance with the following procedures, and requirements: Determination shall be made that all requirements, of the master drawing and contract, have been met including the following: 7.10.1.1 Overall board dimensions, tolerances, route, and panelization requirements 7.10.1.2 Hole sizes and tolerances 7.10.1.3 Plating requirements 7.10.1.4 Solder mask requirements 7.10.1.5 Constructions 7.10.1.6 Material requirements 7.10.1.7 Electrical requirements 7.10.1.8 Trace and space requirements



7.10.1.9 Laminate condition -- surface and subsurface imperfections, measling, crazing, voids, delamination, etc. 7.10.1.10 Cleanliness requirements 7.10.1.11 Warp and twist requirements 7.10.2 Specific requirements for the following shall be met: ELECTROPLATING 7.10.2.1 Plating thickness/quality shall be met in accordance with traveler, and master drawing requirements 7.10.2.2 Hole sizes shall be verified in accordance with traveler, and master drawing requirements 7.10.2.3 Traveler requirements shall be met 7.10.2.4 Strip/scrub quality shall be as required for further processing with no resist residue apparent, and water break requirements met in accordance with process procedures 7.10.2.5 Plate quality shall be as required per traveler, and master drawing requirements with no peeling, or other anomalies 7.10.2.6 Plate thickness shall be as specified on the traveler, and the master drawing 7.10.2.7 Peel testing shall be performed in accordance with POD Laboratory Verification of Quality Procedures 7.10.2.8 Splashes/leakers shall not be acceptable 7.10.2.9 Tape residue shall not be acceptable 7.10.2.10 Traveler sign off shall be required by all personnel/operations indicated REFLOW 7.10.2.11 Smooth, even, shiny surface conditions shall be apparent 7.10.2.12 Total wetting shall be required with no dewetting, non wetting ROUTING 7.10.2.13 Print and traveler requirements shall be met 7.10.2.14 Dimensions tolerances shall be in accordance with master drawing requirements 7.10.2.15 Second drill size/quality shall be in accordance with traveler, and master drawing requirements 7.10.2.16 Pinning holes shall be as required with no apparent damage 7.10.2.17 Traveler sign off requirements shall be met for all personnel/operations indicated 7.10.7.1 All requirements shall be met in accordance with traveler, and master drawing SOLDER MASK -- SCREENING 7.10.2.18 Effective, even coverage shall be required with no evidence of solder mask on pads while meeting clearance/coverage requirements with no traces open to pads 7.10.2.19 Proper thickness with no skips, voids, wrinkles, etc. shall be acceptable 7.10.2.20 Legends shall be clear, legible, and shall be in accordance with traveler, and master drawing requirements SOLDER COATING -- HOT AIR LEVELING 7.10.2.21 Smooth, even, shiny surface conditions shall be apparent 7.10.2.22 Total wetting shall be required with no dewetting, non wetting 7.10.2.23 All holes that are required for component mounting/soldering shall be free of solder, but small vias may remain plugged



Note: Final inspection procedures, specifications, criteria, and methods shall be used in the determination of acceptability of the soldering process, and board quality. POD, QCI-4015, IPC-610 - Class 2, MIL-STD-2000, and MIL-C-28809, shall be used as typical acceptability specifications when used in conjunction with contract requirements. 7.0 PROCEDURE - PCB ASSEMBLY 7.1 RECEIVE LOT CONTROL DOCUMENTATION and lots to be inspected. 7.2 INSPECT DOCUMENTATION for completeness, accuracy, and required inspection and operator stamps and signatures. 7.3 DETERMINE SAMPLE SIZES for sample inspections to be performed. 7.4 INSPECT SAMPLE LOTS in accordance with the requirements of POD, Assembly Acceptance Specifications. 7.5 ACCEPTED LOTS shall be identified and the lot traveler documentation shall be stamped accepted, and the lots shall be moved into shipping or into reliability or laboratory test, holding sites. 7.6 LOTS REQUIRING RELIABILITY, or laboratory testing shall be tested in accordance with appropriate procedures and specifications. 7.7 REJECTED LOTS shall require that attendant lot control documentation be stamped rejected. 7.8 REJECTED LOTS shall then be returned to production for rescreening or 100% inspection. 7.9 UPON RESCREENING, lots shall be reinspected, and upon acceptance an acceptance stamp shall be superimposed over the previous rejection stamp. 7.10 LOTS shall not be reinspected more than three times. 7.11 LOTS That HAVE BEEN REJECTED THREE TIMES shall be scrapped. 7.12 LOTS REQUIRING LABORATORY, and/or reliability testing shall be subjected to the same criteria as indicated above. 7.13 FINAL INSPECTION REQUIREMENTS 7.13.1 SMT REFLOW AND CLEANING 7.13.1.1 Determine requirements of traveler, assembly drawing, and acceptance specifications. 7.13.1.2 Determine operational requirements in accordance with operational procedures, and engineering specifications. 7.13.1.3 Determine excess solder defect. 7.13.1.4 Determine solder bridging. 7.13.1.5 Determine pin holes. 7.13.1.5 Determine fractures.



7.13.1.6 Determine insufficient solder. 7.13.1.7 Determine dewetted, non wetted, or unsoldered joints. 7.13.1.8 Determine solder balling. 7.13.1.9 Determine cold solder joints, or presence of intermetallics. 7.13.1.10 Determine contamination, or other cleanliness defects. 7.13.1.11 Determine missing, wrong, damaged, misaligned, improperly installed components, or damaged boards. 7.13.2 SOLDERING, AND CLEANING 7.13.2.1 Determine requirements of traveler, and assembly drawing, and acceptance specifications. 7.13.2.2 Determine operational requirements in accordance with operational procedures, and engineering specifications. 7.13.2.3 Determine excess solder defect. 7.13.2.4 Determine solder bridging. 7.13.2.5 Determine pin holes. 7.13.2.5 Determine fractures. 7.13.2.6 Determine insufficient solder. 7.13.2.7 Determine dewetted, non wetted, or unsoldered joints. 7.13.2.8 Determine solder balling. 7.13.2.9 Determine cold solder joints, or presence of intermetallics. 7.13.2.10 Determine solder on gold contact fingers. 7.13.2.11 Determine excess warpage. 7.13.2.12 Determine contamination, or other cleanliness defects. 7.13.2.13 Determine missing, wrong, damaged, misaligned, improperly installed components, or damaged boards. 7.13.3 TRACE CUT, MASKING AND HARDWARE REQUIREMENTS 7.13.3.1 Determine requirements of traveler, and assembly drawing, and acceptance specifications. 7.13.3.2 Determine correct trace cut. 7.13.3.3 Determine correct trace cut location. 7.13.3.4 Determine trace cut integrity. 7.13.3.5 Determine correct and proper masking application. 7.13.3.6 Determine correct hardware installation. Note: Upon completion of inspection, in accordance with assembly acceptance specifications, the lot traveler shall be stamped with the appropriate inspection stamp, and the assemblies shall be transferred to the next required operation, or determination. HOW ARCHAIC, EH? 8.0 EVALUATION, QUALIFICATION, ACCEPTANCE, AND USE OF PROCESSES (SPC) All operations, consisting of processes, sub processes, and activities, are evaluated and qualified using statistical methods. They are used only after proven statistically capable of being controlled and managed, by trained and empowered personnel, to meet contract requirements. All statistical evaluations, experiments, qualifications, and acceptance is done in accordance with POD, QMP-3045, Statistical Process Control Procedures.



9.0 PRODUCT EVALUATION, QUALIFICATION, AND ACCEPTANCE All product quality is assured through careful contract, design, process capability review, supply evaluation/qualification, process auditing, control, and management. Test, analysis, and inspection procedures and methods are used to verify product quality, on a sample basis. They also are used to correlate quality findings to process control and management conditions. Assurance is made that appropriate product acceptance criteria and process and inspection/test methods are used to measure and assure product quality relative to contract/specified requirements. All acceptance requirements shall be met in accordance with POD, EMP-0X00, Specifications, Procedures, and Methods. 10.0 CONTINUOUS AUDIT AND IMPROVEMENT -- QUALITY PROGRAM All audit requirements shall be met in accordance with POD, QIMP-4030, Audit Procedures. These procedures shall be understood and met by all personnel within the company to effectively audit and provide objective information to prevent negative process conditions and product quality, and to improve the quality program at POD. AOI AS A PCB AND PCB INSPECTION TOOL Automated optical inspection has been around for many years. It worked well, as it continues doing, in the PCB fabrication industry. This is not the case in the assembly arena. There are too many variables. Variables as solder joint profiles, acceptance criteria, and programming put a damper on effectively replacing human visual inspection. No matter, almost anything is better than visual inspection. It has been reported, with supporting data, that humans simply get it wrong too many times. Also, it has been found that two different individuals see things differently and who could deny that in the human condition as we all see things differently - no matter what we're looking at. Because of this, AOI processes are attempting to make machines look at and better discern what PCB and PCBA conditions are acceptable or not. This has not been an easy task as the process is very complex no matter how good the cameras and vision systems may be. SOME AOI CONSIDERATIONS ARE (BASED MOSTLY ON TERADYNE AOI SYSTEMS): Field Of View - 0.7 inch FOV - 0.6 inch FOV - 0.4 inch FOV



Camera And Resolution Considerations Window Size Resolution Camera Device Pitch Package Type 0.7 inch FOV 1.17 mils/pixel 494 x 652 20 mil 0603 0.6 FOV 1.6 mils/pixel 494 x 652 12 mil 0402 0.4 FOV .97 mils/pixel 494 x 652 <12 mil 0201 ~12 pixels 20 mil pitch ~9 pixels 12 mil pitch ~11 pixels 10 mil pitch Residual Flux After Reflow Soldering Difficulties may be apparent as residual flux films do reflect thus affecting AOI capabilities. Program Process Flow - CAD data prep & entry - Board orientation & alignment - Teach fiducials - Teach warp - Model development (as required) - Performance curves - Program Verification (in production) Statistical Process Control This is available with most AOI equipment and services. It may serve a practical purpose for the reasons I've stated before inspections are useful only to provide data and information for CPI. Cad Interface AOI processes depend upon CAD data output - no matter the data type (Gerber as 274 or ODB). This is true of all AOI and PCB/PCBA manufacturing process requirements. AOI Inspection Process Each component type is defined in terms of a group of "windows" defined in a "library." Each window specifies a location, a size, a camera, a lighting mode, an algorithm and a threshold value. When the library is combined with an "input list" which defines the names, types and locations of components, an inspection program is created. The program is a list of all the windows called for when the library information is combined with the input list information. Each "window" in the program is aimed at detecting and diagnosing a particular kind of fault on a particular component, for example excess solder, insufficient solder, solder bridge, misaligned component, and so forth.



Once Windows are sorted into stripes by geography, lighting mode and camera type, they can be inspected en masse as the camera head scans the board in stripes. During each stripe, each camera has two opportunities to image each point in the stripe with a different lighting mode. Since there are five cameras, there are ten different illumination/camera combinations for each field of view, hence the name "TenPhase™." TenPhase architecture takes in 300 frames per second, each with a different camera - lighting mode combination. Inspection windows are allowed to overlap one another. There is no explicit limit as to how many windows can be in each frame. Images in the TenPhase design flow directly into the computer's main memory, rather than being kept on isolated framegrabber memories as in machines of earlier technology. This makes it unnecessary for the camera head ever to waste time revisiting a location to retake an exposure it has already taken, something that other flying-head machines with conventional framegrabber technologies must occasionaly do whenever a particularly "busy" frame takes too long to process. Images are processed in realtime as the camera head scans, and can be kept in main memory as long as needed. Another advantage of direct-to-memory image acquisition is that the images are available to the processor's caches at memory speed, without the bus delays that are needed with conventional framegrabber architectures. There are a small number of basic algorithms, which, combined with a large number of lighting modes, form the basis for a powerful and adaptable inspection technique. The basic algorithms include average brightness, variance, bridge, void, percent white, and their complements and rotations. Although space in this letter does not permit a full description of everything, here are some simple examples of their use. 1. To detect insufficient solder on the fillet of a SMT chip capacitor, use the vertical camera with brightfield lighting. Place an average brightness window directly where the fillet is supposed to be. If the fillet is missing, the camera will see the white of the pad reflecting light directly up into the camera. If the fillet is present, the brightfield light will be deflected axially, and the window will appear dark to the camera. 2. To detect insufficient solder on the pad under the toe fillet of a QFP lead, choose an angled camera looking in at the tip of the lead. Light at a low angle from both sides. This will make the shoulders of the fillet appear bright, and the central nose will appear dark. A variance window on the toe fillet will give a high reading. If the fillet is flat, it will be entirely dark, and will give a low reading. 3. To detect solder bridges, place a bridge window between each QFP pin and its neighbor. Choose an angled camera looking in at the tips of the leads, and lighting from above or from front and back. The bridge algorithm detects whether or not a dark line can be traced from the bottom to the top of the window. If a solder bridge is present, it will be a white line crossing the window, and will interrupt all attempts to trace a dark line through it.



Resolution And Pixels AOI equipment can be programmed in familiar units such as mils, microns, etc. Pixel size needs to be known to estimate the appropriate FOV for a given application. The field of view represents 400 by 400 pixels. In a 0.4 inch field of view, one pixel is .001 inch square. In a .7 inch field, one pixel is .00175 inch square. If the boards being inspected has "0201" components (.020 by .010 inch), the .4 inch FOV is required because the component is about ten pixels wide. If the .7 inch field of view were used, the 0201 would be less than six pixels wide, which could be too granular for reliable good/bad discrimination. INSPECTION SUMMARY I was able to write inspection procedures, and manage their processes, over twenty years ago. The reason is simple. I grew up in a process management culture from home, to school, to the Marine Corps, and to the electronics industry having found very good fortune in my first civilian job. Now you know why I consider inspection a waste. Simply, there is but one need for it and that is to effect CPI. The positive side of all this is there are tremendous opportunities when inspections are properly done - FOR THE RIGHT REASONS. TEST Test is a different thing, to some extent, than inspections. This is where product quality verification is made to ensure customer product quality validation is found acceptable in accordance with specified, detailed, contract requirements. There are many test types and variants. One is discussed in this book's Part 1 especially concerning in-circuit testing using boundary scan methods, as an example. Others follow: Design debug testing procedures and processes Debug testing continually develops and improves as the design proceeds. This requires dividing testing into individual units, as this is a tool to detect design faults and correcting them - by finding them in isolation. This process focuses on possible design trouble elements or areas. One example is an analog input operating at a low signal level. In this case, a debug test procedure includes noise measurement, thermal drift testing, and possible cross talk source evaluations. This procedure/ and process includes functional testing in accordance with specified requirements. It "mirrors" customer incoming test procedures and processes. Incoming test procedures and processes Incoming test procedures and processes start with customer specified requirements, as with all things quality. This is when customers test what the supplier should have already tested. Again, this may be a case of duplication and the waste associated with it found outside a well-conducted process management environment. DFM/CE is vital here as design for test (DFT) requirements save so much time, money, and effort. Incoming test procedures and process objectives differ from debug test procedures and processes. Often unfortunate, this testing is a big part of the overall proof of design strategy. This is because



its supposed objective is to prove the design meets specified customer contract requirements. General tests usually meet this objective, whereas debug test procedures attempt isolating design faults. This requires thorough design characterization. Manufacturing Test procedures and processes Manufacturing test procedures and processes are used to test product during manufacturing operations. Manufacturing test procedures and processes are not based on debug testing procedures and processes. Nor are they based on customer's incoming test procedure and processes. One exception may be made for small prototype or pilot runs. Manufacturing test procedures and processes completely depend on manufacturing processes and test equipment used. Often, unfortunately, manufacturing testing is cost driven. This is because of yield considerations made in an insecure, non-process managed environment without benefit of DFM/CE, or effective quality programs. Without DFM/CE and effective quality programs, it is impossible to deliver untested printed circuitry and assemblies. In any "modern" manufacturing environment, there is no such fear and associated problems. Outside this environment, failures certainly are effected. Then, costs are incurred both by suppliers and their once valued customers - soon looking for more competent, qualified suppliers. In-Circuit Test (ICT) This type testing is essential to the extent it can be effectively and efficiently accomplished. Just as with all test systems requiring probes, this is becoming much more difficult in today's very high density SMT assembly world. The following information was derived from some work I did with various companies concerning ICT. Flying Probe Test Definition (Mechanical) Benefits (Quick) and Shortcomings (Slow) Faster Engineering Evaluation Units Requirements (BOM, Schematics, ".VAL" file, P.O.) In-Circuit Test Benefits Lower Cost to Manufacture Faster Engineering Evaluation Units Faster Production of Product Feedback for Assembly Process = Improved Yields at ICT



Higher Yields at FPT/ESS/SYST Past, ICT with FPT yields as low as 17% to 39% Future, ICT with FPT yields at 95% or greater Fewer RMAs = Better Screening Lower Life Cycle Costs Requirements Design for Testability (DFT) = Concurrent Engineering Dataset Requirements = Engineering Deliverables (Rrefer to 117291-A, Specification for PCB Deliverables) Dataset Controls Released under Engineering, PCN, or ECO controls Dataset Formats In a form useful to ICT (Timely and Complete Automating the Process = Updating Tools ICT CONSIDERATIONS AND GUIDELINES The following ICT ELECTRICAL TEST GUIDELINES shall be observed and used at this level or design phase. Implement and use the test checklist at the end of the guidelines. Nodal Access All nodes must be accessible using unique test points or through-hole pins. 1) Control Signals All used and unused control signal inputs must have individual test points. Each control signal that will be tied to VCC or GND must have a unique resistor in the path. It is not recommended to rely on the device’s technology to float an unused input. All Digital devices should be tri-stateable so they can be safely back-driven by ICT tester. All devices with internal state-machines with unused "RESET", "WAIT", "HOLD", "SINGLE-STEP" and "INTERRUPT" signals should be accessible from a test point. 2) JTAG Ports All JTAG ports (i.e., Boundary Scan) must be active and usable for in-circuit test. All JTAG ports must have net names with test points. Input JTAG signals that were to be tied to VCC or GND must have a unique resistor in the path. It is not recommended to rely on the device’s technology to float an unused input.



3) JTAG Scan Pins For Boundary Scan devices that are connected together using scan-to-scan pin connections, scan-to-scan pin connections must have test points when and wherever possible. However, for only those Boundary Scan devices that have working "scan-path" (boundary scan) tests at ICT, and if board real-estate does not permit test point access to all scan-to-scan pins, then only as a last resort, test point access can be eliminated (only as required) from scan-to-scan pin connections only - and only where the real-estate is actually needed. 4) NAND Tree Pins All pins involved in the NAND Tree test chain must have test points - even if disconnected internally from the design (i.e., Always Tri-stated & Unused). 5) Unused Inputs All unused signal inputs on a device:

� Must be given individual test points. Or, � Be grouped together and tied to either VCC or GND via a common resistor.

6) Unused Outputs All unused outputs must have unique test points. 7) Unused Bi-Directional Pins All unused bi-directional pins must have unique test points. If the design requires a bi-directional pin to be tied to VCC or GND, this must be via a resistor. 8) True "No-Connects" Device pins not connected to internal substrate (floating or hold-down pins) do not require test points. 9) Other Pins All other pins (used and unused) must have unique test points. BOUNDARY SCAN, IEEE 1149.1A (JTAG) 1) Guideline:

� All Boundary Scan (JTAG) implementation must comply with IEEE Standard 1149.1A-1993.

� Four dedicated pins TDI (Test Data-In), TDO (Test Data-Out), TCK (Test Clock) and TMS (Test Mode Select) are required for the JTAG implementation. TRST (Test Reset) is optional.

� TDI, TMS and TCK should be pulled high. TRST should be pulled low. � Boundary Scan Control signals, TDI, TDO, TCK, TMS and TRST can not be multiplexed or

used for any other function other than Boundary Scan itself. � No inversion of data on all BSCAN control signals is allowed or between chip pins and the

scan cell or scan cell to the functional core when internal scan is implemented.



� No inverters, Flip Flops, Multiplexers or any other gates are allowed between JTAG connector and the device pins.

� Review of TCK should be done to determine if board level termination is required � Do not place JTAG device's TDO and TDI next to each other to reduce the potential of a

short. JTAG is unable to catch this short condition. � Do not tie the system RESET with the JATG device TRST. � TRST Should be tied LOW through a resistor. � The scan chain path between JATG devices should be configured as a single path. � Following are the minimum required instructions for TAP controller, BYPASS,

SAMPLE/PRELOAD, EXTEST, HIGHZ and IDCODE. 2) ISP Guideline:

� All ISP devices supported by IEEE1149.1A must have a separate chain from other JTAG devices.

� ISP device chain must be connected to a connector for manual programming, to program the device via BYTEBLASTER or equivalent if ICT programming fails.

Testability Resistor Resistors used to tie a signal to GND or VCC must have a resistor value of 100 ohms or greater. If this is not done, ICT will not be able to manipulate the signal and control the DUT. Oscillators All oscillators must have the ability to be disabled or have its output isolated from the rest of the circuitry. This can be accomplished with an oscillator whose output can be tri-stated, with a tri-state buffer placed between the oscillator output and the circuitry it is supplying, or by placing a 2-pin header between the oscillator’s output and its destination. If this is not done, ICT will not be able to ‘quiet’ the board, resulting in the inability to test devices that receive that signal. Digital Feedback Loops Avoid the use of feedback loops that do not have the ability to disable or tri-state each of the devices that make up the loop. If this is not done, ICT will have limited or no coverage of the devices that make up the loop or is impacted by the loop. ECO Jumper Wires ECOs which require jumper wires to be added should route the jumper wire on the top side of the PCB versus the bottom side of the PCB. During the prototype and pilot phases of the board design, the CM must provide the TPD with a copy of their internal ECO which implements the PCN and rework instructions that were originated by XXX. And, the CM must update the known good board the TPD has in accordance with the internal ECO requirements. The TPD must accommodate the placement of these ECO jumper wires in the test set(s) being developed. Once the board design goes into production, the CM maintains the test set(s) and must be sure to accommodate such ECO change requirements. This will eliminate the potential of losing contact between the fixture’s nail and the test point caused by wire interference.



VCC and GND Access The ICT equipment requires access to VCC and GND test points which are distributed across the PCB in addition to the unique test points required on every net. The minimum requirement for the number of these VCC and GND test points are determined by the amount of current the test fixture must deliver to the board under test. Typically, no individual test point for power/GND should be required to handle more than 1 ampere of current. For test fixture reliability reasons, it is recommended that no test point carry more that 500 milliamperes (0.5 amps) of current. If the power requirement for the board under test is less than one (1) ampere, the minimum test point requirement is 2 test points per power rail and 4 test points on GND. Keep in mind that GND generally serves as the return path for all power rails. In addition, GND also serves as the return path for all signal pins as well. Today’s testers typically deliver up to 400mA to 500mA per signal pin. In practice, we have found the following guideline to work effectively.

� (total number of nets)(2 %) = VCC test points, absolute minimum = 2 TP’s � (total number of nets)(3 %) = GND test points, absolute minimum = 4 TP’s

Keep in mind, the actual power and GND test point requirements depend on the amount of current the test fixture must provide for each power rail and signal net. Examples: 1) Total number of nets = 1500, VCC test point requirement = 30 TPs GND test point requirement = 45 TPs 2) Total number of nets = 3000, VCC test point requirement = 60 TPs GND test point requirement = 90 TPs 3) Total number of nets = 100, but VCC current = 1.5 Amps, plus all other rails total is less than 0.5 Amp, VCC test point requirement = 3 TPs GND test point requirement = 4 TPs These points must be evenly distributed over the surface area of the bottom side of the PCB. By evenly distributing access to VCC and GND, noise on the test fixture will be reduced. This will help eliminate the tester from flagging false errors. PLD Control To test programmable devices, ICT must be able to put the device’s outputs to a known state; all high or all tri-state, before it can begin to test the device. This can be accomplished several ways, depending upon the type of device, the amount of unused internal logic and the amount of unused input pins to the device. The following are common methods to create a known output state:

� A chip enable input control pin. � Program an unused input pin, tied to VCC or GND via a resistor � tri-state the output pins when ICT drives the pin. � Create an ‘illegal’ input combination, that when applied to the device,



� causes the device to drive its outputs high. If this approach is chosen, � inform the Test Engineer of the “illegal” input combination. � Engineering must provide test vectors for each programmable device.

Analog IC Isolation Isolate op amp outputs from inputs to other op amps with an isolation resistor. Tri-State Devices Use tri-state devices whenever possible. Custom devices should be designed to have tri-state buffers on the outputs and a single input pin that can disable the device. Custom Devices and ASICs Custom devices or ASICs should be designed to have their outputs/bi-directional pins easily tri-stated. NAND-Tree, Boundary Scan or Built-In-Self-Test should be utilized where possible. The control/input/output pins associated with these testing techniques must have test points. Do not use an internal ground plane in the design of these devices. ICT can utilize a test method that checks for pin contact problems by taking measurements through the device’s package. When neither Boundary Scan, NAND Tree, nor Built-In Self-Test is available for a custom device or ASIC, Engineering must provide test vectors for such a device. Mechanical Guidelines 1) Keep Out Areas The following areas should not contain any test points:

� The area that the bracket covers when the bracket is properly attached to the assembly. � The area that the release mechanism on the Hot Swap modules’ brackets will travel. � Locations where labels will be placed. � An area of 125 mils along the edge of the PCB. � An area of 100 mils around tooling holes. � An area of 10 mils around the entire test point.

Often the UUT is fully assembled when it experiences ICT, a new assembly, process return or field return. If test points are in these locations, the assembly will need to be disassembled prior to test. 2) Tooling Holes

� The ICT fixture requires a minimum of two (2), preferably three (3), tooling holes to be placed at opposite corners, maximum distance, with a tolerance between the holes of +0.003 inches. These holes must be non-plated, be a minimum of 119 mils in diameter (tolerance is -.000/+.003 inches) and have a keep out area of 100 mils around the entire hole.

� For PCB’s that are manufactured in panels and then broken out, tooling holes must be placed in both the mother panel and the individual boards.



� The tolerance of the distance from the PCB Datum hole (the Datum also is the UUT’s tooling hole location) to the test point is -0.005/+0.005 inches. This is considered the overall PCB tolerance for ICT testability purposes.

� If these holes do not exist with the required tolerances, test point to fixture nail contact accuracy will not exist.

3) VIA’s and Through-Holes VIA’s not used for test points should be covered with solder mask. All through-holes in the PCB must be filled. This prevents vacuum leaks on the ICT fixture. 4) Test Point Requirements (Pad Size / Spacing - Bottom Side of PCB Only) The preferred (or standard) is: Pad Size = 34 mils (each side) square pad Spacing = 100mils (center-to-center) pitch Then, if necessary, and only where necessary, the pitch can be reduced to 75 mils while still maintaining the 34-mil square test pad size. Then, if necessary, and only where necessary, the pitch can be reduced to 50 mils while still maintaining the 34-mil square test pad size. Every effort should be made to keep the 50 mils spaced Test Points less than 25% of the total number of Test Points. The standard square 34-mil test point must be used wherever possible. Engineering must obtain prior approval from the Test Engineer in order to use the smaller test pad size. The minimum pad size is: Pad Size = 32 mils (each side) square pad Spacing = 100mils (center-to-center) pitch Then, if necessary, and only where necessary, the pitch can be reduced to 75 mils while still maintaining the 32-mil square test pad size. Then, if necessary, and only where necessary, the pitch can be reduced to 50 mils while still maintaining the 32-mil square test pad size. There must be a keep out area of 10 mils around each test point. If a smaller test pad size were to be used, the ICT fixture costs would increase because a "funnel plate" will be needed to maintain probing accuracy. Without this "funnel plate", fixture nail contact with the test point will become unreliable. 5) Pad Size / Spacing - Top Side of PCB Because it is harder for the ICT test fixture to control the tolerance stack-up on the top side (if such access is required), the test pad sizes should be larger in order to maintain the same test probing accuracy. The preferred (or standard) is: Pad Size = 38 mils (each side) square pad Spacing = 100mils (center-to-center) pitch



Then, if necessary, and only where necessary, the pitch can be reduced to 75 mils while still maintaining the 38-mil square test pad size. Then, if necessary, and only where necessary, the pitch can be reduced to 50 mils while still maintaining the 38-mil square test pad size. The minimum pad size is: Pad Size = 36 mils (each side) square pad Spacing = 100mils (center-to-center) pitch Then, if necessary, and only where necessary, the pitch can be reduced to 75 mils while still maintaining the 36-mil square test pad size. Then, if necessary, and only where necessary, the pitch can be reduced to 50 mils while still maintaining the 36-mil square test pad size. Every effort should be made to keep the 50 mils spaced Test Points less than 25% of the total number of Test Points. There must be a keep out area of 10 mils around each test point. A smaller test pad size must not be used. If a smaller test pad is used, fixture nail contact with the test point will become unreliable. 6) Other Criteria - Both Top-Side and Bottom-Side

� The preference is to have all test points on the bottom of the PCB. � Test points must not be covered by solder mask, silk-screen ink or any other substance

that may cause poor contact between the test point and the fixture nail. � All test points must be solder coated or coated with a similar conductive, non-oxidizing

material. � The solder paste layer of the PCB artwork must include the test point openings.

Top-Side or Bottom-Side Component Placement Preference is to have all active components on the top side of the PCB. This provides a maximum amount of area on the bottom side of the PCB for test point placement. Top-Side or Bottom-Side Test Point Access The goal is to provide access from the bottom side of the PCB. Top-side access is possible using of a clam-shell fixture. This fixturing method is very expensive, unreliable in a production environment, and very difficult to maintain or modify for ECOs. Top side access should be avoided. Special SMT Considerations In some cases SMT and PTH technologies present different testability design considerations. For SMT designs, the following design criteria either add to or modify those criteria already discussed. VCC and GND Access Multiple test points for VCC and GND must be provided, use the ratios as defined. Also, the worst case current through any one test point should be limited to 0.5 amps. These test points should be evenly distributed across the bottom side of the PCB.



Test Point Distribution The test points should be evenly distributed over the bottom side of the PCB. If test points are placed in one area, high stress and bowing will result when the assembly is placed onto the ICT fixture. Engineering Deliverables The following documentation and material items are the deliverables required from Engineering for the development of an ICT fixture and program:

� Special Test Requirements � Development Schedule (Layout Start, Artwork Availability, Build Dates) � Schematics (B-Size Postscript Format) � Bill of Materials (on SAP) � Assembly Drawings (.HP and .HP2 files - set of HPGL files for each "flavor") � Fabrication Drawings (.FAB file) � Rework Instructions � Representative Loaded Board for Fixturing � Representative Functional Known Good Loaded Board for Debug � Custom Component Data (Disable Information and Test Vector Data) � PAL / GAL: .JED and .ABL (or .SRC) files � Actel (ACT): .EDO (or .EDN) & .FIT files or .AFL file � Altera EPLD, MAX & FLEX: .EDF or .RPT, .EDO, .ACF & .FIT files

For example:

� Altera MAX 5000, 7000 .EDO and .FIT files � Altera FLEX 8000, 9000 .ACF and .FIT files � Zilinx LCA and Non-LCA: .LCA and .XNF files � AMD MACH: .JED files � LATTICE ISP & Non-ISP: .SIM and .JED and .DLD file � CYPRESS (FLASH 370): .JED file � QUICKLOGIC (QL-pASIC): .EDO file � BOUNDARY SCAN DEVICE:BSDL file � CAD data consisting of: Net-List File (.NET file = Post Artwork)

(.TEL and .DVF files = Pre Artwork) NC Drill File (.DRL file) Test Pad XY Location File (.TPS file) Gerber Files (.APT, .PSM, .PSP, .PSS, .SSM, .SSP and .SSS files) Other CAD files: .BIT file .BRD file .CAM file .CKT file .FAB file .IPC file .PNL file - When Panelized



.DIF file - ".DIFF" file for Artwork Re-spins .HP and .HP2 files - All HPGL files (Assembly) The above documentation and material items shall be handled via the release file controls and the PCN and/or ECO process of Documentation Services. All files must reflect the actual board design. IPC does a good job explaining what type test points and where they are required. It used to be, as with all things obsolete, test points were required for every node. Then, we reduced requirements to net ends. Now, in these high density designs, we have little room for any test points. Therefore, test fixtures, equipment, probes, and other tooling requirements are of little use. This is why it is important to move to JTAG and boundary scan test methods. Of course, this requires designing, using DFM/CE at the earliest possible phase (schematic), to ensure components and boards allow this test type. The following images show some examples of designs so dense, test points and conventional test methods cannot be performed:

Functional Test This testing is vital to system verification and validation. This is where the total package design is proven (POD). I will not go into details now as time and space is running short but I will say there are innumerable test equipment suppliers and test capabilities everywhere on this planet. MoonMan LET US GO TO PART FOUR AND THIS BOOK'S CONCLUSION - FOR NOW

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