bob willis electronics academy webinar presenter · bob willis currentlyoperatesa training and...

Crimp Connector Inspection& Quality Control

Bob Willis

Electronics Academy Webinar Presenter

Your Delegate Webinar Control Panel

Open and close your panelFull screen view

Submit text questionsduring or at the end

FREEElectronics Academy Webinar Series

The Electronics Academy Webinar Series takes an in‐depth look at the issues affectingPCB/SMT assembly and the challenges of achieving Zero Defect Manufacture. Understandthe common causes of solder joint failure and learn how to identify and rectify processdefects – improving quality and reducing costs

Learn expert tips to identify quality issuesUnderstand the common causes of process failuresA convenient and quick way to update your skills

In the future have access to a video library of online training sessions

Bob Willis

Bob Willis has been involved with the introduction and implementa tion of lead‐free process technology for the last seven years. Hereceived A SOLDERTEC/Tin Technology Global Lead‐Free Award for his contribution to the industry, helping implementation of thetechnology. Bob has been a monthly contributor to Globa l SMT magazine for the last six years. He was responsible for co‐ordina tion andintroduction of the First series of hands‐on lead‐free training workshops in Europe for Cookson Electronics during 1999‐2001. These

events were run in France, Italy and the UK and involved lead‐free theory, hands‐on paste printing, reflow, wave and hand solderingexercises. Each non commercial event provided the firs t opportunity for engineers to get first hand experience in the use of lead‐freeproduction processes and money raised from the events was presented to loca l charity. More recently he co‐ordinated the SMARTGroup Lead‐Free Hands On Experience at Nepcon E lectronics 2003. This gave the opportunity for over 150 engineers to process fourdifferent PCB solder f inishes, with two different lead‐free pastes through convection and vapour phase reflow. He a lso organised Lead‐Free Experience 2, 3 + 4 in 2004‐2006.

He has also run tra ining workshops with research groups like ITTF, SINTEF, NPL & IVF in Europe. Bob has organised and run three lead‐free production lines a t international exhibitions Productronica, Hanover Fair and Nepcon E lectronics in Germany and England toprovide an insight to the practical use of lead‐free soldering on BGA Ball Grid Array, CSP Chip Scale Package, 0210 chip and through holeintrusive ref low connectors. This resulted in many technical papers being published in Germany, USA and the United Kingdom. Bob also

defined the process and assisted with the set‐up and running of the first Simultaneous Double Sided Lead‐Free Reflow process us ingtin/silver/copper for reflow of through hole and surface mount products.Bob also had the pleasure of contributing a sma ll section to the first Lead‐Free Soldering text book “Environment ‐ Friendly Electronics:Lead‐Free Technology” written by Jennie Hwang in 2001. The section provided examples of the type of lead‐free defects companies mayexperience in production. Further illus trations of lead‐free joints have been featured in here most recent publication “ImplementingLead‐Free Electronics” 2005. He has helped produce booklets on x‐ray inspection and lead‐free defects with DAGE Industries, Balver Zinn

and SMART Group

Mr Willis led the SMART Group Lead‐Free Miss ion to Japan and with this team produced a report and organised several conferencepresentations on their findings. The mission was supported by the DTI and visited many companies in Japan as well as presenting aseminar in Tokyo at the British Embassy to over 60 technologists and senior managers of many of Japans leading producers. Bob was

responsible for the Lead‐Free Assembly & Soldering "CookBook" CD‐ROM concept in 1999, the world’s first interactive training resource.He implemented the concept and produced the interactive CD in partnership with the National Physical Laboratory (NPL), drawing onthe many resources available in the industry including valuable work from NPL and the DTI. This incorporated many interviews withleading engineers involved with lead‐free research and process introduction; the CD‐ROM is now in its 3rd edition.

Find out more at:[email protected]

Bob Willis currently operates a training and consultancy business based in England. Bob is a member of the SMART Technical Committee. Although aspecialist for companies implementing Surface Mount Technology Mr Willis provides training and consultancy in most areas of electronic manufacture.He has worked with the GEC Technical Directorate as Surface Mount Co-Coordinator for both the Marconi and GEC group of companies and prior tothat he was Senior Process Control Engineer with Marconi Communication Syste ms, where he had worked since his apprenticeship. Following his timewith GEC he became Technical Director of an electronics contract manufacturing company where he formed a successful training and consultancydivision.

As a process engineer, he was involved in all aspects of electronic production and assembly involved in setting up production processes and evaluatingmaterials; this also involved obtaining company approval on a wide range of Marconi's processes and products including printed circuit boardmanufacture. During the period with Marconi, experience was gained in methods and equipment for environmental testing of components, printedboards and assemblies with an interest developed in many areas of defect analysis. Over the last 15 years he has been involved in all aspects ofsurface mounted assembly, both at production and quality level and during that time has been involved in training staff and other engineers in manyaspects of modern production.

Over the past few years Mr. Willis has travelled in the United States, Japan, China, New Zealand, Australia and the Far East looking at areas ofelectronics and lecturing on electronic assembly. Mr. Willis was presented with the Paul Eisler award by the IMF (Institute of Metal Finishing) for the besttechnical paper during their technical programmes. He has conducted SMT Training programs for Texas Instruments and is currently course leader forReflow and Wave Soldering Workshops in the United Kingdom. Mr Willis is an IEE Registered Trainer and has been responsible for training courses runby the PCIF originally one of Europe's largest printed circuit associations. Bob has conducted workshops with all the major organisations and exhibitionorganisers World Wide and is known for being an entertaining presenter and the only presenter to use unique process video clips during his workshopsto demonstrate each point made. Bob has written two book which are free to download on line, Design & Assembly with Pin In Hole Intrusive Reflow& Package On Package Design, Assembly and Inspection

Mr. Willis was Chairman of the SMART Group, European Surface Mount Trade Association from 1990-94 and has been elected Honorary Life Presidentand currently holds the position of SMART Group Technical Director, he also works on BSI Standards Working Parties. He is a Fellow of the InstituteCircuit Technology, an NVQ Assessor, Member of the Institute of Quality Assurance and Society of Environmental Test Engineers. Bob Willis currentlywrites regular features for AMT Ireland, Asian Electronics Engineer and Circuits Asse mbly the US magazine. He also is responsible for writing each ofthe SMART Group Charity Technology reports, which are sold in Europe and America by the SMTA to raise money for worthy causes. Bob ran theSMART Group PPM Monitoring Project in the United Kingdom supported by the Department of Trade and Industry. He was coordinator of the LEADOUTProject for SMART Group. LEADOUT was one of the largest EU funded projects, currently he is coordinating European projects TestPEP, uBGA andChipCheck

In September 2015 Bob voted the Best Speaker at SMTA International Conference in Chicago

Find out more at:[email protected]

Electronics Academy Webinar Series

Printed Circuit Board Inspection & Quality Control2.30pm GMT Wednesday 12th October

Inspection of Conductive Adhesive Joints2.30pm GMT Thursday 10th November

Future webinars may cover

Bare PCB inspectionSolder paste and stencil inspectionCrimp connector and wire inspectionComponent inspection and recognitionMicrosection inspectionInspection of conductive adhesive jointsInspection of underfill and staked componentsDestructive solder joint assessment and inspection

Register on line at http://www.visioneng.com/electronics‐academy‐webinar‐series

Crimping Inspection & Quality Control Webinar

Topics covered:

Introduction to crimpingCable types and strippingStripping toolsEstablishing strip lengthsCrimp typesCompatibility of crimp terminations and wiresCrimping tool operation

Standards & Text Books

IPC/WHMA-A-620

International and National Standards

UL 486A/486B www.ul.com USCAR 21 www.uscar.org IPC/WHMA-A-620 www.ipc.org SAE AS7928 www.sae.org MOD 59-71NASA Std 8739Mil C 22520BS7609 & BS7727

What is a Crimp Connection

A crimp connection is a semi gas tight joint formed by compression betweena single or multi stranded cable and a specifically designed crimptermination. All strands in a multi stranded wire are deformed to create alow resistance connection which may also form a cold weld.

Crimp terminations have been successfully used in commercial and militaryapplications as far back as the 1940s. Surface finish depends on matingsurfaces but is most commonly tin, nickel/gold or gold on copper

Provided the correct wire preparation, termination type, tooling and settingare maintained the crimp has proven to be a very reliable connection.

Can be unreliable if the correct procedures are not followed!!!!!



Wire barrelInsulation barrel

Insulation barrelWire barrel

Wire barrel

Inspection hole

The crimp barrel surface topography can be seen on the surface of the wire strands, rightimage, under high magnification SEM (Scanning Electron Microscope) analysis. Thisillustrates the compression forces present on the surface of the stranded wires


Surface analysis using SEM shows metal being transferred between surfaces duringcompression of the wire and the crimp barrel surfaces

Cu – CopperZn - ZincAg - Silver

Wire

Crimp TerminationsCalibrated Crimping Tool

Manual (retaining ratchet)Semi/fully Automatic (powered)

Crimping Procedures

Trained production staff

Crimping Process Requirements

Crimping Process

Crimping Process

Crimping Process

Satisfactory Crimp Terminations

Microsections of the wire barrel showing the outer wall of the crimp contact and the copper wire strands





Example Crimp Terminations

Microsections of the wire barrel showing the outer wall of the crimp contact and the single copper wire strand. The retentionof force of the wire would be less on the first example, the voltage drop across the joint may not be seen initially

Single copper wire strand under crimped Satisfactory single copper wire strand crimped

Crimp Termination Inspection Guide

Electronic Production magazine1988

Unacceptable Crimp Terminations

Incorrect wire being used in the crimp


Incorrect wire being used in the crimp


Incorrect crimp tool or setting used. Using undersize wire may have also been the issue


Incorrect wire size being used in the crimp

Unacceptable Crimp Terminations Using X-Ray


Defects caused by poor design

Incorrect crimp tool settings

Incorrect wire size

Damaged wire strands

Damaged crimp tool

Crimping a contact twice

Untrained production staff

Crimping Process Control

Evaluation of crimping applications

Minimise the number of crimp types usedAssembly InstructionsCalibration of tooling

Certification of operators (Selected applications)Process control methods

Crimp impression marks

Crimp heightsCrimp pull testingResistance measurements



Crimp Height

Crimp Height Measurement

AMP Corporation

PCB Mechanical Inspection

Calibrated steel pins are used for measurement of crimp tool sets. The crimp tool and die are fully compressed and the go and no go pin size as specified by the supplier are inserted in the opening. These pins are also used in PCB manufacture for finished hole size measurement

The pin set is very accurate and expensive do not crimp on to the pins

Crimp Height Measurement

Please make sure any solder wire is removed from the surface of the crimp die


Measurement of the pull strength of a particular wire, crimp and crimp tool setting combination are testedmanually or semi automatically


Measurement of the pull strength of a particular wire, crimp and crimp tool setting combination are testedmanually or semi automatically. Most testing systems will interface with PC software, the example is fromMecmesin

Voltage Drop Test

Test often specified by the MOD

Voltage Drop Test

Measurement is conducted between the wire and the crimped barrel after any formof environmental testing procedure

It can also be conducted from the wire to the interconnecting crimp for the total change inresistance, in this case it is not just an assessment of the crimping performance

Voltage Drop Test Results Example

Wire Barrel Wire Size (AWG) Test Current Max. Voltage Drop (mV)

12 12 23 3.014 17 3.5

16 16 13 3.518 9.0 4.020 7.5 4.0

20 20 7.5 4.022 5.0 4.024 3.0 4.0

22 22 5.0 4.024 3.0 4.026 2.0 4.0

24 24 3.0 4.0

Wire Barrel Wire Size (AWG) Test Current Max. Voltage Drop (mV)

12 12 23 3.014 17 3.5

16 16 13 3.518 9.0 4.020 7.5 4.0

20 20 7.5 4.022 5.0 4.024 3.0 4.0

22 22 5.0 4.024 3.0 4.026 2.0 4.0

24 24 3.0 4.0

Voltage Drop Test

Tensile Strength Curve

Voltage Drop Curve – Initial

Voltage Drop Curve – after use


Typical form for operator/process approval

Always state failure mode:Broken wireWire break in crimpWire pulled out:

Wire Preparation

Insulation and wire strip length

Always allow for re-terminationDamage to insulation

PTFE (Polytetraflouroethylene)

Damage to conductorsBroken or missing strands

Wire Preparation

? mm

Wire Preparation

Wire Preparation

Wire Preparation

Wire Preparation

The contact/terminal conductor range is usually specified in AWG(American Wire Gauge) or by the cross sectional area in squaremillimetres (mm2).

SWG (Standard Wire Gauge)

All crimp types have a maximum and minimum crossectional areacapability. Too small a wire size there will be under crimping, toolarge an area cracking of the connector can occur

Wire PreparationSWG gauge No. Diameter Inches Diameter mm

10 0.128 3.25111 0.116 2.94612 0.104 2.64213 0.092 2.33714 0.08 2.03215 0.072 1.828816 0.064 1.625617 0.056 1.422418 0.048 1.219219 0.04 1.01620 0.036 0.914421 0.032 0.812822 0.028 0.711223 0.024 0.609624 0.022 0.558825 0.02 0.50826 0.018 0.457227 0.0164 0.416628 0.0148 0.375929 0.0136 0.345430 0.0124 0.315

Wire Number Imperial Standard American

Wire Gauge Wire Gaugegauge ins. dia. ins. dia.

9 0.144 0.114410 0.128 0.101911 0.116 0.090712 0.104 0.080813 0.092 0.07214 0.08 0.064115 0.072 0.057116 0.064 0.050817 0.056 0.045318 0.048 0.040319 0.04 0.035920 0.036 0.03221 0.032 0.028522 0.028 0.025323 0.024 0.022624 0.022 0.020125 0.02 0.017926 0.018 0.015927 0.0164 0.014228 0.0148 0.012629 0.0136 0.011330 0.0124 0.01

Wire Preparation

Wire Preparation/Stripping

Crimping Process

Hold insulation to support terminationsCompress wires to form a gas tight joint

Provide high strength connectionRepeatable termination process

Crimping Tools

Crimping Tools

Crimp Terminal Types

Crimp Terminal Types

Crimped Terminations



Poor Crimped Terminations


Wire outside of crimp barrel:Poor wire preparation, cut and re-strip the cable

Bent or distorted crimp termination


Maximum wire visible at the end of the crimp barrel:

No wire visible at the end of the barrel before crimping:??


No insulation visible at the end of the barrel:

No wire visible of solder joint in the inspection window:

Limited wire visible at the end of the crimp barrel:

Insulation, braid and wire strip length

Damage to insulation

Damage to braid

Broken or missing wire strands

Co-Axial/Shielded Wire Preparation

Coaxial Centre Pin Connection

From IPC/WHMA-A-620

Coaxial Ferrule Crimp

From IPC/WHMA-A-620

Bobwillis.co.uk

Do you have any questions ?


Inspection

The process of crimping; terminals to wire(s) or braid is semiautomatic, and provided the processprocedures are properly carried out with tools which are in good adjustment and condition, acceptablejoints will be produced

Inspection will be in 5 phases

Calibration of tools

Certification of tools

Certification of operator

Process Control

Final Inspection


Calibration of tools

The tool will be inspected for loose, bent, misaligned, or broken parts. Any one of these is considered adefect

The tool in the closed position shall conform to GO/NO-GO gauges, the sizes are given by the supplier

The tool shall be used for crimping 2 connectors on suitable lengths of wire and these crimps shall thenbe measured and the dimensions recorded. They shall conform to the manufacturers figures

The crimps shall be visually examined for correctness of form. They shall be regular and free from burrs,cracks or flash

Samples must be subjected to a tensile test. A record of test results shall be kept by the Inspector


A tool which passes all the above tests shall be certified as suitable for use.

A tool which fails on one or more of the above tests shall be withheld from production untilrepair/adjustment has been carried out. After correction a full complement of tests must be satisfactorilycompleted before the tool can be certified as suitable for use.

Certification of tools

Each new tool when received into the Company shall be given a serial number and have a history cardopened for it. Each new tool will be calibrated and certified before being issued for use in production.

Tools being used in production will be re-calibrated and re-certified at intervals of not more than onemonth. Each hand tool will carry in its box a log card giving the date on which re-certification is requiredor alternatively the last date on which certification took place. Each machine tool will have a similar logcard attached to it.


Certification of operator

This shall be at the discretion of the Senior Inspector. However all multi termination connectors like coaxialparts with inner solder or crimp connections and outer braid and ferrules do require certification

Process control

It is the responsibility of Inspection to see that the crimping process is being carried out in accordance withthis Workshop Practice. This supervision will be carried out by visiting at irregular intervals the operatorscarrying out the process. the rate at which these visits are made will depend on the skill and experience ofthe operator. In any case at least one visit each shift will be made to each operator

The inspector will particularly note that the tool in use has a valid certificate and check also that the tool isnot obviously damaged. The tool/die set/locator combination being used must be that one suitable for theterminal in use, the terminal and wire must be those specified in the schedule


Check that the wire ends are being stripped in accordance with instructions and verify thatstrands are not being nicked in the stripping operation. The stripped end must not be given anyadditional twist, it is only necessary to lightly dress the cut end to remove any distortion of thelay due to stripping

The finished crimped terminal should have a regular appearance, it should not be bent orotherwise distorted. The conductor must be correctly positioned i.e. the terminal must havebeen located correctly in the tool. The end of the conductor must be visible at the end of theconductor crimp unless the design precludes this view

bob willis electronics academy webinar presenter · bob willis currentlyoperatesa training and...

Documents