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Internship Industrial ReportSubmitted By

Umer Khalid

Submitted toProduction Appliance Division

Internship DurationJuly 23, 2010 to August 19, 2010

Internship DepartmentDevelopment - AD

Program

BE Materials Engineering

InstitutionSchool of Chemical and Materials Engineering (SCME)

National University of Sciences and Technology (NUST) H-12

National University of Sciences and Technology (NUST) H-12 Islamabad 1


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Islamabad

Acknowledgement

The whole praise is to almighty Allah, creator of this universe. Who made us the super creature with great knowledge and who able me to accomplish this work, I feel great pleasure inexpressing my deepest appreciation and heartiest gratitude to the staff of Pakistan ElecktronLimited (PEL) their guidance and great help during the internship period.

I would like to express my deepest affection for my parents and my friends who prayedfor my success and encouraged me during this internship period. I appreciate and acknowledgethe patience, understanding and love provided by employees of PEL.

A token of special thanks to the people who had been very friendly, co-operated with methroughout my internship and made it possible for me to learn and gather information. These arethe people who in spite of their busy scheduling took time out to explain to me the proceduresand mechanics of work in the organization.

Umer Khalid

Table of contents



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Executive Summary4

Background of PEL.....4

1. Thermoforming....62. Extrusion83. Harness Assembly...94. Foaming..95. Pre-Assembly and Assembly line116. Condensor and anti-condensate.127. Deep Freezer.148. Split AC...159. Press Shop1610. Plastic Injection Moulding.1711. Dies and Moulds...1912. Power Division..2113. Development.21

Refrences ..22



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Executive summary of PEL

Pak Elektron Limited (PEL) is the flag bearer of the Saigol Group of Companies.

Pak electron ltd is the pioneer manufacture of electrical goods. It was establish in 1956 in

technical collaboration with M/S AEG of Germany. In October 1978 the group was bought by

saigol group of industries. Since its inception, the company has always been contribution

towards the advancements and development of the engineering sector in Pakistan by producinghundreds of engineers, skilled workers and technicians through its apprenticeship schemes and

training program.

The products manufactured by PEL have always been of high standard and the name 'PEL' is

synonymous with QUALITY all over Pakistan. Since its inception, the company has been

working for the advancement and development of engineering know-how in Pakistan. The

company has produced hundreds of engineers, skilled workers and technicians through its

apprenticeship schemes & training programs.

PEL has been continuously adding new products to its range. As a result, PEL has

registered a significant increase in its sales volume, during the last ten years.

Background of PEL

Pak Elektron Limited (PEL) is the pioneer manufacturer of electrical goods in Pakistan. It was

established in 1956 in technical collaboration with M/s AEG of Germany. In October 1978, the

company was taken over by Saigol Group of Companies. Since its inception, the company has

always been contributing towards the advancement and development of the engineering sector in

Pakistan by introducing a range of quality electrical equipments and home appliances and by



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producing hundreds of engineers, skilled workers and technicians through its apprenticeship

schemes and training programmes.

The company comprises of two divisions:

Appliances Division

Power Division

APPLIANCES DIVISIONThis Division of PEL consists of appliances manufacturing.

PEL A IR CONDITIONERSPEL window-type air conditioners were introduced in 1981 in technical collaboration with

General Corporation of Japan. Ever since their launch, PEL air conditioners have a leading

position in the market. PEL air conditioners cooling performance has been tested and approved

by Copeland and ITS USA. With the shift of users preference from window type to split type air

conditioners, PEL has started manufacturing split type air conditioners.PEL R EFRIGERATORSThe manufacturing of refrigerators started in 1986-87 in technical collaboration with M/s IAR-

SILTAL of Italy. Like the air conditioner, PEL's refrigerators are also in great demand. Today,

PEL Crystal has 30% market share. Its cooling performance is tested and approved by Danfoss,

Germany and its manufacturing facility is ISO 9002 certified by SGS Switzerland.

PEL D EEP F REEZERSPEL deep freezers were introduced in 1987 in technical collaboration with M/s Ariston of Italy.

Because of durability and high quality, PEL deep freezers are the preferred choice of companies

like Unilever.



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POWER DIVISIONPEL Power Division manufactures energy meters, transformers, switchgears, Kiosks, compact

stations, shunt capacitor banks etc. All these electrical goods are manufactured under strictquality control and in accordance with international standards.

PEL is one of the major electrical equipment suppliers to Water and Power Development

Authority (WAPDA) and Karachi Electrical Supply Corporation (KESC), which are the largest

power utilities in Pakistan.

Over the years, PEL electrical equipment has been used in numerous power projects of national

importance within Pakistan. PEL has the privilege of getting its equipment approved and

certified by well-reputed international consultants such as:

Preece, Cardew and Rider, England

Harza Engineering Company, USA

Snam Progeti, Italy

Societe Dumezm, France

Miner & Miner International Inc. USA

Ensa, France

1. Thermoforming

The Air slip thermoforming machine with sheet feed system arebeing used in thermoforming section. HIPS sheet is placed in the machine and heatersmove forward and sheet is heated to softening point. Then compressed air is blownfrom down side of sheet to form a balloon for the purpose of even wall thicknessdistribution. The preheated mold moves up to level of sheet and the Stretched plastic isthen forced against the mold by application of vacuum. Air is blown on mold from upper side for cooling purpose and water circulate in the mold to keep it temperature withinlimited range. After cabinet or door forming the extra sides (which is used for clampingthe sheet) are trimmed by operator or helper with handheld knives.



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T HERMOFORMING P ROCESS

The thermoforming process consists of four phases:

1. Sheet transportation2. Heating3. Forming/cooling4. Trimming.

D EVELOPMENT OF HIGH IMPACT POLYSTYRENES (HIPS)

POLYSTYRENES (PS) are one of the eldest commercially producedthermoplastic polymers, having been introduced in the 1930s. The homopolymer,known as crystal PS. is a brilliant, clear, non-crystalline plastic with excellent stiffnessand processibility. However, the low impact strength of crystal PS limits its use. High-impact polystyrene (HIPS) was developed in the early 1950s to meet the demand for atougher resin.

Commercial Forms

Standard HIPS grades are widely used in packaging and in durable goods. In recentyears, many specialty grades that have been developed to satisfy new applicationscompete with more costly engineering thermoplastics. Grades are now available that



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provide improved resistance to stress cracking from fats, oils and chlorofluorocarbon(CFC) blowing agents. Usually the HIPS grade plastic is used in the refrigenerator industry.

2. ExtrusionGasket:

The gasket profile is extruded using soft PVC. While extrusion compressed air isblown from inside the die so that Gasket should keep its profile uniform and keep it

inflated. The gasket is immediately cooled with water spray which solidifies the material

Normal Line Speed: 10m/min

The gasket is cut into required length with 45 angle at corners. Now Flexible FerriteMagnetic Strip is entered in and then foam. The gaskets are joined by hot weldingprocess to form rectangular profile for refrigerator and freezer door.

THERMO PLASTIC EXTRUSION

In extrusion, a melted polymer is forced through an orifice with a particular cross

section (the die), and a continuous shape is formed with a constant cross section similar to that of the orifice. A longitudinal section of a screw extruder is shown in Figure.Among the products that can be produced by extrusion are film, sheet, tubing, pipes,insulation, and home siding. In each case the profile is determined by the die geometry,and solidification is by cooling.



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POLYVINYL CHLORIDE (PVC)

Poly(vinyl chloride) is the plastic known at thehardware store as PVC. This is the PVC from which pipes aremade, and PVC pipe is everywhere. The plumbing in your house is probably PVC pipe, unless it's an older house. PVC pipe is what rural highschools with small budgets use to make goal posts for their football fields. But there'smore to PVC than just pipe. The "vinyl" siding used on houses is made of poly(vinyl

chloride). Inside the house, PVC is used to make linoleum for the floor. In the seventies,PVC was often used to make vinyl car tops.

PVC is difficult to recycle, resulting in much of it ending up in landfills. Chemicals,such as phthalates are added to PVC to make it soft and flexible.

1. Harness AssemblyHarness:

A gathering of electrical wires terminating in a central plug that usually operates the turn

signals, brake lights, and electrical brakes for a mobile office. Wiring Harness created

here is used to convey signal from thermostat to compressor, from door to light bulb and

contact the system to the power.



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Wires of required length are cut down form wire roll. Different terminals and connectors

are added to it and step by step working thermostat is formed. After completion it is

checked my meter. Usually the harness terminates in the thermostat, bulb andcompressor terminals.

2. Foaming

In this section the bodies and doors are foamed with polyurethane

Cabinet are kept pre-oven at 40-45C for some time. The amount of material to be

injected in the body is controlled by maintaining 31 Kg/m3 density. Density is keptconstant and volume is measured hence mass can be calculated.If the ratio starts increasing than it start becoming harder and its insulation property startdecreasing. And if it start decreasing then it becomes soft, providing poor structuralstrength.

POLYURETHANES (PUR)

Polyisocyanates represents the key substance in the polyurethane (PUR) chemistry.

The general structure in R-(NCO)n, where n typically equals 2 to 4, or even higher and

R is a n aromatic or aliphatic group. In many cases, both hydroxyl and amine reactions

are involved. The resulting polymers are poly (urea urethanes). If water is present, it too

can react with isocyanate group, forming urea linkage and carbon dioxide.

The formation of CO2 leads to generation of gas in the reaction mixture. This effect is

used to produce PUR foams.ISOCYANATES :

The aromatic isocyanates are important members of this family. They are most reactive

than the aliphatic type and less expensive and therefore claim the largest share of

production volume. In spite of their inherits toxicity, isocyanates can be safety

precautions are used. Toluene diisocyanate (TDI) is the largest product (in volume) of

National University of Sciences and Technology (NUST) H-12 Islamabad10


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all isocyanates. It is a diisocyanate that is usually of 80% 2,4-isomer and 20% 2,6-

isomer

P OLYOLS , C ROSS LINKERS , AND CHAIN EXTENDERS :The counterparts for the reaction wit the diisocyanates (the so-called iso side) are

hydroxyl or amino-terminated components (the so-called poly side).

Low molecular weight components are used as chain extenders (bi-functional) or cross

linkers higher functionalities). In combination with the diisocyanates, they especially

influence the high temperature properties of resulting PURs. Typical structures are

PUR IN THE REFRIGERATION INDUSTRY

RIGID FOAMThe primary application for rigid PUR foam is the thermal insulation. These foams are of

major importance to the transportation industry, especially with respect to frozen food,

and for containers for trucks, aircraft, trains and ships. They are used in warehouses,

walk-in coolers, displays cases, refrigerators, and deep freezers.

In many cases, using PUR rigid foam could reduce wall thickness by up to 45%

compared to other insulation materials. This is a consequence of the low thermal

conductivity of the foam and its use as a structural elements in the most of these frozen

storage applications. Additional applications are found in the insulation for the storage

vessels, pipelines, doors, roofs, and tank; as lightweight concrete aggregate for wall

panels and windows sills; and as integrated insulation for building blocks

3. Pre assembly

This area consumes different parts of refrigerator produced by different sections which

are press shop, injection molding, paint plant, thermoforming and some parts from



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vendors. This Section only assembles empty bodies of refrigerator without interior and

any electrical parts and ready for foaming.

BASE

CABINET INSTALLATION ON BASE (ON CONTINUOUSLY MOVING CONVEYOR)

Base + Foaming Plug + Cabinet + Cabinet Pipe (on back) + Sealing with shine +Freezer Cabinet + Sides + Back + Back Box + Foaming Plug

DOOR ASSEMBLY

Door Front Sheet (from Press) + Plastic Ends (Injection Molding FOAMING

SECTION after foaming Removing Tapes

Door from Foaming

+ Locks and support

+ (Door Inner Plate Holes +Gasket)

+ Handle (from Injection Molding)

4. Assembly Line


Screwing Final Door


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In this section refrigerator is given final shape. Refrigerator bodies and door after

foaming and preassembly are handed to assembly line.

First of all thermostat and ref evaporator are fixed, then compressor (according torefrigerator size), after marking date on it, is fixed and leveling screws are tightened

Compressor According to Cabinet Size

Date & Serial Marking

Foam Cabinet Evaporator Plate +Thermostat Box Condenser Plate

Connections Gas Welding Vacuum Creation Gas Charging (R-134) Leak

Test Final Inspection Door (Freezer+ Refrigerator) Accessories (Vegetable Box,

Balcony, etc) Cleaning Cosmetic Inspection Packing Dispatch.

5. Condensate and Anti C ondensate

The materials used in the condensate and anti condensate are

CR 0.4mm x 80 mm Bundy Tube (MS Tube with Cu Coating) = 4.76 mm Cu Tube =3/16 inch Condenser Side Strip (Press Shop)

Process :

CR Press in Condenser Shop +

Bundy Tube Cutting Grinding Reaming

Bending Leak Test

+


Auto Spot welding


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Condenser Side Strip (From press Shop)

Rubber Plugging Washing Final Bending Spot

Checking (400Psi N2 Gas)

(N2 used because it doesnt have any moisture)

Condenser

Leak Test --- Standard Pressure 150-200 Pisa

Spot welding --- Electric Spot at 440V, and daily tips are changed

Anti Condensate

Cu Tube Cutting Grinding Reaming Swaging 1 end Bending Leak Test

1. DEEP FREEZER

Process Flow Chart



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Material Bending Inner cabinet joining Copper stacking sealing

Stacking Chemical filling Bottle stacking Welding + Taping

Inner & Outer joining Pre-heating oven Foaming process. Components (Fr-11 + polyon+ iso-cyner)

Condensing unit fitting Vacuuming Nitrogen check for leakage

Recharging of refrigerant R-134a. Final performance check Packing.

Eutectic Bottles

They contain a chemical which can be frozen in a plate freezer andused for 18hrs cooling. Cool banks use R-404a as refrigerant.

2. SPLIT AIR-CONDITIONRS

Split Air conditioners consists of two units

Indoor unit Outdoor unit



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Indoor Unit:

It consists of evaporator, blower and controls.

Outdoor Unit:

It consists of condenser, fan and compressor.

ASSEMBLING OF SPLIT A.C.

OUT DOOR UNIT:

Compressor assembly with the condenser.

Nitrogen check for leakages.Vacuuming is done.

Recharging of refrigerant F-22 (about 2,000gm).

Leak checking.



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Packing.

INDOOR UNIT:

It consists of an evaporator, capillary tube, blower etc.

These parts are assembled to form the indoor unit. It is checked by connectingwith outdoor unit and then is packed.

1. Press Shop

Press Shop uses metal sheets to make sheet metal part of refrigerator (doors, sidepanels, top, base, freezer side plates, different supports, etc)

Process include cutting of sheets of required length and width on shearing machines.Then according to design of product other process are completed steps include arenotching, bending, pressing, pressing, drawing, etc. on presses

The raw materials used in the press shop are cold rolled sheets, galvanized iron, VCMand stainless steel sheets.

The number of presses in the press shop are

Shearing Machines 8 Vertical presses 10 OBI Presses 40 Side forming machines 1 Hydraulic presses 18 Spot Welding Machines 7 Tapping Machines 02



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Manufacturing Processes

Shearing Side Forming

Blanking Tapping Piercing Notching Bending Spot welding Drawing Pruning

1. Plastic Injection Moulding

Injection Molding is the process of forcing melted plastic in to a mold cavity. Once theplastic has cooled, the part can be ejected. Injection molding is often used in mass-

production and prototyping. Injection molding is a relatively new way to manufactureparts

Injection molding is perhaps the most common and versatile method of forming plasticinto products. In essence, the injection molding process converts raw material plastic, inthe form of solid pellets, into a highly viscous fluid; the material is then pushed or injected into a mold. Once the product is formed, and the mold is opened and the partextracted: at this point, it is essentially ready for use. This process allows for partdesigns with a great deal of intricacy, including fine small parts, thin webs decorativedesigns and surface finishes, extremely high gloss surface finishes, and highly complex

contours and shapes

COMPONENTS



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For thermoplastics, the injection molding machine converts granular or pelleted raw plastic into final molded parts via a melt, inject, pack, and cool cycle. Atypical injection-molding machine consists of the following major components, as

illustrated in Figure 2 below. Injection system Mold system Hydraulic system Clamping system Control system

Material Product

PC crush + Virgin Single Phase Back EM

PS Butter & Cheese Cover, Front Lip, Ice Container

PS crush +S.L.O Vegetable box, balcony

S.L.O (HIPS crush) Vegetable box, balcony, grid frame

ABS Color Top Frame, Kick Plate, Drain Tray, Handle Base

Conceal Handle, End Cap

ABS crush Handle Upper Strip, Kick Cavity, Bike Side Cover

ABS DC Chill Box, Freezer Plate (left + right), Center Railing Plate,

Freezer Frame

ABS crush Chilled Box, Ice tray frame

Color for ABS BN, GG, DG, LGG, GSB, Black

1. DIES & MOLDS

DIE CASTING



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Die casting is the process of forcing molten metal under high pressure into mold cavities

(which are machined into dies). Most die castings are made from non-ferrous metals,

specifically zinc, copper, aluminium, magnesium, lead, and tin based alloys, althoughferrous metal die castings are possible. The die casting method is especially suited for

applications where a large quantity of small to medium sized parts are needed with

good detail, a fine surface quality and dimensional consistency. This level of versatility

has placed die castings among the highest volume products made in the metalworking

industry. In recent years, injection-molded plastic parts have replaced some die castings

because they are cheaper and lighter.

MOLDS



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Molding or moulding is the process of manufacturing by shaping pliable raw materialusing a rigid frame or model called a pattern.A mold or mould is a hollowed-out block that is filled with a liquid like plastic, glass,metal, or ceramic raw materials. The liquid hardens or sets inside the mold, adopting itsshape. A mold is the opposite of a cast. The manufacturer who makes the molds iscalled the mold maker. A release agent is typically used to make removal of thehardened/set substance from the mold easier.

TWO-PLATE MOLD:

The vast majority of molds consist essentially of two halves, as shown below.This kind of mold is used for parts that are typically gated on or around their edge, withthe runner in the same mold plate as the cavity.

THREE-PLATE MOLD:

The three-plate mold is typically used for parts that are gated away from their edge. The runner is in two plates, separate from the cavity and core, as shown in Figurebelow .

(left) a two-plate mold . (right) a three-platemold.

SINGLE CORE MOLD:



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Only one product is obtained from a single core mold.

MULTIPLE CORE MOLD:

We get more than one same product from a multiple coremold.

DIFFERENCE BETWEEN DIES & MOLDS :

1. Dies are used for metals and molds are for plastics.2. Materials cannot be filled in die, & vice versa.3. Different operations such as shearing, blanking, piercing etc can be done by die

only.4. The whole is through the die whereas there is a partial hole in the molds.

1. Power Division

The Power Division of PEL has the following products;

EPC ContractingPower Transformer Distribution Transformer Drytype Transformer Energy Meter Switchgear Transformer Services

2. Development

We get a feedback from the management department. They give their requirement.Then it is sent to the design section.

After approval of design



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Molds & dies are designed

Trial run

If it is OK then

Production.

This section works with the aim to bring new development. This department starts fromscratch to new designs, which can attract the new market and will give new concepts of refrigeration. For the designing they also consider the refrigerator by other local &international firms.

From virtual to reality the modeling is brought by prototyping. The drawings arethen converted into prototype models made of wood, ABS, Acrylic Sheets.

The prototypes are shown to marketing department and to executives from for the final selection. The new options are included in the design and final drawing andprototype

REFERENCE S:

Wikipedia How stuff works Self observation & workers in the shop.

National University of Sciences and Technology (NUST) H-12 Islamabad

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