INDUSTRIALINDUSTRIAL TRAININGTRAINING

-CUM--CUM-PROJECTPROJECTREPORTREPORT

Auto DivisionAuto DivisionAtAt

88thth km stone,Delhi road km stone,Delhi roadSaharanpur-uttar PradeshSaharanpur-uttar Pradesh

(247001)(247001)

Submitted to:- Submitted by:-Submitted to:- Submitted by:-Mr. N.K Batra Aditya GoelMr. N.K Batra Aditya GoelHOD 11082327HOD 11082327Mech. Deptt. Mech-cMech. Deptt. Mech-c

AcknowledgmentAcknowledgement is not only a ritual, but also an expression of indebtedness to all those who have helped in the completion process of the project.I express gratitude and am thankful to all the people at Unitech Machines Limited who helped make my training a success. The help, assistance and guidance that I have received here will be earnestly cherished throughout my life. I have no doubt now that my choice of training was right and the exposure and experience gained at UML has been unique .I feel I have been part of the UM group if only for a short time and shared the work culture which teaches a goal oriented approach. I owe my success to many people who guided me in time of need and shared with me their valuable time so that I could develop. I would like to take this opportunity to thank:

Ms Sajina (HR) For helping me decide my department and assigning me under Mr.

Vivek Shirivastav for the duration of my training.

Mr. Vivek Shirivastav (project incharge) I am thankful to him. It was he under whom I learnt many things. I am

thankful to him for introducing me to the members of company and for guiding me throughout my training.

Mr. Gurdeep singh (ENGG. department.) For constantly attending to me and explaining to me the

organizational structure of the company and clearing my doubts on various technical process.

Mr. Ankur (Sr. Executive Materials) who helped me procure the required bills for the project and explain

various processes.

All the workers and operators who patiently explained to me the processes and procedures followed

in the Plant and also those in the store for constantly helping me in the materials.

Index:-S.no Particulars1 Introduction2 Products and clients3 Infrastructure4 Auto Division5 Main shops6 Tool shop7 Moulding shop8 Surface treatment shop9 Assembly shop10 Press shop11 Welding shop12 Phosphating shop13 Powder coating shop14 conclusion

INTRODUCTION

Company Profile:

UM Group is a USD 250 million technology driven, people focused, equal opportunities employer. Each group company contributes uniquely to the group’s strength and to the ‘Unity in Diversity’ ideology. 

For over two decades UM Group has consistently held on to the initial idea of ethical business. We explore, innovate, create, deliver and serve to fulfill the demand of the best International brands in their respective fields. 

Whether it involves harnessing available technology and resources to design and create new products or  identifying a requirement for collaborative efforts to design, manufacture or improve upon the quality of an existing product, UM Group’s approach to manufacturing and quality control ensures that perfected processes are immaculately repeated and it is on constant lookout to improvise, innovate and upscale.

With world class engineering and manufacturing infrastructure, the company has major focus on Automotive, Engineering, Manufacturing , Power, Oil & Gas and Telecom Sectors of the Economy.

To ensure that the group companies and day to day operations including procurement, vendor management, supply chain management are all seamless and easily accessible. The UM Group has implemented ERP across all divisions.

The group comprises of following respected brands in their respective fields: 

Unitech machines limited

Alpha toyo limited

Nikko auto limited and Techno auto components

The Road Ahead: CMD’s visionToday’s competitive economic environment calls for competitive edge, minimum costs and consistent growth to survive into the future. 

For any organization, Innovation and Research form the core source of designing new products and bringing improvement to existing portfolio. It is a proven fact that companies have to consistently innovate to survive and sustain. We would focus not only on improving our quality and minimizing costs and errors, but also on devising new methods and products to maintain a competitive advantage. 

The progress however, must be achieved in harmony with the environment. A commitment to community welfare and environmental protection are an integral part of our corporate vision and we would continue to invest and do more for our surroundings. As responsible Corporate Citizens, we would strive hard to come at par with expectations of Corporate Social Responsibility.  

We would continue to build on our present expertise in Automotive, Infrastructure, Power and Telecom Sectors and exploring new areas for growth. Two decades of a consistent world class quality and customer-focused approach has enabled UM to attain and sustain leadership in all its major lines of business.   Today we have international presence, with an office in Dubai.  

Moving ahead responsibly and building on our strong heritage of professionalism, placing the highest value on merit and integrity, we would be setting new goals and achieve them consistently. UM Group would continue contributing to society by creating opportunities for the young and carving a workplace that unifies different businesses through its strings of unity in diversity.

V. K. Chhabra

CMD

UM Group

HISTORY OF UML

CHRONOLOGICAL PRESENTATION:

1986: Started Business in Engineering & Heavy Fabrication.

1990: Set-up Lighting Components Business.

1993: Set up Infrastructure Projects Division.

1994: Set up Rubber Components Unit. 1996: acquired Alpha Toyo & Nikko Auto. 2000: Acquired and turned around Trading Engineers:

an ailing Genset manufacturing unit, now profitable and growing.

2004: Establishment of R&D centre at HO and Heavy

Engineering Works. 2007: Joint venture with Technical Resources EST of  AL Bawardy Group U.A.E.

2008: Joint ventures with Nohmi Bosai Limited  –  Japan, Magneti Marelli – Italy. 2009: Joint

venture with ZADI CEV.

UNITECH MACHINES LIMITED

The Flagship company of the UM Group, Unitech Machines Limited (UML) operates two distinct business divisions – Auto and Engineering with ISO 9001/14001 & TS-16949 Certification. 

The Auto Division at UM, known as a manufacturer and supplier of repute, caters to leading global automotive manufacturers, with clear goals to build up a leadership with sincere effort, cost effectiveness and flawless customer centric approach. A 100 percent OEM/DOL supplier to ‘Hero Honda’, the world’s largest two wheeler manufacturer, the Auto Division has been growing steadily with assuring strengths over the last decade.

For Project Group,  Balance of Plant (BOP) Bussiness is the key area of expertise. It has strong and proven capability to handle on EPC/LSTK basis, wide range of BOP for Thermal Power Plants. The highly skilled core team of  Engineers & CAD operators is equipped to handle Civil/Structural, Mechanical, Electrical and Instrumentation disciplines, with Project management and Construction management as part of the EPC set up. Each day the Project Group reinforces its commendable ability in continuing the relationship through Construction, Installation, Operation and Maintenance of the Plants and enhancing customer delight. Project Group have expanded business profile to implement Projects on EPC mode in Hydrocorbon/Oil & Gas Sectors

R&D Centres of Engineering Division at Gurgaon Head-Office and at Saharanpur Works was established in April, 2004 with focus on Design, Product and Processes Development. R&D activities have been consistently strengthened over the years and are growing at fast pace to meet challenges of excellence and competitiveness. R&D Centres at Head Office and at Works are managed by team of Scientists and other professionals pooled from different specialist disciplines.

Unitech Machines maintains its repute among customers and employees alike. It understands its responsibility for the simple reason that it will be setting an example by every news it creates, for all the group companies at UM group. Since attitude reflects leadership it is inevitable that Unitech Machines carries forward in every move as the relentless brand ambassador of the  UM group, to ensure every individual associated with it in any capacity can vouch for its credibility.

Products And Clients

Products:-High Quality approach to manufacturing and vigorous attention to meet On Time Delivery has won Auto division numerous awards and rave review from clients time and again. Its commitment and approach to become a focused and respected manufacturer and supplier for Global Auto Manufacturers is evident in its product portfolio, as below.

Head Lamps Tail Lamps Blinkers Plastic Moulded Components Sheet Metal Components

Clients:- Hero Honda Motors Limited Maruti Suzuki India Limited Mahindra & Mahindra TVS Motors Limited Yamaha Motors India Limited General Motor India Fiat-India Fiat Tata Volkswagen Ashok Leyland Force Motors JCB India Punjab Tractors Limited Escorts Tractor New Holland Tractor Escorts Construction Equipment Limited

Infrastructure

UM Auto Division – Sound platform for Sound manufacturing.Global Auto manufacturers are increasingly demanding for the quality and finish of the components installed in their vehicles. New benchmarks set every day ensure that only the best manufacturers would establish themselves globally. UM Auto division conforms to international standards in manufacturing of an array of auto parts. It relies on high performance and focused infrastructure to ensure its global customers are sure of the service and quality delivery. That combined with trained manpower skills leads to remarkable efficiency in utilizing the material and process to its optimum. Products are manufactured, tested and packaged with an in-tandem set up of man-machine combination that leaves no stone unturned in ensuring that timelines and standards are met alike.

Plant & Machinery Tool Room Moulding Shop Press Shop

Shapers Milling M/C Surface Grinders EDM Lathe Machines Polishing

Machine Drilling M/C Pantagraph CNC Milling

M/C’S

Moulding M/C from 60 Ton 450 Ton

Centralized Automatic preheating & dehumidifying Raw Material Conveying System

Drying Ovens

Mechanical Presses from 10 Ton TO 150 ton

Double Action Power presses upto 200 Ton

Pneumatic Presses from 30 Ton to 150 Ton

Shearing M/Cs

Assembly Shop

Metalizing Plant

Lacquering Shop

Automatic Assembly Conveyors

Hot Melt Applicator

Ultrasonic Welding Machines

Cold Melt Applicator

Jigs & Fixtures for Assembly

Testing Equipments

Vacuum Metalizing Plants

o Horizontal 1.24” – 01 No.

o Horizontal 2.36” – 03 Nos.

o Vertically Planetary Motion 48” – 02 Nos

o Vertical Planetary Motion 55” – 02 No.

 

Double Dip Sheet Metal Drying Conveyor.

Spray Coating booth and drying conveyors for Base coat, Top Coat

Plastic Lacquer spray Coating Booth with drying  Conveyors

Welding Shop

Mig Welding M/Cs from 250 Amp. to 400 amp. Spot Welding M/Cs 15 kva to 35 kva Projection Welding M/Cs 50 kva to 150 kva

 

Head Light Lens Hard Coating Conveyors Conveyorised Phosphating and Powder coating Plants

Quality Assurance Lab

Photometric Testing And Environmental Testing Lab

Photometric Testing (ECE, SAG, JIS, IS) Dark Room (36M x 6M) Photogoniometer GP2000 Make OPT Australia Spectro 1000 (Spectro Radiometer Colour Measurement System)

OPT Australia Automatic Licence Plate Meter (ALP100) Retro Reflex Meter Retro1000 (OPT Australia) Photo Integrated Sphere PHB Digital LUX Meter Vibration Shock Testing Machine Salt Spray Test Chamber Environment Test Chamber (Hot & Cold) (40° to 125°C) Dust Chamber Rain Test Chamber Bulb Life Test Rig Bulb LCL profile Tool Room Moulding Shop Press Shop Lacquering Shop Metalizing Plant Conveyorised Assly, Line  Photometric Testing and Environmental Testing Lab Other Lab Equipments

Auto Division Workshop at

SaharanpurOverview :-Founded and operated with clear vision of the future to transform the automotive components industry, Unitech Machines’ Auto division is one of the foremost manufacturers of a range of automotive components in the country. 

A division of the Flagship company of the UM Group, Auto Division designs and manufactures a range of lighting and signaling equipment under ISO 9001, ISO 14001 and TS 16949 standard. It is a 100 percent OEM supplier to ‘Hero Honda’, the world’s largest two wheeler manufacturer.

Hailed as a manufacturer and supplier of repute, catering to leading global automotive manufacturers, offering technologically advanced products, its goal is to build up a leadership with sincere effort, cost effectiveness and flawless customer centric approach. Needless to say, quality goes into each and every material and process and forms the lifeline of the company’s philosophy. 

the works of the auto division of UM Group is carried out at saharanpur.

the factory is huge and is equipped with modern equipments required to meet the needs of modern world.the factory runs 24 hours with 3 shifts in a day.

The parts of various products manufactured by the company are manufactured under various sheds or shops,and then after passing through various finishing processes they are assembled in assembly shop to make the final product.and then the product is sent for dispatch.each piece goes under many inspection processes carried out by different workers and engineers at different stages.

The main shops in the company are :-

Tool Shop Molding Shop Surface Treatment Shop

Aluminium Coating ShopLacquering shop

Assembly shop Press Shop Welding Shop Phosphating Shop Powdering Shop

Testing Labs Pre Dispatch Inspection

Tool Room

Main work:-

Making of Molds or Dies.This place can be called as the heart of the company.this is the place where the main thing of the company, The DIE or MOLD is manufactured.

A die is a specialized tool used in manufacturing industries to cut or shape material using a press. Like molds, dies are generally customized to the item they are used to create.these molds arethen clamped in the injection molding machine to get desired product.

Forming dies are typically made by tool and die makers and put into production after mounting into a press. The die is a metal block that is used for forming materials like sheet metal and plastic. For the vacuum forming of plastic sheet only a single form is used, typically to form transparent plastic containers (called blister packs) for merchandise. Vacuum forming is considered a simple molding thermoforming process but uses the same principles as die forming. For the forming of sheet metal, such as automobile body parts, two parts may be used, one, called the punch, performs the stretching, bending, and/or blanking operation, while another part, called the die block, securely clamps the workpiece and provides similar, stretching, bending, and/or blanking operation. The workpiece may pass through several stages using different tools or operations to obtain the final form. In the case of an automotive component there will usually be a shearing operation after the main forming is done and then additional crimping or rolling operations to ensure that all sharp edges are hidden and to add rigidity to the panel.

Machines

Lathe Machine:-A lathe is a machine tool which spins the workpiece to perform various operations such as cutting, sanding, knurling, drilling, or deformation with tools that are applied to the workpiece to create an object which has symmetry about an axis of rotation.

Lathes are used in woodturning, metalworking, metal spinning, and glassworking. Lathes can be used to shape pottery, the best-known design being the potter's wheel. Most suitably equipped metalworking lathes can also be used to produce most solids of revolution, plane surfaces and screw threads or helices. Ornamental lathes can produce three-dimensional solids of incredible complexity. The material can be held in place by either one or two centers, at least one of which can be moved horizontally to accommodate varying material lengths. Other workholding methods include clamping the work about the axis of rotation using a chuck or collet, or to a faceplate, using clamps or dogs.

Parts

A lathe may or may not have a stand (or legs), which sits on the floor and elevates the lathe bed to a working height. Some lathes are small and sit on a workbench or table, and do not have a stand.

.At one end of the bed (almost always the left, as the operator faces the lathe) is a headstock. The headstock contains high-precision spinning bearings. Rotating within the bearings is a horizontal axle, with an axis parallel to the bed, called the spindle. Spindles are often hollow, and have exterior threads and/or an interior Morse taper on the "inboard" (i.e., facing

to the right / towards the bed) by which workholding accessories may be mounted to the spindle. Spindles may also have exterior threads and/or an interior taper at their "outboard" (i.e., facing away from the bed) end, and/or may have a handwheel or other accessory mechanism on their outboard end. Spindles are powered, and impart motion to the workpiece.

The spindle is driven, either by foot power from a treadle and flywheel or by a belt or gear drive to a power source. In most modern lathes this power source is an integral electric motor, often either in the headstock, to the left of the headstock, or beneath the headstock, concealed in the stand.

In addition to the spindle and its bearings, the headstock often contains parts to convert the motor speed into various spindle speeds. Various types of speed-changing mechanism achieve this, from a cone pulley or step pulley, to a cone pulley with back gear (which is essentially a low range, similar in net effect to the two-speed rear of a truck), to an entire gear train similar to that of a manual-shift auto transmission. Some motors have electronic rheostat-type speed controls, which obviates cone pulleys or gears.

The counterpoint to the headstock is the tailstock, sometimes referred to as the loose head, as it can be positioned at any convenient point on the bed, by undoing a locking nut, sliding it to the required area, and then relocking it. The tailstock contains a barrel which does not rotate, but can slide in and out parallel to the axis of the bed, and directly in line with the headstock spindle. The barrel is hollow, and usually contains a taper to facilitate the gripping of various type of tooling. Its most common uses are to hold a hardened steel centre, which is used to support long thin shafts while turning, or to hold drill bits for drilling axial holes in the work piece. Many other uses are possible.[2]

Metalworking lathes have a carriage (comprising a saddle and apron) topped with a cross-slide, which is a flat piece that sits crosswise on the bed, and can be cranked at right angles to the bed. Sitting atop the cross slide is usually another slide called a compound rest, which provides 2 additional axes of motion, rotary and linear. Atop that sits a toolpost, which holds a cutting tool which removes material from the workpiece. There may or may not be a leadscrew, which moves the cross-slide along the bed.

Lathe machine in UML

Model Manufacturer No of machinesETM 510 Dalian Machine tool

group,china8

Main Features

■ Big spindle bore ■ Hardened and ground guideway ■ Light lathe bed ■ Brand-new design Exterior ■ Head Stock with clutch   

Standard accessories

Full length splash guard   CenterSteady rest 8-100mm(no including 500mm)   Center sleeveFollow rest 8-50mm(no including 500mm)   Oil gun3-jaw chuck 200mm   Face plate4-jaw chuck 250mm   Drive plateTools  

Specification

Specification

Max swing over bed 320mmMax swing over carriage 180mmCenter distance 500mmMax swing in gap 520mmWidth of bed 280mm

Head stock

Spindle nose D6Spindle bore 52mmTaper of spindle bore M6SpindIe speeds 59-2100 rpm(1 2speeds)

Thread

Range of whitworth thread 56—2TPI(52)Range of metric thread 0.4—14mm(40)Range of module thread 0.2—3.5mm(46)Range of Di metrical pilch thread 112—6DP(33)

Tailstock

Tlaper of tail quill M4Travel of tail quill 125mmDiameter of tail quill 50mm

Motor

Power of main motor 3.3/2.2kWPower of coolant motor 60WNet weight 980kg 1030kg 1080kgGross weight 1330kg 1430kg 1530kgOverall dimensions(L×W×H) 1610mm×935mm×1200mm(500mm)

1860mm×935mm×1200mm(750mm)2110mm×935mm×1200mm(1000mm)

Grinding Machine:-

A grinding machine, often shortened to grinder, is a machine tool used for grinding, which is a type of machining using an abrasive wheel as the cutting tool. Each grain of abrasive on the wheel's surface cuts a small chip from the workpiece via shear deformation.

The grinding machine consists of a power driven grinding wheel spinning at the required speed (which is determined by the wheel’s diameter and manufacturer’s rating, usually by a formula) and a bed with a fixture to guide and hold the work-piece. The grinding head can be controlled to travel across a fixed work piece or the workpiece can be moved whilst the grind head stays in a fixed position. Very fine control of the grinding head or tables position is possible using a vernier calibrated hand wheel, or using the features of numerical controls.

Grinding machines remove material from the workpiece by abrasion, which can generate substantial amounts of heat; they therefore incorporate a coolant to cool the workpiece so that it does not overheat and go outside its tolerance. The coolant also benefits the machinist as the heat generated may cause burns in some cases. In very high-precision grinding machines (most cylindrical and surface grinders) the final grinding stages are usually set up so that they remove about 200 nm (less than 1/100000 in) per pass - this generates so little heat that even with no coolant, the temperature rise is negligible.

Grinding machine in UML

Model Manufacturer No of machines3 axis manual Perfect Machine co.

ltd.,Taiwan4

Milling Machine

A milling machine is a machine tool used to machine solid materials.

Millingmachines exist in two basic forms: horizontal and vertical, which terms refer to the orientation of the cutting tool spindle. Unlike a drill press, in which the workpiece is held stationary and the drill is moved vertically to penetrate the material, milling also involves movement of the workpiece against the rotating cutter, the latter of which is able to cut on its flanks as well as its tip. Workpiece and cutter movement are precisely controlled to less than 0.001 in (0.025 mm), usually by means of precision ground slides and leadscrews or analogous technology. Milling machines may be manually operated, mechanically automated, or digitally automated via computer numerical control (CNC).Milling machines can perform a vast number of operations, some very complex,such as slot and keyway cutting, planing, drilling, diesinking, rebating, routing, etc.Cutting fluid is often pumped to the cutting site to cool and lubricate the cut, and to sluice away the resulting swarf.

The Milling Process

Milling is the most versatile of machining processes. Metal removal isaccomplished through the relative motions of a rotating, multi-edge cutter and multi-axis movement of the workpiece. Milling is a form of interrupted cutting where repeated cycles of entry and exit motions of the cutting tool accomplish the actual metal removal and discontinuous chip generation. Milling has more variations in machine types, tooling, and workpiece movement than any other machining method.All milling machines, from compact tabletop models to the standard vertical knee mill and the massive CNC machining centers, operate on the same principles and operating parameters. The most important of these operating parameters are:

cutting speed, which is the speed at which the tool engages the work

feed rate, which is the distance the tool edge travels in one cutter revolution

the axial depth of cut, which is the distance the tool is set below an unmachined surface

the radial depth of cut, which is the amount of work surface engaged by the tool

The capabilities of the milling machine are measured by motor horsepower which determines maximum spindle speeds and spindle taper size.

Milling machine in UML

Unitech uses cnc milling machine

Model Manufacturer No of MachinesS 56 Makino milling machine co.

ltd.,Japan2

Specifications

Table Size: 39.4" x 19.7"X: 35.4"Y: 19.7"Z: 17.7"Spindle RPM: 13,000Rapid Traverse: 1,574 in/minCutting Feedrate: 1,574 in/minMaximum Workpiece:

39.4" x 19.7" x 17.7"

Maximum Payload: 1,100 lbsATC Capacity: 20 (30)Tool to Tool: 1.2 secsChip to Chip: 4.5 secsMaximum Tool Length: 11.81"

Maximum Tool Diameter: 5.12"

Maximum Tool Weight: 17.6 lbs

Elecrical Discharge machining

EDMElectric discharge machining (EDM), sometimes colloquially also referred to as spark machining, spark eroding, burning, die sinking or wire erosion,is a manufacturing process whereby a desired shape is obtained using electrical discharges (sparks). Material is removed from the workpiece by a series of rapidly recurring current discharges between two electrodes, separated by a dielectric liquid and subject to an electric voltage. One of the electrodes is called the tool-electrode, or simply the ‘tool’ or ‘electrode’, while the other is called the workpiece-electrode, or ‘workpiece’.

When the distance between the two electrodes is reduced, the intensity of the electric field in the volume between the electrodes becomes greater than the strength of the dielectric (at least in some point(s)), which breaks, allowing current to flow between the two electrodes. This phenomenon is the same as the breakdown of a capacitor (condenser) (see also breakdown voltage). As a result, material is removed from both the electrodes. Once the current flow stops (or it is stopped - depending on the type of generator), new liquid dielectric is usually conveyed into the inter-electrode volume enabling the solid particles (debris) to be carried away and the insulating proprieties of the dielectric to be restored. Adding new liquid dielectric in the inter-electrode volume is commonly referred to as flushing. Also, after a current flow, a difference of potential between the two electrodes is restored to what it was before the breakdown, so that a new liquid dielectric breakdown can occur.

Types of EDM

Sinker EDM:-Sinker EDM, also called cavity type EDM or volume EDM, consists of an electrode and workpiece submerged in an insulating liquid such as, more typically, oil or, less frequently, other dielectric fluids. The electrode and workpiece are connected to a suitable power supply. The power supply generates an electrical potential between the two parts. As the electrode approaches the workpiece, dielectric breakdown occurs in the fluid, forming a plasma channel, and a small spark jumps.

These sparks usually strike one at a time because it is very unlikely that different locations in the inter-electrode space have the identical local electrical characteristics which would enable a spark to occur simultaneously in all such locations. These sparks happen in huge numbers at seemingly random locations between the electrode and the workpiece. As the base metal is eroded, and the spark gap subsequently increased, the electrode is lowered automatically by the machine so that the process can continue uninterrupted. Several hundred thousand sparks occur per second, with the actual duty cycle carefully controlled by the setup parameters. These controlling cycles are sometimes known as "on time" and "off time", which are more formally defined in the literature.

The on time setting determines the length or duration of the spark. Hence, a longer on time produces a deeper cavity for that spark and all subsequent sparks for that cycle, creating a rougher finish on the workpiece. The reverse is true for a shorter on time.

Wire EDM:-

In wire electrical discharge machining (WEDM), also known as wire-cut EDM and wire cutting, a thin single-strand metal wire, usually brass, is fed through the workpiece, submerged in a tank of dielectric fluid, typically deionized water. Wire-cut EDM is typically used to cut plates as thick as 300mm and to make punches, tools, and dies from hard metals that are difficult to machine with other methods.

The wire, which is constantly fed from a spool, is held between upper and lower diamond guides. The guides, usually CNC-controlled, move in the x–y plane. On most machines, the upper guide can also move independently in the z–u–v axis, giving rise to the ability to cut tapered and transitioning shapes (circle on the bottom square at the top for example). The upper guide can control axis movements in x–y–u–v–i–j–k–l–. This allows the wire-cut EDM to be programmed to cut very intricate and delicate shapes.

The upper and lower diamond guides are usually accurate to 0.004 mm, and can have a cutting path or kerf as small as 0.12 mm using Ø 0.1 mm wire, though the average cutting kerf that achieves the best economic cost and machining time is 0.335 mm using Ø 0.25 brass wire. The reason that the cutting width is greater than the width of the wire is because sparking occurs from the sides of the wire to the work piece, causing erosion. This "overcut" is necessary, for many applications it is adequately predictable and therefore can be compensated for (for instance in micro-EDM this is not often the case). Spools of wire are long—an 8 kg spool of 0.25 mm wire is just over 19 kilometers in length. Wire diameter can be as small as 20 micrometres and the geometry precision is not far from +/- 1 micrometre.

The wire-cut process uses water as its dielectric fluid, controlling its resistivity and other electrical properties with filters and de-ionizer units. The water flushes the cut debris away from the cutting zone. Flushing is an important factor in determining the maximum feed rate for a given material thickness

EDM in Unitech

Model Manufacturer No of machinesEdge 3 Makino 1

Specification:-

Table Size: 23.6" x 17.7"X: 17.7"Y: 11.8"Z: 12.6"Tank Size: 31.5" x 21.6" x 13.8"Rib Head Available: YesDrop Tank: YesRapid Traverse: 196 in/minOptional ATC Capacity: 8, 16, 32Maximum Electrode Weight: 110 lbsMaximu Available Amperage: 30 (60)

Moulding ShopInjection moulding:-

• Injection Moulding is a manufacturing technique for making parts from plasti material. Molten plastic is injected at high pressure into a mould, which is the inverse of the desired shape. The mould is made by a mouldmaker (or toolmaker) from metal, usually either steel or aluminium, and precision-machined to form the features of the desired part. Injection moulding is very widely used for manufacturing a variety of parts, from the smallest component to entire body panels of cars. It is the most common method of production, with some commonly made items including bottle caps and outdoor furniture.

In Unitech,this plastic injection molding machine is used for making winkers,utility box and other plastic frames and items which company manufactures.

• Injection molding machines, also known as presses, hold the molds in which the components are shaped. Presses are rated by tonnage, which expresses the amount of clamping force that the machine can generate. This pressure keeps the mold closed during the injection process. Tonnage can vary from less than 5 tons to 6000 tons, with the higher figures used in comparatively few manufacturing operations.

Injection Molding Cycle• The basic injection cycle is as follows: Mold close • injection carriage forward • inject plastic• metering • carriage retract• mold open• eject part(s)

Inject plastic• Molten plastic material is injected into the mold. The material travels

into the mold via the sprue bushing, then the runner system delivers the material to the gate. The gate directs the material into the mold cavity to form the desired part. This injection usually occurs under velocity control. When the part is nearly full, injection control is switched from velocity control to pressure control. This is referred to as the pack/hold phase of the cycle. Pressure must be maintained on the material until the gate solidifies to prevent material from flowing back out of the cavity. Cooling time is dependent primarily on the wall thickness of the part. During the cooling portion of the cycle after the gate has solidified, plastication takes place. Plastication is the process of melting material and preparing the next shot. The material begins in the hopper and enters the barrel through the feed throat. The feed throat must be cooled to prevent plastic pellets from fusing

together from the barrel heat. The barrel contains a screw that primarily uses shear to melt the pellets and consists of three sections. The first section is the feed section which conveys the pellets forward and allows barrel heat to soften the pellets. The flight depth is uniform and deepest in this section. The next section is the transition section and is responsible for melting the material through shear. The flight depth continuously decreases in this section, compressing the material. The final section is the metering section which features a shallow flight depth, improves the melt quality and color dispersion. At the front of the screw is the non-return valve which allows the screw to act as both an extruder and a plunger. When the screw is moving backwards to build a shot, the non-return assembly allows material to flow in front of the screw creating a melt pool or shot. During injection, the non-return assembly prevents the shot from flowing back into the screw sections

Mold open

• Once the shot has been built and the cooling time has timed out, the mold opens. Mold opening must occur slow-fast-slow. The mold must be opened slowly to release the vacuum that is caused by the injection molding process and prevent the part from staying on the stationary mold half. This is undesirable because the ejection system is on the moving mold half. Then the mold is opened as far as needed, if robots are not being used, the mold only has to open far enough for the part to be removed. A slowdown near the end of travel must be utilized to compensate for the momentum of the mold. Without slowing down the machine cannot maintain accurate positions and may slam to a stop damaging the machine. Once the mold is open, the ejector pins are moved forward, ejecting the part.

Shot built

• The resin, or raw material for injection molding, is usually in pellet or granule form, and is melted by heat and shearing forces shortly before being injected into the mold. Resin pellets are poured into the feed hopper, a large open bottomed container, which feeds the granules down to the screw. The screw is rotated by a motor, feeding pellets up the screw's grooves. The depth of the screw flights decreases towards the end of the screw nearest the mold, compressing the heated plastic. As the screw rotates, the pellets are moved forward in the screw and they undergo extreme pressure and friction which generates most of the heat needed to melt the pellets. Heaters on either side of the screw assist in the heating and temperature control during the melting process

Eject part(s)

• The cycle is completed when the mold opens and the part is ejected with the assistance of ejector pins within the mold. When the ejector pins retract, all criteria for a molding cycle have been met and the next cycle can begin.

• The channels through which the plastic flows toward the chamber will also solidify, forming an attached frame. This frame is composed of the sprue, which is the main channel from the reservoir of molten resin, parallel with the direction of draw, and runners, which are perpendicular to the direction of draw, and are used to convey molten resin to the gate(s), or point(s) of injection. The sprue and runner system can be cut or twisted off and recycled, sometimes being granulated next to the mold machine. Some molds are designed so that the part is automatically stripped through action of the mold.

Defects in moulding

Molding Defects

Alternative name Descriptions Causes

Blister Blistering Raised or layered zone on surface of the part

Tool or material is too hot, often caused by a lack of cooling around the tool or a faulty heater

Burn marks Airburn/gas burn/dieseling

Black or brown burnt areas on the part located at furthest points from gate or where air is trapped

Tool lacks venting, injection speed is too high

Color streaks (US)

Colourstreaks Localized change of color/colour

Masterbatch isn't mixing properly, or the material has run out and it's starting to come through as natural only. Previous colored material "dragging" in nozzle or check valve.

Flash BurrsExcess material in thin layer exceeding normal part geometry

Mold is over packed or parting line on the tool is damaged, too much injection speed/material injected, clamping force too low. Can also be caused by dirt and contaminants around tooling surfaces.

Flow marks Flow linesDirectionally "off tone" wavy lines or patterns

Injection speeds too slow (the plastic has cooled down too much during injection, injection speeds must be set as fast as you can get away with at all times)

Knit lines Weld lines Small lines on the backside of core pins or windows in parts that look like just

Caused by the melt-front flowing around an object standing proud in a plastic part as well as at the end of fill where the melt-front comes

lines.

together again. Can be minimized or eliminated with a mold-flow study when the mold is in design phase. Once the mold is made and the gate is placed, one can minimize this flaw only by changing the melt and the mold temperature.

Short shot Non-fill / Short mold Partial part

Lack of material, injection speed or pressure too low, mold too cold, lack of gas vents

Stringiness StringingString like remain from previous shot transfer in new shot

Nozzle temperature too high. Gate hasn't frozen off

Voids Empty space within part (Air pocket)

Lack of holding pressure (holding pressure is used to pack out the part during the holding time). Filling too fast, not allowing the edges of the part to set up. Also mold may be out of registration (when the two halves don't center properly and part walls are not the same thickness).

Weld lineKnit line / Meld line / Transfer line

Discolored line where two flow fronts meet

Mold/material temperatures set too low (the material is cold when they meet, so they don't bond). Point between injection and transfer (to packing and holding) too early.

Warping Twisting Distorted part

Cooling is too short, material is too hot, lack of cooling around the tool, incorrect water temperatures (the parts bow inwards towards the hot side of the tool) Uneven shrinking between areas of the part

Plastic Used

Most polymers may be used, including all thermoplastics, some thermosets, and some elastomers. In 1995 there were approximately 18,000 different materials available for injection molding and that number was increasing at an average rate of 750 per year. The available materials are alloys or blends of previously developed materials meaning that product designers can choose from a vast selection of materials, one that has exactly the right properties. Materials are chosen based on the strength and function required for the final part, but also each material has different parameters for molding that must be taken into account. Common polymers like Epoxy and phenolic are examples of thermosetting plastics while nylon, polyethylene, and polystyrene are thermoplastic.

Surface Treatment Shop

Lacquering:- In a general sense, lacquer is a clear or coloured varnish that dries by solvent evaporation and often a curing process as well that produces a hard, durable finish, in any sheen level from ultra matte to high gloss and that can be further polished as required.

Metallizing:-metallizing is the general name for the technique of coating metal on the surface of non-metallic objects. Because a non-metallic object tends to be a poor electrical conductor, the object's surface must be made conductive before plating can be performed.

Techniques for metallization started as early as mirror making. In 1835, Justus von Liebig discovered the process of coating a glass surface with metallic silver, making the glass mirror one of the earliest items being metallized. Plating other non-metallic objects grew rapidly with introduction of ABS plastic. The plastic part is first etched chemically by a suitable process, such as dipping in a hot chromic acid-sulfuric acid mixture. The etched surface is sensitised and activated by first dipping in tin(II) chloride solution, then palladium chloride solution. The processed surface is then coated with electroless copper or nickel before further plating. This process gives useful (about 1 to 6 kgf/cm or 10 to 60 N/cm or 5 to 35 lbf/in) adhesion force, but is much weaker than actual metal-to-metal adhesion strength.

Vacuum metallizing involves heating the coating metal to its boiling point in a vacuum chamber, then letting condensation deposit the metal on the substrate's surface. Resistance heating, electron beam, or plasma heating is used to vaporize the coating metal. Vacumm metallizing

was used to deposit aluminum on the large glass mirrors of reflecting telescopes, such as with the Hale telescope.

In vacuum metallizing a metallic coating material placed in a vacuum chamber with the workpiece to be coated. The material that is being applied is then heated until it starts to evaporate, this vaporized metal condenses on the product or workpiece as a thin metallic film. As this is happening the part is being rotated for uniformity of the coat

Process characteristics Done within a vacuum Vaporizes the metal Can be used on glass, plastic, metal, ceramic, and paper materials Pieces being coated must be extremely clean It produces a very thin coat of metal

Target materialsThickness ranges for 0.01 to 0.2 micrometres. When coating a piece it changes its conductivity, it improves its corrosion resistance, and it enhances its appearance. Some target metals are aluminum, copper, platinum, titanium, chromium titanium, gold, lead, nickel, silver, tin and tantalum.

How it works

The pieces that you want coated are placed in a rotating rack, to ensure even coating, inside the vacuum chamber. Once the vacuum has been created in the chamber, the metallizing material is then heated until it evaporates. Meanwhile the piece is being rotated on the racks to make sure that it is being evenly coated with the vaporized metals.

DegreasingIt is the Removal of soils prior to powder coating is essential to the successful life of the product. It affects the initial adhesion and the ultimate performance in the field. Soils that are present on metal parts can be removed by a variety of mechanical and chemical methods. What method should be used in a given situation is determined by the part to be coated (size, configura-tion, material), the type of soil to be removed (dust, wax, oil, salt crystals, etc.) and the performance requirements of the finished product.

Assembly shop

This the shop where all the manufactured and finished products are brought together and assembled into a single product.

Assembly of blinker:-

Pass the wire through winker light base And fix a spring beneath the attachments of wire.

Then attach the stay winker and bulb. Attach a lens and pack the blinker

Head Lamp Assembly:-

Fix the reflector and lens through Adhesive.

Fix the bulb with the help of spring lamp support Fit a cover rubber Fit another bulb in the wire harness and then fix that wire in

the bulb pins.

Tail light Assembly:-

Holders are previously attached to the wire harness. Fix the 2 bulbs in the tail light reflector. Fix the gasket and lens.

Press shop

This is the shop where the parts of head light brackets are produced.

The process starts from the big sheet rolls of steel and bars of iron of suitable diameter.

First of all the basic shape of the product such as square plate or circular plate is cut from main sheet or small iron bars are cut from long bars.

Then these parts passes through many machine presses to get the required shape and size.the dies which were made in tool room are fitted in the press to get the required shape.this die can be changed to get another required shape.

Machine pressA machine press, commonly shortened to press, is a machine tool that changes the shape of a workpiece. On the basis of the type of die set or the type of operations the machine press perform,it can accordingly be called as punch press for punching,bending press for bending.

Die setA die set consists of a set of punches (male) and dies (female) which, when pressed together, form a hole in a workpiece (and may also may deform the workpiece in some desired manner). The punches and dies are removable, with the punch being attached to the ram during the punching process. The ram moves up and down in a vertically linear motion, forcing the punch through the material into the die.

Bending is a manufacturing process that produces a V-shape, U-shape, or channel shape along a straight axis in ductile materials, most commonly

sheet metal. Commonly used equipment include box and pan brakes, brake presses, and other specialized machine presses. Typical products that are made like this are boxes such as electrical enclosures and rectangular ductwork.

Coining is a form of precision stamping in which a workpiece is subjected to a sufficiently high stress to induce plastic flow on the surface of the material. A beneficial feature is that in some metals, the plastic flow reduces surface grains size, work hardening the surface, while the material deeper in the part retains its toughness and ductility. The term comes from the initial use of the process: manufacturing of coins.

Coining is used to manufacture parts for all industries and is commonly used when high relief or very fine features are required. For example, it is used to produce money (coins), medals, badges, buttons, precision-energy springs and precision parts with small or polished surface features.

Coining is a cold working process (similar to forging which takes place at elevated temperature) that uses a great deal of force to plastically deform a workpiece, so it conforms to a die. Coining can be done using a gear driven press, a mechanical press, or more commonly, a hydraulically actuated press. Coining typically requires higher tonnage presses than stamping, because the workpiece is plastically deformed and not actually cut, as in some other forms of stamping.

Blanking and piercing are shearing processes in which a punch and die are used to modify webs. The tooling and processes are the same between the two, only the terminology is different: in blanking the punched out piece is used and called a blank; in piercing the punched out piece is scrap.

Welding shopIn this shop the various components manufactured in the press shop are brought together and welded together to make a single unit or product.

Welding is a fabrication or sculptural process that joins materials, usually metals or thermoplastics, by causing coalescence. This is often done by melting the workpieces and adding a filler material to form a pool of molten material (the weld pool) that cools to become a strong joint, with pressure sometimes used in conjunction with heat, or by itself, to produce the weld. This is in contrast with soldering and brazing, which involve melting a lower-melting-point material between the workpieces to form a bond between them, without melting the workpieces.

ArcThese processes use a welding power supply to create and maintain an electric arc between an electrode and the base material to melt metals at the welding point. They can use either direct (DC) or alternating (AC) current, and consumable or non-consumable electrodes. The welding region is sometimes protected by some type of inert or semi-inert gas, known as a shielding gas, and filler material is sometimes used as well.

Mig welding is used in this shop

Gas metal arc welding:-Gas metal arc welding (GMAW), sometimes referred to by its subtypes metal inert gas (MIG) welding or metal active gas (MAG) welding, is a semi-automatic or automatic arc welding process in which a continuous and consumable wire electrode and a shielding gas are fed through a welding gun. A constant voltage, direct current power source is most commonly used with GMAW, but constant current systems, as well as alternating current, can be used. There are four primary methods of metal transfer in GMAW,

called globular, short-circuiting, spray, and pulsed-spray, each of which has distinct properties and corresponding advantages and limitations.

Originally developed for welding aluminum and other non-ferrous materials in the 1940s, GMAW was soon applied to steels because it allowed for lower welding time compared to other welding processes. The cost of inert gas limited its use in steels until several years later, when the use of semi-inert gases such as carbon dioxide became common. Further developments during the 1950s and 1960s gave the process more versatility and as a result, it became a highly used industrial process. Today, GMAW is the most common industrial welding process, preferred for its versatility, speed and the relative ease of adapting the process to robotic automation. The automobile industry in particular uses GMAW welding almost exclusively. Unlike welding processes that do not employ a shielding gas, such as shielded metal arc welding, it is rarely used outdoors or in other areas of air volatility. A related process, flux cored arc welding, often does not utilize a shielding gas, instead employing a hollow electrode wire that is filled with flux on the inside.

EquipmentTo perform gas metal arc welding, the basic necessary equipment is a welding gun, a wire feed unit, a welding power supply, an electrode wire, and a shielding gas supply.

Welding gun and wire feed unit

The typical GMAW welding gun has a number of key parts—a control switch, a contact tip, a power cable, a gas nozzle, an electrode conduit and liner, and a gas hose. The control switch, or trigger, when pressed by the operator, initiates the wire feed, electric power, and the shielding gas flow, causing an electric arc to be struck. The contact tip, normally made of copper and sometimes chemically treated to reduce spatter, is connected to the welding power source through the power cable and transmits the electrical energy to the electrode while directing it to the weld area. It must be firmly secured and properly sized, since it must allow the passage of the electrode while maintaining an electrical contact. Before arriving at the contact tip, the wire is protected and guided by the electrode conduit and liner, which help prevent buckling and maintain an uninterrupted wire feed. The gas nozzle is used to evenly direct the shielding gas into the welding

zone—if the flow is inconsistent, it may not provide adequate protection of the weld area. Larger nozzles provide greater shielding gas flow, which is useful for high current welding operations, in which the size of the molten weld pool is increased. The gas is supplied to the nozzle through a gas hose, which is connected to the tanks of shielding gas. Sometimes, a water hose is also built into the welding gun, cooling the gun in high heat operations.

The wire feed unit supplies the electrode to the work, driving it through the conduit and on to the contact tip. Most models provide the wire at a constant feed rate, but more advanced machines can vary the feed rate in response to the arc length and voltage. Some wire feeders can reach feed rates as high as 30.5 m/min (1200 in/min), but feed rates for semiautomatic GMAW typically range from 2 to 10 m/min (75–400 in/min).

GMAW torch nozzle cutaway image. (1) Torch handle, (2) Molded phenolic dielectric (shown in white) and threaded metal nut insert (yellow), (3) Shielding gas diffuser, (4) Contact tip, (5) Nozzle output face

Tool Style

The top electrode holder is a semiautomatic air-cooled holder; compressed air is circulated through it to maintain moderate temperatures. It is used with lower current levels for welding lap- or butt joints. The second most common type of electrode holder is a semiautomatic water-cooled; the only difference being that water takes the place of air. It uses higher current levels

for welding T- or corner joints. The third typical holder type is an automatic electrode holder that is water cooled; this holder is used typically with automated equipment

Power supplyMost applications of gas metal arc welding use a constant voltage power supply. As a result, any change in arc length (which is directly related to voltage) results in a large change in heat input and current. A shorter arc length will cause a much greater heat input, which will make the wire electrode melt more quickly and thereby restore the original arc length. This helps operators keep the arc length consistent even when manually welding with hand-held welding guns. To achieve a similar effect, sometimes a constant current power source is used in combination with an arc voltage-controlled wire feed unit. In this case, a change in arc length makes the wire feed rate adjust in order to maintain a relatively constant arc length. In rare circumstances, a constant current power source and a constant wire feed rate unit might be coupled, especially for the welding of metals with high thermal conductivities, such as aluminum. This grants the operator additional control over the heat input into the weld, but requires significant skill to perform successfully.

Alternating current is rarely used with GMAW; instead, direct current is employed and the electrode is generally positively charged. Since the anode tends to have a greater heat concentration, this results in faster melting of the feed wire, which increases weld penetration and welding speed. The polarity can be reversed only when special emissive-coated electrode wires are used, but since these are not popular, a negatively charged electrode is rarely employed.

ElectrodeElectrode selection is based primarily on the composition of the metal being welded, the process variation being used, joint design and the material surface conditions. Electrode selection greatly influences the mechanical properties of the weld and is a key factor of weld quality. In general the finished weld metal should have mechanical properties similar to those of the base material with no defects such as discontinuities, entrained contaminants or porosity within the weld. To achieve these goals a wide variety of electrodes exist. All commercially available electrodes contain

deoxidizing metals such as silicon, manganese, titanium and aluminum in small percentages to help prevent oxygen porosity. Some contain denitriding metals such as titanium and zirconium to avoid nitrogen porosity.[Depending on the process variation and base material being welded the diameters of the electrodes used in GMAW typically range from 0.7 to 2.4 mm (0.028–0.095 in) but can be as large as 4 mm (0.16 in). The smallest electrodes, generally up to 1.14 mm (0.045 in) are associated with the short-circuiting metal transfer process, while the most common spray-transfer process mode electrodes are usually at least 0.9 mm (0.035 in).

GMAW Circuit diagram. (1) Welding torch, (2) Workpiece, (3) Power source, (4) Wire feed unit, (5) Electrode source, (6) Shielding gas supply.

Shielding gases are necessary for gas metal arc welding to protect the welding area from atmospheric gases such as nitrogen and oxygen, which can cause fusion defects, porosity, and weld metal embrittlement if they come in contact with the electrode, the arc, or the welding metal. This problem is common to all arc welding processes; for example, in the older Shielded-Metal Arc Welding process (SMAW), the electrode is coated with a solid flux which evolves a protective cloud of carbon dioxide when melted by the arc. In GMAW, however, the electrode wire does not have a flux coating, and a separate shielding gas is employed to protect the weld. This eliminates slag, the hard residue from the flux that builds up after welding and must be chipped off to reveal the completed weld.

The choice of a shielding gas depends on several factors, most importantly the type of material being welded and the process variation being used. Pure inert gases such as argon and helium are only used for nonferrous welding; with steel they do not provide adequate weld penetration (argon) or cause an erratic arc and encourage spatter (with helium). Pure carbon dioxide, on the

other hand, allows for deep penetration welds but encourages oxide formation, which adversely affect the mechanical properties of the weld. Its low cost makes it an attractive choice, but because of the reactivity of the arc plasma, spatter is unavoidable and welding thin materials is difficult. As a result, argon and carbon dioxide are frequently mixed in a 75%/25% to 90%/10% mixture. Generally, in short circuit GMAW, higher carbon dioxide content increases the weld heat and energy when all other weld parameters (volts, current, electrode type and diameter) are held the same. As the carbon dioxide content increases over 20%, spray transfer GMAW becomes increasingly problematic, especially with smaller electrode diameters.

Argon is also commonly mixed with other gases, oxygen, helium, hydrogen, and nitrogen. The addition of up to 5% oxygen (like the higher concentrations of carbon dioxide mentioned above) can be helpful in welding stainless steel, however, in most applications carbon dioxide is preferred. Increased oxygen makes the shielding gas oxidize the electrode, which can lead to porosity in the deposit if the electrode does not contain sufficient deoxidizers. Excessive oxygen, especially when used in application for which it is not prescribed, can lead to brittleness in the heat affected zone. Argon-helium mixtures are extremely inert, and can be used on nonferrous materials. A helium concentration of 50%–75% raises the required voltage and increases the heat in the arc, due to helium's higher ionization temperature. Hydrogen is sometimes added to argon in small concentrations (up to about 5%) for welding nickel and thick stainless steel workpieces. In higher concentrations (up to 25% hydrogen), it may be used for welding conductive materials such as copper. However, it should not be used on steel, aluminum or magnesium because it can cause porosity and hydrogen embrittlement. Additionally, nitrogen is sometimes added to argon to a concentration of 25%–50% for welding copper, but the use of nitrogen, especially in North America, is limited.

Shielding gas mixtures of three or more gases are also available. Mixtures of argon, carbon dioxide and oxygen are marketed for welding steels. Other mixtures add a small amount of helium to argon-oxygen combinations, these mixtures are claimed to allow higher arc voltages and welding speed. Helium is also sometimes used as the base gas, with small amounts of argon and carbon dioxide added. However, because it is less dense than air, helium is less effective in shielding the weld than argon– which is denser than air. It also can lead to arc stability and penetration issues, and increased spatter.

due to its much more energetic arc plasma. Helium is also more expensive than other shielding gases. Other specialized and often proprietary gas mixtures claim even greater benefits for specific applications.

The desirable rate of gas flow depends primarily on weld geometry, speed, current, the type of gas, and the metal transfer mode being utilized. Welding flat surfaces requires higher flow than welding grooved materials, since the gas is dispersed more quickly. Faster welding speeds, in general, mean that more gas needs to be supplied to provide adequate coverage. Additionally, higher current requires greater flow, and generally, more helium is required to provide adequate coverage than argon. Perhaps most importantly, the four primary variations of GMAW have differing shielding gas flow requirements—for the small weld pools of the short circuiting and pulsed spray modes, about 10 L/min (20 ft³/h) is generally suitable, while for globular transfer, around 15 L/min (30 ft³/h) is preferred. The spray transfer variation normally requires more because of its higher heat input and thus larger weld pool; along the lines of 20–25 L/min (40–50 ft³/h).

Operatio n

GMAW weld area. (1) Direction of travel, (2) Contact tube, (3) Electrode, (4) Shielding gas, (5) Molten weld metal, (6) Solidified weld metal, (7) Workpiece.

For most of its applications gas metal arc welding is a fairly simple welding process to learn requiring no more than a week or two to master basic welding technique.

Spot WeldingSpot welding is a resistance welding method used to join two to four overlapping metal sheets which are up to 3 mm thick each. In some applications with only two overlapping metal sheets, the sheet thickness can be up to 6 mm. Two copper electrodes are simultaneously used to clamp the metal sheets together and to pass current through the sheets. When the current is passed through the electrodes to the sheets, heat is generated due to the higher electrical resistance where the surfaces contact each other. As the heat dissipates into the work, the rising temperature causes a rising resistance, and the heat is then generated by the current through this resistance. The surface resistance lowers quickly, and the heat is soon generated only by the materials' resistance. The water cooled copper electrodes remove the surface heat quickly, since copper is an excellent conductor. The heat in the center has nowhere to go, as the metal of the workpiece is a poor conductor of heat by comparison. The heat remains in the center, melting the metal from the center outward. As the heat dissipates throughout the workpiece in less than a second the molten, or at least plastic, state grows to meet the welding tips. When the current is stopped the copper tips cool the spot weld, causing the metal to solidify under pressure. Some coatings, such as zinc, cause localized heating due to its high resistance, and may require pulsation welding to dissipate the unwanted surface heat into the copper tips.

Phosphating shopPhosphate conversion coating

Phosphate coatings are used on steel parts for corrosion resistance, lubricity, or as a foundation for subsequent coatings or painting. It serves as a conversion coating in which a dilute solution of phosphoric acid and phosphate salts is applied via spraying or immersion and chemically reacts with the surface of the part being coated to form a layer of insoluble, crystalline phosphates. Phosphate conversion coatings can also be used on aluminium, zinc, cadmium, silver and tin.

The main types of phosphate coatings are manganese, iron and zinc. Manganese phosphates are used both for corrosion resistance and lubricity and are applied only by immersion. Iron phosphates are typically used as a base for further coatings or painting and are applied by immersion or by spraying. Zinc phosphates are used for rust proofing (P&O), a lubricant base layer, and as a paint/coating base and can also be applied by immersion or spraying.

ProcessThe application of phosphate coatings makes use of phosphoric acid and takes advantage of the low solubility of phosphates in medium or high pH solutions. Iron, zinc or manganese phosphate salts are dissolved in a solution of phosphoric acid When steel or iron parts are placed in the phosphoric acid, a classic acid and metal reaction takes place which locally depletes the hydroxonium (H3O+) ions, raising the pH, and causing the dissolved salt to fall out of solution and be precipitated on the surface. The acid and metal reaction also creates iron phosphate locally which may also be deposited. In the case of depositing zinc phosphate or manganese phosphate the additional iron phosphate is frequently an undesirable addition to the coating.

The acid and metal reaction also generates hydrogen gas in the form of tiny bubbles that adhere to the surface of the metal. These prevent the acid from reaching the metal surface and slows down the reaction. To overcome this sodium nitrite is frequently added to act as an oxidizing agent that reacts

with the hydrogen to form water. This chemistry is known as a nitrate accelerated solution. Hydrogen is prevented from forming a passivating layer on the surface by the oxidant additive.

The following is a typical phosphating procedure:

1. cleaning the surface2. rinsing3. surface activation (in some cases)4. phosphating5. rinsing6. neutralizing rinse (optional)7. drying8. application of supplemental coatings: lubricants, sealers, oil, etc.

The performance of the phosphate coating is significantly dependent on the crystal structure as well as the weight. For example, a microcrystalline structure is usually optimal for corrosion resistance or subsequent painting. A coarse grain structure impregnated with oil, however, may be the most desirable for wear resistance. These factors are controlled by selecting the appropriate phosphate solution, using various additives, and controlling bath temperature, concentration, and phosphating time. A widely used additive is to seed the metal surface with tiny particles of titanium salts by adding these to the rinse bath preceding the phosphating. This is known as activation.

Phosphating

Tank no. Process. description1 Degreasing Temp 65-75 degree celcius

Pointage 70-90Dip time 10-15 mins

2 Anodic cleaning

Temp 70-85 degree celciusVoltage 10-12 voltsDip time 8-10 mins

3 Water rinsig Dip time 3-4 dips4 derusting Temp ambient

Pointage 12-16Dip time 8-10 mins

5 Water rinsing Dip time 3-4 dips6 Surface

activationpH 8.5-10dip time 40-60 sec

7 phosphating Temp 60-70 degree celciusPointage 28-32Dip time 5-6 mins

8 Water rinsing Dip time 3-4 dips

9 passivation Temp 40-50 degree celciuspH 5-6.5dip time 30-60 seconds

10 D.M water rinsing

Temp 35-45 degree celciuspH 6.5 – 7.5dip time 3-4 dips

UsesPhosphate coatings are often used to provide corrosion resistance, however, phosphate coatings on their own do not provide this because the coating is porous. Therefore, oil or other sealers are used to achieve corrosion resistance. This coating is called a phosphate and oil (P&O) coating. Zinc and manganese coatings are used to help break in components subject to wea and help prevent galling.

Most phosphate coatings serve as a surface preparation for further coating and/or painting, a function it performs effectively with excellent adhesion and electric isolation. The porosity allows the additional materials to seep into the phosphate coating and become mechanically interlocked after drying. The dielectric nature will electrically isolate anodic and cathodic areas on the surface of the part, minimizing underfilm corrosion that sometimes occurs at the interface of the paint/coating and the substrate.[3]

Powder CoatingPowder coating is the technique of applying dry paint to a part.

In powder coating, the powdered paint may be applied by either of two techniques.

The item is lowered into a fluidised bed of the powder, which may or may not be electrostatically charged, or

The powdered paint is electrostatically charged and sprayed onto the part.

The part is then placed in an oven and the powder particles melt and coalesce to form a continuous film.

There are two main types of powder available to the surface finisher:

Thermoplastic powders that will remelt when heated, and Thermosetting powders that will not remelt upon reheating. During

the curing process (in the oven) a chemical cross-linking reaction is triggered at the curing temperature and it is this chemical reaction which gives the powder coating many of its desirable properties.

ConclusionI have no doubt now that my choice of training was right and the exposure and experience gained at UML has been unique .though I feel I have been part of the UM group if only for a short time and shared the work culture which teaches a goal oriented approach,I spent my golden period of my life here.