1

INDUSTRIAL TRAINING REPORT ON

INSTRUMENTATION LIMITED, KOTA

(In Partial Fulfilments of the requirement of the Degree)

Guided By: Submitted By:

Mr. A.P. PADRAHA RAM SWAROOP KUSHWAH

(AGM, Training & Development) (121769)

Submitted to

DEPARTMENT OF MECHANICAL ENGINEERING

JAYPEE UNIVERSITY OF ENGINEERING & TECHNOLOGY

GUNA, (M.P.)

2

CERTIFICATE

This is to certify that RAM SWAROOP KUSHWAH (121769) student of

Mechanical Engineering Department, Jaypee University of Engineering and Technology,

Guna has completed the industrial training at INSTRUMENTATION LIMITED, KOTA for 6

weeks for the partial fulfilment of the requirement for the award of Bachelors of Technology

(Mechanical Engineering) degree of JUET, Guna.

This is a record of student’s own study carried under my supervision and guidance. It

is further certified that candidate has worked under supervision required under the industrial

rules.

Mr C.P. Verma Mr A.P. Padarha

(General Manager, T & SD) (AGM, HRD)

3

PREFACE

To expose the student to the industrial environment.

To provide an opportunity to observe the processes, procedures and standards that the

industry uses to ensure quality, productivity and economy of the products or services that is

undertakes.

The major objective of training is to make students familiar with the organization culture and

practical work environment. Moreover it also provides in- depth knowledge of the topic

assigned.

Project Report enable the student to undertake a theoretical project in order to study, interpret

and report on one or more management problems and situation. To relate the knowledge with

the industrial experience.

My Summer training at Instrumentation Limited, Kota was a memorable experience as it

allowed me to learn a lot of things in a programmatic manner.

Ram Swaroop Kushwah

4

ACKNOWLEDGEMENT

It has been made possible through the direct and indirect co-operation of various

persons to whom I wish to express my appreciation.

I express my deep gratitude to Mr. A. P. PADARHA (AGM, HRD) who provided me

an insight into the working that enhanced my knowledge and with their support and co-

operation this report has taken a presentable form. I am gratified to Mr. C.P. VERMA

(DGM,T&D) who guided me and provided the opportunity to get acquainted with the

organization culture and also supported to know the various operations of the organization.

I take this opportunity to express my profound gratitude and deep regards to Mr A.P.

Padarha for his exemplary guidance, monitoring and constant encouragement throughout the

course of this training. The blessing, help and guidance given by him time to time shall carry

me a long way in the journey of life on which I am about to embark.

I would also like to thank the training in charge of Jaypee University Of Engineering

And Technology, Guna, M.P. and all the faculty members of Mechanical Engineering

Department for their effort of constant co- operation, which have been a significant factor in

the accomplishment of my industrial training.

This dissertation will not be complete and I to will be failing in my work if I do not

work place in the record my gratitude to our sir who in their respective capacities as lecturer

guide in my work. he gave me invaluable suggestion and timely advice.

`` RAM SWAROOP KUSHWAH

(121769)

5

CONTENTS

PAGE NO.

CERTIFICATE I

PREFACE II

ACKNOWLEDGEMENT III

CHAPTER 1: INTRODUCTION TO INSTRUMENTATION LIMITED 1-16

1.1 Introduction 1

1.2 Organizational Structure 2

1.3 Kota Unit 3

1.4 Product from Kota Unit 4

1.5 Product from Phalghat Unit 4

1.6 Departments in Kota unit 5

1.7 Present status 6

1.8 Important Milestones Achieved 6

1.9 Some other awards 7

1.10 I. L. infrastructure 7

1.11 Costumers of IL

CHAPTER 2: SAFETY MANAGEMENT 8-9

2.1 Introduction 8

2.2 Employee Responsibilities 8

2.3 Personal protective Equipment 9

CHAPTER 3: Quality and Assurance 10-11

3.1 Introduction 10

3.2 Quality Control System 11

3.3 Dimensions of Quality 11

CHAPTER 4: PREPARATORY SHOP 12-15

4.1 Introduction 12

4.2 Shearing 12

4.3 Bending 13

4.4 Notching 14

CHAPTER 5: FABRICATION SHOP 16-20

6

5.1 Introduction 16

5.2 Arc welding Process 17

5.3 Gas Welding Process 18

5.4 Resistance Welding Process 19

5.5 Resistance Seam Welding 19

5.6 Welding Defects & Preventations 20

CHAPTER 6: CNC MACHINNG CENTRE 21-23

6.1 Introduction 21

6.2 CNC Lathe Centre 21

6.3 Features of CNC 22

6.4 Absolute System 22

6.5 Part Programming 23

6.6 CNC Milling Machine 24

6.6 G-Code & M-Code 24

CHAPTER 7: Conclusions 25

References 26

Appendix 27-31

7

LIST OF FIGURES

FIGURE

NO.

FIGURE NAME

PAGE NO.

1.1

1.2

1.3

Organizational structure

Kota Unit

IL department

2

3

5

2 Safety Equipments 8

4.1

4.2

4.3

4.4

CNC Shearing Machine

Bending Operation

Geometry of Bending Allowance

Copy Press Punch Operation

12

13

13

15

5.1

5.2

5.3

Arc Welding Set up

MIG set up

Electrode Wire Seam Welding Process

17

18

19

6.1

6.2

CNC Lathe Machine

CNC Milling Machine

23

24

8

Chapter 1

INTRODUCTION TO INSTRUMENTATION LIMITED

1.1 INTRODUCTION

The Instrumentation Limited a Govt. of India Enterprises was set up at Kota in April 1964 in

collaboration with Russia with a provision to set up second unit at Palghat in Kerala. The

production was started in October 1968. It holds good rank in India in the field of Process

control instruments. Whatever the capacity of field may be one can only rely on IL board

based engineering capability expertise for instruments for requirements. Whatever the

capacity of the control system required whether in computer electronics or pneumatic field.

I.L. is supplying the said system on turnkey basis.

Kota office basically a co- ordination office which is to co-ordinate between marketing

head quarter branch office and various departments at Kota for timely execution of order and

complete customer satisfaction. Kota office is also responsible for booking of orders for all

telecom products. I.L. specializing in the turnkey Process Control Instrumentation to record,

monitor and control process parameters in process industries. Instrumentation Ltd. Takes

total responsibility for engineering, manufacturing, erection and commissioning of

instruments with a backup of sales services.

Just from the first year of production the company has been successfully supplying

instrumentation and control equipment’s and has achieved all time high record of production,

turn over in profit. It has continued to play its vital role in speedy development of process

industries throughout the countries in such a brief period and the company has achieved a

leading, reputable and important position not only in India but in abroad also. In recent past,

the company had entered into technical collaboration with M/s Hartmann and Braun., West

Germany in March 1986, for manufacturing of gas analyser the production of which was

started in Dec 1986.

This production unit was set up in collaboration with M/s Premmash Export USSR. This

plant commenced its sophisticated process control instruments in various ranges. The Kota

plant cater the need of industrial Process Control Instruments required by various thermal

power stations, electricity boards, Steel and Chemical plants, Chemical industries, Paper

industries and and other heavy engineering units.

Kota office basically a co- ordination office which is to co-ordinate between marketing

head quarter, branch office and various departments at Kota for timely execution of order and

complete customer satisfaction. Kota office is also responsible for booking of orders for all

telecom products. The purpose of setting up of IL was to attain self-reliance in C&I field for

process industries. After contributing its share towards this objective it was thought proper to

utilize the expertise gained in field of high tech electronics and manufacturing facilities in

other areas. It was decided to use the expertise gained to help Defence forces in getting the

equipment Indigenously. Keeping this in view a separate group was formed to liaison with

agencies like MOD, Ordnance factories etc to find out the requirement which IL can design,

9

develop, manufacture and supply meeting the stringent Defence specifications. IL has till

now developed and supplied following items to Defence establishments.

1.2 ORGANIZATIONAL STRUCTURE

Once the decision has been made to begin a retail venture, it is necessary to plan its

organizational structure in a way that maximizes efficiency and profitability. All of the duties

and responsibilities of those in the company must be identified, and lines of authority must be

carefully delineated so that all members of the organization will understand what their job

responsibilities are. By doing so, everyone knows who will report to whom, who the

decisionmakers are, and which advisory personnel is on hand to assist in the decision-making

process. IL lays great emphasis on documentation from start to finish. , it is necessary to plan

its organizational structure in a way that maximizes efficiency.

Fig.1.1 Organizational Structure in IL

10

1.2 KOTA UNIT

This plant is located at Kota-Jhalawar road kota-5 (Rajasthan). It is the berth place of

Instrumentation Ltd. This production unit was set up in collaboration with M/s Premmash

Export USSR. This plant commenced its sophisticated process control instruments in various

ranges. The Kota plant cater the need of industrial process control instruments required by

various Thermal Power Stations, Electricity Boards, Steel and chemical plants, chemical

industries, paper industries and other heavy engineering units.

Fig. 1.2 KOTA UNIT (Ref-IL)

Just from the first year of production the company has been successfully supplying

instrumentation and control equipment’s and has achieved all time high record of production,

turn over in profit. It has continued to play its vital role in speedy development of process

industries throughout the countries in such a brief period and the company has achieved a

leading, reputable and important position not only in India but in abroad also. In recent past,

the company had entered into technical collaboration with M/s Hartmann and Braun., West

Germany in March 1986, for manufacturing of gas analyser the production of which was

started in Dec 1986.

1.3 PRODUCT FROM KOTA UNIT

This is the oldest unit. Main products from this are:

1. Annunciators

2. Gas Analyser & Pollution Monitoring Instruments

3. Microprocessor Based Controller and Recorder

4. Electronics Transmitter

5. Pneumatic Instruments And transmitter panel

6. Telecom Circuits

7. Railway signalling system

8. Modern DDC system

9. Power and process simulator

11

1.5 PRODUCT FROM PALGHAT UNIT

Main products from this unit are:

1. Tank level gauging system

2. Control valves

3. Valves Stand for Steel Melting Shop

4. Low Noise Valves

5. Pneumatic control drives

6. Control valves for High Pressure drop

7. Special Below sealed valves for nuclear Service

8. Safety Relief Valves

9. Electrical Actuator

10. Butterfly valves

1.6 DEPARTMENTS IN KOTA UNIT

There are 9 departments or sections in kota unit.

1. Assembly Shop

2. Telecom Division

3. Digital Electronics Unit

4. Maintenance Shop(e)

5. Railway relay

6. Gas analyser(production)

7. Defence Project department

8. PCB centre UPS centre

1.7 PRESENT STATUS

The major project that IL presently manufacture are:

1. Process Control Instruments

2. Control Valves

3. Railway Signalling Relay

4. Sets of telecommunication

5. Microprocessor based recorders

6. Digital switching system

7. Panels

8. Defence products

1.8 IMPORTANT MILESTONES ACHIEVED

Here are the achievements as following:

1964 – Established with Registered Office at Kota

1968 - C & I Production Commencement

1975 - Control Valve Production Commencement at palghat

1982 - Special Temperature Sensor For Nuclear Plant

12

1985 - Railway Signalling

1987 - Digital electronics Production Commenced

1998 – Diversification in Defence Products etc.

1.9 SOME OTHER AWARDS

I.L. is an ISO-9002 Company Certified

International Export Award

Top Export Award

National Safety award

Pollution Control Award etc.

1.10 I.L. INFRASTRUCTURE

The Instrumentation Ltd A Govt. of India enterprises was set up at kota in April 1964 in

collaboration with Russia with a provision to setup second unit at Palghat in Kerala. The

production was started in October 1968. It holds good rank in India in the field of process

control instruments. Whatever the capacity of field may be one can only rely on I.L. board

based engineering capability expertise for instruments for requirements. Whatever the

capacity of the control system required whether in computer electronic or pneumatic field.

I.L. is supplying the said system on turnkey basis.

Fig. 1.3 IL Department (Ref-IL)

Kota office basically a co- ordination office which is to co-ordinate between

marketing head quarter, branch office and various departments at Kota for timely execution

13

of order and complete customer satisfaction. Kota office is also responsible for booking of

orders for all telecom products. I.L. specializing in the turnkey Process Control

Instrumentation to record, monitor and control process parameters in process industries.

Instrumentation Ltd. Takes total responsibility for engineering, manufacturing, erection and

commissioning of instruments with a backup of sales services.

This production unit was set up in collaboration with M/s Premmash Export USSR.

This plant commenced its sophisticated process control instruments in various ranges. The

Kota plant cater the need of industrial Process Control Instruments required by various

thermal power stations, electricity boards, Steel and Chemical plants, Chemical industries,

Paper industries and and other heavy engineering units.

1.11 CUSTOMER OF INSTRUMENTATION LIMITED

Customer of instrumentation Ltd., Kota are in the following sector.

Steel Plants

Steel authority of India limited

Bhilai steel plant

Bokaro steel plant

Durgapur steel plant

Rourkela steel plant

Tata iron & steel Co. , Jamshedpur

Paper Industries

Hindustan Paper corporation limited

Andhra paper mills(AP)

Mysore paper mills

Power

NTPC

BHEL

SAIL

Atomic energy

Nuclear power corporation India limited

Department of Atomic Energy

Sugar

Space

ISRO, SHAR Centre, Shriharikota

VSSC Centre, Trivendram

Cement

Cement Corporation of India Limited

14

Rasi Cement

Shriram Cement

Dalmia Cement

Minerals & Metals

Hindustan Zinc Ltd

Hindustan Copper Ltd

Bharat aluminium Corporation Ltd

Process industries, Fertilizers, Railway

Petrochemical companies

Refineries etc.

15

Chapter 2

SAFETY MANAGEMENT

2.1 INTRODUCTION

A Safety Management System (SMS) is a systematic approach to managing safety, including

the necessary organizational structures, accountabilities, policies and procedures. As per

ICAO requirements, service providers are responsible for establishing an SMS, which is

accepted and overseen by their State.

Any real or potential conditions produced by industries that can cause injury or death to

personal or loss of product or property Safety department provide all the measures to

safeguard there employees and machinery and environment .

house keeping

wearing apparel

protective appliances

guarding of machinery

prevention of fire

wiring protection etc.

Fig. 2.1 safety Equipments (Ref-IL)

16

2.2 EMPLOYEE RESPONSIBILITIES

Each employee is responsible to follow established policies and procedures. Regular

attendance is required of all. Following directions is critical. Responsibility does not end with

just taking care of you. Unsafe working conditions and acts must be reported to management.

It is the responsibility of each employee to work in a professional and safe manner.

2.3 PERSONAL PROTECTIVE EQUIPMENT

Personal Protective Equipment (PPE) includes all clothing and accessories designed to

protect against workplace hazards. In some situations the only available protection for

employees will be the use of PPE and often in emergencies, PPE will be required for the

safety of the workers.

As required by federal and state regulations, personal protective equipment is

essential for the protection of eyes, ears, face and other body parts when working around

hazardous machinery and equipment. All PPE must meet established standards (ANSI,

NIOSH, OSHA, etc). All Personal Protective Equipment (PPE) is provided by XYZ

Manufacturing Company. Employees are not allowed to provide their own PPE unless

authorized by the Safety Director. As a general rule, only company provided PPE is allowed.

Hazard Assessments have been completed throughout the production and warehouse areas of

IL Manufacturing Company. PPE is required in the following areas:

Warehouse

All employees and visitors are required to wear approved hard hats and eye protection. Steel-

toed shoes/boots required of warehouse workers.

Welding Shop

All employees and visitors are required to wear approved eye protection. Approved hard hats

required of all welders. Approved hearing protection required of all welders. Welders are also

required to don approved PPE in the form of goggles, helmet, leather coat, apron, steel-toed

work boot, gloves, no cuff pants and other 11 equipment as deemed necessary by the Safety

Director. Mechanical ventilation is required at all welding stations.

Paint Shop

All employees and visitors are required to wear approved eye protection. Spray painters are

required to wear company provided work clothing (disposable shirt/pants).

17

Chapter 3

QUALITY ASSURANCE

3.1 INTRODUCTION

Quality Control (QC) is a system of routine technical activities, to measure and control the

quality of the inventory as it is being developed.

3.2 QUALITY CONTROL SYSTEM

The QC system is designed to:

Provide routine and consistent checks to ensure data integrity, correctness, and

completeness;

Identify and address errors and omissions;

Document and archive inventory material and record all QC activities.

QC activities include general methods such as accuracy checks on data acquisition and

calculations and the use of approved standardised procedures for emission calculations,

measurements, estimating uncertainties, archiving information and reporting. Higher tier QC

activities include technical reviews of source categories, activity and emission factor data,

and methods.

Quality Assurance (QA) activities include a planned system of review procedures

conducted by personnel not directly involved in the inventory compilation/development

process. Reviews, preferably by independent third parties, should be performed upon a

finalised inventory following the implementation of QC procedures. Reviews verify that data

quality objectives were met, ensure that the inventory represents the best possible estimates

of emissions and sinks given the current state of scientific knowledge and data available, and

support the effectiveness of the QC.

QA and Testing are two of the most critical components to maintaining a competitive edge

Quality assurance & Testing of the product is an essential process that is undertaken for

clients so that company can deliver them the kind of product that will match their standards

of their brand name.

IL understands the amount of labor and efforts goes behind manufacturing products.

QA team leaves no stone unturned to assure 100% quality and accuracy. One quality

assurance evaluation of management and non-management work used is called "Plan Do

Check Act" uses a continuous loop of activities to accomplish work and to improve jobs. The

objective is to get the job done right and on time the first time and maybe better the next time.

3.3 DIMENSIONS OF QUALITY

The meaning of quality cannot easily be captured in a simple short statement. To sharpen the

definition, Garvin defines eight dimensions of quality that are applicable in particular to a manufactured product.

18

1. Performance. Performance refers to the totality of the product's operating

characteristics. For example, in an automobile, it refers to factors such as acceleration,

top speed. Braking distance, Steering and handling, and ride.

2. Features. These refer to the special characteristics and options that are often intended

by the designer to distinguish the product from its competitors. In a television, these

features might include a larger viewing screen and "picture-in-picture.

3. Aesthetic appeal. This usually refers to the appearance of the product. How pleasing

is the product to the senses, especially the visual sense? A car's body style, front grille

treatment, and color influence the customer's aesthetic appeal for the car.

4. Conformance. This is the degree to which the product's appearance and tunetion

conform to pre-established standards. The term workmanship is often applicable here.

In an automobile,confonnance includes the body's fit and finish and absence of

squeaks.

5. Reliability. Reliability III a product means that it is always available for the customer

and that it lasts a long time before final failure. In a car, it is the quality factor that

allows the car to be started in cold weather and the absence of maintenance and repair

visits to the dealer.

6. Durability. If the product and its components last a long time despite heavy use, then

it possesses durability. Signs of durability III a car include a motor that continues to

run for well over 100,000 miles, a body that does not rust,a dashboard that does not

crack, and upholstery fabric that does not wear out after many years of use.

7. Serviceability. How easy is the product to service and maintain? Many products have

become so complicated that the owner cannot do the servicing. The product must be

taken back to the original dealer for service. Accordingly, serviceability includes such

factors as the courtesy and promptness of the service provided by the dealer.

8. Perceived Quality. This is a subjective and intangible factor that may include the

customer's perception (whether correct or not) of several of the preceding dimensions.

Perceived quality is often influenced by advertising, brand recognition, and the

reputation the company making the products. '

19

Chapter 4

PREPARATORY SHOP

4.1 INTRRODUCTION

It is a mechanical shop where all operations are done before the complete assembly of the

product. Preparatory means serving as or carrying out preparation. When the all operations in

a particular sequence is done then the sheet is transfer to the fabrication shop where it joined

completely. All operations are done on the sheet that may be stainless steel or non ferrous

metal like Al, copper, brass etc. the sheet thickness varies from 1mm to 8mm. There are some

operations that are done in the preparatory shop.

Shearing

bending

cut out

notching

4.2 SHEARING

Shearing is the process of cutting off of sheets using a die and punch, applying shear stress

along the thickness of the sheet. A die and punch or a pair of blades are used in shearing.

Shearing happens by severe plastic deformation locally followed by fracture which

propagates deeper into the thickness of the blank or Shearing in continuum mechanics refers

to the occurrence of a shear strain, which is a deformation of a material substance in which

parallel internal surfaces slide past one another. It is induced by a shear stress in the material.

The clearance between the die and punch is an important parameter whichdecides the

shape of the sheared edge. Large clearance leads to rounded edge. The edge has distortion

and has burr. The shearing load is also higher for larger clearance. For harder materials and

larger sheet thickness, larger clearances are required. Generally, clearance can vary between

2% and 8% of the sheet thickness. Usually shearing begins with formation of cracks on both

sides of the blank, which propagates with application of shear force.

A shiny, burnished surface forms at the sheared edge due to rubbing of the blank

along the shear edge with the punch or the die wall. Shear zone width depends on the speed

of punch motion. Larger speed leads to narrow shear zone, with smooth shear surface and

vice-versa. A rough burr surface forms if clearance is larger. Similarly, a ductile material will

have burr of larger height. Shearing a blank involves plastic deformation due to shear stress.

Shear strain is distinguished from volumetric strain, the change in a material's volume in

response to stress. A plastic shear strain is a continuous (non-fracturing) deformation that is

irreversible, such that the material does not recover its original shape. It occurs when the

material is yielding.

Therefore, the force required for shearing is theoretically equal to the shear strength of

blank material. Due to friction between blank and tool, the actual force required is always

greater than the shear strength. Variation of punch force during shearing process is shown

below. The maximum force required on the punch for shearing can be empirically given as:

20

Fmax = 0.7 tL t is blank thickness and L is the length of the sheared edge. For reducing the

shearing force, the cutting edges of the punch are made at an angle.

Fig. 4.1 CNC Shearing machine (Ref-IL)

4.3 BENDING

Bending is the operation of deforming a flat sheet around a straight axis where the neutral

plane lies. It is a very common forming process for changing the sheets and plates into

channel, drums, tanks, etc.

Fig.4.3 geometry of bend allowance (Ref-google)

21

Two different scheme of bending are shown in the figure 4.3. Spring back is a major

problem during bending of sheets that occurs due to elastic recovery by the material causing a

decrease in the bend angle once the pressure is removed. The springback can be minimized

by introducing excess amount of bending so that the finished bending angle is the same after

the elastic recovery.

However, a careful estimate of the elastic recovery based on the mechanical

behaviour of the sheet material is necessary to achieve the same.

Fig.4.2 Bending operation (Ref-NPTEL)

Bending Allowance Formula

Where, K = Factor is to Estimate Streching

If IR < 2 MT, K = 0.33

If IR >= 2 MT, K = 0.50

MT = Material thickness or Stock thickness

I.R. = Internal Radius, B = Bend Angle

1. Bend Allowance - The length of the arc through the bend area at the neutral axis.

2. Bend Angle - The included angle of the arc formed by the bending operation. It is

denoted by B.

3. Bend Compensation – The amount by which the material is stretched or compressed

by the bending operation. All stretch or compression is assumed to occur in the bend

area.

22

4. Bend Lines – The straight lines on the inside and outside surfaces of the material

where the flange boundary meets the bend area.

5. Inside Bend Radius – The radius of the arc on the inside surface of the bend area. K-

factor – Defines the location of the neutral axis. It is measured as the distance from

the inside of the material to the neutral axis divided by the material thickness.

4.4 NOTCHING

It is an operation in which a specified small amount of metal is cut from a blank. It is

different from punching in the sense that in notching cutting line of the slug formed must

touch one edge of the blank or strip. A notch can be made in any shape. The purpose of

notching is generally to release metal for fitting up.

Fig. 4.4 copy press punch operations (Ref-IL)

23

Chapter 5

FABRICATION SHOP

5.1 INTRODUCTION

Fabrication is action or process of manufacturing or inventing something that is used to

joining the metals or non-metals. Fabrication shops and machine shops have overlapping

capabilities, but fabrication shops generally concentrate on metal preparation and assembly as

described above. By comparison, machine shops also cut metal, but they are more concerned

with the machining of parts on machine tools. Firms that encompass both fab work and

machining are also common. Blacksmith has always involved fabrication, although it was not

always called by that name. The products produced by welders, which are often referred to as

weldmesh, are an example of fabrication.

Boilermakers originally specialized in boilers, leading to their trade's name, but the

term as used today has a broader meaning. Similarly, millwrights originally specialized in

setting up grain mills and saw mills, but today they may be called upon for a broad range of

fabrication work.

Ironworkers, also known as steel erecters, also engage in fabrication. Often the

fabrications for structural work begin as prefabricated segments in a fab shop, then are moved

to the site by truck, rail, or barge and finally are installed by erectors.

In the fabrication shops welding processes are generally used to joining the similar or

dissimilar metals using with or without filler metal (by the use of pressure). Some welding

process that are generally used in the fabrication are

Arc welding

Resistance welding

Thermic welding

Gas welding

5.2 Arc Welding

Arc Welding Process All arc welding processes apply heat generated by an electric arc for

melting the faying surfaces of the base metal to develop a weld joint (Fig. 11.1). Common arc

welding processes are manual metal or shielded metal arc welding (MMA or SMA), metal

inert gas arc (MIG), tungsten inert gas (TIG), submerged arc (SA), plasma arc (PA), carbon

arc (CA) selding etc. Arc Electrode holder Power cable work piece Power terminals Power

source Electrode.

Shielded Metal Arc Welding (SMAW) In this process, the heat is generated by an

electric arc between base metal and a consumable electrode. In this process electrode

movement is manually controlled hence it is termed as manual metal arc welding. This

process is extensively used for depositing weld metal because it is easy to deposit the molten

weld metal at right place where it is required and it doesn’t need separate shielding. This

process is commonly used for welding of the metals, which are comparatively less sensitive

24

to the atmospheric gases. This process can use both AC and DC. The constant current DC

power source is invariably used with all types of electrode (basic, rutile and cellulosic)

irrespective of base metal (ferrous and non-ferrous). However, AC can be unsuitable for

certain types of electrodes and base materials.

Therefore, AC should be used in light of manufacturer’s recommendations for the

electrode application. In case of DC welding, heat liberated at anode is generally greater than

the arc column and cathode side. The amount of heat generated at the anode and cathode may

differ appreciably depending upon the flux composition of coating, base metal, polarity and

the nature of arc plasma. In case of DC welding, polarity determines the distribution of the

heat generated at the cathode and anode and accordingly the melting rate of electrode and

penetration into the base metal are affected. Heat generated by a welding arc (J) = Arc

voltage (V) X Arc current (A) X Welding.

Fig. 5.1 Arc welding setup (Ref-NPTEL)

5.3 GAS WELDING

This chapter presents the basic components and principle of metal inert gas welding (MIG)

and pulse-MIG welding process with help of suitable schematic diagrams besides the

influence of welding parameters in melting rate, and metal transfer. This process is also

termed as gas metal arc welding (GMAW). Further, the factors affecting the metal transfer in

MIG welding process have been elaborated. Keywords: Metal inert gas welding, burn-off

rate, electrode extension, metal deposition rate, metal transfer in GMAW, transition current,

pulse GMAW process

Fundamentals of MIG welding

This process is based on the principle of developing weld by melting faying surfaces of the

base metal using heat produced by a welding arc established between base metal and a

consumable electrode. Welding arc and weld pool are well protected by a jet of shielding

inactive gas coming out of the nozzle and forming a shroud around the arc and weld.

MIG weld is not considered as clean as TIG weld. Difference in cleanliness of the

weld produced by MIG and TIG welding is primarily attributed to the variation in

effectiveness of shielding gas to protect the weld pool in case of above two processes.

Effectiveness of shielding in two processes is mainly determined by two characteristics of the

25

welding arc namely stability of the welding arc and length of arc besides other welding

related parameters such as type of shielding gas, flow rate of shielding gas, distance between

nozzle and work-price. The MIG arc is relatively longer and less stable than TIG arc.

Difference in stability of two welding arcs is primarily due to the fact that in MIG arc is

established between base metal and consumable electrode (which is consumed continuously

during welding) while TIG welding arc is established between base metal and

nonconsumable tungsten electrode. Consumption of the electrode during welding slightly

decreases the stability of the arc.

Therefore, shielding of the weld pool in MIGW is not as effective as in TIGW. Metal

inert gas process is similar to TIG welding except that it uses the automatically fed

consumable electrode therefore it offers high deposition rate and so it suits for good quality

weld joints required for industrial fabrication . Consumable electrode is fed automatically

while torch is controlled either manual or automatically.

Fig. 5.2 MIG Set up (Ref-NPTEL)

This process is found more suitable for welding of comparatively thicker plates of

reactive metals (Al, Mg, Stainless steel). The quality of weld joints of these metals otherwise

is adversely affected by atmospheric gases at high temperature. B E B A C D F G Fig. 17.1

Schematic of GMAW process showing important elements A) Welding spool, B) Shielding

gas cylinder, C) welding torch, D) base plate, E) welding power source, and F) consumable

electrode.

5.4 RESISTANCE WELDING PROCESS

Resistance welding process makes use of the electrical resistance for generating heat required

for melting the work piece. It is generally used for joining thin plates and structures. It has

different variants such as Seam welding, Projection welding and Spot welding.

Distinct Advantages of Resistance Welding

Welding over other welding processes, there are a number of distinct advantages that account

for wide use of the resistance welding processes, particularly in mass production. These

advantages include:

They are very rapid in operation.

The equipment can be fully automated.

They conserve materials as no filler material, shielding gas or flux is required.

Skilled operators are not required.

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Dissimilar metals can be easily joined.

A high degree of reliability and reproducibility can be achieved.

Resistance Welding has some limitations, the principal ones being:

The equipment has a high initial cost. There are limitations to the type of joints that

can be made (mostly suitable for lap joints).

Skilled maintenance persons are required to service the control equipment.

Some materials require special surface preparations prior to welding.

5.5 Resistance Seam Welding

The seam consists of a series of overlapping spot welds. These are made by two distinct

processes. In one case, the weld is made between overlapping sheets of metal As the overlap

assure th usually h the process, electrode resistance. the process automobile mu e metal

passes ing welds. That the weld higher than th cent welds, e a continuous. The type e seam

weld ss is used to mufflers and h es between t The timing ds overlap a he convention external

cool us seam is welding ding which a produce liquid heat exchange the electrode of the weld .

Fig. 5.3 Electrode wire seam welding process (Ref. nptel)

5.6 Welding defects & preventation

A welding defect is any flaw that compromises the usefulness of a weldment there is a great

variety of welding defects. Welding imperfections are classified according to ISO 6520 while

their acceptable limits are specified in ISO 5817 and ISO 10042.

Residual Stresses and Warpage

Rapid heating and then uncontrolled cooling result in uneven expansion and Contraction in

the work piece and weldment. This causes development of residual Stresses in the weldment.

Distortion and warpage may also be there. Sometimes Wrong selection of filler metal and

welding technique may also be the cause of Residual stress and warpage.

Preventation-it is removed by heating of work piece after welding in stress reliving furnace

(S.R furnace) through heating and cooling in atmospheric temperature.

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Cracks-This is a serious welding defect appears as fracture type interruptions in the weld.

Crack works as a point of stress concentration so reduce the strength of the joint.

Preventation - Prevent by pre heating of work piece before the welding.

Cavities or Porosity-Porosity consists of small voids in weld metal formed by gases

entrapped During solidification. Shape of the voids may be spherical holes or Elongated

holes. Therecan be another type of voids named as shrinkage Voids formed due to shrinkage

of metal during solidification.

Preventation – reduce by back chipping and use good quality of flux.

Solid Inclusions-This is the entrapped non-metallic solid material. It may be the inclusion of

slag Generated in a welding process.

Preventation- Reduced by back chipping of material and grinding.

Incomplete Fusion-It is also called lack of fusion. It is a weld bead in which fusion has not

occurred throughout the entire cross-section of the joint. In other words it is a lack of

penetration. That is molten metal has not penetrated up to root of the joint.

Preventation- reduces by increase in welding current and mention proper gap between

work piece and electrode.

Imperfection in Shape For a particular type of edge preparation the weldment should

acquire a predefined Shape for maximum strength. If actual shape of weldment different from

the Predefined one it is called imperfect shape. It contributes to poor strength to the Welded

joint.

Preventation- prevented by give proper support to work piece and heating the work piece.

Undercut- Undercutting is when the weld reduces the cross-sectional thickness of the base

metal, which reduces the strength of the weld and workpieces. One reason for this type of

defect is a excessive current, causing the edges of the joint to melt and drain into the weld.

Prevention-It is prevented by using proper current and welding skill.

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Chapter 6

CNC Machining Centre

6.1 INTRODUCTION

To keep pace with time and to meet the changing technological demand of the manufactured /

machined components, CNC Centre was established in 1988. Following three machines are

installed in CNC machining Centre.

1) CNC CHUKER HMT.STC.25

2) CNC VERTICAL MACHINING CENTRE PAL.VA.35

3) CNC 3-D MEASURING MACHINE CARL ZEISS UC550

6.2 CNC LATHE MACHINE

Computer numerical controlled (CNC) lathes are rapidly replacing the older production lathes

(multi-spindle, etc.) due to their ease of setting, operation, repeatability and accuracy. They

are designed to use modern carbide tooling and fully use modern processes. The part may be

designed and the tool paths programmed by supervision of an operator.

The machine is controlled electronically via a computer menu style interface, the

program may be modified and displayed at the machine, along with a simulated view of the

process. The setter/operator needs a high level of skill to perform the process, however the

knowledge base is broader compared to the older production machines where intimate

knowledge of each machine was considered essential. These machines are often set and

operated by the same person, where the operator will supervise a small number of machines

(cell)The design of a CNC lathe varies with different manufacturers, but they all have some

common elements. The turret holds the tool holders and indexes them as needed, the spindle

holds the workpiece and there are slides that let the turret move in multiple axis

simultaneously. The machines are often totally enclosed, due in large part to Occupational

health and safety (OH&S) issues.

Computer NC systems include additional features beyond what is feasible with

conventional Hard-wired NC. These features, many of which are standard on most CNC MCVs whereas others are optional, include the following:

6.3 FEATURES OF CNC

Storage of more than one part program. With improvements in computer storage

technology. newer CNC controllers have sufficient capacity to store multiple

programs.

Various form of program input. Whereas conventional (hard-wired) MCVs are

limited to punched tape as the input medium for entering part programs. CNC controllers generally possess multiple data entry capabilities, such as punched tape.

These machines have given us assured production with negotiable process rejections.

These machines enabled IL to indigenise various product ranges speedily. It would be much

faster to execute on-time order at minimum cost. For quick inspection of first work piece

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produced by CNC machines & for random sampling of production runs, IL have CNC-3D

Co-ordinate measuring machine in CNC Centre.

CNC-3D Co-ordinate measuring machine is an advance, multipurpose quality control

system used to help the inspection to keep pace with modern requirements.

It replaces long, complex and inefficient conventional inspection methods with simple

procedures that are much faster as well as accurate. It reduces or eliminates CNC down time,

cuts down scrap and rework. A CMM can check the dimensional and geometric accuracy of

every item from big complex mechanical parts to flexible rubber, plastic moulded parts. It

measures virtually any part at any stage of production with exact precision and substantial

time savings.

Fig. 6.1 CNC lathe(Ref-IL)

CNC machine tool systems can be classified in various ways such as:

Point-to-point or contouring: Depending on whether the machine cuts metal while the work

piece moves relative to the tool.

Incremental or absolute: Depending on the type of coordinate system adopted to

parameterise the motion commands.

Open-loop or closed-loop: Depending on the control system adopted for axis motion control.

6.4 ABSOLUTE SYSTEM

An absolute NC system is one in which all position coordinates are referred to one fixed

origin called the zero point. The zero point may be defined at any suitable point within the

limits of the machine tool table and can be redefined from time to time. Any particular

definition of the zero point remains valid till another definition is made.

Considering the X-coordinate for point A as zero, the X-coordinate for points B and C

would be 50 and 70, respectively, in an absolute coordinate system. Most modem CNC

systems permit application of both incremental and absolute programming methods. Even

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within a specific part program the method can be changed These CNC systems provide the

user with the combined advantages of both methods.

6.5 PART PROGRAMMING

As mention earlier, a part program is a set of instructions often referred to as blocks, each of

which refers to a segment of the machining operation performed by the machine tool. Each

block may contain several code words in sequence. These provide:

1. Coordinate values (X, Y, Z, etc.) to specify the desired motion of a tool relative to a

work piece. The coordinate values are specified within motion code word and related

interpolation parameters to indicate the type of motion required (e.g. point-to-point, or

continuous straight or continuous circular) between the start and end coordinates. The

CNC system computes the instantaneous motion command signals from these code

words and applies them to drive units of the machine.

2. Machining parameters such as, feed rate, spindle speed, tool number, tool offset

compensation parameters etc.

3. Codes for initiating machine tool functions like starting and stopping of the spindle,

on/off control of coolant flow and optional stop. In addition to these coded functions,

spindle speeds, feeds and the required tool numbers to perform machining in a desired

sequence are also given.

4. Program execution control codes, such as block skip or end of block codes, block

number etc.

5. Statements for configuring the subsystems on the machine tool such as programming

the axes, configuring the data acquisition system etc.

6.5 CNC Milling Machine

Milling is the machining process of using rotary cutters to remove material from a work piece

advancing (or feeding) in a direction at an angle with the axis of the tool. It covers a wide

variety of different operations and machines, on scales from small individual parts to large,

heavy-duty gang milling operations. It is one of the most commonly used processes in

industry and machine shops today for machining parts to precise sizes and shapes.

Milling can be done with a wide range of machine tools. The original class of machine

tools for milling was the milling machine (often called a mill). After the advent of Computer

Numerical Control, (CNC) milling machines evolved into machining centers (milling

machines with automatic tool changers, tool magazines or carousels, CNC control, coolant

systems, and enclosures), generally classified as vertical machining centers (VMCs)

and horizontal machining centers (HMCs).

The integration of milling into turning environments and of turning into milling

environments, begun with live tooling for lathes and the occasional use of mills for turning

operations, led to a new class of machine tools, multi-tasking machines (MTMs), which are

purpose-built to provide for a default machining strategy of using any combination of milling

and turning within the same work envelope. . It is one of the most commonly used processes

in industry and machine shops today for machining parts to precise sizes and shapes.

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Fig.6.2 CNC Milling Machine

6.6 G-CODE & M-CODE

In the appendix-1 and appendix-2, we provide list of G and M-codes for the reader to have an

idea of the kind of functionality that can be realized using these codes. These codes were

originally designed to be read from paper tapes and are designed to direct tool motion with

simple commands.

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CHAPTER 7

CONCLUSION

The Changing industrial environment need trained engineering man power at all levels and

accordingly engineers find placement in all functional areas like technical, research and

development etc.

As a student of B.Tech I was privileged to undergo training here at Instrumentation

Limited Kota, Here not only did I learn how to work in an industrial atmosphere, but also

learnt how to deal with the real life problems in the industry.

I have learnt about the working of industrial CNC Lathe machine and CNC Milling

machines and tool changing in CNC machines. I have learnt the Processes Planning in the

industry and how to reduces the time to get the maximum efficiency by the utilization of

advanced technology.

My visit to various departments of the industry gave me a clear idea about the working

of Industrial Machines, Which I think was helpful not only during my project but will also

help me to solve problems in any of the organization I will work in the coming future.

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REFERENCES

1) Manual from Instrumentation Limited.

2) John A. Schey, Introduction to Manufacturing Process, McGraw Hill, 2000, 2nd

Edition, NY

3) R S Parmar, Welding Engineering & Technology, Khanna Publisher, 2002, 2nd

Edition, New Delhi.

4) Manual from CNC Centre of Instrumentation Limited.

5) Richard Little, Welding and Welding Technology, McGraw Hill, 2001, 1st Edition,

NY

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APPENDIX-1

G-Codes

G00 - Rapid move (not cutting)

G01 - Linear move

G02 - Clockwise circular motion

G03 - Counter clockwise circular motion

G04 - Dwell

G05 - Pause (for operator intervention)

G08 - Acceleration

G09 - Deceleration

G17 - x-y plane for circular interpolation

G18 - z-x plane for circular interpolation

G19 - y-z plane for circular interpolation

G20 - turning cycle or inch data specification

G21 - thread cutting cycle or metric data specification

G24 - face turning cycle

G25 - wait for input to go low

G26 - wait for input to go high

G28 - return to reference point

G29 - return from reference point

G31 - Stop on input

G33-35 - thread cutting functions

G35 - wait for input to go low

G36 - wait for input to go high

G40 - cutter compensation cancel

G41 - cutter compensation to the left

G42 - cutter compensation to the right

G43 - tool length compensation, positive

G44 - tool length compensation, negative

G50 - Pre-set position

G70 - set inch based units or finishing cycle

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G71 - set metric units or stock removal

G72 - indicate finishing cycle

G72 - 3D circular interpolation clockwise

G73 - turning cycle contour

G73 - 3D circular interpolation counter clockwise

G74 - facing cycle contour

G74.1 - disable 360 deg arcs

G75 - pattern repeating

G75.1 - enable 360 degree arcs

G76 - deep hole drilling, cut cycle in z-axis

G77 - cut-in cycle in x-axis

G78 - multiple threading cycle

G80 - fixed cycle cancel

G81-89 - fixed cycles specified by machine tool manufacturers

G81 - drilling cycle

G82 - straight drilling cycle with dwell

G83 - drilling cycle

G83 - peck drilling cycle

G84 - taping cycle

G85 - reaming cycle

G85 - boring cycle

G86 - boring with spindle off and dwell cycle

G89 - boring cycle with dwell

G90 - absolute dimension program

G91 - incremental dimensions

G92 - Spindle speed limit

G93 - Coordinate system setting

G94 - Feed rate in ipm

G95 - Feed rate in ipr

G96 - Surface cutting speed

G97 - Rotational speed rpm

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G98 - withdraw the tool to the starting point or feed per minute

G99 - withdraw the tool to a safe plane or feed per revolution

G101 - Spline interpolation

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APPENDIX-2

M-Codes Control Machine Functions

M00 - program stop

M01 - optional stop using stop button

M02 - end of program

M03 - spindle on CW

M04 - spindle on CCW

M05 - spindle off

M06 - tool change

M07 - flood with coolant

M08 - mist with coolant

M08 - turn on accessory (e.g. AC power outlet)

M09 - coolant off

M09 - turn off accessory

M10 - turn on accessory

M11 - turn off accessory or tool change

M17 - subroutine end

M20 - tailstock back

M20 - Chain to next program

M21 - tailstock forward

M22 - Write current position to data file

M25 - open chuck

M25 - set output #1 off

M26 - close chuck

M26 - set output #1 on

M30 - end of tape (rewind)

M35 - set output #2 off

M36 - set output #2 on

M38 - put stepper motors on low power standby

M47 - restart a program continuously, or a fixed number of times

M71 - puff blowing on

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M72 - puff blowing off

M96 - compensate for rounded external curves

M97 - compensate for sharp external curves

M98 - subprogram call

M99 - return from subprogram, jump instruction

M101 - move x-axis home

M102 - move y-axis home

M103 - move z-axis home