INDUSTRIAL TRAINING REPORT OF

INTERNSHIP AT VICTORA TOOLS’S AND

ENGINEERS

Submitted ByTarun kumar11-ME-4114

Reporting OfficerMr. Sunil pandey

DEPARTMENT OF MECHANICAL ENGINEERINGECHELON INSTITUTE OF TECHNOLOGY

SYNOPSIS

Industrial exposure is the most crucial part of the technical studies in which a student is able

to synchronize his technical knowledge with practical knowledge gained in any of the

organization in which he gets his training from. I worked in the production department in which I

learned how the manufacturing of gears take place.

I hope that the word of my project report communicates the actual experience gained with

subtlety and precision, which is unapproachable, by any other means. From the medium of this

project report, I would like to thank each and every honourable employee of ESCORTS AGRI

MACHINERY GROUP, who has helped me to gain all the knowledge in the respective

Production shop and Maintenance, where production process was involved.

.

ACKNOWLEDGEMENT

Although my name appears on the cover page of this dissertation, a great many have contributed

to make it a success. That is why I dedicate this page to thank everyone who had helped me to

complete this training successfully, for without their help I wouldn’t have come this far.

First of all I would like to thank my reporting officer Mr. Ajay Bansal for the support and

guidance given to me throughout the training directing me towards the right directions. I greatly

appreciate his help.

I am also grateful to my family for their support they had given me throughout my training. They

not only provided me with the support and guidance but also helped me by providing me the

necessary information needed to produce a good report.

Finally I would also like to take this opportunity to thank all the staff and management of the

Escorts Agri Machinery and Echelon institute of technology and all my friends for the support

given to me in completing the training.

CONTENTS

Company profile

The founding Philosophy

Background

Manufacturing Overview

Manufacturing processes

Numerical control lathe

Broaching

Shaping

Hobbing

Deburring

Shaving

Washing

Heat treatment

Grinding

Assembly

COMPANY PROFILE

ABOUT THE COMPANY

The Escorts Group is among India's leading engineering conglomerates operating in the high

growth sectors of agri-machinery, construction & material handling equipment, railway

equipment and auto components. Having pioneered farm mechanization in the country, Escorts

has played a pivotal role in the agricultural growth of India for over five decades. One of the

leading tractor manufacturers of the country, Escorts offers a comprehensive range of tractors,

more than45 variants starting from 25 to 80 HP. Escort, Farmtrac and Powertrac are the widely

accepted and preferred brands of tractors from the house of Escorts. A leading material handling

and construction equipment manufacturer, we manufacture and market a diverse range of

equipment like cranes, loaders, vibratory rollers and forklifts. Escorts today is the world's largest

Pick 'n' Carry Hydraulic Mobile Crane manufacturer. Escorts has been a major player in the

railway equipment business in India for nearly five decades. Our product offering includes

brakes, couplers, shock absorbers, rail fastening systems, composite brake blocks and vulcanized

rubber parts. In the auto components segment, Escorts is a leading manufacturer of auto

suspension products including shock absorbers and telescopic front forks. Over the years, with

continuous development and improvement in manufacturing technology and design, new reliable products

have been introduced.

Throughout the evolution of Escorts, technology has always been its greatest ally for growth. In

the over six decades of our inception, Escorts has been much more than just being one of India's

largest engineering companies. It has been a harbinger of new technology, a prime mover on the

industrial front, at every stage introducing products and technologies that helped take the country

forward in key growth areas. Over a million tractors and over 16,000 construction and material

handling equipment that have rolled out from the facilities of Escorts, complemented by a highly

satisfied customer base, are testimony to the manufacturing excellence of Escorts. Following

the globally accepted best manufacturing practices with relentless focus on research and

development, Escorts is today in the league of premier corporate entities in India. Technological

and business collaboration with world leaders over the years, Globally competitive indigenous

engineering capabilities, over 1600 sales and service outlets and footprints in over 40 countries

have been instrumental in making Escorts the Indian multinational. At a time when the world is

looking at India as an outsourcing destination, Escorts is rightly placed to be the dependable

outsourcing partner of world's leading engineering corporations looking at outsourcing

manufacture of engines, transmissions, gears, hydraulics, implements and attachments to

tractors, and shock absorbers for heavy trailers. In today's Global Market Place, Escorts is fast on

the path of an internal transformation, which will help it to be a key driver of manufacturing

excellence in the global arena. For this we are going beyond just adhering to prevailing norms,

we are setting our own standards and relentlessly pursuing them to achieve our

desired benchmarks of excellence.

THE FOUNDING PHILOSOPHY

Over six decades back two young men set out on a journey together armed with little beyond

intelligence, business acumen and determination and dreams aplenty. They believed that India

could only achieve total freedom with a breakthrough in the field of agriculture and

mechanization would have to rule the fields. Their youthful enthusiasm had kindled the hope that

one day they would make a mark of their own. They were in fact writing the first chapter of what

has come to be widely recognized as one of the greatest success stories in Indian industry.

Escorts came into being with a vision. A vision that eschewed easy paths to profitability, and

sought instead for ways to make a contribution. A vision that led two young brothers, Yudi and

Hari Nanda, to branch out of their family's prospering transport business and institute ventures

that were to become the foundations of Escorts Limited. On 17thOctober 1944, Escorts Agents

Limited was born at Lahore (now in Pakistan) with Mr. Yudi Nanda as Managing Director and

Mr. Hari Nanda as Chairman. It was a trend setting marketing house driven by the same business

philosophy, which had given their family enterprise an unrivalled reputation: customer concern.

Not long afterwards, this driving ambition to go beyond the expected led Hari Nanda to the first

of his many successful business insights - the discovery of the great business potential that lay in

India's villages. This led to the launch, in 1948, of Escorts (Agriculture and Machines) Ltd., with

Yudi Nanda as Director. Though separate business entities then, both companies had two great

strengths in common: the dynamic Nanda brothers and the unifying force of the name they gave

their companies; Escorts, literally 'escorting' their products and services to the customer while

most other businessmen were just selling.

Tragically, Mr. Yudi Nanda died in an accident in 1952 - but his spirit remained embedded in the

foundations of the company. Mr. H P Nanda then took on the mantle to realize the dreams which

he had always seen with his brother.

Escorts (Agents) Ltd. and Escorts (Agriculture and Machines) Ltd. merged in 1953 to create a

single entity -Escorts Agents Pvt Ltd. Having initially started with a franchise for Westing house

domestic appliances, by this time the Company had already expanded its marketing and service

operations, representing internationally known German and American organizations such as

MAN, AEG, Haniel & Leug, Knorr Bremse, MIAG and BMA for sophisticated electrical and

mechanical engineering equipment and Minneapolis Moline and Wisconsin for agricultural

tractors, implements and engines. Escorts made a major thrust into the agricultural arena by

taking on the marketing and service franchise for Massey Ferguson tractors in Northern India,

which soon comprised 75% of MF's all-India sales - a signal tribute to Escorts' inherent

strengths. Its first industrial venture came up in1954, in partnership with Goetzewerke of

Germany for the manufacture of piston rings and cylinder liners - followed by production of pistons in

collaboration with MAHLE, also of Germany, in 1960. The company's incorporation in its present

name, Escorts Limited, was effected on 18th January, 1960. Escorts' next major industrial

activity was the assembly of tractors in 1961 in technical cooperation with URSUS of Poland.

Subsequently this led to the manufacture of the country's first indigenous tractors under Escorts'

own brand name, which were to play a pivotal role in the Green Revolution. This went on to lay

the foundations that even today are the Company's core strengths -relevant, world-standard

technology through strategic international alliances; a broadbased marketing and service network

yet unrivalled. Beyond the growth of the organization, these principles have ensured that Mr. H.

P. Nanda's contribution to the cause of industry and the consumer will endure. He pioneered the

revolutionary concept of 'interdependence' between ancillary and large industries,

institutionalizing vendor development and in the process building Faridabad and the entire belt

of townships in the region. He introduced the discipline of service going before marketing,

reassuring the customer that Escorts would stay with them, that they were here for the long run.

He built lasting alliances with an array of the world's most respected names in tractors, industrial

equipment, two-wheelers, construction equipment and telecommunications. Going further, he

created institutions devoted to value engineering and training, not only as investments in the

company's future but also as catalysts for the enhancement of Indian industry as a whole the

Escorts R&D Centre and the unique Escorts Institute of Farm Mechanization. His concern

extended to the society in which he worked, and he manifested it by establishing the Escorts

Medical Centre at Faridabad, Escorts Heart Institute and Research Centre at New Delhi, as well

as numerous village development programmes. And above all, he imbued the corporation with

his own pioneering. Escorts is testimony to the valor, vision and values of its Founder Mr. H P Nanda. He

remains the inspiration for our courage, spirit of adventure and ability to ‘Think Big’. These

qualities are his enduring legacy and have inspired and encouraged us down the decadesand will

continue doing so in all our endeavors.

BACKGROUND

In 1960, the parent company, Escorts, set up the strategic Agri Machinery Group (AMG)

to venture into tractors.

In 1965, the company rolled out their first batch of tractors under the brand name of

Escort.

In 1969 a separate company, Escorts Tractors Ltd., was established with equity

participation of Ford Motor Co., Basildon, UK for the manufacture of Ford agricultural

tractors in India.

In the year 1996 Escorts Tractors Ltd. formally merged with the parent company, Escorts

Ltd.

Since inception, the company have manufactured over 1 million tractors.

MANUFACTURING OVERVIEW

Escorts - AMG has Tractor manufacturing capacity of 98,940 trs / annum which is the highest in

Asia at one location. Its manufacturing operations are divided in three plants as

 Component Plant

 Tractor Assembly Plant

 Crankshaft & Hydraulic Plant

Component Plant consists of Machine shops in which all major castings such as Engine blocks,

Gear Box housings, Differential housings are being machined along with Gears & Shafts.

Machine shop consists of State of the Art machines such as CNC Horizontal Machining Centers,

CNC Turning Centers and variety of other precision machines, including Gear Hobbing and

Shaving machines, etc. It is important to note that all critical components are machined in house.

Tractor Assembly Plant is divided into two lines as Farmtrac Line and the Powertrac Line.

Farmtrac Line is a composite line that has machining as well as assembly activities of Engine,

Transmission & Tractor whereas on Powertrac line only Assembly activities of Engine,

Transnmission & Tractor are being carried out. Tractor Assembly Plant has State of the Art Paint

Shop that has CED paint shop facilities. Engine Shop has State of the Art testing facilities that

includes AVL make Eddy Current Dynamometers in Engine Test House.

Crankshaft & Hydraulic Plant is divided into two parts as Crankshaft Line and Hydraulics Line.

Crankshaft line consists of machine shop where crankshafts of all Tractor models are being

machined. It has State of the Art machines such as Rotary Miller, Pin Grinder, Journal Grinder,

etc. Hydraulic line consists of Machining as well as Assembly activities where critical parts of

tractor hydraulics such as Distributor, Hydraulic Cylinder, etc are being machined and

assembled. It has State of the Art Honing and other precision machines.

GEAR TRANSMISSION COUNTER SHAFT

PART NAME: 7113AA

MATERIAL: - 20 Mn5 Cr5

Chemical composition in weight (%):-

Carbon : - 0.17-0.22

Silicon : - 0.10-0.35

Manganese : - 1.0 -1.40

Chromium : - 1.00-1.30

Hardness : - 160-200

Figure (1) Helical Gears

GEAR SPECIFICATION:

1 No. of teeth 57

2 Module 2.74963

3 Pressure Angle 17˚29’43”

4 Helix Angle 30˚00’00”

5 Base Circle Dia. 170.0608mm

6 Base Helix Angle 28˚28’52”

7 Face Width 23.75mm

8 Length Ev. La 7.95˚

9 Length Ev. LE 21.37mm

10 Approx. Length M1 16.81˚

11 Stylus Diameter 2mm

Table (1)

1 No. of teeth 30

2 Module 3.628571

3 Pressure Angle 20˚

4 Helix Angle 00˚

5 Base Circle Dia. 102.2923mm

6 Base Helix Angle 00˚

7 Face Width 23.88mm

8 Length Ev. La 20.2˚

9 Length Ev. LE 19.1mm

10 Approx. Length M1 12.7˚

11 Stylus Diameter 2mm

Table (2)

MANUFACTURING PROCESSES

GEAR MANUFACTURING PROCESS

Figure (2)

Figure (3)

Process flow diagram:

Figure (4)

1. NUMERICAL CONTROL LATHE

Numeric control Lathe(NCL)

Shaping

Hobbing

Deburring

Shaving

Washing

Heat treatment

Grinding

Assembly

It is the first process of machining it includes various processes such as:

a) Turning

b) Facing

c) Grooving

d) Chamfer

Turning: it is a process of removing material from outer diameter of rotating

work piece i.e. parallel to the axis of rotation.

Facing: it is a process of removing material perpendicular to the axis of rotation

of work piece.

Grooving: The process of cutting a narrow channel or passageway into the

outside diameter of a cylindrical work piece.

Chamfering: Machining an angled edge around the end of a cylindrical work

piece. Chamfering is done to remove residual stress from the component and to

avoid any danger firm sharp edge.

Tapering: An operation performed on a lathe that feeds a tool at an angle to the

length of the work piece in order to create a conical shape.

Chucking the workpiece

For longer work pieces we would need to face and center drill the free end and use a

dead or live center in the tailstock to support it. Without such support ,the force of the

tool on the work piece would cause it to bend away from the tool ,producing a

strangely shaped result .There is also the potential that the work could be forced to

loosen in the chuck jaws and fly out which may cause serious injury.

Adjusting the tool bit

Choose a tool bit with a slightly rounded tip. This type of tool should produce a nice

smooth finish. For more aggressive cutting, if you need to remove a lot of metal, you

might choose a tool with a shaper tip. Make sure that the tool is tightly clamped in the

tool holder. Adjust the angle of the tool holder so that the too is approximately

perpendicular to the side of the work piece. Because the front edge of the tool is

ground at an angle, the left side of the tip should engage the work, but not the entire

front edge of the tool.

Machine specifications

Capacity swing over carriage ………………………..381mm

Chuck size ……………………………………………315mm

Max turning dia. (chucking/between center) .………..400/315mm

Max turning length …………………………………..1000/1500/2000mm

Spindle –spindle nose ……………………………….A2-8 TYPE

Figure (5) Numeric control lathe

Spindle speed range …………………………………..30-3000 rpm

Hole through spindle ………………………………....90mm

Spindle motor power Continuous / 30 min...………….18.5/22KW

Feed –cross travel(X axis) …………………………….. 354mm

Longitudinal travel (Z axis) …………………………… 1081/1581/2081mm

Rapid traverse rate (x/Z axis) …………………………. 12/12m/min.

Turrent –turrent tool stations …………………………. 12

Tool shank size ………………………………………… 32x32mm

Tail stock quill dia. …………………………………….. 130mm

Controller, drives and motors: ………………………….Fanuc /Siemens type

2. BROACHING

Broaching is a machining operation which rapidly forms a desired contour in a work piece by

moving a cutter, called a broach, entirely past the work piece. Both external and internal gear

teeth, spur or helical, can be broached, but conventional broaching is usually confined to cutting

teeth in internal gears. Figure shows progressive broach steps in cutting an internal spur gear.

The form of the space between broached gear teeth corresponds to the form of the broach teeth.

Figure (6) Vertical broach machine

The cutting action of any single broach tooth is similar to that of a single form tool. Each cross

section of the broach has as many teeth as there are tooth spaces on the gear. The diameter of

each cross section increases progressively to the major diameter that completes the tooth form on

the work piece. Broaching is fast and accurate, but the cost of tooling is high. Therefore,

broaching of gear teeth is best suited to large production runs. The broaching of internal spur

gear teeth is restricted to work piece having configurations that permit the broach to pass

completely through the piece.

Broaching Principle:

Broaching is based up on the principle of hydraulics.

Broaching is a machining process that pushes or pulls a cutting tool (called a broach) over or

through the surface being machined.

Its high-production, metal-removal process is sometimes required to make one-of-a-kind parts.

Early broaching applications were cutting keyways in pulleys and gears. After World War 1,

broaching contributed to the rifling of gun barrels.

Advances in broaching machines and form grinding during the 1920s and 30s enabled tolerances

to be tightened and broaching costs to become competitive with other machining processes.

Today, almost every conceivable type of form and material can be broached.

It represents a machining operation that, while known for many years, is still in its infancy.

New uses for broaching are being devised every day.

Figure (7) Broaching Tool

3. SHAPING

Shaving Operation is used for GEAR 2(30 teeth). Because of a very small clearance space

between the two gears the smaller one cannot be fabricated using gear Hobbing method.

Therefore, Gear Shaping is used.Shaping is a gear cutting method in which the cutting tool is

shaped like a pinion. The shaper cuts while traversing across the face width and rolling with the

gear blank at the same time.

Shaping can produce high accuracy in cutting spur gears because shaping is a generating process.

Although seldom as fast as Hobbing, shaping is used for a wide range of production quantities.

Many types of gears can be produced to requirements by either shaping or Hobbing and the

availability of equipment determine which of the two processes is used. However, if the work

piece configuration cannot be hobbed, shaping is often the only practical method.

Gear shaping is the most versatile of all gear cutting processes. Although shaping is most

commonly used for cutting teeth in spur and helical gears, this process is also applicable to

cutting herringbone teeth, internal gear teeth(or splines) , chain sprockets , ratchets , elliptical

gears, face gears, worm gears , and racks. Shaping cannot be used to shaping is practical for any

quantity of production. Work piece design often prevents the use of milling cutters or hobs

(notably, for cluster gears) , and shaping is the most practical method for cutting the teeth.

Gear shaping is a generating process that uses a toothed disk cutter mounted on a spindle that

moves in axial strokes as it rotates. The work piece is carried on a second spindle. The work

piece spindle is synchronized with the cutter spindle and rotates as the tool cuts while it is being

fed gradually into the work.

Figure (8) Shaper tool

Advantages of gear shaping:

Only one cutter is used for cutting all spur gears of the same pitch

The cutter has a very accurate profile. The profile of a cutter is generated after hardening and

grinding to exact size. The gears produced by this method are of very high accuracy.

The finished gear has a generated profile.

It is suitable for cutting internal gears while passing through different teeth, the cutter

automatically corrects any tooth interference in the blank.

4. HOBBING

Hobbing operation is carried out on a H400 Gear Hobbing Machine. This operation is used for

GEAR 1 (57 TEETH).

Helix Angle…………30˚

Max. Diameter……..400mm

Max. RPM………….480

Two types of gears are used to drive the mob:

a. Differential Gears

b. Indexing Gears

Hobbing is a gear cutting method that uses a tool resembling a worm gear in appearance, having

helically spaced cutting teeth. In a single-pitch hob, the rows of teeth advance exactly one pitch

as the hob makes one revolution. With only one hob, it is possible to cut interchangeable gears of

a given pitch of any number of teeth within the range of the Hobbing machine.

Hobbing is a practical method for cutting teeth in spur gears, helical gears, worms, worm gears,

and many special forms. Conventional Hobbing machines are not applicable to cutting bevel and

internal gears. Tooling costs for Hobbing is lower than those for broaching or shear cutting.

Therefore, Hobbing is used in low quantity production or even for a few pieces. On the other

hand, Hobbing is a fast and accurate method (compared to milling, for example) and is therefore

suitable for medium and high production quantities.

Hobbing is a generating process in which both the cutting tool and the work piece revolve in a

constant relation as the hob is being fed across the face width of the gear blank. The hob is a

fluted worm with relieved teeth that cut into the gear blank in succession, each in a slightly

different position. Instead of being formed in one profile cut, as in milling, the gear teeth are

generated progressively by a series of cuts.

The decision to advance or retard the work piece rotation depends mainly on whether the hob is

right hand or left-hand type whether the helix angle is of right-hand or left-hand configuration.

The amount by which the work piece is retarded or advanced depends on the helix angle.

In medium to high production, it is common to use fixtures that allow Hobbing of two or more

identical gears in one loading of the machine. Gears with integral shanks can usually be hobbed

without difficulty. The shank can assist in clamping and handling for loading and unloading.

When warranted by high-volume production, Hobbing can be done in automatic machines

utilizing automatic loading and unloading.

Although hob life decreases as work piece hardness increases, helical gears of hardness as high

as 48 HRC are sometimes hobbed. When hardness of 48 HRC or lower can be tolerated, the

sequence of rough Hobbing, heat treatment, and finish Hobbing is likely to cost less than

grinding after heat treatment.

Hobbing Tool

The hob is the cutter used to cut the teeth into the work piece. It is cylindrical in shape with

helical cutting teeth. These teeth have grooves that run the length of the hob, which aid in cutting

and chip removal. There are also special hobs designed for special gears such as the spline and

sprocket gears.

The cross-sectional shape of the hob teeth are almost the same shape as teeth of a rack gear that

would be used with the finished product. There are slight changes to the shape for generating

purposes, such as extending the hob's tooth length to create a clearance in the gear's roots. Each

hob tooth is relieved on the back side to reduce friction.

The most commonly used tool is HSS DIN3972 gear Hobbing tool.

Figure (9) Hobber tool

Figure (10) Hobber specification

Most hobs are single-thread hobs, but double-, and triple-thread hobs increase production rates.

The downside is that they are not as accurate as single-thread hobs. Depending on type of gear

teeth to be cut, there are custom made hobs and general purpose hobs. Custom made hobs are

different from other hobs as they are suited to make gears with modified tooth profile. The tooth

profile is modified to add strength and reduce size and noise of gears.

Specifications of hob cutter:

Module Outside Dia. Overall Length Hole Dia.

150 40

22

1.25

1.5

5545

1.75

250

2.25 60

2.565 55

2.75

3 70 60

27

3.2575

65

3.570

3.7580

4 75

4.2585

80

4.5 85

5 90 90

5.5 100 95

326 105100

6.5 110

Table (3)

Advantages of Gear Hobbing Process

High productivity rate

Economical and efficient operation

Accuracy

Close tolerances

Versatility of operations

Smooth finishes

Figure (11) Deburring process

5. DEBURRING

A burr is a raised edge or small pieces of material remaining attached to a work piece after a

modification process.

It is usually an unwanted piece of material and when removed with a Deburring tool in a

process called ‘Deburring’. Burrs are most commonly created after machining operations, such

as grinding, drilling, milling, engraving or turning.

It may be present in the form of a fine wire on the edge of a freshly sharpened tool or as a raised

portion of a surface; this type of burr is commonly formed when a hammer strikes a surface.

Gear debburing machines are designed to correctly remove burrs or sharp edges as a result of

castings, drilled holes, cut grooves and other machining operations used to complete parts. The

Deburring process of gears makes the parts capable of a performance for which they were

designed. It eliminates all the unwanted elements that obstruct their productivity.

6. SHAVING

Shaving is a finishing operation that uses a serrated gear shaped or rack –shaped cutter to shave

off small amounts of metal as the gear and cutter are meshed at an angle to one another .The

crossed axes create a sliding motion which enable the shaving cutter to cut .Its purpose is to

correct errors in index, helix angle, tooth profile, and eccentricity. Shaving is carried out prior to

gear heat treatment.

Gear shaving is a finishing operation that removes small amount of metal from the flanks of gear

teeth. It is not intended to salvage gears that have been carelessly cut, although it can correct

small errors in tooth spacing, helix angle, tooth profile, and concentricity .Shaving improves the

finish on tooth surfaces and can eliminate tooth end load concentration, reduce gear noise, and

increase load –carrying capacity. Shaving has been successfully used in finishing gears of

diametric pitches from 180 to 2. Standard machines and cutters are available for shaving gears

that range In size from 6.4to 5590 mm(to 220 in.) pitch diameter. Leaving excessive stock for

shaving will impair the final quality of the shaved gear .For maximum accuracy in the shaved

gear and maximum cutter life,a maximum stock should be allowed for removal by shaving ; the

amount depends largely on pitch .

Operation principle:

The shaving operation is done with cutter and gear at crossed axes helical cutters are used for

spur gears, and vice versa .The action between gear and cutter is a combination of rolling and

sliding .Vertical teeth .During operation, the tip of the shaving cutter must not contact the root

fillet, or uncontrolled, inaccurate involute profiles will result. For gears to be shaved,

protuberance –type hobs that provide a small undercut at the flank of the tooth may be

preferred .This type of hob avoids the initial tip loading of the shaving cutters.

Crown shaving:

Is used to relieve load concentration at the ends of gear teeth causes by the misalignment of axes

in operation. Crowning is a modification of the tooth profile in both the radial and axial and axial

planes. In the axial traverse method of shaping, crowning is done by rocking the worktable as it

is reciprocated. In the higher production angular traverse method, the cutter is modified to

provide crowing .The amount of crown varies, but usually .0003 to .0005 mm/mm (0003

to .0005)of face width is sufficient.

Advantages:

Gear Shaving gives the gear the following advantages:

Improves tooth surface finish.

Eliminates, the problem of tooth end load concentrations.

Effective reduction in the noise of gears with modification in the tooth profile.

Increase the gear’s load capacity Improved safety and service life.

MACHINE USED: HURTH ZS -350 GEAR SHAVING MACHINE

MACHINE SPECIFICATIONS:

Manufacturer ……………………………….HURTH

Type:……………………………………….. ZS-350 CNC

YEAR OF CONSTRUCTION ……………..1988

Control………………………………………CNC

TECHINICAL DATA:

Max. Wheel Dia …………………………………350mm

Gear width………………………………………150mm

Max. Module ……………………………………8mm

Min. Module ……………………………………1mm

Shaving –spindle speed range …………………50-400U/MIN

Clamping length ………………………………..350mm

Table surface area………………………………2050x700mm

Total power requirement ………………………20 kW

Weight of the machine ………………………..5.5 Ton

Accessories: SIEMENS Sinumerik CNC –CONTROL MACHINE USED: GSM -12 CNC

GEAR SHAPER (KARATS)

Figure (12) Shaper tool

Machine specifications :

Max. diameter of pitch circle (external gear) 180 mm

Max. diameter of pitch circle (internal gear ) 120mm

Max. module 4

Max. width of gear face 40mm

Diameter of hole through work table 70mm

Diameter of cutter spindle 90mm

Taper hole in cutter spinal 45(1/12 Taper )

Number of cutter spindle 30-1500 str./min.

Rotary feed rate of cutter for 300str./min.

For 1500 str /min.

1.5-2250deg/min.

0.005-7.5mm/str.

.001-1.5mm/str.

Radial in feed rate.

For 300 str /min

For 1500str /min

1-500 mm/min

.003-1.67mm/str.

.001-033mm/str.

Table (4)

7. HEAT TREATMENT

Processes of heat treatment:

Carburising

Quenching

Washing

Tempering

Shot blasting

Straightening press

Inspection

Figure (13) Heat treatment layout

Heat treatmentcarburising

quenching

Washing

tempering

Shot blasting

Straightening press

inspection

Carburizing

It is estimated that 90% of gear carburizing is performed In a carbonaceous gas

temperature. In this type of carburizing, carbon is induced into the ferrous base material

heated in the gaseous atmosphere with a carbon potential that allows the surface to absorb

carbon. The most commonly used medium is endothermic (commonly known as ‘endo’)

gas produced by reacting natural gas (mainly methane, CH4) with air (1:2.5 to2.7 ratio)

over a heated catalyst.

Figure (14) Carburising furnace

Varying the ratio of ethane to air filters the composition of endo and the chemical

reactions slightly. Free carbon resulting from chemical reaction is then dissolved in the

austenite that is formed when gears are heated above 720 ᵒc (1330 ᵒF) and precipitates as

iron carbide (Fe3C).There are special components to check whether the furnace is ready

for operation are called master piece.

Emery paper is a type of paper that can be used for sanding down hard and rough surfaces.

The master piece is put into the furnace for pre-determined time and after that it is scrubbed on

emery paper to remove coating from it. Then checked on rock well hardness tester whether it got

the required hardness or not.

Before pouring the material into the furnace the hardness is check here so that the component

manufacture will be perfect.

Recently, nitrogen-methanol has been used for supplying the carburizing atmosphere.

This type of system offers a number of benefits over a conventional endo gas generator. Here,

N2 plays the most important function to keep air out of the furnace and prevents the gears from

being oxidized. Typically, N2 is more than 90% of the nitrogen-methanol atmosphere.

Carburizing in nitrogen-methanol systems also ensures accurate carbon potential for

improved carburized case properties. Because of higher cost with nitrogen methanol system,

most of the gears are still carburized in endo gas.

Temperatures as low as 790 ᵒc (1450 ᵒF) and as high as 985 ᵒc (1800 ᵒF) have been used

for carburizing gears, although it should be kept in mind that the life of a furnace deteriorates

rapidly above 955 ᵒc (1750 ᵒF). with the desired amount of carbon absorbed into the tooth

surface, gears are quenched in a suitable medium (generally oil ) to obtain the required case

hardness.

Quenching may be performed either directly from the carburizing temperature or from a

somewhat lower temperature. In some instances, parts after carburizing are completely cooled to

room temperature, reheated to the austenizing temperatures, and then quenched. As already

mentioned, the depth case is dependent on time and temperature selected during carburizing.

Carburising process parameters

1 Carburizing Temp 915 ± 10 T c

2 Carburizing Time As per sample

3 Diffusion Temp 915 ± 10 T c

4 Diffusion Time 30 minutes max.

5 Hardening Temp 820 ± 10 T c

6 Hardening Time 30 minutes

7 Quenching Media Oil

8 Quenching oil Temp 70 ± 10 T c

9 Carbon Potential Set Pt. 1.0 ± 0.1 %

10 Tempering Temp 180 ± 10 T c

11 Tempering Time 1 hr.

Table (5)

Quenching:

After carburizing, gears are quenched in a cooling medium for hardening. Quenching develops a

martensitic case with core microstructures other than a mixture of pro-eutectoid ferrite and

pearlite.

Thus, the selection of a proper quenchant is of utmost importance, and the cooling rate, ideally,

should be just fast enough to produce the desired core structure but not so fast that the case

cracks or that an undue amount of austenite is retained.

For industrial and automotive gears, however, quenching conditions often are chosen solely on

the basis of developing required surface hardness, especially in applications where the core

properties are known to have little or no effect on product performance.

Depending on part size and shape and on transformation characteristic of the steel, gears may be

quenched in water, oil, or any proprietary fluids. Most often oil is used because it is a suitable

quenchant for most carburizing grades of steel, especially for relatively fine pitch gears. Small

DP gears may require a more drastic quench, particularly if densely packed, and often are

susceptible to quench cracks.

Regardless of the type of quenchant used, good circulation within the quench bath is extremely

important to promote uniform cooling of gears. Sometimes, for some materials, the desired

properties of the case can be developed without resorting to a liquid quench, in which case air

cooling, furnace cooling, or gas cooling may be appropriate.

Any of these three cooling media can be used when parts are to be reheated for hardening. If

intermediate operation such as straightening or machining are needed prior to hardening, furnace

or gas cooling is preferred. Both are done under a protective atmosphere that keeps the gears

clean and free of oxide scale and prevents decarburizing of the surface.

Variation in the surface hardness of gears within a lot is a problem that is often encountered

when many small gears are heat treated in the same basket. This variation is due to the parts

being too densely loaded, especially at the center of the load. This restricts the flow of quenching

in such a manner that gears near the basket’s parameters may attain full surface hardness while

those in the center do not.

If it is not possible to space out the gears for economic reasons, at least divider screens should

be inserted to “layer” the load. Another possible cause of gear surface hardness variation in a lot

is insufficient quench bath agitation. The obvious solution is to speed up the circulation system

of the quench tank in order to move more material through the load faster.

Alkaline washing:

In this process components are washed with help of thinner so that there oil or lubricant can be

removed properly and completely. Thinner is used by using jets which pressurizes it and strikes

on components for removal of lubricant.

With the help of this process components are also cooled down.

Tempering:

Tempering is a process of reheating quench hardened gears to a temperature below the

transformation range of steel and holding at this temperature to reduce thermal stresses induced

during quenching and improve dimensional stability.

Normal tempering temperature for carburized and quenched gears varies b/w 115 and 175

T c (240 and 350 T F). The surface hardness of quenched gears decreases as the tempering

temperature increases.

In addition, tempering temperature has a significant effect on core hardness. Furthermore, higher

tempering temperatures reduce both case hardness and case depth. In applications where gears

are required to maintain high compressive and bending strengths at an elevated temperatures,

carburizing steels that are least affected by tempering temp. are preferred to enhance the effect of

tempering, it should follow soon after quench but not until the gears can be comfortably touched

with bare hands.

Tempering too early can cause serious problems by interrupting the martensitic transformation.

To the other extreme, too long a delay before tempering might create a major distortion

problem and even cracking of the gears. Tempering is a necessary finishing treatment after

hardening. However, it also involves heating and cooling. This may again regenerate new

stresses in the gears being processed. Fortunately, the influence of these new stresses on

geometric shapes of gears is very small due to low temperature levels involved. Nevertheless,

uniform heating and cooling is advisable during tempering to keep distortion-causing stresses at

a minimum. Some controversy still exists concerning the value of tempering carburized and

quenched gears.

For critical applications, experience has proved that tempering is definitely beneficial.

Carburized and hardened gears used in aerospace applications invariably need to be tempered.

The reasoning is that tempering is not harmful and provides some benefit to resist cracking or

chipping of gears under edge loading. However, in thousands of other less critical applications, it

is difficult or sometimes impossible to prove the need of a tempering operation for carburized

and hardened gears.

Shot blasting:

Shot Blasting is a surface treatment process using high velocity steel abrasive. Shot blasting is

method through which it is possible to obtain excellent cleaning and surface preparation for

secondary finishing operations. Shot blasting is commonly used for :

• The cleaning of iron, steel, non-cast parts, forgings, etc.

• Mechanical cleaning of sheets, rods, coils, wire, etc.

• Shot peening to alter mechanical properties (increasing resistance to Fatigue for springs, gears,

etc.)

• Preparing surfaces to be painted, coated, etc.

In general shot blasting concentrates abrasive particles at high speed (65-110 m/second) in a

controlled manner at the material thereby removing surface contaminates due to the abrasive

impact.

Initially in the 1930’s the shot blasting process used compressed air for propelling the steel shot.

This method remains in use today for cleaning metal frames.

Shot blast production lines, both manual and automated systems, became possible with the introduction of centrifugal wheel blast machines. The system of shot blasting by centrifugal wheel is more productive than by compressed air and achieves a better more uniform surface finish.

The criteria used for selecting the type of shot blasting system depends on the size and shape of the parts, the condition of the surface to be cleaned, final surface finish specification and overall process required.

Straightening:

The straightening process begins with the determination of what constitutes a good part and how

this can be measured. Straightness is a linear measurement that determines the deviation from a

theoretical centerline of the work piece measured from one end of the part to the other.

Since this poses difficulties in fixturing and measuring the part in a production process,

straightening measurements are determined by measuring TIR (Total Indicated Run out) at

critical surfaces along the linear axis of the work piece.

Causes of distortion

The need to straighten parts results from distortions caused by the manufacturing processes

specific to these parts. They can include processes such as:

Forming processes such as extrusion or upsetting. Parts such as axle shafts an pinions which are

formed in this manner distort due to the extreme forces placed on the part. Worn or misaligned

tooling can further exacerbate the problem.

Cut to length operations can result in distortions at the ends of parts if cut off tooling wears,

material quality varies, or if fixturing devices fail.

Material handling or improper storage of parts can lead to distortion.

Heat treatment is a significant cause of distortion in parts. This is especially true if the part

quenching process is not well maintained. The reason that parts distort in heat treatment is the

differential cooling rates for different cross sections of the work piece.

Typical parts that require straightening due to these factors include:

Transmission shafts and drive train components such as pinions

Axle shafts

Camshafts and Crankshafts

Steering components such as steering racks and steering pinions

Pump shafts and compressor shafts

Electric motors and armature shaft

Inspection:

In this process we check following points or parameters:-

I. Case depth of material

II. Hardness required for particular component.

III. Grain structure of the components.

IV. Fatigue if there any.

Inspection process

This process is carried out in Material Testing Lab and the procedure for it is as follows:-

CUTTING

GRINDING

SHINING

FINISHING

POLISHING

MICROSCOPE TESTING

HARDNESS TESTING

Figure (15)

Grinding

Grinding practice is a large and diverse area of manufacturing and tool making. It can

produce very fine finishes and very accurate dimensions; yet in mass production contexts it

can also rough out large volumes of a metal quite rapidly. It is “regular” machining (that is,

cutting larger chips with cutting tools such as tool bits or milling cutters ), and until recent

decades it was the only practical way to machine such materials as hardened steels.

Compared to “regular” machining, it is usually better suited to taking very shallow cuts, such

as reducing a shaft’s diameter by half a thousand of an inch (thou) or 12.7 um.

Grinding is a subset of cutting, as grinding in a true metal-cutting process. Each grain of abrasive

functions as a microscopic single-point cutting edge (although of high negative rake angle), and

shears a tiny chip that is analogous to what would conventionally be called a “cut” chip.

Cylindrical grinding

Cylindrical grinding (also called center type grinding) is used in the removing the cylindrical

surfaces and shoulders of the work piece. The work piece is mounted and rotated by a work piece

holder, also known as a grinding dog or center driver. Both the tool and work piece are rotated

by separate motors and at different speeds. The axes of rotation tool can be adjusted to produce a

variety of shapes. The five types of cylindrical grinding are: outside diameter (OD) grinding,

inside diameter (ID) grinding, plunge grinding, creep feed grinding, and center less grinding.

Figure (16) Cylindrical grinding machine

A cylindrical grinder has a grinding (abrasive) wheel, two centers that hold the work

piece, and a chuck, grinding dog, or other mechanism to drive the machine. Most

cylindrical grinding machines include a swivel to allow for the forming of tapered pieces.

The wheel and work piece move parallel to one another in both the radial and

longitudinal directions.

The abrasive wheel can have many shapes. Standard disk shapes wheels can be used to

create tapered or straight work piece geometry while formed wheels are used to create a

shaped work piece. The process using formed wheels creates less vibration than using a

regular disk shaped wheel. Tolerances for cylindrical grinding are held within five-

thousandths of an inch (+/- 0.0005) (metric: +/- 13 um) for diameter and one ten-

thousandth of an inch (+/- 0.0001) (metric: 2.5 um) for roundness.

LIST OF REFERENCES

Company production documents

Books

www.google.com

www.wikipedia.com

www.escortsagri.com