Chapter 1

Introduction

1.1. Company profile

The renowned industrialist, late Shree B. M. Birla founded National Engineering

Industries Ltd., Jaipur in the year 1946 as a pioneer industry in the field of bearing

manufacture, under the name of "National Bearing Company Ltd."

The first bearing was manufactured in 1950 with a modest start of 30,000 bearings

in 19 sizes. The company is now manufacturing nearly 3.8 million bearings per

month in over 500 different sizes ranging from 6 mm bore to 1300 mm outer

diameter and has the capacity to manufacture bearings upto 2000 mm outer

diameter. At NEI, the development of bearings is a never ending job. With ever

increasing activities and grant of industrial licenses for other vital industries and

manufacturing of Roller Bearing Axle Boxes for Railway Rolling Stock, Steel

Balls, Tapered Roller Bearings, Spindle Inserts etc., the name of the company was

changed in 1958 to "National Engineering Industries Ltd." retaining its original

trade mark NBC.

The industry is spread over 118 acres of land in Jaipur and 56 acres in Gunsi

(Newai). This is the only unit in the country manufacturing wide variety and range

of bearings such as Ball Bearings, Steel Balls, Tapered Roller Bearings, Cylindrical

Roller Bearings & Axle Boxes for Railway Rolling Stock including Spherical

Roller Bearings, Cartridge Tapered Roller Bearings and Large Diameter special

Bearings in separate fully equipped factories. The development of National

Engineering Industries Ltd., was pioneered with a theme “Indigenization and

Self-reliance".

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NBC Bearings are widely used by 2 and 3 Wheelers, Cars, Trucks, Tractors,

Electric Motors, Railway wagon, Coach and Locomotive manufacturers as Original

Equipment and Steel Mills, Heavy Engineering Plants, Bulldozers, Shovels, Tillers

and Thermal Power Plants all across the country.

1.2. Milestones

Fig.1.1 Milestones of NEI

i. 1946 -Company established as National Bearing Company (NBC) under

technical collaboration with Hoffman, U.K.

ii. 1950 Ball Bearing Production started.

iii. 1958 Company is renamed National Engineering Industries Limited (NEI);

NBC Trademark retained.

iv. 1967 Tapered Roller Bearing production started

v. 1975 Spherical Roller Bearings production begins

vi. 1981 Second Plant inaugurated in Newai.

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vii. 1982 Cartridge Tapered Roller Bearing in Technical Collaboration with

Brenco Incorporated of U.S.A.

viii. 1985 Technical Collaboration with NTN Corporation of Japan for Ball,

Cylindrical & Spherical Roller Bearing.

ix. 1995 ISO - 9001 Quality Management System Certification

x. 1996 Technical collaboration with Izumi Kinzoku Kogyo Co. Ltd., Japan for

Machine Retrofitting

xi. 2007 Third Plant inaugurated in Manesar.

xii. 2008 NBC receives TPM Excellence Award

xiii. 2010 NBC receives Deming Award

xiv. 2012 NBC receives the ACMA awards for Manufacturing and Technology

Excellence

1.3. Technical collaboration

(i) BRENCO Incorporated of U.S.A. Since 1982 - For Cartridge Tapered Roller

Bearings for Railroad applications.

(ii) NTN Corporation of JAPAN Since 1985 - For Ball Bearings, Cylindrical &

Spherical Roller Bearings, JPU Bearings, Double Row Angular Contact Bearings,

Hub Bearings Since 1997 - for Tapered Roller bearings.

(iii) Izumi Kinzoku of JAPAN Since 1996 for remanufacturing, retrofitting and

overhauling of Grinding and Super-finishing machines for bearing races.

1.4. Main Customers

Rolling Stock: -

DLW (Diesel Locomotive Work)

CLW (Chittaranjan Locomotive Works)

ICF (Integral Coach Factory, Chennai)

RCF (Rail Coach Factor, Kapurthala)

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CIMMCO

BEML (Bharat Earth Movers, Bangalore)

TEXMACO

Hindustan Motors Ltd.

Maruti Udyog Ltd.

Mahindra & Mahindra

Automobiles-LCV: -

Ashok Leyland

Force Motors

Eicher Motors

Tata Motors

Automobiles-Two/ Three Wheelers:-

Bajaj Auto Ltd.

Hero Honda Motors Ltd.

Honda Motorcycle & Scooters India Ltd.

Suzuki Motorcycle India

Majestic Auto

Piaggio India Ltd.

Royal Enfield Ltd.

Yamaha Motors India Pvt. Ltd.

TVS

Tractors: -

Eicher

Escorts

HMT

International tractors

Mahindra & Mahindra

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Punjab Tractors

TAFE

VST Tillers

Electric Motors & Pumps:-

Crompton Greaves

G.E. Motors

Kirloskar Electric

NGEF

MICO

Fans: -

Bajaj Electricals

Crompton Greaves

1.5. Manufacturing Facilities-

NBC has manufacturing facilities at Jaipur (established in 1946), Newai

(established in 1980) and Manesar (established in 2006). A fourth plant, a green

field project, at Savli in Gujarat will ship out its first bearing in November 2013,

ramping up production capacity to 150 million bearings per year once it is fully

operational.

Jaipur Plant

Newai (Gunsi) Plant

Manesar Plant

1.5.1. Newai (Gunsi) Plant-

Established in the year 1980-81 as an expansion project of NEI Ltd . The factory is

equipped with fully automated grinding lines with electronic in-process & post-

process gauging and centrally air-conditioned assembly lines with auto gauging and

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test equipments for quality and reliability of the products, The plant is spread over a

covered area

of 7,200 Sq.

Meters.

Fig1.2: Newai (Gunsi) plant

1.5.2 Manesar Plant

NEI has set up its third Ball Bearing manufacturing plant in the fastest growing

industrial town of Manesar in Haryana. The plant is having a covered area of

5200 sq. meters. with the most advanced and sophisticated machines imported

from reputed manufacturers from Europe and Japan .This plant is equipped with

state of the art fully automated grinding lines, assembly lines and inspection

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equipments.

Fig1.3: Manesar Plant

Chapter 2

NBC Jaipur

2.1. Introduction

This plant is located in the heart of Pink City of India, which is also famous for its

Tourists spots. Spread over a total area of 4,78,900 m2 and a covered area of 75,310

m2, Jaipur plant has state of the art manufacturing facilities and capable to

manufacture all types of Ball and Roller Bearings of NEI product range. . It has a

separate division to manufacture all these spread across large area. The plant at

Jaipur includes-

i. Ball Bearing

ii. Precision Ball Making

iii. Tapered Roller Bearing

iv. Railway Bearing

v. Research & Development

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vi. Large diameter bearings

vii. SAP-ERP

2.2. Ball Bearing-

The latest advanced techniques for manufacturing and Quality Assurance are

implemented to meet the rapid increase in demand for Quality, diversity of

specifications and new types of bearings.

Type of Ball Bearing:-

a. Radial Ball Bearing

b. Angular Contact Bearing

c. Self-Aligning Two-Row Ball Bearing

Radial ball bearing Angular Contact Bearing Self-Aligning Two-Row

Ball Bearing

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(a) (b) (c)

Fig. 2.1 Ball Bearings

The initial technology was from Hoffman Manufacturing Company Ltd., U.K. a

collaboration, which continued for 20 years. They offer a wide range of both metric

and inch series deep groove ball bearings, angular contact ball bearings, self-

aligning ball bearings etc. With their tie up with the world's leading bearing

manufacturing company NTN Corporation, JAPAN, They have gained access to the

most advanced ball bearing technology i.e. thermo mechanical bearings (TMB) and

tensioner bearings available today and their wide range of ball bearings is increasing

under this collaboration. Precision ball bearing from 6mm bore to 160mm OD is

manufactured with latest advance techniques. The unit has advanced assembly line

with auto gauging and testing equipment. NEI has 22 automatic Grinding lines from

M/s. NTN & Izumi, Japan. All machines with in process & post process gauges to

ensure grinding accuracy. Use of High Quality coolants for consistent grinding

quality and surface finish. Complete automation by flex-link conveyor system. NEI

has automatic plant for Track Grinding, Bore Grinding and Honing, The latest

advanced techniques for manufacturing and Quality Assurances are implemented to

meet the rapid increase in demand for quality, diversity of specifications and new

types of bearings. The plant is spread over a covered area of 14,694 sq. meters.

2.3. Precision Ball Making

Precision Steel balls up to 25 mm diameter for NEI bearings are being manufactured

in a separate well equipped factory. Precision quality balls are manufactured on

precision Grinding & Lapping machines to achieve super finished surface, accuracy

and roundness as per ISO standards. The plant is spread over a covered area of

4,700 sq.mtr.

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Fig. 2.2 Steel Balls

2.4. Tapered roller bearing

Type of Tapered Roller Bearing

a. Single Row Tapered Roller Bearing

b. Double Row Tapered Roller Bearing

Double Row Tapered Roller Bearing

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Single Row Tapered Roller Bearing

(a) (b)

Fig 2.3 Tapered Roller Bearings

This plant with the most modern equipment was set up in the year 1968.

Manufactured at an ultra-modern plant, with technology obtained from our earlier

collaborators, Federal Mogul Corporation, USA and now with NTN Corporation,

JAPAN, these bearings are used by all major automobiles, truck and tractor

manufacturers in the country as original equipment. The above bearings are

manufacture in inch & metric series form 15.857mm bore to 95.25mm bore. For

TRB NEI has Automatic Grinding Lines with in-process & post process gauges.

Complete automation by Flex link conveyor. Crowning provision on Inner (Cone)

& Outer (Cup). Complete Automatic Line for Roll Grinding, Super finishing,

Inspection and Sorting imported from NTN, Japan automatic checking & prevention

of inverted roller & roller missing. Automatic checking of stand height, noise and

run outs. Presently under modernisation and expansion plan the new latest state of

the art technology lines are installed. The plant is spread over a cover area of 11,652

sq. mtr.

2.5. Railway bearing

Railway Bearings included in three sections

a. Roller Bearing & Axle Boxes

b. Spherical Roller Bearing

c. Cartridge Tapered Roller Bearing

2.5.1 Roller bearing & axle boxes

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Fig 2.4 Axle Boxes

With the production of Roller Bearings and Axle Boxes, since 1952 the company

has fully met the requirements of the Indian Railways (one of the largest systems of

the world) by designing and developing axle boxes and bearings for fitment to

Locomotives manufactured by Diesel Locomotive.

Works & Chittaranjan Locomotive Works, various Wagon Builders, the ICF Broad

and Meter Gauge Coaches. Over a million NBC Bearings and Boxes are in service

with the Indian Railway The development of completely indigenise axle boxes and

bearings for the high speed Rajdhani Locomotive and the Yogoslavia and Egyptian

Railway Wagons are the highlights of the design capabilities at NEI.

The most of the production of this type of bearing for Indian Railways, Production

of the bearing started in 1952, on date plant is producing 100 different types of Axle

Box bearing, over a million NEI bearings and boxes are in service with the Indian

railways. New Automatic Grinding and Assembly Line has been purchased for

manufacturing of Axle Unit Bearings (DRAC bearings) from M/s Izumi Kinzoku.

2.5.2. Spherical roller bearing

The manufacture of Spherical Roller Bearings was started in the year 1975-76 for

fitment to broad gauge and meter gauge passenger coaches with designs,

technology, machines and equipment procured from the collaborators

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Cartridge Tapered Roller Bearing Spherical Roller Bearing

(a) (b)

Fig 2.5 Railway Bearings

2.5.3. Cartridge tapered roller bearing

For fitment to the new BOX-N Uprated Wagons designed by the RDSO, NEI is the

only manufacturer in the country who is the first to indigenise these bearings to a

high percentage under collaboration with the largest manufacturer of these bearings

in the world. Production of these bearings is grease packed and requires no field

lubrication for a period of 7 year. The Railway Bearing Division is spread over a

covered area of 1.2acres.

2.6. Large diameter bearing

Self-sufficiency in steel is the call of the day so is the importance of bearings in

steel Mills Equipment NEI has the distinction of being one of the ten manufacturers

of these bearings up to 2000 mm diameter. The largest bearing produced by NEI for

fitment to plate will of Rourkela Steel Plant was released by Mr G.P. Birla in

September 1985. This 4-row tapered roller bearing measures 1300 mm diameter and

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weighs 4.39 tones. The large diameter bearings are mainly produced out of case

carburizing steels, heat treated on special equipment and

furnaces developed by NEI. The precision grinding is done to close tolerances on

CNC Twin Spindle Programmable Berthiez Machine for bearings ranging from 500

to 2000 mm diameter with electronic sizing and numerical display. Production of

these bearings started in 1975 and to date over 100 different types of special large

diameter bearings have been manufactured and successfully used.

2.7. Research and development

2.7.1. Design and development

Complete in-house facility for design & development of all types of bearings and

tooling is available. The design is done on CAD. The large diameter bearings and

tooling have been entirely designed and developed by NEI’s R&D at its Computer

centre. Complete engineering and research facility is available to solve problem of

design development, manufacturing, installation and maintenance of bearings. With

the signing of the technical collaboration agreement with NTN CORPORATION

JAPAN & BRENCO IN CORPORATED OF USA, the capability to offer the finest

engineering services in the bearing industry has enhanced.

2.7.2. Machine building

The NEI has the capability of Machine Building to design, develop and manufacture

special purpose CNC grinding lines, HT lines, material handling equipment’s and

other special purpose machines, which have been made for its captive use to keep

pace with latest technology A Well-equipped electronic design, development

laboratory with all testing facilities supports the M/c Building division. Machine

Building has the capability and supports the Manufacturing divisions by

overhauling and retrofitting of the existing equipment’s so that these are upgraded

to help produce quality and improve productivity. R& D is spread over a covered

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area of ½ acres.

2.8. SAP-ERP

In order to re-engineer and integrate the Business processes for Sales, Production,

Materials and Finance, NEI has success- fully implemented SAP ERP. By use of

this Package, our processes now conform to World Class best practices.

Chapter 3

Railway Bearing Department

(Spherical Roller Bearing)

3.1. Introduction

I did my training at Railway Baring Department (Spherical Roller Bearing) .This

division is spread over covered area of 4,855 Sq. Meters. The manufacturing of

Spherical Roller Bearings was started in the year 1975-76 for fitment to broad gauge

and meter gauge passenger coaches with designs, technology, machines and

equipment procured from the collaborators .Spherical roller bearing has bore

(minimum) 40 mm and outer diameter (maximum) 420 mm. These bearings are

used by Indian Railway in all zones in the country as original equipment as well as

in other countries such as U.S., China, and Indonesia.

3.2. Spherical Roller Bearing

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A spherical bearing is a bearing that permits angular rotation about a central point in

two orthogonal directions (usually within a specified angular limit based on the

bearing geometry). Typically these bearings support a rotating shaft in the [bore] of

the inner ring that must move not only rotationally, but also at an angle.

Spherical Roller bearings for passenger coach applications are especially important

and require extremely high levels of performance, durability and reliability. In order

to achieve these high levels, NEI (NBC) performs strict inspection and quality

control at every stage of design, and production, from selection of material to the

processing technology used for manufacturing the bearings.

Spherical roller bearings have a large capacity for radial loads, axial loads in either

direction, and complex loads. They are suited for the applications such as railways

rolling stocks where vibrations and shock loads are encountered. All NBC spherical

roller bearing are fitted with machined brass cages. Brass is the most preferred cage

material for bearing used in railways all over the world. NBC spherical roller

bearings for Meter Gauge and Broad gauge passenger coaches have symmetrical

roller design. Where as in case of bearing used in Broad Gauge EMU, rollers are of

asymmetric design.

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Fig3.1: Spherical Roller Bearing

3.3. Bearing materials.

The functional performance and endurance of a dimensionally perfect bearing with

ideal internal geometries and surfaces, correct mountings, and professional

operating conditions are significantly influenced by characteristics of its material.

The major criteria to be considered for the satisfactory performance of bearing

including material selection and processing with resultant physical properties. Let’s

discuss material selection for spherical roller bearing at NBC –

Bearing contains varying amount of carbon, iron, chromium, manganese,

phosphorus, sulphur, silicon etc. Each of these elements plays a role in making final

steel suitable for bearings. Chromium and carbon allows deep hardening. The

combination of chromium, carbon & iron helps to minimize failure. As they

increase the surface resistance to abrasion & wear increase. In short, proper

combination of all these elements make final bearing steel which is tough under

shocks, heavy loads & hard enough to withstand fatigue. Generally bearings are

made from bars. But now a day, many manufacturers are making bearings by

forging rings. The latest techniques adopted recently are the “Vacuum Processing”.

The bearing steel is made through vacuum processing, which assists rod to be clean

& free from defects & give substantially larger bearing life.

Table 3.1 Contents of impurities in a Raw material

ELEMENT AMOUNT

Manganese 0.25 to 0.35

Silicon 0.025 to 0.35

Sulphur 0.025 max.

Phosphorus 0.025 max.

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Nickel 0.025 max.

Copper 0.35 max.

Molybdenum 0.10 max.

3.3.1. Raw material for outer ring, inner ring and cages

As railway bearing is included in three sections

Roller Bearing & Axle Boxes

Spherical Roller Bearing

Cartridge Tapered Roller Bearing.

A spherical roller bearing contains the following parts-

Main parts of Spherical Roller Bearings are follows-

(i) Races (outer and inner)

(ii) Rollers

(iii) Cage

The demand on the steel industry to provide higher quality alloy steels promoted the

development of the cold charges in the basic material-lined, electric arc furnaces.

These furnaces let higher-and lower grade alloy scarps be mixed with plain carbon

scarp; economical operation and product quality are achieved through proper

selection and weight control of these materials. Knowing the exactly chemistry of

scarp charge reduce the consumption of more costly alloys that are added to the

melt and minimizes the introduction of undesirable tramp alloying elements. A

variety of steel and brasses are used for different components for bearings

depending upon the properties required in the final product.

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Table 3.2 Materials of Different components of a Bearing

Balls Ni-Cr Steel wire

Rollers High Carbon chrome steel rods

Races High carbon steel

Cage Brass and mild steel

NBC was the first one in India who made the cartridge tapered roller bearing with

the help of BRENCO Incorporated of USA.

3.4 Raw material suppliers

These are the industries which supply the forged raw material to NBC-

a) Ajanta turnings

b) Balaji engineering

c) Keshav engineering

d) Microtech engineering

e) Microtech rollers

The raw material first come in the inspection room and the following parts

inspects-

a) Turned finish inner ring

b) Turned finish outer ring

c) Cage or retainer

d) Semi finish/Finish rollers

Parameters that need to be check:19 | P a g e

For outer ring-

a) Width size

b) ID(Track Size)

c) ID roundness

d) OD Size

e) OD roundness

f) Eccentricity (Bore to OD)

g) Surface defects- free from damage, tool mark, black spot, rust, roughness,

burr etc.

h) Oiling

For inner ring-

a) Width size

b) Bore

c) Undercut size

d) Oil groove size

e) Surface defects

f) OD size

g) For SEMI-FINISH/FINISH ROLLER-

a) OD size

b) OD Ovality

c) OD Taper

d) Length

e) Recess Depth

f) Surface Roughness

g) Radius of large end

h) Radius of small end

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i) Hardness

j) Oiling

For RETAINER-

a) Total width

b) Small bore diameter

c) Pocket length

d) OD size at top

e) Sheet thickness at bore

f) Visual inspection

g) No. of pockets

3.5. Manufacturing processes of spherical roller bearing

NBC gets forged and roller bearings from their vendors, as there are no separate

dept. for forging or rolling. Than they do carburizing or other heat treatment to

strengthen the bearing or finally grinding or other finishing operation is performed

to make it able to operate in automotive vehicle, railway etc. The processes through

which bearing has to go are shown in flow diagram below-

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Fig: 3.2 Flow diagram of material flow in industry

Before going to discuss various dept. in railway division we will go through the

bearing material, which we are using in NBC.

3.6. Heat treatment and laboratory

Heat treatment of bearing steel components necessitates heating and cooling under

controlled atmospheric conditions to impact the desired material characteristics and

properties such as hardness, a diffused high carbon surface layer, high fracture

toughness or ductility, high tensile strength, improved machinability, proper grain

size, or reduced stress state. The specific thermal cycles that produce these material

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characteristics are:

(i) Annealing

(ii) Normalizing

(iii) Hardening

(iv) Carburizing

(v) Tampering and

(vi) Stress reliving.

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Figure: 3.3 Heat treatment sequence

Let’s discusses each process with respect to these parts for simplicity of

understanding

Fig: 3.4 Flow diagram of heating sequence of spherical bearings

3.7. Carburizing

Carburizing is a is a heat treatment process in which iron or steel absorbs carbon

liberated when the metal is heated in the presence of a carbon bearing material,

such as charcoal or carbon monoxide, with the intent of making the metal harder.

Depending on the amount of time and temperature, the affected area can vary in

carbon content. Longer carburizing times and higher temperatures lead to greater

carbon diffusion into the part as well as increased depth of carbon diffusion. When

the iron or steel is cooled rapidly by quenching, the higher carbon content on the

outer surface becomes hard via the transformation from austenite to martensite,

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while the core remains soft and tough as a ferritic and/or pearlite microstructure.

The carburizing is performed 940º to 980ºc in rotary hearth furnace with time of

10hrs. But carburizing is done for only cup and cone with Air: LPG =10:1 (Endo

Gas).

Fig 3.5 Rotary hearth furnace

3.8. Hardening Furnace

To control the mechanical properties, it is essential to start a structure with a

structure of austenite since it is state where the carbon atoms are distributed into

the iron matrix uniformly. The austenitic structure in steel is achieved by heating it

and soaking at a temperature above 7230C, depending on the carbon percentage.

In hardening furnace “case hardening” of the job is carried out in the presence of

R-Gas. R-Gas is a mixture of CO+H2+N2+CO2+H2O. R-Gas is formed by the

reaction of LPG with air. This reaction is taken place in retort at a temperature of

950 0C in the presence of catalyst.

Hardening furnace has four chambers. First chamber is at 840 0C and rest three

chambers are at 850 0C. After the hardening furnace bearing material (steel) is

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converted into austenite form.

3.9. Quenching-

Quenching is a process of cooling a metal at a rapid rate. This is most often done to

produce a martensite transformation. In ferrous alloys, this will often produce a

harder metal, while non-ferrous alloys will usually become softer than normal. To

harden by quenching, a metal (usually steel or cast iron) must be heated above the

upper critical temperature and then quickly cooled.

In NBC Oil is used in the quenching process and the oil is kept at a temperature of

250C. Agitator is used to stir the oil in the oil quenching tank.

From the figure 4.3, we can find that when we rapidly cool austenite form then

martensite will form and it will have more hardness in comparison to austenite

form. Then through the conveyor job is sent to the washing tank which is held at a

temperature near about 220C. The conveyor speed is 400 mm/Min. Then drying is

done with the help of air.

3.10 Tampering-

Martensite formed during the quenching process is extremely hard and brittle, and

lack toughness. Thus these steels are not suitable for some baring applications

requiring impact resistance; hence a secondary heat treatment process called

tempering is carried out on quenched steel to achieve the necessary toughness and

ductility by marginally sacrificing hardness. This process also relives the internal

stresses thus improving the ductility . The tempering temperature is about 200 C

for 2.5 hrs. The above mentioned time and temperatures during heat treatment

explanations are for cup, cone, and wear rings.

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Fig :3.6 Tempering furnace

3.11. Rockwell hardness test

To see the effect of tampering on bearing races Rockwell hardness test is being

used to check the hardness of races before and after the tampering. Before the

tampering hardness range lies between is 62 to 64 HRC and after tampering

hardness range is 60-62HRC. The overall effect of tampering also affects the

hardness and this reduced by 2HRC.

Principal of the Rockwell Test

The indenter moves down into position on the part surface

A minor load is applied and a zero reference position is established

The major load is applied for a specified time period (dwell time) beyond

zero

The major load is released leaving the minor load applied

The resulting Rockwell number represents the difference in depth from the zero

reference position as a result of the application of the major load. If HRC doesn’t

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meet our requirements then we reject the tampered lot. Behind this there may

be following causes-

a) Manufacturing Faultb) Furnace temperature faultc) Tampering fault

Fig: 3.7 Rockwell hardness test setup

3.12. Grinding Section

Grinding is a finishing process used to improve surface finish, abrade hard

materials, and tighten the tolerance on flat and cylindrical surfaces by removing a

small amount of material. In grinding, an abrasive material rubs against the metal

part and removes tiny pieces of material. The abrasive material is typically on the

surface of a wheel or belt and abrades material in a way similar to sanding. On a

microscopic scale, the chip formation in grinding is the same as that found in other

machining processes. The abrasive action of grinding generates excessive heat so

that flooding of the cutting area with fluid is necessary.

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During the grinding operations coolant is used regularly. Coolant is mixture of

water and oil. In coolant percentage of oil 3.5% and rest is water. For O.D grinding

in N.E.I. Ltd. HOCUT B-60 oil is used.

The objectives of cooling is are-

i. In grinding operations, due to contact of grinding wheel and job they

become hot so cooling is necessary.

ii. The chip, which is produced by grinding also, flows away.

3.12.1 Operational step to grind Inner race:

Fig3.8: process sequence

(a) O.D. grinding-

OD is the circumferential surface of the outer race of the bearing. The OD should

be surface finished since the bearing has to be assembled in machine. It is obtain in

an OD grinding machine. In this machine the outer race is rotated between two

grinding wheel. The outer race is passed in machine three times to get highly

finished as follows:

1. Rough1

2. Rough2

3. Fine finish

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O.D. Grinding Face Grinding Rail Grinding Flane grinding Bore Grinding

(b) Face grinding-

After hardening process the first of grinding is face grinding and this process is

done on facing wheel grinding machine by manual feeding of cup and cone. Facing

wheel grinding machine grind the face of races at an average speed of 225 races

per hour with maximum capacity of 550 races per hour. After facing inspection of

dimension also checked to ensure to quality of grinded face.

(c)Flange grinding-

The flange should be surface finished since the bearing has to be assembled in

machine. It is obtain in the flange grinding machine. In this machine one grinding

stone is used to cut and grind the flange portion of cone.

NC Mode - AUTO

Feed Mode - AUTO

Override - 120% (used to change machine speed.)

Tool movement during grinding is in all three dimensional axes i.e. X, Y, Z

axis.

(d) Bore grinding-

Bore is the inner circumferential surface of the bearing. The bore should be

surface finished since the bearing has to be assembled in machine. It is obtain in

the bore grinding machine. In this machine the grinding stone is moved in X and

Y axis.

Size Limit : +4 µm to -4 µm.

TOOL movement during grinding is in only two dimensional axes i.e. X, Z axis.

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(e) Honing machine (super finishing)

Honing is an abrasive machining process that produces a precision surface on

a metal work piece by scrubbing an abrasive stone against it along a controlled

path. Honing is primarily used to improve the geometric form of a surface, but

may also improve the surface texture.

3.12.2. Operation steps to outer race grinding

Fig: 13.9 Process sequences for outer race grinding

(a) Face grinding-

Facing of outer ring(cup) also takes place between two facing wheel, out of which one wheel is hard and one wheel is soft. Soft wheel used to take into account wear resistance of hard wheel. After facing inspection takes place with the tolerance of 40 micrometers. Flange width also checked with the tolerance of 15 micrometers

(b) Rail grinding-

Track is the path on which rollers will move so track of the cup should be grinded properly. So that rollers will move smoothly.

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Face Grinding O.D Grinding Rail Grinding

Fig: 3.10 Face grinding

(c) Honing machine (cup super finishing)

As rollers will move on the track so the track surface should be super finished

so the rollers will move smoothly. For this purpose honing is done.

Now Cup & Cone are ready to send assembly section. They reached assembly

section via conveyor.

3.12.3 Operational step in grinding of roller

Fig: 3.11 Rollers of spherical bearing

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Fig: 3.12 Process sequence for grinding of rollers

(a) Face Grinding-The face grinding is done after centerless grinding of rollers. Specially made machines used for face grinding.

Fig: 3.13 Face grinding of roller

(b) Body Grinding-

Body grinding of spherical rollers is done by specific grinding wheels made for ths

operation.

Fig: 3.14 Body grinding of rollers

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Body Grinding Face Grinding

(c) Roller super finishing (honing)-

Mostly one or two stage super finishing machines are used for rollers. The rollers

are supported and driven by control wheels. The stone oscillates across the O.D.

Fig: 3.15 Roller super finishing

3.13. Assembly section

The assembly part in NEI is done manually. The parts after going through various

in line inspection or a separate inspection for all bearing components sent to

assembly line. In assembly line each parts width, bore, track is checked again

through various gauges.

Assembly of Spherical Roller Bearings Components: -It includes

a) Inner race.

b) Outer race.

c) Roller section (Retainer Section).

d) Roller Cage.

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Fig 3.16 Elements after assembly of spherical bearings

3.14. Maintenance and inspection section

3.14.1 For machines

Maintenance and inspection is that section where various types of machines, tools

and machine parts are inspected for life requirement and better working features.

Various types of pressure gauges, vibration inspection machines and the noise

inspection machines are the special features of this section.

Maintenance and inspection is that section where various types of machines, tools

and machine parts are inspected for life requirement and better working features.

Various types of pressure gauges, vibration inspection machines and the noise

inspection machines are the special features of this section.

The machines used in this section are as follows:-

i. LATHE m/c,

ii. SHAPER m/c,

iii. BORING m/c,

iv. PLANNER m/c,

v. DRILLING m/c,

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vi. MILLING m/c,

vii. Universal type,

viii. Vertical and Common type, Plain Milling m/c

3.14.2. For bearing components

All these inspections are done manually

Inline Inspection After every specific operation there is checking of bearing

components (1 out of 20) through gauging processes like width, track or bore

gauge after width, bore or track grinding Resp.

Final Inspection when the complete grinding of a particular product is completed

like for cone all processes width, bore or track grinding is completed than it sent to

final inspection.

In Final Inspection we detect crack check by two methods:

a. Crack check Machine :- kerosene or magnetic flux is

used

b. Demagnetize Washing

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Chapter 4

Learning and Suggestions

4.1. Learning-

This training is very fruitful to me. I got immense knowledge of the industry

environment as I worked in the Taper Roller Bearing department. Besides that

outcomes of the training are pointed out beneath-

4.1.1. Effect of quenching medium-

We are using oil in quenching process but we can also use water, Brine solution or

air for quenching purpose. As we know that water has high thermal conductivity

and air has the least. So if we use water then cooling of the austenite steel will be

very fast and due to this crack will be formed on the surface of the steel or

material. If we use air that it will not remove the heat fast because it has low

thermal conductivity and it will not serve the purpose.

4.1.2. Rockwell hardness test process-

Before and after tampering to check the difference in hardness of bearing races that

comes in tampering process Rockwell Hardness Test is being used. The following

steps are to check the hardness-

Table:4.1 According to material/job, we select the load indenter and scale-

Material Load Indenter Scale

Hard job 150 kg Diamond C (Blake)

Soft job 100 kg Ball (HCS) B (Red)

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1. Set the polished job (by Mb paper) and apply the load by hand lever

2. Hold the load for 10 seconds

3. Release the lever and note the scale reading

Note: The range of hardening of standard piece should lies between +1.5 to -

1.5

4.1.3 Why material is demagnetized in Assembly section?

As we have noticed that material is demagnetized in the assembly section because

bearings will be set at a place where they will rotate and we know if a magnet will

rotate then it will produce electric field. So it may hamper the other activities of the

system. In machines it will tend to attract the machine parts.

4.1.4 How wastage reduced?

To reduce the wastage NBC come on a solution with the help of NTN Corporation.

They recognized six type of waste-

(a) Over Production-

They produce according to demand of customers.

It helps to reduce the waste & scrape.

(b)Waiting-

Process which takes maximum time, identify that process (bottle neck process) and

try to reduce the process time to reduce the idle time of other processes which

depends on that.

(c)Transportation-

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Try to minimize the distance between raw material and distance. This will save the

worker’s time and money and productivity will be increased. To do this a new

process can be stabilized or we can change the layout.

(d)Inventory-

Raw material should not be more than the demand. This stops the money in terms

of inventory.

(e)Motion-

Cause of this- not placing tools at their proper place, it effects the motion of

worker. So there is loss of worker time and loss of machine production. For this we

should apply the work standard and design the work table according to need.

(f)Re-work-

Cause- if product is not in proper size than there is need to again work on that. This

effects the loss of money, loss of worker and loss in production. For this we need

to understand the root of problem and try to make product correct in first time.

4.2 Flaking of rollers

Fig:4.1 Flaking of rollers

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Table:4.2 Causes and corrective of flaking

Causes Corrective

Excessive loads, fatigue life, improper handling

Find the cause of heavy, load

Improper mounting Check internal clearance, regularlyInsufficient precision of journal or housing

Improve precision of journal and housing

Insufficient clearance Improve operating conditionsContamination, Rusting Improve method of assembly and

handlingSoftening due to abnormal temperature rise

Check grease and greasing method

4.3 Comparisons between NBC Bearing and Bajaj Bearing-

Table:4.3 Comparison between NBC Bearing and Bajaj Bearing

Type NBC Bearing Bajaj BearingStake 11% 3.7%

Turnover(2012-13) Rs. 1326 crores Rs. 204 crores

Quantity 45.6 Million Bearings per annum

7.592 Million Bearings per annum

Range 6mm bore to 1300 mmOD 11mm bore to 95mm OD

Quality(Rejection) 1 PPM 6PPM

Customers More than 34 big industries and 21 countries

12 industries in India and 21 other countries

The comparison between NBC Bearing and Bajaj Bearing show that NBC bearings

is better than Bajaj Bearings in quantity wise and quality wise.

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Chapter 5

Conclusion and Discussion

5.1. Training experienceMy training period of 45 days turned out to be a wonderful experience both industrially and learning wise; experiencing the functionalities of Heavy Fabrication Block, flow of knowledge as well as decision making processes within the block. Working with the employees and learning from them was such a life changing experience.

5.2. About reportThrough this report, I have tried to present a comprehensive study of the various

functionalities and responsibilities of NBC Bearings. Starting from the overview of

the company till the explanation of various type of process i.e. heat treatment,

grinding, facing and the different type of machines used in that processes like for

grinder, machines for honing & super finishing machines are available, for heat

treatment rotary hearth furnace and tampering furnace and CNC machines. This

report tries to throw light on each and every aspect of the NBC Bearings.

5.3 Conclusion

Maximum of their work was done manually. While in railway bearing division, the

whole processing is automatic. But now days they are trying to set up new NOVA

CNC machines. It will reduce the human effort or will increase productivity up to a

large extent. This setting up of new nova machines will place the NBC at a

position to compete with other worldwide bearings mfg. co.

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How an Industry works.

Learning of practical aspects of various dept. (Heat treatment, Grinding) in

railway bearings.

Got a brief idea about various heat treatment processes along-with their

industrial use.

Working of conventional machining process (grinding).

Industrial applications of all types of grinding and finishing processes.

Use of various gauges along-with applications of dial indicators in gauges.

How all the maintenance and inspections is done on in line processing or

after processing.

Various techniques of inspection methods.

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REFERENCES

BHANDARI V.B., Rolling Contact Bearing, Tata McGraw Hill

Education Private Limited, Fifth Reprint 2011.

RAO P.N, volume 2, Abrasive Processes, Tata McGraw Hill Education

Private Limited, Tenth Reprint 2011.

RAO P.N, volume 1, Engineering Materials, Tata McGraw Hill

Education Private Limited, Second Reprint 2009.

RAJVANSHI A.K., Manufacturing Processes, Genius Publications.

http://www.nbcbearings.in/nbcpdf/Spherical_Roller_Bearings_catalatue_F i

na.pdf, on 15/06/2013

http://www.nbcbearings.in/nbcpdf/TechnicalCatalogue2012.pd f , on

15/06/2013

http://www.nbcbearings.in/nbcpdf/CTRBM.PD F , on 15/06/2013

http://www.nbcbearings.in/nbcpdf/SRBMM.PD F , on 15/06/2013

http://smartinvestor.business

standard.com/BSCMS/PDF/SKF_20080703.pdf

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