A report on

Vocational Summer Training

“NATIONAL BEARING CORPORATION”

Submitted To:

Vivekananda Institute of Technology – (East), Jaipur

In partial fulfillment for the Award of Degree of

Bachelor Of Technology (Mechanical)

Submitted by- Submitted to:

Prem Prakash Khatri Mr. Rahul Goyal

B.Tech, 7th Semester H.O.D, Department of

Mechanical Engineering

CERTIFICATE

PREFACE

 

As per the requirement of B. Tech. Course, National Engineering Industries Ltd. (NEI), Jaipur has been kind enough to permit me to complete my Practical Training under TAPER ROLLER BEARING Division.

Practical training is an essential part of an engineering student as it adds to the technical knowledge of the student. It gives the student the much needed exposure to the real world and helps him to relate his theoretical knowledge with the field conditions. As a part of engineering curriculum each student has to undertake it for a prescribed duration.

According to our syllabus each student of B. Tech. Final year of VIVEKANANDA INSTITUTE OF TECHNOLOGY - EAST, JAIPUR has to complete a training of 30 days. Therefore, preferred to undergo my practical training at ‘NATIONAL ENGINEERING INDUSTRIES LIMITED’, JAIPUR which is a leading bearing manufacturer in Asia.

This report prepared during the practical training which is student’s first and greatest treasure as it is full of experience, observation and knowledge.

The summer training was very interesting and gainful as it is close to real what have been studied is all the years through was seen implemented in a modified and practical form.

The student wishes that this Gorgeous Private Sector undertaking success so that it may flourish and serve the nation which has reached significant years of its independence and has to achieve many goals.

ACKNOWLEDGEMENT

I feel privileged to express my genuine thanks and deepest sense of gratitude to my project guide Mr. S S Pradhan, Head DRAC Dept., R.B.Division, NEI JAIPUR for his timely & valuable suggestions and constant support, throughout the training period which motivated me to pursue my training with great enthusiasm and dedication. His way of dealing the problem and encouragement are constant source of inspiration.

I am also highly indebted to Mr. Devesh khandelwal Engineer, R.B. Division for constant encouragement and guidance on each and every step of my training period.

I sincerely acknowledge them for extending their valuable guidance , critical reviews of the project and the report and above all the moral support they had provided to me with all stages of this project.

Further, I am grateful to the entire team of NEI/JAIPUR Site for their constant support during the tough times.

Prem Prakash Khatri Vocational Trainee

CONTENTS

1. INTRODUCTION 2. PLANT AT JAIPUR

A. BALL BEARINGB. STEEL BALLC. TAPERED ROLLER BEARINGD. RAILWAY BEARING

I. ROLLER BEARING AND AXEL BOXII. SPHERICAL ROLLER BEARINGIII. CARTRIDGE TAPERED ROLLER BEARING

E. LARGE DIAMETER BEARING

3. PLANT AT GUNSI4. PLANT AT MANESAR

A. MACHINE BUILDINGB. RESEARCH AND DEVELOPMENT

BALL BEARING

1. HISTORY2. TYPES OF BEARING

A. RADIAL DEEP GROOVE BALL BEARINGB. FLANGED RADIAL DEEP GROOVE BALL BEARINGC. ULTRA THIN RADIAL BALL BEARINGD. DOUBLE ROW ANGULAR CONTACT BALL BEARINGE. PARTS DOUBLE ROW ANGULAR CONTACT BALL BEARING

3. ABOUT STEEL BALL BEARING

A. OUTER RACEB. INNER RACEC. ROLLER BALLSD. SHIELD

FLOWCHART OF BALL BEARING

1. PROCEDURE TO MAKE A BEARING

A. HARDNINGB. PRE-GRINDINGC. GRINDINGD. ASSEMBLYE. POST WASHERF. TEMPERATURE FURNACE

PRE GRINDING

1. NIPPEY2. FOR OUTER DIAMETER GRINDING

A. UMICRONB. MICRON

3. GRINDING

INTRODUCTION

National Engineering Industries Ltd.,part of the 150 year old, multi-billion dollarC.K. Birlagroup manufactures a wide range of bearings for automotive and railway industryas well as for general industrial applications under the brand name nbc . NEI, founded inthe year 1946 as a pioneer industry in the field of bearing manufacture, now manufacturesnearly 80 Million Bearings per annum in over 500 different sizes ranging from 6 mm bore to1300 mm outer diameter having capability to manufacture bearing upto 2000 mm. diameter.NEI is one of the largest domestic bearing manufactures with gross annual turnover of Rs. 1051 crore in 2010-11. The company exports bearings to more than 20 countries and is also exporting to OEMs in Europe and USA. NEI has grown at a CAGR of 19% since 2007-08.

NEI manufactures a wide range of bearings namely ball and cylindrical roller bearings,double row angular contact bearings, tapered roller bearings for automobiles, railways and industrial applications and large diameter bearings for steel plants and rolling mills. The three plants situated at Jaipur, Newai and Manesar manufacture these products with approx. 2300-strong team, supported by a well-equipped R&D with bearing life testing facility.

NEI Ltd. has been awarded the coveted 2010 Deming Application Prize, by the Union of JapaneseScientists and Engineers (JUSE), Japan, for achieving distinctive performance improvement through the application of Total Quality Management (TQM).The Deming medal confirms that our quality management systems are one of the best ,globally .For our customers, this means enjoying consistently superior products and assurance of highest quality for every NBC bearings they use .

R&D is equipped to introduce new technology in the field of bearings and related products .All functions from concept design to product launch are an integral part of R&D . The activitybegins from customer interaction by Application Engineering and QFD approach is used to understand customer requirements to translate into a useful product . It has a full fledged test centre for endurance as well as application testing .The test lab is being expanded to double the capacity in next four years. Advanced functions like Tribology ,Simulation ,Materials Technology and Lubrication technology have been added .The centre relies on the associate strength that has vast experience in the bearing industry . Academics excellence is being promoted by inclusion of specialists from IIT’s and REC’s .The centre will be a leading technology centre in next 4 to 5 years.

 

I) PLANT AT JAIPUR :

(i). Ball Bearing:Precision Ball Bearings from 6 mm bore to 75 mm bore diameter are manufacturedon state of the art manufacturing facilities with in-process and post-process gauging in grinding and centrally air conditioned assembly lines with auto gauging and testing equipments. The latest advanced techniques for manufacturing and Quality Assuranceare implemented to meet the rapid increase in demand for Quality, diversity of specifications and new types of bearings.

This Division  is spread over a covered area of 14,694 Sq. Meters.

II). STEEL BALL :Precision Steel Balls up to 25 mm diameters for NBC Bearings are manufactured on precision grinding and lapping machines to achieve super finished surface, accuracy and roundness as per ISO standards.This Division is spread over a covered area of 4,700 Sq. Meters

III). TAPERED ROLLER BEARING :Precision Tapered Roller Bearings are manufactured in Inch and Metric series from 15.875mm bore to 95.25mm bore with technology obtained from our earlier collaborator, Federal Mogul Corporation, USA and now with NTN Corporation, Japan. These bearings are used by all major Automobile manufacturers in the country as Original Equipment.This Division is spread over a covered area of 11,652 Sq. Meters.

(iv). Railway Bearing : 

(a)

Roller Bearing in Axle Box:

With the production of Roller Bearings and Axle Boxes since 1952, the company hasfully 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 Railways. The development of completely indigenised Axle Boxes and bearings for the high speed Rajdhani Locomotive,  the Yugoslavian and Egyptian Railway wagons are the highlights of the design capabilitie at NEI. On date more than 100 types of Axle Boxes & Bearings have been manufactured.

 (b)

Spherical Roller Bearing:

The manufacturing of Spherical Roller Bearings was started in the year 1975-76 for fitmentto broad gauge and meter gauge passenger coaches with designs, technology, machinesand equipment procured from the collaborators.

 (c)

Cartridge Tapered Roller Bearing:

For fitment to the new BOX-IN Uprated Wagons designed by the RDSO, NEI is the only manufacturer in the country to indigenise these bearings to a high percentage under collaboration with the largest manufacturer of  these bearings in the world. Production of these bearings commenced in the year 1984. These bearings are grease packed and require no field lubrication for a period of 7 years.

(v). 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 in the world, who can manufacture large diameter bearings up to 2000 mm diameter.The largest bearing manufactured by NEI for fitment to the Plate Mill of Rourkela Steel Plant was released by Mr. G.P. Birla in September 1985. This 4-Row Tapered Roller Bearing measures 1300 mm dia and weigh 4.39 tons.The large diameter bearings are mainly manufactured out of case carburising steel, heat treated on special equipment and furnaces developed by NEI. 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 diameterbearings have been manufactured and successfully used, saving considerable foreign exchange for the country.

The Large Diameter Bearings Division is spread over a covered area of 2,508 Sq. Meters.

(II) PLANT AT GUNSI (NEWAI) :

Established in the year 1980-81 as an expansion project of NEI Ltd. The factory is equippedwith fully automated grinding lines with electronic in-process & post- process gauging and centrally air-conditioned assembly lines with auto gauging and test equipments for quality and reliability of the products.The plant is spread over a covered area of 7,200 Sq. Meters. 

(III) PLANT AT MANESAR :

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 equipments.

RESEARCH & DEVELOPMENT AT JAIPUR

(a)

Design & Development :

Complete in-house facility for design development of all types of bearings and tooling is available. The design of all types of bearings is done on ProEngineer 3D  Modeling & Analysis Software. The capability to offer finest engineering services in thebearing industry has enhanced. Services of team of experienced engineers are availablefor selection of bearing as per application Complete engineering and research facility is available to solve intricate problems withexpert advice on design, development, manufacturing, installation and maintenance of

bearings. With the signing of the technical collaboration agreement with NTN  Corporation, Japan & BRENCO Inc of USA, the capability to offer finest engineering services in the bearing industry has enhanced. Services of team of experiencedengineers are available for selection of bearing as perapplication.

(b)

Machine Building :

NEI has the capability of machine building to design, develop and manufacture special purpose CNC Grinding Lines, HT Lines, Material Handling Equipments 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 facilitie supports the Machine Building Division.Machine Building has the capability and supports the Manufacturing Divisions by overhauling and retrofitting of the existing equipments, resulting in upgraded quality and improved productivity.R&D  Division is spread over a covered area of 2,007 Sq. Meters 

  SAP ERP:

In order to reengineer and integrate the Business processes for sales, production,materials and finance, NEI has successfully implemented SAP- ERP. By use this. Package, our processes now conform to international standard.

BALL BEARING

A ball bearing is a type of rolling-element bearing that uses balls to maintain theparationbetweenreduce rotational friction and support radial and axial loads. It achieves this by using atleast two races to contain the balls and transmit the loads through the balls. In most applications,one race is stationary and the other is attached to the rotating assembly (e.g., a hub or shaft). As one of the bearing races rotates it causes the balls to rotate as well. Because the balls are rolling they have a much lower coefficient of friction than if two flat surfaces were sliding against each other.

Ball bearings tend to have lower load capacity for their size than other kinds of rolling-element bearings due to the smaller contact area between the balls and races. However, they can tolerate some misalignment of the inner and outer races.

In the case of ball bearings, the bearing has inner and outer races and a set of balls. Each race is a ring with a groove where the balls rest. The groove is usually shaped so the ball is a slightly loose fit in the groove. Thus, in principle, the ball contacts each race at a single point. However, a load on an infinitely small point would cause infinitely high contact pressure. In practice, the ball deforms (flattens) slightly where it contacts each race, much as a tire flattens where it touches the road. The race also dents slightly where each ball presses on it. Thus, the contact between ball and race is of finite size and has finite pressure.There are opposing forces and sliding motions at each ball/race contact. Overall, these cause bearing drag.

HISTORY

In late eighteenth century that the basic design for bearings was developed. In 1794, Welsh ironmaster Philip Vaughan patented a design for ball bearings to support the axle of a carriage. Development continued in the nineteenth and early twentieth centuries, spurred by the advancement of the bicycle and the automobile.

There are thousands of sizes, shapes, and kinds of rolling bearings; ball bearings, roller bearings, needle bearings, and tapered roller bearings are the major kinds. Sizes run from small enough to run miniature motors to huge bearings used to support rotating parts in hydroelectric power plants; these large bearings can be ten feet (3.04 meters) in diameter and require a crane to install. The most common sizes can easily be held in one hand and are used in things like electric motors.

In these bearings, the rolling part is a ball, which rolls between inner and outer rings called races. The balls are held by a cage, which keeps them evenly spaced around the races. In addition to these parts, there are a lot of optional parts for special bearings, like seals to keep oil or grease in and dirt out, or screws to hold a bearing in place. We won't worry here about these fancy extras.

Types of Bearing

The single row radial deep groove ball bearing is NMB's most widely produced ball bearing. In addition to open radial ball bearings, NMB also offers bearings with shields or seals. Shielded or sealed bearings provide a protective boundary from excess grease and other efficiency-compromising substances. Snap ring and flange type bearings provide improved housing fits. NMB also makes available, ultra thin type radial ball bearings.

Radial deep groove ball bearings (R-, L-, RI-)

Characteristics: The radial deep groove ball bearing is a very popular bearing. It is able to carry both radial and axial forces.

Types: Open, shield, and seal types Metric and inch series

Flanged radial deep groove ball bearing:(RF-, LF-, RIF-)

Characteristics: The flanged radial deep groove ball bearing is a radial ball bearing with a flange featured on one side of the outer ring surface. The flange makes the axis direction for housing assembly easier to discern.

Types: Open, shield, and seal types Metric and inch series. Stainless steel is the standard material.

Radial deep groove ball bearings with a snap ring on the outer ring (RNR-, LNR-)

Characteristics:. A radial deep groove ball bearing with a snap ring on the outer ring is comprised of an outside containing ring on a face of the outer ring surface, which makes axis orientation more identifiable and construction less time consuming.

Types :Open and shield types * High carbon chromium steel is the standard material.

Ultra thin radial ball bearings (A-)

Characteristics :The bore to outer diameter ratio in ultra thin radial ball bearings exceeds that of standard radial ball bearings.

Types :Open and shield types Stainless steel is the standard material.

DOUBLE ROW ANGULAR CONTACT BALL BEARING

Double row angular contact ball bearings are units with solid inner and outer rings and ball and cage assemblies with polyamide or sheet steel cages. Their construction is similar to a pair of single row angular contact ball bearings in an O arrangement but they are narrower to a certain extent. The bearings are available in open and sealed designs. Due to the manufacturing processes used, open bearings can have turned recesses in the outer ring for seals or shields. Sealed bearings are maintenance-free and therefore allow particularly economical bearing arrangements. Due to the raceway geometry and the two rows of balls, the bearing can support forces in both radial and axial directions. They are therefore particularly suitable for use in pumps and agricultural machinery. Furthermore, double row angular contact ball bearings are used in applications including conveying equipment, packaging equipment, elevators and compressors.

An angular contact ball bearing uses axially asymmetric races. An axial load passes in a straight line through the bearing, whereas a radial load takes an oblique path that tends to want to separate the races axially. So the angle of contact on the inner race is the same as that on the outer race. Angular contact bearings better support "combined loads" (loading in both the radial and axial directions) and the contact angle of the bearing should be matched to the relative proportions of each. The larger the contact angle (typically in the range 10 to

45 degrees), the higher the axial load supported, but the lower the radial load. In high speed applications, such as turbines, jet engines, and dentistry equipment, the centrifugal forces generated by the balls changes the contact angle at the inner and outer race. Ceramics such as silicon nitride are now regularly used in such applications due to their low density (40% of steel). These materials significantly reduce centrifugal force and function well in high temperature environments. They also tend to wear in a similar way to bearing steel—rather than cracking or shattering like glass or porcelain.

Most bicycles use angular-contact bearings in the headsets because the forces on these bearings are in both the radial and axial direction.

PARTS OF DOUBLE ROW ANGULAR CONTACT BAAL BEARING

1.Retainers/Cage

The following retainers are available in most of our Ball Bearings.

Ribbon Retainer/Cage (Symbol R)

It is composed of two press molded steel parts. The balls are held between the two steel parts, and the tabs of one of the steel parts are bent over the second steel part to unite them together. This is the most common type.

Crown Retainer/Cage (Symbol H)

It is composed of a press molded steel part. The small difference in inner and outer diameters of the retainer allows them to be used for thin type and very small ball bearings.  

Plastic Retainer/Cage (Symbol MN etc.)

It is composed of a molded and cut plastic part. The plastics include Polyamide, Polyacetal, and so on. It is used for high speed rotation and low noise level.

2. About Steel Ball Bearings

Inner Ring, Outer Ring, and Ball Bearing Materials

Stainless Steel ball bearings are machined components that include outer ring, inner ring, ball bearings, shielded bearings, snap rings, and more. Stainless Steel ball bearings are used when there is a need for high efficiency, low torque, long bearing life, and a low noise level. Using stainless steel as the material for ball bearings delivers all these advantages. Stainless Steel ball bearings are also used when applications require bearings to provide superior hardness and anti-corrosion or heat-resistance. NMB has a wide variety of ball bearings, so you can be sure you’ll find the exact ball bearing you need with us. Search for ball bearings by metric and inch sizes, flanged or unflanged bearing options, and by open or shielded bearings.

Ring and Ball materials are subjected to severe stress reversals of approximately 1000 MPa. For applications with so many high pressure compressive stress reversals endured for such prolonged periods, an extremely pure and hard material is required. Therefore, careful selection of the raw material is necessary for bearings. NMB mainly uses high performance carbon chromium steel; or when good corrosion resistance is required, martensitic stainless steel. Our high carbon chromium steel is supplied to the specification JIS G4805/SUJ2, AISI/SAE52100 or equivalent, which is hardened, providing long life and high load capacity for our bearings.

Almost all parts of all ball bearings are made of steel. Since the bearing has to stand up to a lot of stress, it needs to be made of very strong steel. The standard industry classification for the steel in these bearings is 52100, which means that it has one percent chromium and one percent carbon (called alloys when added to the basic steel). This steel can be made very hard and tough by heat treating. Where rusting might be a problem, bearings are made from 440C stainless steel.The cage for the balls is traditionally made of thin steel, but some bearings now use molded plastic cages, because they cost less to make and cause less friction.

3.OUTER RACE:

OUTER DIAMETER: BORE FACE

4. INNER RACE:

OUTER DIAMETER TRACK FACE

5. ROLLER BALLS

The balls are a little more difficult to make, even though their shape is very simple. Surprisingly, the balls start out as thick wire. This wire is fed from a roll into a machine that cuts off a short piece, and then smashes both ends in toward the middle. This process is called cold heading. Its name comes from the fact that the wire is not 

.

heated before being smashed, and that the original use for the process was to put the heads on nails (which is still how that is done). At any rate, the balls now look like the planet Saturn, with a ring around the middle called "flash."

5 The first machining process removes this flash. The ball bearings are put between the faces of two cast iron disks, where they ride in grooves. The inside of the grooves are rough, which tears the flash off of the balls. One wheel rotates, while the other one stays still. The stationary wheel has holes through it so that the balls can be fed into and taken out of the grooves. A special conveyor feeds balls into one hole, the balls rattle around the

groove, and then come out the other hole. They are then fed back into the conveyor for many trips through the wheel grooves, until they have been cut down to being fairly round, almost to the proper size, and the flash is completely gone. Once again, the balls are left oversize so that they can be ground to their finished size after heat treatment. The amount of steel left for finishing is not much; only about 8/1000 of an inch (.02 centimeter), which is about as thick as two sheets of paper.

6 The heat treatment process for the balls is similar to that used for the races, since the kind of steel is the same, and it is best to have all the parts wear at about the same rate. Like the races, the balls become hard and tough after heat treating and tempering. After heat treatment, the balls are put back into a machine that works the same way as the flash remover, except that the wheels are grinding wheels instead of cutting wheels. These wheels grind the balls down so that they are round and within a few ten thousandths of an inch of their finished size.

7 After this, the balls are moved to a lapping machine, which has cast iron wheels and uses the same abrasive lapping compound as is used on the races. Here, they will be lapped for 8-10 hours, depending onhow precise a bearing they are being made for. Once again, the result is steel that is extremely smooth.

8 Steel cages are stamped out of fairly thin sheet metal, much like a cookie cutter, and then bent to their final shape in a die. A die is made up of two pieces of steel that fit together, with a hole the shape of the finished part carved inside. When the cage is put in between and the die is closed, the cage is bent to the shape of the hole inside. The die is then opened, and the finished part is taken out, ready to be assembled.

9 Plastic cages are usually made by a process called injection molding. In this process, a hollow metal mold is filled by squirting melted plastic into it, and letting it harden. The mold is opened up, and the finished cage is taken out, ready for assembly.

6. SHIELD

Shields and Steels (Enclosures)

Steel Shield-Snap Ring Type

NMB part number symbol : ZZ

The metal shield is a steel plate secured in the outer ring with a steel snap ring.

Steel Shield-Caulking Type

NMB part number symbol : KK or HHJIS part number symbol : ZZ 

The shield is a formed steel plate, pressed into a recess in the outer ring.

          

Rubber Non-Contact Steel

Symbol SS

Refers to NMB & JIS numbering system. The rubber non-contact seal is constructed with a snap-fit into the outer ring.

Rubber Contact Seal

Symbol DD

Refers to NMB & JIS numbering system. The rubber contact seal provides a positive contact onto the inner ring and is a snap fit into the outer ring.

CUTTING OIL: This is the fluid which is used for cooling of bearing during all operations.

The fluid we use is R-gas which is a combination of L.P.G gas and air at high temperature

(O2 + N2) + (C4H10 + C3H8) + air+ catalyst R-gas(Co + N2 +H2) +other gas (21% + 79%) (63.5% + 36.5%) (At 950°c) (23.4%+31.4%+45.3%) (1.2%)

R-gas is made furnace without o2 environment

FLOWCHART OF AU0504-6LX2X/L 588 BALL BEARINGS

OUTER RACE (OR) INNER RACE (IR)

SAE – 52100 (BAR/FORGING)

R.M. INSPECTION -BAR

FORGING AND ANNEALING

SAE-52100 (BAR/FORGING)

R.M. INSPECTION -BAR

FORGING AND ANNEALING

COMPLETE FINISHING, TURNING WITH REAL GROOVE TURNING

RECORD INSPECTION, METEORIGICAL INSPECTION

HEAT TREATMENT

100% CRACK CHECKING

FACE GRINDING

OUTER DIAMETER GRINDING

TRACK AND SEAL GROOVE GRINDING

TRACK SUPERFINISHING AND WASHING OR

OR ID CHECKING, OR TRACK PITCH CHECKING

COMPLETE FINISHING AND TURNING

RECORD INSPECTION, METEORIGICAL INSPECTION

HEAT TREATMENT

100% CRACK CHECKING

FACE GRINDING

TRACK OD AND FACE GRINDING

BORE GRINDING

TRACK SUPERFINISHING AND WASHING

IR WASHING, IR ID CHECKING, IR PITCH CHECKING

BALL FALLING IN CAGE

CAGE BALL ASSEMBLY PLACING IN OUTER RACE

HEATING OF OR AND CAGE BALL ASSEMBLY IR FORGING AND FITTING

BEARING COOLING

DEMAGNETISER

WASHING AND DRYING

PROCEDURE TO MAKE A BEARING

1. HARDENING

2. PRE – GRINDING

3. GRINDING

4. ASSEMBLY

HARDENING

NOISE TESTING AND AXIAL CLEARANCE CHECKING

GREASE FILLING AND WEIGHT CHECKING, SEAL FILLING BOTH SIDES AND CHECKING

LASER MARKING

100% VISUAL INSPECTION

OILING

WRAPPING AND PACKING

DESPATCH ASSURANCE

DELIVERY TO FINISH GODOWN

SHIPMENT

Hardening of steels is a procedure for modifying the metal's characteristics to better suit the job it has to perform. In the case of tool bits it enables them to machine other materials and still retain a sharp cutting edge, while in the case of work pieces it can materially alter their wear characteristics and tensile strength. Virtually all steel hardening processes involve the inclusion of particular carbon compounds either at the metal's surface or throughout the body of the metal via the application of heat. It's true that metals can also be 'work-hardened' or forged or laminated but the application of these processes will not be considered here. Some types of tool steel have other trace elements such as cobalt and tungsten in addition to carbon which augment the ultimate hardness achieved and the temperature at which they can operate. The hardening and tempering of such tool steels ('high-speed' steels as they are known) are beyond the scope of the average home workshop and these steels are usually purchased as shaped bits in the ready hardened state.

At critical temperature (about 800 degrees C) steel has an affinity for carbon which will be actively absorbed to form a compound called iron carbide. It's an interesting observation that at the critical temperature where the carbide compound forms magnetic attraction disappears, a useful method for determining the correct temperature for hardening purposes. If the steel is then left to cool slowly this carbon-iron compound will spontaneously dissociate back into its component elements of carbon and iron again. In contrast, if the steel is cooled very rapidly this dissociation does not have chance to take place and the carbon remains trapped in the form of the iron carbide compound. This carbon may already be present in the steel in a variable proportion as part of its manufacture (but usually not as the carbide form) in which case the steel is known as a 'carbon steel'. Alternatively, extra carbon may be made available to the steel by packing it together with carbon-rich compounds and applying heat over a period of hours, whereupon the carbon is drawn into the outer layers of the metal's surface (a process called case-hardening). Iron carbide is a very hard material but is also very brittle and has little structural strength. The art of hardening and tempering is to balance the very hard characteristics of iron carbide with the toughness, resilience and ductility (i.e., resistance to breakage) of the base metal. An added complication is changes which occur in the metal's crystalline grain structure which is also dependent upon rate of heating and cooling.

The rough cut races are put into a heat treating furnace at about 1,550 degrees Fahrenheit (843 degrees Celsius) for up to several hours (depending on the size of the parts), then dipped into an oil bath to cool them and make them very hard. This hardening also makes them brittle, so the next step is to temper them. This is done by heating them in a second oven to about 300 degrees Fahrenheit (148.8 degrees Celsius), and then letting them cool in air. This whole heat treatment process makes parts which are both hard and tough.

JOB OR BEARING

PRE WASHING AT 60°C 

Procedure:

1. LOADING DUMPER:No smoke, no fuel, no noise, no pollution . Environment – friendly. It respects the operator and the others. it is easy to understand the big success it will meet. it is the perfect solution for:  indoors historic centre’s beaches public places tunnels, all the places where it is necessary to work without any risks,  gases,  smokes, noises.

2. PRE WASHER: it is used to clean the bearing from dust or any other impurities. It is used to clean up dust which is being accumulated during storage so that we use the oiling of bearing so that no rust can be formed on them and we can use them.

ZONE

1

840°C 

ZONE

2

850°C 

ZONE

3

850°C

ZONE

4

850°C

AIR+LPG+MIXTURE AT 950°C

QUENCHING OIL AT 105°C

------------------------------------------------------------------------------------------------------------------------------------------------------------------

COOLING WASHER + AIR DRYER

(22°C) + (8°C)

WATER AND AIR THROUGH RETORD

TEMPERING ZONE at 148.8°C

FOR 90 MINUTES

AIR COOLING

3. RABBIT CONVEYOR:A gate for pipe conduits of pneumatic rabbit conveyors, in which two rigidly interconnected branch pipes having a diameter corresponding to that of the pipe conduit accommodate there between, a gate valve having an opening for the passage of rabbits and working fluid and being displaceable with the aid of a drive. The branch pipes are interconnected by means of tie pieces, while the gate valve is defined by a section of pipe, having a diameter corresponding to that of the branch pipes, and two packing supporting sides

HEATING FURNACE: A method for producing a bearing ring having an annular race, the method comprising the steps of:

Providing a first side inductor and a second side inductor, each inductor for generating an electric field for heating;providing a first side sprinkler and a second side sprinkler for quenching;arranging the first side inductor and the second side inductor at a joint zone of the annular race to be hardened and heating a peripheral layer juxtaposed at the joint zone, with the first side inductor and the second side inductor, to the hardening temperature;moving the first side inductor along a first side of the annular race and moving the second side inductor along a second side of the annular race, such that the first side inductor and the second side inductor move in opposite directions along the annular race for heating of the subsequent central zone along the first side of the annular race and the central zone along the second side of the annular race;

Turning on sprinklers directed onto the heated peripheral layers to quench these layers, proceeding from the center of the joint zone;moving the inductors and the sprinklers until they coincide again at a zone lying opposite to the joint zone and again form a second joint zone;after reaching the required hardening temperature of the second joint zone, lifting both the first side inductor and the second side inductor from the surface of the race;

Directing the sprinklers onto the second joint zone. It is done at different temperature zones- Heating furnace 1- Furnace 2 Furnace 3 Furnace4

4. QUENCHING: In materials science, quenching is the rapid cooling of a work piece to obtain certain material properties. It prevents low-temperature processes, such as phase transformations, from occurring by only providing a narrow window of time in which the reaction is both thermodynamically favorable and kinetically accessible. For instance, it can reduce crystallinity and thereby increase toughness of both alloys and plastics (produced through polymerization).

In metallurgy, it is most commonly used to harden steel by introducing martensite , in which case the steel must be rapidly cooled through its eutectoid point, the temperature at which austenite becomes unstable. In steel alloyed with metals such as

nickel and manganese, the eutectoid temperature becomes much lower, but the kinetic barriers to phase transformation remain the same. This allows quenching to start at a lower temperature, making the process much easier. High speed steel also has added tungsten, which serves to raise kinetic barriers and give the illusion that the material has been cooled more rapidly than it really has. Even cooling such alloys slowly in air has most of the desired effects of quenching.

5. POST WASHER: In this process the bearing is dried after being quenched in oil.

6. TEMPERING FURNACE:Tempering is a process of heat treating, which is used to increase the toughness of iron-based alloys. It is also a technique used to increase the toughness of glass. For metals, tempering is usually performed after hardening, to reduce some of the excess hardness, and is done by heating the metal to a much lower temperature than was used for hardening. The exact temperature determines the amount of hardness removed, and depends on both the specific composition of the alloy and on the desired properties in the finished product. For instance, very hard tools are often tempered at low temperatures, while springs are tempered to much higher temperatures. In glass, tempering is performed by heating the glass and then quickly cooling the surface, increasing the toughness.

7. Tempering is a process in which previously hardened or normalized steel is usually heated to a temperature primarily to increase ductility and toughness. but also to increase the grain size of the matrix. Steels are tempered b) reheating after hardening to obtain specific values of mechanical properties and also to relieve quenching stresses and to ensure dimensional stability.

PRE – GRINDING

When a new tool has been built and has been heat-treated, it is pre-ground before welding or hard facing commences. This usually involves grinding the OD slightly higher than the finish grind OD to ensure the correct finish size.

THIS PROCESS CAN BE DONE THROUGH MANY MACHINES SUCH AS:

1. FOR FACE GRINDING

NIPPEY NISSEOUTER RACE

1. FACE GRINDING: In this process we remove the excess of FACE material from the face of outer and inner race of the material of bearing. It is the first operation after the hardening process. The rollers are ground parallel to the final dimension and quality.This is usually done in a double disc grinder in mostly one pass. For larger rollers or small series, grinders with cup wheels or grinding cups are used.

Firstly, the bearing is passed to the conveyor to the machine. The bearing passed through a small area in horizontal bearing position through guide vanes to the two wheels which push them with force into the main machine chamber where the two grinding wheels(one grinding wheel and other regulating wheel) The both wheels are used to grind the face of bearing which revolve in opposite directions. It produce good quality and high output This is FACE GRINDING

NIPPEY:

Put bearing to the conveyor which takes it to the machine on which a big grinding wheel is placed having holes of specific bearing size used to place bearing in them in horizontal position The big wheels rotate inside the machine and bearing inside the holes with them. The two wheels inside the machine(grinding wheel and other regulating wheel) when passed through the big wheel on which bearing are fixed gets their face grinded This process occurs for other face also

2. For OUTER DIAMETER GRINDING: UMICRON MICRON

OUTER DIAMETER GRINDING: In this process the outer surface of the machine is grinded and excess of the material is removed. The ovality and wave from the hardening process has to be reduced to low tolerances by this process.

The bearing is taken from conveyor to the machine. Here centerless plunge grinders are used. The bearing takes a horizontal position and enters the main machine

chamber which contain two wheels(grinding wheel and regulatingwheel)

The two wheels used to grind the outer diameter of bearing. It removes about 1-2 mm of material

The basic difference between u micron and micron is that the in U MICRON small size of bearing is placed and operated automatic through computer whereas in MICRON large size bearing is used and is manually operated.

GRINDING

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

Grinding is used to finish work pieces which must show high surface quality (e.g., low surface roughness) and high accuracy of shape and dimension. As the accuracy in dimensions in grinding is on the order of 0.000025mm, in most applications it tends to be a finishing operation and removes comparatively little metal, about 0.25 to 0.50mm depth. However, there are some roughing applications in which grinding removals high volumes of metal quite rapidly. Thus grinding is a diverse field.

The Procedure of GRINDING

1. INNER TRACK GRINDING2. INNER BORE GRINDING3. INNER TRACK SUPER FINISHING

4. OUTER TRACK GRINDING5. OUTER TRACK SUPERFINISHING

INNER TRACK GRINDING:

In this process the track of the inner race is produced Firstly, the bearing is placed inside the machine and is made fixed Secondly, the big wheel of small thickness is placed just In opposite side to the bearing in such a way that it touches the top surface of bearing and grinding it perfectly It is also provided with a diamond darker which is used to sharpen the wheel and the process continues

INNER BORE GRINDING:

In this process the inner surface or bore is made and the bore has to be ground concentric and perfectly straight to the profile of the inner ring track

Firstly, the bearing is placed inside the machine with the help of robot works automatically as feeded

Secondly, the small size of wheel is used so that it can fixed inside the inner part of inner race and produce bore of appropriate size of inner track

It is also provided with a diamond dracer which is used to sharpen the wheel and the process continues.

INNER TRACK SUPERFINISHING:

In this process the roughing, honing and finishing is done to make the bearing most fit to use.

It is the final operation for bearing races. All qualities like roundness, form and surface finish have to meet low tolerances.

The rings are usually supported and driven by steel rolls and the stone oscillates around the race

There are two types of chalks are used:

Green –which is used for honing and finishing of the inner race

White -which is used for roughing of the bearing and removing unwanted material from its surface

It is used for the super finishing of the inner track of bearing

OUTER TRACK GRINDING:

In this process the track on the outer race is grinded means the unwanted material is removed from surface

Firstly, the bearing is fixed onto the machine with the help of robot

Secondly for outer track grinding we use a small wheel to grind the inner surface of outer race

It is also provided with the dracer for sharpening of the wheel and grind the wheel perfectly for good grinding of bearing

It is used to remove 1-2 mm of material

OUTER TRACK SUPER FINISHING:

In this process the unwanted material is removed from the surface with the help of roughing, honing and super finishing of the bearing with the help of stones

It is the final operation for bearing races. All qualities like roundness, form and surface finish have to meet low tolerances.

The rings are usually supported and driven by steel rolls and the stone oscillates around the race

Two types of stones used:

Green stone- for honing and finishing. It removes up to .2 mm of unwanted particles

White stone- for roughing of bearing. It removes micron mm of material

ASSEMBLY

An assembly line is a manufacturing process in which parts are added to a product in a sequential manner to create a finished product much faster than with handcrafting-type methods.Assembly lines are designed for the sequential organization of workers, tools or machines, and parts. The motion of workers is minimized to the extent possible. All parts or assemblies are handled either by conveyors or motorized vehicles such as forklifts, or gravity, with no manual trucking.

The principles of assembly are these:

(1) Place the tools and the men in the sequence of the operation so that each component part shall travel the least possible distance while in the process of finishing.

(2) Use work slides or some other form of carrier so that when a workman completes his operation, he drops the part always in the same place—which place must always be the most convenient place to his hand—and if possible have gravity carry the part to the next workman for his operation.

(3) Use sliding assembling lines by which the parts to be assembled are delivered at convenient distances

LINE LAYOUT OF AU1103

INNER RACE FROM GRINDING

WASHING OF INNER RACE

BORE CHECK

OUTER RACE FROM GRINDING

WASHING OF OUTER RACE

OD CHECK

RANDOM MACHINE MATCH

HEATING AND FITTING

AIR COOLING

DEMAGNITISER

LASER MARKING

BEARING WASHING (KEROSENE)

NOISE AND AXIAL CLEARANCE

GREASE FILLING AND SEAL FITTING

PROCEDURE

1. OUTER RACE AND INNER RACE MEASUREMENT: This method is used to find whether the inner race and outer race are having good surface finish or notIf not, then it is rejected else it is passed to 2 step

2. WASHING OF INNER AND OUTER RACE: Here the inner and outer race is washed with the help of kerosene and then with water to remove the dust and impurities present on surface

3. BORE CHECK FOR IR AND OD CHECK FOR OUTER: In this method, the bore is checked for inner race and outer diameter is checked for outer race whether its dimension are suitable or not, if does not suit the type of bearing then it is rejected or else it is passed on

4. RANDOM MACHINE MATCH: This is the major step where every part of bearing is made to assemble.Firstly, the outer race is passed to the machine where it is fixed with the roller balls which are preparing somewhere else and only assembled here.Secondly, it s passed on to fixed with the inner race from the both sides of the outer race and passed on.The random machine match means the machine picks up the right choice for inner and outer race of same dimension to fit into each other and proceed on.

5. HEATING AND FITTING: In this method, the bearing s passed to the next machine after passing through the random machine match .It is passed to heating chamber contain a high temperature and pressure which allow the bearing to expand and fix them properly into each other and no type of compression occur between inner and outer race.Then the bearing is passed to the cooling area where the heating done in previously is cooled and the bearing is made to fit better.

OILING

STACKET

VISUAL INSPECTION AND PACKING

6. AIR COOLING: Then the bearing is passed to the air cooling so that the bearing is cooled and used for the further process7. DEMAGNITISER: It is used to neutralize the effect of magnet produced due to heating and washing.

8. BEARING WASHING: The machine is passed to the washing machine where it is washed with the help of kerosene so that every time of impurities are removed from the bearing and passed on

9. NOISE AND AXIAL CLEARANCE: Here the testing of noise and axial clearance is tested.

10. GREASE FILLING AND SEAL FILLING: In this process the bearing is passed to the grease filling machine and seal is fitted over the inner race and roller ball on those outer part .The seal is fitted to the both sides of the bearing.

11. LASER MARKING: In this process the bearing is passed through laser machine where when bearing is passed to the laser it prints the company name, date of manufacturing, and product name so that when any type of error came they can identify the date and under whom the error came

12. OILING: Then it is passed to oiling machine where it is oiled properly

13. STACKER: Then it is passed to the stacker for the inspection

14. VISUAL INSPECTION: Then it is sent for visual inspection for the checking of the material where it is perfectly appropriate or not if minor mistake is their not caught by machine it should be caught in visual inspection

15. PACKING: Then the bearing s packed in the fibre and sent for shipment

APPLICATIONS

Today the ball bearing is used in numerous everyday applications. Ball bearings are used for dental and medical instruments. In dental and medical hand pieces, it is necessary for the pieces to withstand sterilization and corrosion. Because of this requirement, dental and medical hand pieces are made from 440C stainless steel, which allows smooth rotations at fast speeds.

Hard drive bearings used to be highly spherical, and were said to be the best spherical manufactured shapes, but this is no longer true, and more and more are being replaced with fluid bearings. German ball bearing factories were often a target of allied aerial bombings during World War II; such was the importance of the ball bearing to the German war industry.[5]

In horology, the company Jean Lassall designed a watch movement that used ball bearings to reduce the thickness of the movement. Using 0.20 mm balls, the Caliber 1200 was only 1.2 mm thick, which still is the thinnest mechanical watch movement.[6]

Aerospace bearings are used in many applications on commercial, private and military aircraft including pulleys, gearboxes and jet engine shafts. Materials include M50 tool steel (AMS6491), Carbon chrome steel (AMS6444), the corrosion resistant AMS5930, 440C stainless steel, silicon nitride (ceramic) and titanium carbide-coated 440C. Skateboarding. The wheels in a skateboard contain two bearings in each of the four wheels. Most commonly bearing 608-2Z is used (a deep groove ball bearing from series 60 with 8 mm bore diameter) There are Ball bearings in the center of high quality Agricultural Equipment. The many moving parts in a piece of farm machinery depend on several different types of bearings to operate. Under the heavy loads and dusty conditions, these bearings need to be lubricated, repaired, or replaced often.

TAPERED BALL BEARING:

In many applications tapered roller bearings are used in back-to-back pairs so that axial forces can be supported equally in either direction.

Pairs of tapered roller bearings are used in car and vehicle wheel bearings where they must cope simultaneously with large vertical (radial) and horizontal (axial) forces. Applications for tapered roller bearings are commonly used for moderate speed, heavy duty applications where durability is required. Common real world applications are in agriculture, construction and mining equipment, axle systems, gear box, engine motors and reducers.

Conclusion: This organization has a great work culture, great minds and very high quality of work. I learned a lot about Bearing and its manufacturing. I have tried to learn many new thing as much as possible from NBC and even got very encouraging results with some of them. The whole experience of working at NBC was great.