01-09-2014, 10:47 AM
t is my esteem privilege, to express deep sense of gratitude and indebtedness to my major advisors, Mr. Balbir Singh {personnel department officer} & Mr. P S Nanda (Manager of the Unit) GNA Duraparts {GNA auto parts}, Mehtiana for their expert and inspiring guidance, constructive criticism and constant encouragement during the course of this practical industrial training. I am very thankful to my contact persons i.e. incharges of the various shops/departments and personnel department officers who gave me such a use full guidance. I would be failing in my duties if I do not thank Mr.Gurdeep Singh Director, GNA Duraparts – Mehtiana, Who allowed me to undergo practical industrial training. Thanks are also due to all staff members of GNA Duraparts and others who took lots of interest in assisting me during the training period and in making the repot a success.
PURPOSE OF INDUSTRIAL TRAINING
It is a well-known fact that theoretical knowledge is totally handicap without the practical approach to the thing. Main purpose of the industrial training is to expose the trainees with practical experience of actual industrial conditions in which they will require to work in future and make them aware of the difference between the environment of industrial and college or homes. Thus the aim of the industrial training is to understand the layout of the industry, dealings with the various operations going in it and makes trainees to learn from the experiences of the professional Managers and skilled workmen with whom they are placed for training who have to work together with cooperation to achieve the common goal of the industry. This type of training gives chance for future advancement, thus giving trainee’s chance for specialization in particular fields. In industry, we perform the work, which we have studied in our theory portions. We get an extra knowledge by working in an industry and we also came to know the problems to be faced in future. This type of training gives chance for further advancements. Thus, it gives the trainees a chance for specialization in particular fields. INTRODUCTION TO THE UNIT The existence of GNA came into being in 1946, in a small village called Bundala in District Jalandhar of Punjab. GNA has made its presence prominent not only in India but also across the world. Today, more than 6000 families are proud to be associated with this giant colossal tree that bloomed from a seedling sown 62 years ago. Founded with a modest beginning by Late Mr. Amar Singh Ji and nourished by his sons Mr. Rachhpal Singh and Mr. Gursaran Singh, with the artistic creativity that was gifted to the next generation by tradition, GNA is now boosted and taken care by the third generation Mr. Jasvinder Singh, Mr. Maninder Singh, Mr. Ranbir Singh and Mr. Gurdeep Singh. Today GNA group has created an important place for itself in Indian as well as Global Automotive Industry. GNA group is on a fast moving track towards growth and globalization. The company has a large customer base covering different sectors of the automotive industry with diversified product range. Along with this the company shows steady growth profile even during the time when there is demand fluctuations in the automotive sector. GNA is an Original Equipment supplier to various Automobile Majors besides having a strong presence in the replacement market.GNA has been accredited with ISO 9002 and QS 9000 certifications for its quality systems holds a reliable name in the world of automotive components. Quality Management at GNA is a timeless concept wherein, changes in customer expectations are a driving force to go beyond conformance to standards. GNA’s quality assurance is equipped with the finest equipment ranging from metallurgical microscope to mobile spectrometer, ultrasonic flow detector, micro hardness testers, surface roughness testers, profile projectors and involutes profile testers. GNA sincerely believes in technology up-gradation for keeping a competitive edge. Indeed, this explains the continuous replacement of conventional manufacturing equipment with modernized transfer lines resulting in increased productivity and efficiency at low cost. GNA’s core competency lies in its strong knowledge base of engineering and over 59 years of experience in manufacturing. GNA has come a long way yet journey toward excellence is never ending Sri. Amar Singh Ji made a modest beginning with an ‘atta-chakki’ {Flour mill. Late Sardar Amar Singh established a small unit for the manufacture of axles under the name of ‘Nirankar Auto Engg. works in the late 1946. Through the last 62 years the company has grown in leaps and bounds and established itself as a major source of vehicle pates in India as well as in world. Exports market of GNA range of products have a wide spectra of applications in heavy, medium and high commercial vehicles i.e. passenger cars, jeeps, tractors, trucks etc. GNA group is today spread over area of 3, 50,000 sq.mts. Employing a total man power of about 2000 personnel with a turn over of 29.78 million US $ coming from all units. Valued customers of G.N.A DIVISIONS Developing on the bases of Quality, GNA has come a long way since its beginning (more than fifty years ago) with an annual turnover nearly Rs200 Crores per annum coming from four divisions GNA Axles Ltd, GNA Duraparts, GNA Udyog Ltd. The following data gives details of GNA’s different plants: DIVISION PLACE COVERED AREA (sqr meters) PRODUCTS INSTALLED CAPACITY GNA Axles Ltd GNA Duraparts GNA Udyog Ltd Mehtiana Mehtiana Bundala 2400 1550 2020 Rear axle shafts, Hydraulic lift shafts, Powers take of shafts. Super, bevel & Pinions Propeller shafts assembly, Inter drive shaft assembly, Steering components 500,000 pcs 100,000 pcs 100,000 pcs 100,000 sets 70,000 pcs 25,000 pcs DEPARTMENTS AND INCHARGES DEPARTMENTS PERSON INCHARGE 1. FORGING MR. Anil Kumar 2. GEAR SHOP-1 MR. Naresh Sabharwal 3. GEAR SHOP-2 MR.B.K. Thakur 4. HEAT TREATMENT MR.V.L Kadam 5. ENGG. DEPTT MR. A.K. Jain 6. GEAR SHOP- 4 MR. J.S. Bhullar 7. GEAR SHOP-3 MR. Anil Kumar Product range of GNA Duraparts Private Limited QUALITY: THE HALL MARK OF GNA According to the management, GNA has always been striving for achieving the highest possible standards of quality through the application of most technology and effective quality control procedures. Equipped with in – house integrated manufacturing facilities, GNA got ISO – 9002 and is heading forwards getting qs-9000 in a short time. Accounting to S Gursharan Singh, Managing Director of GNA “The quality policy of GNA is to be the international market leader in the quality of products it makes and serve the customer by providing quality product and services at competitive costs. Our objective is to provide reliability and customer satisfaction. It’s also GNA’s ongoing policy to create a congenial atmosphere and quality culture for its employees.” ENGINEERING DEPARTMENT Engineering department is the backbone of the plants. This is because it accomplishes the tasks that are vital for the functioning of the other plants. This department possesses a team of sound and ingenious engineers, managed by qualified and experienced technical managers. The major functions of this department are performed before the actual production begins. The department makes the quotations before the order received and also conducts the feasibility study of new products. It planes the system (the process flow, tooling and facilities required inspection techniques etc) for the development of new products. Apart from this the department meets with the routine production requirement like modification of the existing systems and tooling methods etc. it also provides documentary support to the manufacturing and inspection sections in the form of process instruction sheets and inspection parameters list etc. a tool room is there the function of which is to calibrate the inspection equipments, inspection of various gauges and tools used after the completion of pre-settled time period. It also inspect the tools and master components being manufactured in the tool room. As stated earlier the functions of the engineering department are classified into three divisions vi: New Product Development Routine Production Requirement and Data Collection Each of the functions is explained below in detail: NEW PRODUCT DEVELOPMENT: The following text provides a technical and vivid flow of the works that is performed in the engineering department. The text has been divided into the steps in a proper sequence, which is actually followed actually starts from the Marketing department, which receives the complete technical description of the products to be manufactured from the clients. The client may give it in the from of drawings or they may give an actual sample of the products If the actual samples are provided then a detailed inspection of the sample is carried out and the various dimensions are noted down. From the inspection data so collected a complete engineering drawing of the product is made using CAD systems It is a point worth nothing that the actual designing of the component is not the work of the engineering Department of GNA AXLES. It is rather done by the client himself as per the requirements of his assembled machinery. DRAWINGS: Drawing shows the exact size and shape of the products, its different parts and subassemblies. These drawing are made on the standard sized drawing sheets in order to facilitate their storage. The drawings contain the following information: • Part number (for identification) and part description. • Dimensions set at standard scale explicitly shown on the drawing. • Tolerances and limits. • Material details including specifications size and finish description. • Title block. • Scale and projection. • Details of any inspection requirement Usually the drawings contain all the necessary technical information required by the engineering department of the GNA Duraparts Ltd yet there may be some information on a separate sheet. These sheets are rarely required as the axles are in the form of single component, so all the necessary information can be supplied on the drawing sheet itself. These sheets contain: 1. Conditions of testing 2. Heat-treatment requirement, etc. QUOTATION MAKING: The quotation making is accomplished in the following steps: a) Marketing Analysis: The aspect of the marketing assumes higher proportions for the complex and assembled products. In case of GNA DURAPARTS, as single components are manufactured, the direct engineering involvement in the marketing section is not necessary. The marketing department’s functions are limited to the supply of the engineering drawings and other design specifications to the engineering department for the feasibility study. However some technical persons are employed in the marketing for negotiating with the clients over technical aspects. Also they assist in giving a nod to the client for the acceptance of their order as they know better about the existing facilities. If the marketing department gives green signal then the need for high-level feasibility study is felt. b) Feasibility Study: Once the need for the product/process planning is established, it is necessary to determine whether the technology currently exists to satisfy the need, and if not, when it will become available. In this instance technology refers to the technical methodology or techniques required for achieving a practical purpose. The feasibility study includes. a. A detailed need analysis (i.e. definition of system operations and maintenance support requirements) b. Identification of alternate configuration c. Screening and evolution of the available alternatives and d. Selection of a preferred approach. The output of the feasibility study constitutes a proposal covering the technical characteristics of the preferred system configuration. This information combined with the other data is reviewed to determine whether the work should be further done or it should be ceased. c) Estimation: GNA DURAPARTS produces goods on the job order basses so they have to quote the rates before to receive a job order and thus they have to compete with several other rival concerns all over the India. The careful estimation is thus urgent here. The calculation of the probable cost of an article before its actual manufacture is known as estimating. It is fully technical job and is geared here by this engineering department. However, the products here require almost similar operations thus rendering the job of estimator a little bit easier. After doing all this, a quotation is made which is then sent to the client through marketing department. SAMPLE DEVELOPMENT ORDER: After this, the sample development order is received from the client if they feel viable. Then the engineering department has to accomplish three major tasks: a) Tool Procurement: -This includes giving orders to the tool room for making the Tools then the tools are purchased with the help of Purchase department. Drawings, specs etc are supplied to the Purchase section. -The tools hence obtained are then inspected for the dimensions and other parameters. -If the tools are found to be not O.K., they are sent back to the source with the inspection report and feedback. -If the tooling is up to the mark then it is sent to the shop. b) Correspondence with Party: -The correspondence with the party/client is done through the marketing department regarding the unavoidable deviations, if any. With the agreement of the client, these deviations are incorporated in the design for the sample development c) Material Procurement and processing: Two departments come in to the picture for accomplishing this task. These are (I) Production Planning and Control Section (ii) Purchase Section. The purchase department is supplied with the specifications according to which it purchases the material. The PPC department helps to provide the material in the inventory. . d) Sample Development: The sample is then developed in the shop in the batches of 4 or 5 pieces. SENDING TO THE CLIENT: These samples are sent to the client through the marketing department, along with the required reports. The party then sends back the reaction in the form of feedback if necessary. PILOT BATCH MAKING: After the checking of the samples by the party pilot batch is developed. This is actually the manufacturing of comparatively large number of pieces. HAND OVER TO THE PRODUCTION DEPARTMENT: After the accomplishment of all the above written takes the charge of the product making is handed-over to the Production Department. The Production Department is submitted the following documents: 1. Tooling 2. Tool specifications 3. Production Drawings 4. Check sheets 5. Order to the store for the issuance of material from inventory 6. Process instruction sheets etc. The Production Starts with the Schedule ROUTINE PRODUCTION REQUIREMENTS: The engineering department also completes the routine production requirement of the factory. This heading includes the functions given below: Tooling: Both manufacturing tooling and the inspection tooling are suggested and provided by the engineering department. Both the tooling are procured from two sources viz.: a. Purchase Section: The tools are bought out against specifications. b. In-house Manufacturing: Tooling drawing is send to the tool room and tools are made. After this the tools from both the sources are checked for the specification in the Standard Room. Then these are supplied to the inspection section and the production section. Documentary Support: This includes the formation of some necessary documents and supplying them to the shop for whenever required. The important documents include: i) Production Drawing ii) Process Instruction Sheets iii) Stage check sheet iv) Process flow charts i) Production drawings: Production drawing provide to the shop supervisor for ready consultancy and checking of the dimension of various portions of the shaft whenever required. ii) Process Instruction Sheets: Process instruction sheets provide sufficient detail for all the operating personal that have direct responsibility for the operation or the process. Process instruction sheets for the standard operating procedures are posted on the etc and are easily accessible to the operators and the supervisors. iii) Process Flow Chart: Process flow chart is a schematic representation of the current or proposed flow. The flow chart helps to analysis the total process rather than individual steps in the process. STANDARD ROOM Standard room is situated in a separate building, yet its functioning is controlled by the engineering department. The main reason for the existence of the standards room is to check the various dimensions of the master pieces, inspection equipments, gauges etc. specified by the engineering department. It also checks the quality of the purchased equipments. The details of the responsibility of the standards room can be had from the following text: The responsibilities of the engineering department can be divided broadly into two headings: a. Inspection of Incoming Materials: 1. Receive the material against drawing number/work order number. 2. Put some identification number on tooling. 3. List out the equipments required for inspection 4. Inspect the tools 5. Make the report against drawings 6. Get it checked by the authorized signatory 7. Hand over the inspection report to the concerned departments. b. Periodic Calibration: 1. List out the tooling whose calibration is to be done. 2. Recall the tooling against the corresponding drawing 3. Inspection the tooling against the corresponding drawing 4. Make periodic inspection report 5. Get the reports checked by the authorized persons 6. If O.K. send back to the shop after revising calibration status code 7. Make entries in the corresponding History Card 8. If the tools are rejected handover to Engg Department with report Inspection Report: This report contains the information in the tabulated format regarding the periodic inspection of some tool or gauge etc. The format followed in the GNA Axles Ltd is as followed: GNA Tool Inspection Report TOOL DESCRIPITION……………………………………… TOOL DRAWING NUMBER…………………………………. SUPPLIER…………………………………………………………………. APPLICABLE TO…………………………………………………………. SR. NO. SPECIFIED DIMENSIONS ACTUAL DIMENSIONS PRODUCTION PLANNING AND CONTROL (P.P.C) Production of the whole production shops and serving department is planned and Mentioned by P.P.C .We start from raw material (steel for axles, shafts and other components) 1. Steel receiving and stock maintaining is the job of P.P.C. 2. Steel purchasing is planned by P.P.C on the behalf of customer requirement. 3. Planning for steel yard for blank cutting and forging and then heat treatment is also mentioned by P.P.C date wise and according to customer schedule. 4. Daily production meeting is conducted by P.P.C in which all production shops have to report and get planning for day. 5. Daily loading plan for production shop like hobbing, induction and machine shop for all models. 6. Daily production for original equipment customer is maintained by P.P.C in which production report of W.T.P, product transportation for dispatch for daily dispatches etc. 7. Stage wise movement of all departments from steel yard to O.E shop is maintained on the computer system by P.P.C. 8. System application and house keeping is additional job for this department. 9. P.P.C is the main joint of plant connecting marketing and production and customer in one chain and drive the system smooth. FORGING SHOP This shop is the first shop carry out the manufacturing operations on the raw material. The raw material is in form of cylindrical blanks of steel which are unloaded here from the truck after the necessary inspection by the chemical laboratory. Forging is a process of giving required shape to metals or alloys at sufficiently high temperature. This is the shop where these blanks acquire the shape similar to that of an axle shaft or any other shaft (PTO or rock shaft) excellent forging facilities for the forging are provided which include both drop forging as well as up-setting forging. Continuous shaft oil furnaces are provided to heat the metal stock. The report about this shop, which follows this text, explains the capacities and the process description of the shop in a systematic way. LAYOUT Forging is the process by which metal is heated and is shaped by plastic deformation by suitably applying compressive force. Usually the compressive force is in the form of hammer blows using a power hammer or a press. Forging refines the grain structure and improves physical properties of the metal. With proper design, the grain flow can be oriented in the direction of principal stresses encountered in actual use. Grain flow is the direction of the pattern that the crystals take during plastic deformation. Physical properties (such as strength, ductility and toughness) are much better in a forging than in the base metal, which has, crystals randomly oriented. Forgings are consistent from piece to piece, without any of the porosity, voids, inclusions and other defects. Thus, finishing operations such as machining do not expose voids, because there aren't any. Also coating operations such as plating or painting are straightforward due to a good surface, which needs very little preparation. Forgings yield parts that have high strength to weight ratio-thus are often used in the design of aircraft frame members. A Forged metal can result in the following • Increase length, decrease cross-section, called drawing out the metal. • Decrease length, increase cross-section, called upsetting the metal. • Change length, change cross-section, by squeezing in closed impression dies. This results in favorable grain flow for strong parts PROCESS FLOW: The forging shop also includes a unit for the cutting of the incoming raw material (in the from of standard length blanks) into smaller specified lengths. After this the heating of the metal stock is carried out to attain the temperatures required for the forging operation. After this the forging is carried out on any one of the three machines. Sometimes more than two machines are used for the single shaft. The forged shafts are then sent to the heat-treatment section for further treatments. FACILITIES: The forging shop of GNA axle is equipped with all the modern facilities required by the operations performed herein. These facilities include the forging machines and the furnaces along with material handing equipments and the shaft cutting facilities. List of the various machines and equipments available in the forging and blank cutting shop is hereby given as under: Horizontal Bank Saw (3 no.s) Upset Forging Press (2 no.s) Drop Hammer Continuous Shaft Oil -Fired Furnace Screw Compressor Over-Head Hoists Following is the text, which contains the description of each type of the machines mentioned above along with the general specifications and working: Horizontal Band Saw: Specifications: Number of machines available – 3 Model –FC-245 Capacity – 245 mm diameter shafts Mfg. By – SPM Tools, Ichalkaranji (Maharashtra) Working: The shaft to be cut is fitted on the fixture provided on the machine and switching on the power carries out the cutting operation. Before it the required length of the blank is measured and marked. Before using band saw the tension of the blade is checked with tension meter. It is calibrated in PSI (Pound per square Inch). The tension required is different for different materials to be cut. But usually the reading should be between 25000 PSI to 30000 PSI. 1. Upset Forging Press: These are the costliest and heaviest machines at GNA axle. The production of the whole plant depends upon the performance of these machines. These machines have been imported from Russia. Specifications: Type – Horizontal forging press Model – IHK 1200 Mfg. By – Smeral Works, Berno – Russia Overall Length – 6400 mm Width – 4420 mm Height – 3830 mm Total Weight – 137000 Kg Total input of Machine – 76.1 KW There are two horizontal forging presses in the forging shop. The capacity of second machine is also 1200 tones. Forging Possibilities And Performance of The Machine: The horizontal forging machine is designed for the hot upsetting, broaching, stepping and bending of the forging of black and non-ferrous metal. According to the manufacturer’s manual maximum utilization is possible in forging shops for serial production of motor cars, tractors, transport equipments and upsetting etc. Kinematics Description and Working: 1200 T means maximum horizontal force that is applied by the press is 1200 Tonns. The operative units of the press are powered from motor mounted on the press frame. By means of V-belt drive power is transmitted from Pulley to the flywheel mounted on the auxiliary shaft. The flywheel is equipped with a friction safety device to prevent the overloading of shaft. The flywheel is stopped by the auxiliary brake which is automatically engaged when the motor is switched off. On the other end of the shaft a gear is mounted. It meshes with gears which drive the crankshaft. The latter through the pitman reciprocates in the sideway. The crank mechanism is engaged by a pneumatic clutch which is controlled by a paddle. The band brake stops the crankshaft and hence the slide when the pneumatic clutch is disengaged. The top half of the is secured to the slide and the bottom half to the bed which is provided with a double wedge device for adjusting the die space. 2. Drop Hammer: The axles having large flange (like: Mahindra Large, Carraro-644, L & T, New Holland) are drop forged after their partial upsetting. Specifications: Type – Vertical Drop Hammer Type Forging Machine Weight of The Die-Block – 5 Tonns Input Power – 75 H.P Number of Strokes Required –depends upon the size and shape of the forging The other dimensions and specifications were not shown by the concerned foreman due to some legitimate reasons. Working: Drop hammer having two columns made of thick steel plates of 35mm V-ways is provided on the facing sides of the column to guide the ram connected with upper die block. Stairs are provided on the side of the hammer for checking out the functioning and maintenance of the driving unit. Columns are provided on the heavy cast iron casting which is foundational in the concrete below the floor level. Columns are fastened to the heavy cast iron casting with very large bolts and spring washers to exert a regular tightening pressure and to absorb the stock. An anvil is provided between the two columns and so the upper side of the heavy base. On the anvil lower die block is mounted using keys. When the ram falls with high impact on the lower die block fitted on the anvil then the shaft placed in the lower die block is forged to the shape given by the upper die block (fitted on the ram) and the lower die block. Foundation of the machines: The foundation is to be made up of rammed concrete according to the attached foundation plan. The machines are mounted on thoroughly hardened concrete to avoid subsequent setting. 3. Continuous Oil Fired Furnace: The furnaces serve the need for heating of the blanks prior to the forging process. The cut blanks are first place in these furnaces and then forging is done. Specifications: Number of furnaces-3 Type- Continuous Shaft Oil – Fired Furnace Fuel Used – Rough Furnace Oil Alternative Fuel load – 1200 C (approx.) Construction and working: Outer body of the furnace is covered with thick mild steel sheet. Inside is covered with fire clay refractory bricks. Upper portion is called gate, which is covered with bricks from inside. Heating area is divided into two parts: 1. Pre-heating Zone 2. Heating Zone Pre-Heating Zone is smaller and at a sufficient distance from the burner. Burner is provided to heat up the shall through which hot flame is exerted. Furnace oil and air from the blower is fed to the burner. A hood is there to collect smoke and is exhausted through the chimney. Centrifugal blowers are drive by electric motors. Airflow can be controlled by the values at the burner. 4. Material Handling: There are monorails provided overhead in the forging shop. These monorails traverse the way right from the furnaces to the drop hammer after passing over the up setter. The manual hoists are provided which can pick up the load tethered to the hook attached to its hanging chains. The worked can take the shafts to any area within the reach of the monorail. The path of the monorail will be clearly comprehended by watching the layout of the forging shop. Apart from these forklifts are also available. These are used to pick up a lot of axles contained in a rack made of steel. PROCESSES 1. Blank Cutting: The blank are purchased from the market through the purchased department. The latter is submitted the specifications and the amount of the material to be purchased. The specifications depend upon the requirement of the product and the client. The blanks available in the market possess standard length, which are quite large than the required length of the blank to begin with. So these blank are first cut to the required size by using the horizontal band saws. 2. Heating: The forging is done after heating the blanks up to the appropriate temperature. The temperature required depends upon the composition of the steel. The metal is heated above its recrystalisation temperature. The forging is carried out at this temperature, when the metal is in the plastic stage by applying compressive force. The oil used RFO and freeze at temperature below 80-degree C. the oil is heated to this temperature and is kept at the same temperatures. The end of the shaft to be foraged is placed inside the furnace. The other end remains out side the furnace. There are two zones viz. a. Pre-heating Zone b. Heating Zone A number of blanks can be placed at the same time in the furnace. First the blanks are placed in the pre-heating zone while the previously placed blanks are being heated in the heating zone. When the blank is the heating zone acquired sufficient pressure, these are taken to the forging presses using hoists while the blanks placed in the pre-heating zone are moved to the heating zone. 3. Forging: Forging is the process of giving required shape to the metal or alloys at the sufficiently high temperature, when the metal is in the plastic state by applying compressive force. It eliminates certain defects in the metal. Blowholes, porosity etc are eliminated. Grains of the metal are refined. Physical properties are improved due to improved grain structure. Forging is a relatively quicker process and save a good amount of time and expense. There are so many different forging processes. GNA Axles Ltd uses two methods of forging viz. a) Upset Forging: This is also called machine forging. It consists of gripping a heated bar stock between two dies and striking the protruding end with another die. The material can be increased considerably in diameter, and the other blow can be used to make the metal conform to the die cavities. This is the prime requirement in the manufacturing of the axles. In GNA Axles Ltd four blows in total are used to make the axle shape on the upsetting machines. b) Drop Forging: This method is used where a large number of similar jobs are to be produced. In this process metal is heated to the plastic stage and is then hammered to the shape in closed impression die. Half the impression is cut in one die and remaining on the other die. One die is allowed to fall on the other from a height of about 3 meters thus squeezing the metal in between the dies and converting it to the required shape. 4. Cooling: The forgings are placed in the steel racks and are taken out of the shop for air-cooling. HEAT TREATMENT Forgings produced in forging shop have developed a considerable amount of harmful internal stresses. These internal stresses are harmful as far as the end use of the product is concerned. These internal stresses are to be removed now and also the axles are to be hardened in the Heat Treatment Shop. PROCESS FLOW: The forgings are brought from the forging shop and are heat treatment in the suitable furnace. This includes a number of heat treatment processes (e.g. normalizing, annealing, hardening and tempering etc.) All the heat treatment consists for the sufficient time viz: heating to a suitable temperature, soaking at that temperature for the sufficient time and cooling by a suitable method. After that the heat treatment axles are checked against the requirement value of hardness. If the axles are O.K then further processing is done otherwise reworking is required. FACILLITIES: The heat treatment shop of GNA Axles Ltd is equipped with the Facilities to carry out normalizing, annealing, hardening and tempering. The shop also has the equipments to check the hardness obtained during the heat treatment and hence to decide whether further processing should be done or not. Following machine and equipments are installed: 1. Heat Treatment Furnaces: Specifications: o Type: Indirect Fired HT Furnace o Total number of furnace: 7 o Fuel used: Light diesel oil o Air Source: Electrically driven blowers Working and construction: The structure of the furnace is a rectangular parallelepiped whose out side is made up of steel. The furnace is lined with refractory bricks from inside. 1. Oil Tank For Quenching: Specifications: o Oil used: Polymer oil 304 mixed with water o Minimum Concentration: 9% of oil o Capacity of tank: 1200 Lts 3. Water Storage Tank for Quenching: The water level in the tank is such that the lot of axles should dip property in the water. 4. Cooling Tower: The tanks are connected to a cooling tower which is furnished with an electric pump which keeps the water circulating during the quenching so that hot water may be cooled in the tower continuously and fresh may become available in the tank. 2. B.H.N Testing Machine: The machine is provided for the inspection of hardness attained. Note: Tow more facilities are available in the same shop viz. a) Shot Blasting Machine b) Ultra Sonic Flaw Detector These however, will be discussed in the nest chapter. PROCESS DETAIL Heat –Treatment: It is a process involving the heating and cooling of metals or alloys in the solid state to produce certain desired properties (e.g.; hardness, stiffness and ductility etc.). The axles are an extremely important and high load-taking component of the automobile. The axles are to bear a number of forces some of which include; weight of the vehicle, driving torque, the impact forces due to shocks. The load on the axle becomes more under the Indian conditions of roads thus increasing the demand for more reliable and more rigid axels. So if the maximum service is expected of a steel forging it becomes necessary to give the forging one or more heat treatments before it goes to service. Principle of Heat Treatment: The theory of heat treatment is based on the principle that an alloy experiences change in structure when heated above a certain temperature and it again undergoes a change when it is again cooed to the room’s temperature. The cooling rate is an important factor in the development of shaft and hard structures. All the heat treatment processes may be considered to be consist of following three main parts: 1. The heating of all metal to the predetermined temperature 2. The soaking at that temperature unit structure becomes uniform throughout the mass. 3. The cooling of the metal at some specified cooling rates to cause the formation of desired structures within the metal/allow for the desired purpose. Reason: Axles are heat treated for the following technical reasons: o Improve mach inability o Relive internal stresses o Improve mechanical properties such as hardness and strength HEAT TREATMENT PROCESS USED: 1. Annealing: Annealing process consists of heating the forgings in the furnace to a temperature of about 750 to 900 c. depending upon the composition of the steel (to a temperature of about 30 to 50 C above higher critical point) with subsequently slow cooling. This result in: Refinement of grain Removal of internal stresses Comparative softening of the steel This process is done prior to the hardening and tempering. 2. Normalizing: This involves heating the forged parts in the furnace as in annealing and subsequent cooling in air. Almost similar results are produced as in annealing. However mechanical properties such as tensile strength etc is perceptibly improved. 3. Hardening of Axles: We know that the operation of hardening of steel requires the formation of martensite, which is obtained following the hardening procedure described below: a) Heating: Forged axles are heated above critical point in a box type oil furnace. b) Sacking: The axle is hold at this temperature for considerable time as prescribed by the process instruction sheet. c) Quenching: Rapid cooling of the soaked axle in water bath for some time according to the process instruction sheet. The time and temperature for soaking is different for the different materials and depends mainly upon carbon contents. 4. Tempering: When axle is taken out of the quenching medium it is hard, brittle and have server unequally distributed internal stresses besides other unfavorable characteristics. The axle in this condition is poor shock resistant and has poor stiffness. Tempering is done for three main reasons: a) To remove brittleness b) To retain hardness c) To induce toughness Following steps are involved in tempering: a) Heating the gears or axle hardening in a box type furnace to a temperature between 500-650 C range. b) Holding at this temperature for some time. c) Slow cooling in air Note: Tempering of auto parts comes under High Temperature Tempering which is applied to the parts subjected to high stresses and impacts. 5. Carburizing (Case Hardening): Crown Wheel & Pinions etc are case hardened. This process is just heating the steel parts to red heat in contract with some carbonaceous materials such as wood, bone leather charcoal with compounds such as carbonates of barium, calcium or sodium which are termed as energizers. The carbon thus enters the metal to form a solid solution with iron and converts the outer surface into high carbon steel. MACHINE SHOP This is the shop where most of the work is performed on different machines. In machine shop, the raw material which had under gone Forging, Hot Blasting etc. is machined to final product with the help of different machines. Different types of machines used in machine shop are: 1. Lathe machine 6. Hobbing machine 2. High speed lathe (Churchill) 7. Drilling machine 3. Straightening machine 8. Tapping machines 4. Horizontal machining centre 9. CNC lathe machines 5. Milling machine 10. Grinding machine SYSTEMATIC WORKING IN MACHINE SHOP TO GET FINAL PRODUCT (AXLE): Raw material after Forging and Hot Blasting comes to vendor. The job of a vendor is to do rough turning of the material with the help of Churchill, Gobber and lathe machine. All these lathe machines are copy turning machines. After this the job is mounted on straightening machine and is straightened, run out if any also gets removed on this machine. After straightening job is mounted on CNC lathe machines where final turning is done and size achieved is nearly same to the size of final product but having some tolerance for grinding. Now the job is mounted on the Hobbing machine where various types of splines according to demand are cut on the job on various machines. After that job is sent for heat treatment processes like Induction Hardening and Tempering. These heat treatment processes are only applied to shaft of axle not to flange part. After heat treatment processes job is sent for MPT testing, HRC test. After this job again comes to machine shop where first of all its straightening is done. After that Radial Drilling machine is used drill flange holes of different diameters. Then these flange holes are tapped with help of tapping machine. After that these tapped holes are counter sunken with help of counter sunk machine. Final work done in machine shop is grinding. Job is mounted on the Grinding machine and required sizes of collars and flange are achieved during grinding. After that axle is sent for final inspection to quality department. Where random selection of an axle is done. Different sizes of axle, Grain size, Grain structure is checked. Then approved product is sent for packing. DETAILS OF VARIOUS MACHINES AND VARIOUS PROCESSES PERFORMED ON THESE MACHINES • LATHE MACHINE : This is one of oldest machines used in industries to remove metal from a piece of work to give it a required shape and size. This is accomplished by holding the work securely and rigidly on the machine and then turning it against cutting tool which will remove metal from the work in form chips. To cut the material properly the tool should be harder than the material of the work piece, should be rigidly held on the machine and should be fed or progressed in a definite way relative to work. Lathe machine Processes performed on lathe by a vendor to prepare an axle are Rough Turning with copy turning attachment and Facing. Rough turning is the process of removal of excess material from work piece in minimum time by applying high rate of feed and heavy depth of cut. Principle of Copy turning by copy turning attachment is to guide the tool in a path which produces the exact shape as that of specimen on the job. CNC MACHINES WHAT DOES 'CNC' MEAN ? CNC means Computer Numerical Control. This means a computer converts the design into numbers which the computer uses to control the cutting and shaping of the material. HOW TO USE A TYPICAL CNC MACHINE 1. The design is loaded into the computer which is attached to the CNC machine. The computer changes the design into a special code (numerical) that controls the way the CNC cuts and shapes the material. 2. The material to be shaped is taped on to a block with double sided tape. This must be done carefully so that it does not come off the block during machining. 3. The block is then placed in the vice, inside the CNC. It must be tightened up carefully. If it is not secure when the machine starts to cut the material it can come away from the vice. When the machine starts working, the vice moves up, down, right and left according to the design. 4. The guard is placed in position. It protects the machine operator in case the material is pulled out of the vice by the power of the cutter. For safety reasons, if the guard is not in position the motor will not start. 5. The CNC is turned on and the shape is cut from the material. When the cutter has stopped the shaped material can be removed from the vice. Total time - for simple designs - 15 minutes. • Grinding machine: Grinding is metal cutting operation performed by means of a rotating abrasive wheel that acts as a tool against the work piece. This is used to finish work pieces which must show a high surface quality, accuracy of shape and dimensions. Grinding machines remove the material in little amount, 0.25 to 0.50 mm in most of operation and accuracy in dimensions is in order of 0.000025 mm. grinding is basically classified into two groups. 1. Rough grinding 2. Precision grinding GRINDING PROCESS CLASSIFICATION OF GRINDING MACHINES Grinding machines according to the quality of surface finish are classified as i. 2. Rough grinders 3. Precision grinders In industry the most of work is done on precisely on precision grinders and CNC grinding machines. Different precision grinders used are as 1. Cylindrical grinders (ex. CENTRELESS GRINDERS) 2. Surface grinders(ex. HORIZONTAL GRINDERS) 3. Special grinders (ex. CNC GRINDERS) 4. Internal grinders 5. Tool and cutter grinders MATERIALS USED FOR GRINDING WHEEL Now a days use of abrasive belts is becoming more wide spread in industry. An abrasive should have properties like purity uniform physical properties of hardness, toughness and resistance to fracture. Abrasives may be classified into two groups: 1. Natural 2. Artificial or manufactured GRINDING WHEELS The natural abrasive includes sand stone or solid quartz, emery, corundum and diamond. Emery and corundum are natural aluminum oxides artificial abrasives chiefly include silicon carbide, aluminum oxide, powdered coke, saw dust. DRESSING AND TRUING GRINDING WHEEL Dressing removes loading and breaks away the glazed surface so that sharp abrasive particles are again presented to work. This is done with various types of dressers. A common type of wheel dresser, known as the star dresser, is shown in figure. It consist of a number of a hardened steel wheels with on their periphery. The dresser is held against the face of revolving wheel and moved across face to dress the whole surface. Abrasive wheel dressers operating at high speeds are frequently used to dress other wheels. They are used where a fair degree of finish is required on the product. STAR DRESSER For precision and high finish grinding and industrial work, small industrial diamonds, known in trade as bort, are used. The diamond or group of diamonds is mounted in holder. The diamond should be kept pointed, since only the point can be used for cutting. This is done by holder down at a 15 degree angle and using a new surface each time the wheel is dressed. A god supply of coolant should be used while dressing with a diamond, as over heating of diamond can cause it to fracture. DIAMOND DRESSERS TRUING: Truing is the process of changing the shape of grinding wheel as it becomes worn from its original shape, owing to break away of the abrasive and the bond. This is done to make the wheel true and concentric with bore, or to change face contour for form grinding. Truing and dressing are done with same tools but not for same purpose. DIAMOND DRESSERS CENTRELESS GRINDING: Centre less grinding is a method of grinding exterior cylindrical, tapered and formed surfaces on work pieces that are not held and rotated on centers. The principal elements of an external centre less grinder shown are the grinding wheel, regulating or back up wheel and work rest. Both the wheels are rotate in same direction. The work rest is located between the wheels. The work is placed upon the work rest, and the latter, together with regulating wheel, is fed forward, forcing the work against the grinding wheel. CENTRELESS GRINDING MACHINE The axial movement of the work past the grinding wheel is obtained by tilting the regulating wheel at a slight angle from horizontal, an angular adjustment of 0 to 8 or 10 degrees is provided in the machine for this purpose. Centre less grinding may be done in one of three ways. These are illustrated as In through grinding, the work is passed completely through the space between the grinding wheel and regulating wheel, usually with guides at both ends. This method is used when there are no shoulders or other forms to interfere with passage of work. In infeed grinding, which Is similar to plunge grinding or form grinding, the regulating wheel is drawn back so that work piece may be placed on work rest table. Then it is moved in o feed the work against the grinding wheel. This method is used to grind shoulders. • RADIAL DRILLING MACHINE: The radial drilling machine is intended for drilling medium to large and heavy work pieces. The machine consists of a heavy, round, vertical column mounted on large base. The column supports a radial arm which can be raised and lowered to accommodate work pieces of different heights. The arm may be swung to any position over the work bed. The drill head containing mechanism for rotating and feeding the drill is mounted on a radial arm and can be moved horizontally on guide ways and clamped at any desired position. These three movements in a radial machine when combined together permit the drill to be located at any desired point on a large work piece for drilling a hole. When several holes are to be drilled on a large work piece, the position of arm and drill head is altered so that drill spindle may be moved from one position to other after drilling the hole without altering the setting of work. This versatility allows it to work on large work pieces. The main parts of Radial drilling machine are: 1. Base 6. Motor for driving spindle 2. Column 7. Drill head 3. Radial arm 8. Drill spindle 4. Motor for elevating the arm 9. Table 5. Elevating screw As mentioned earlier these machines are used for drilling straight holes. After final turning of the axle the work piece is mounted on this machine and flange holes are drilled in it with help of this machine. • GANG DRILLING MACHINE: When number of single spindle drilling machines are placed side by side on common base and have a common work table, the machine is known as gang drill machine. In a gang drill machine four to six spindles can be mounted side by side. In some machines the drill spindles are permanently spaced on work table, and in others position of column may be adjusted so that space between the spindles may be varied. The speed and feed are controlled independently. This type of machine is specially adapted for production work. A series of operations may be performed on the work by shifting the work from one position to other on work table. Moreover each spindle may be set up properly with different tools for different operations. Figure of a gang drill containing 18 spindles is as shown. GANG DRILL Description of various machines 1. Gear shaper machine: A gear shaper is a machine tool for cutting the teeth of internal or external gears. The name shaper relates to the fact that the cutter engages the part on the forward stroke and pulls away from the part on the return stroke, just like the clapper box on a planer shaper. To cut external teeth, a different machine called a hobbing machine can be used. The cutting tool is also gear shaped having the same pitch as the gear to be cut. However number of cutting teeth must be less than that of the gear to be cut for internal gears. For external gears the number of teeth on the cutter is limited only by the size of the shaping machine. The picture of the gear shaper machine is shown below: Here this picture shows the shaper machine for internal gear cutting on a ring. The cutter reciprocates in vertical direction. This cutter cut gears in forward stroke and pulls away from the part in backward stroke. The job as well as is rotating in pre-described speed. This rotating movement helps the cutter to cut teeth on the whole inside circumference. 2. Hobbing machine: A hobbing machine is a special form of milling machine that cuts gears. It is the major industrial process for cutting (as opposed to grinding) spur gears of involute form. The machine forms the gear via a generating process by rotating the gear blank and the cutter (called a hob) at the same time with a fixed gearing ratio between hob and blank. The hob has a profile given in cross-section by the fundamental rack for the gear tooth profile and is in the form of a helix so that the sides of the teeth on the hob generate the curve on the gear. The helix has a number of cuts parallel to the axis to form the cutting teeth and the profile is suitably relieved to provide cutting clearance. For a tooth profile which is a theoretical involute, the fundamental rack is straight-sided, with sides inclined at the pressure angle of the tooth form, with flat top and bottom. The necessary addendum correction to allow the use of small-numbered pinions can either be obtained by suitable modification of this rack to a cycloidal form at the tips, or by hobbing at other than the theoretical pitch circle diameter. Since the gear ratio between hob and blank is fixed, the resulting gear will have the correct pitch on the pitch circle, but the tooth thickness will not be equal to the space width. Hobbing is invariably used to produce throated worm wheels, but it is not possible to cut all useful tooth profiles in this way; if any portion of the hob profile is perpendicular to the axis then it will have no cutting clearance generated by the usual backing off process, and it will not cut well. Hob cutter of hobbing machine. Job and hob cutter in working position. 3. Gear shaving machine: Gear shaving machines are used to remove the burr of to make smooth the surface of the gear teeth after gear cutting. We know that after gear cutting, the profile of the gear teethes is not smooth or burr or irregularities are presents on its surface. So to make the profile of teethes smooth, we use gear shaving machines. The axis of the cutter is inclined at some angle to that of job. Both cutter and job move in opposite direction. The profile of the cutter teeth has special shape. These teeth of cutter mesh with the teeth of the gear. So in this way, the burr or irregular surface is removed by these cutters. The picture of gear shaver machine describes all things. Gear shaver cutter and job. 4. Surface broach machine: Broaching machines are special purpose machines. A broaching machine is widely used as a metal cutting machine used for surface finishing by pressing a broaching tool on a work piece surface. A broaching tool acts as a cutter, which consists of cutting teeth arranged in a row. A broaching machine works on the principle of proper offsetting of the work piece and then performing work on it. The centerline of a work piece and a broaching tool are aligned to each other at an offset position of 1°. This position generates a scalloping effect on the work piece and allows the broaching tool to shear the work piece. A work piece is kept stationary and the broaching tool is rotated. In this way, only the leading edge of the work piece is broached instead of the full surface. There are many types of broaching machines.