27-08-2014, 12:21 PM
INTRODUCTION The country, India, is basically an agricultural country where more than 65 % of population population, enough food has to be produced. This cannot be produced with our conventional bullock drawn implements. So there was need felt to invent such machine which speeds up the agricultural production. Due to this reason the tractor was invented. Before we start, it is necessary to know how the word ‘tractor’ is derived. Prior to 1900, the machine i. e. tractor is known as traction machine (pulling machine). After 1900, both the words joined by taking ‘tract’ from traction and ‘tor’ from motor calling ‘tractor’. The tractor is the machine which is used for applying high traction. In our country, tractors were started manufacturing in real sense after independence and at present, we are self sufficient in meeting demand of country’s requirements for tractors. At present in India, there are different tractor producing factories present like Hindustan machine tools, Punjab tractors, Kirloskar tractors, etc is directly o
I. INTRODUCTION
The country, India, is basically an agricultural country where more than 65 % of population population, enough food has to be produced. This cannot be produced with our conventional bullock drawn implements. So there was need felt to invent such machine which speeds up the agricultural production. Due to this reason the tractor was invented. Before we start, it is necessary to know how the word ‘tractor’ is derived. Prior to 1900, the machine i. e. tractor is known as traction machine (pulling machine). After 1900, both the words joined by taking ‘tract’ from traction and ‘tor’ from motor calling ‘tractor’. The tractor is the machine which is used for applying high traction. In our country, tractors were started manufacturing in real sense after independence and at present, we are self sufficient in meeting demand of country’s requirements for tractors. At present in India, there are different tractor producing factories present like Hindustan machine tools, Punjab tractors, Kirloskar tractors, etc is directly or indirectly connected to agriculture. Moreover for increasing . II. COMPANY PROFILE 2.1 Birth of HMT In 1949 the idea of public sector tools was commissioned to be a corner stone for the government’s industrial development plans. This led to the birth of HINDUSTAN MACHINE TOOLS at Bangalore in 1953 which started a single machine tools factory to produce lathes at Bangalore, in collaboration with M/s Oerlikon of Switzerland. Next, the company widened its product range beyond lathes by entering into technical collaboration with other international leaders in machine tools such as Fritz Werner, Herman Kolb, Errantly Somua, Gildermeister, Liebherr etc. The second machine tool unit was set up in Bangalore in 1961 making use of the Company’s own resources. The company diversified itself when, in collaboration with Citizen Watch Company of Japan, the first watch factory was setup in Bangalore in 1962 to produce hand watches. The third machine tool unit was set up in 1963 at Pinjore, Haryana to produce milling machines. In next few years, Machine Tool Units were set up at Kalamessary in Kerala and in Hyderabad. The Printing Machinery division was attached to machine tools factory at Kalamessary to qualities Printing Machine. HMT’s tractor business commenced its operations in 1971 in technical collaboration with M/s MOTOKOV, Czechoslovakia because of the priority given to the agriculture in the national development plan and to take advantage of the green revolution. HMT started the operations with the manufacturing of 25 Hp tractors. Over the years, it has developed tractors ranging from 25 – 75 Hp. The unit in Hyderabad began to make lamps and lamp making machines in 1973 to cater to the growing needs of rural. This was followed by producing automatic watches. A third watches factory was established in Srinagar to manufacture hand wound watches for men. In 1975, the company took over the machine tool corporation of India’s unit in Ajmer, Rajasthan and its name was changed to HMT Limited. In 1975, a separate international scales network called HMT was set up comprising of company’s own agencies as well as other sales agents in Australia, Europe and America. This network was to handle the marketing strategy and operations of the company overseas and it also extended its services to the other leading Indians and overseas engineering companies. Since then this international arm of the company has set up the turkey project in Algeria, Indonesia, Iraq, Kenya, Nigeria and Srilanka. 2.2 HMT’s Products The main products produced by HMT ltd are – • Machine tools, • Watches, • Tractors, • Bearings, • Printing Machinery, • Die Casting Machinery. The divisions of HMT are described below – 2.2.1 Bangalore It produces lathes (both CNC and Non CNC), milling/ machining centers, grinding machines, gear cutting machineries, simple drilling machines, special purpose machines, die casting and plastic injection moulding. It also produces refurbishing and retrofitting like heavy duty, turret lathe, multi spindle drilling machines and fine boring machines. The other application components include the jigs, fixtures, some radar and transonic components. It also develops hinomerik control system, Hyderabad. 2.2.2 Hyderabad It produces the machining centers, CNC, Boring machines, milling machines, die and mould machining centers, presses and brakes. It also produces special purpose machines like CNC tube chamfering machines, cam shaft milling machines, filament winding machines, horizontal and vertical coil winding machines, multi spindle machining centers. 2.2.3 Kalamessary It produces CNC lathes and printing machineries. 2.2.4 Ajmer It produces grinders and lathes. It also manufactures some application components like hydraulic lift mechanism for tractors, valve devices and oil priming pump. The retrofitting includes center less grinders and double disc grinders. After establishing two machine factories and a watch factory in Bangalore, the Pinjore unit was established as the third machine tool factory. Breaking the ground on 2nd may, 1962, this factory III. TRAINING CENTRE In training centre, the basic machines are studied such as Lathe Machine, Milling machine, Drilling Machine, etc. 3.1 Structure of Training Centre Training center is divided into four sections, 1. Turning section, 2. Fitting section, 3. Milling section, 4. Tractor training section. 3.2 Turning Section In turning section, we have learnt about the lathe machine which is mother of all machines and play a basic role in mechanical line. 3.2.1 Lathe Machine Lathe is probably the oldest machine tools. The basic idea about turning or lathe machine came out in 17 century. Until 1770, lathes were useless metal cutting because they lacked power and holding device, were not strong enough and accurate enough to guide the tools. For its development to the form in which we know it now, we owe much to Henry Muldsley, who developed the sliding carriage and in 1880 built a screw cutting lathe. 3.2.2 Classification of Lathe Machine 1. Engine Lathe, 2. Speed Lathe, 3. Turret Lathe, 4. Toll Room Lathe, 5. Hollow Spindle Lathe, 6. Capstan Lathe, 7. Bench Lathe. Lathe is also called Complete Machine. This single machine can do number of operation. 3.2.3 Facing This operation is carried out to produce flat surface at the end of part, which is useful for parts that are attached to other components, or face grooving to produce grooves for O-ring seals. 3.2.4 Drilling In this process a drilling of desire diameter is held in the tail stock and the operation of drill is carried out. 3.2.5 Boring In this enlargement of hole or cylinder cavity made by previous process is done. It improves accuracy and surface finish. 3.2.6 Threading In this operation internal and external threads on the surface are prepared. 3.2.7 Knurling In this operation a regularly shaped roughness is prepared on the cylindrical surface for fascinating easy gripping. 3.3 Fitting Section Fitting work is very important work in engineering. In fitting shop unwanted material is removed with the help of hand tools. It is done for mating, repair and manufacturing purpose. The person working in fitting shop is called as fitter. Commonly used tools are hacksaw, files, chisels etc. 3.3.1 Tools Used in Fitting Shop 1. Clamping Tools 2. Measuring and Marking Tools 3. Cutting Tools 4. Striking Tools 5. Drilling Tools 3.4 Milling Section Milling machine were basically developed to machine flat surface. But, the present machine can machine flat, countered and helical surfaces, cut gears and do various other jobs. Due to this all milling machine is one of the most useful and necessary machine tools found in the shop and it rank next to the lathe in importance. Milling machine are designed to hold and rotate milling cutter or cutters, hold the work piece and feed the work piece to the milling cutter in one several directions. IV. FOUNDRY MECHANISMS Since there are certain basic steps in the metal casting process, these may be used as unit of mechanism. Processing steps which lead them to the mechanism are, 1. Sand preparation, 2. Core making, 3. Moulding, pouring and shakeouts, 4. Melting, 5. Cleaning. Foundry is divided into following section, 1. Sand plant system, 2. Sand handling system, 3. Core making and baking system, 4. Moulding making and handling, 5. Core setting system, 6. Melting system, 7. Metal pouring system, 8. Testing lab, 9. Fettling section, 10. Painting and printing section. 4.1 Sand plant system The main objective of it is to reuse the used lad to the installation of sand plant system. The vital task of sand plant system is to deliver well prepared sand at required place that will determine the efficient working of the foundry. After casing are knocked out of moulding box on a vibratory shakeout box that the used sand is returned to the fixed amount of new sand, binders, catalysts and hardeners to get to the required composition of the sand. Green sand, dry sand and oil sand are being prepared in the sand plant. These constitutes are added in Muller in which all contents are mixed thoroughly and then supplied via belt conveyor system to working stations. Green sand composition: Muller batch capacity 700 kg New sand 35 kg (5%) Bentonite 660 kg (94.4%) Water 3.6 kg (0.4 %) Return sand 1.4 kg (0.2%) Dry sand composition: Return sand 80% New sand 10% Bentonite 1.2% Dextrin 1.8% Moisture 7% Composition of oil sand (100 kg of sand): Bentonite 12 kg Dextrin 25 kg Linseed oil 15 kg Moisture 20 G 4.2 Sand handling system For handling the sand i. e. move it from one place to another, the bucket elevator and belt conveyor are used. 4.2.1 Bucket elevator When sand is to be conveyed vertically upward, a bucket is ideal. There are two pulleys, one at the top and other at the bottom which carry an endless belt. The belt carries number of buckets all around and the whole assembly is enclosed in steel casting which has two openings, one at bottom for feeding and other at top for discharge. 4.2.2 Belt conveyor It is used for transferring sand from one place to another. It consist of endless belt, two pulleys or idlers for carrying a loaded belt and returning the empty belt, a belt tightening mechanism and the belt cleaner. The angle of inclination should not be exceeding 150 for dry sand. 4.3 Core making and baking system As patterns are made to get to outer shape of the casting, the inner shapes are used to for whole generation core placed in the moulds. As the core comes in contact of molten metal that must possess following characteristics: 1. Core sand must have high strength to bear the pressure of metal when poured. 2. The sand must have high refractory characteristics so that it may not fuse due to high temperature being in contact with molten metal. 3. It must have high cohesive property so as to get good finish castings. Zircon paint (alcohol base) dried just by lightning it up. Large and heavy cores are baked along with the dry sand moulds in oven. Core drying cycles for oven: 3000 C – 1 hrs. 2000 C - 2 hrs. Cooling time in oven 3 hrs. After baking, the hardness is tested by using hardness meter 4.4 Mould making section Moulds are being made on moulding machine pedantically powered rammers. Metallic patterns are being used. After mould being made on moulding machine, it goes to sand cutter which removes extra sand present and level the mould base, from on to the power operated roller conveyor, the mould is handled using the swing type crane. Core setting is done in drag part of mould. Zircon painting is sprayed on to the mould (as paint is alcohol based hence get dry up by lighting fire). 4.4.1 Mould baking Dry sand moulds are to bake to acquire hardness to with sand the pressure produced by the flow of molten metal. These are baked in ovens. Mould baking cycles for ovens 300C for 2 hrs. and Cooling time in oven 3 hrs. 4.4.2 Melting section It is having two types of furnace. 1. Electric induction furnace, 2. Copula furnace. 4.5 Fettling After they are knocked out on vibrator shake, the casting head to be finished by the removal of projections whether they are gets riser or runner that where there as a part of design aspect or the projection which has appeared as a defect like fins or blow holes. The process that involves all these procedure of casting finish is termed as fettling. Fettling operation is divided into following stages: 1. Knocking out of dry sand cores, 2. Removal of gates and risers, 3. Extraction of fins and other projections, 4. Cleaning and smoothing of the surface, 5. Repair casting by filling of the blow holes, straightening the wrap or deformed casting. 4.6 Priming and painting After all the cleaning process has been performed then the final step is priming and the painting casting. The machine tool castings are generally big and are handled with crane during painting. Painting is done by brushes only.