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Introduction 1.1 Fulcrum of Indian Industrial Development: HMT synonymous with excellence in precision engineering is a multi product company established in 1953. Built on a strong foundation of technical know how acquired from world leaders in machine tools such as Oerlikon, Manurhin, Glidemeister, Liebherr, Rino Berardi, Fritz Werner, Pegard, Waldrich Coburg etc. HMT’s machine tools expertise has been developed to such an extent that HMT can design and develop any kind machine. Having established as a machine tool manufacturer, HMT diversified into other product lines. From simple lathes to multi-station transfer lines from stand alone CNC machine to flexible manufacturing systems, leading to factory automation, HMT’s broad range of machine tools cover General Purpose Machine, Special Purpose Machines and CNC machines, meetings the application needs to every engineering industry. Pioneering the concept of CNC technology in India HMT has the destination of being the first company to successfully manufacture its own CNC system in association with Siemens. HMT’s commitment to the development of the machine tools technology is clearly reflected in the fact that HMT has as many as seven exclusive machine tool units, spread across the country. Each superbly equipped to meet the most challenging demand for machine tools. These units are in Banglore, Pinjore, Kalamassery, Hyderabad, and Ajmer are all ISO 9000 certified. Today HMT is well positioned at the fore front of the precision engineering field. Its manufacturing plants employ highly skilled workforces strongly supported by R&D. Today over 780000 machine tools manufactured by HMT are in used in India and elsewhere. In tune with changing business environment, HMT limited restructured into holding company tractors as its core business and the following subsidiaries: HMT Machine Tools Limited, HMT Watch Limited, HMT Bearings Limited, HMT Chinar Watches Limited, HMT (International) Limited, Praga Machine Tools Limited. 1.2 Brief Introduction When HMT was founded in 1953, it dedicated itself to a clear objective: empowering the emergence of Indian Industry. With the virtue of being founded on a strong technical base, HMT donned the role of a one-of-its kind precision engineering company. HMT leveraged its technical know-how, acquired from world leaders in machine tools, to arm a wide spectrum of industries with vital manufacturing machinery and solutions. Strongly supported by excellent R&D prowess, a highly-skilled workforce and as many as nine exclusive machine tool units across the country, HMT contributed enormously to the precision engineering arena. HMT Machine Tools’ expertise in machine tools has been honed to a point that it can design and develop any kind of machine. From simple lathes to multi-station transfer lines, from stand-along CNC machines to flexible manufacturing systems, leading to factory automation, HMT Machine Tools’ Products cover general purpose machines, special purpose machines and CNC machines to meet the application needs of every engineering industry. To date, over 100,000 machine tools on par with international standards in quality and performance, manufacture by HMT, are in use all over India. The Company also manufactures sheet fed offset printing machines in single, two, four, and five colours, programmable paper guillotines, ball screws, and CNC Control Systems. HMT’s pioneering spirit and cutting-edge marketing abilities enable it to showcase its products and services to a worldwide clientele. The establishment of HMT (International) Limited leveraged the Company’s international trading experience. HMT(I) markets the products through a global network that extends over 40 countries to service its customers worldwide. HMT(I) has a diverse clientele with more than 18,000 machines in over 70 countries including the developed ones. HMT Machine Tools, jointly with HMT(I) has been instrumental in executing various international turnkey projects in Algeria, Tanzania, Nigeria, Malaysia, Iraq, Mauritius, Indonesia, Kenya, Ethiopia, Iran, Maldieves, Senegal, Turkemenistan, Nepal. 1.3 Evolution of HMT Machine Tools Limited Our first Prime Minister, Pandit Jawaharlal Nehru"s dream to build modern India paved the way for setting up of various Public sector undertakings in different industrial sectors. This initiative led to rapid industrialization of the country and he acknowledged the same as "Temples of Modern India". Hindustan Machine Tools Ltd. in the year 1953 was established with the same thought and was termed as"Jewel of Nation". Machine Tools industry , being the mother industry , has strategic importance and is a major support for growth of various other industries. Initially it started with an objective of producing a limited range of machine tools, required for building an industrial edifice for the country. Thus, Hindustan Machine Tools Limited, or HMT began in a small way to meet a big commitment -"To manufacture mother machines to build modern industrial India". 1953 - 2000: With the success achieved in the initial years in absorbing the technology and in attaining production competence far ahead of the original plans, the Company launched a bold plan of diversification and expansion which resulted in the duplication of the Bangalore Unit and the setting up of new units at Pinjore, Kalamassery and Hyderabad. In 1967, recession struck the Indian Engineering Industry and the consumption of machine tools dipped drastically. The traumatic years of recession did indeed serve to bring to the fore two latent strengths of HMT, namely, the urge to survive and the confidence to innovate With these strengths at full play, the Company emerged from the recession - with the world's widest range of machine tools and associated services under a single corporate entity. With action plans firmly launched for diversification into Presses and Press Brakes, Printing Machines, Die Casting and Plastic Injection Moulding Machines, that were considered to have economic cycles that are different from those of machine tools, with export markets of enormous potential under active development. During 1970s, HMT took over Machine Tool Corporation at Ajmer as its sixth machine tool unit. Consequent to the wide diversification, in September,1978 , the company dropped the name Hindustan Machine Tools Limited and instead adopted the acronym "HMT" itself as its name, and thus the company came to be known as HMT Limited. During the"1980s, HMT, as a part of vertical integration efforts, launched units to manufacture : CNC Systems at Bangalore Ball screws at Bangalore The"1990s witnessed the formation of Central Reconditioning Division at Bangalore, and formation of the Machine Tool Business Group as part of business reorganisation, along with other groups such as Watches, Tractors and Industrial Machinery within the company, HMT Limited. 1.4 The New Millennium In the year 2000, the various diversified businesses of the Company were reorganized into separate subsidiaries and thus in April,2000 HMT Machine Tools Limited was born as a wholly-owned subsidiary of the holding company, HMT Limited along with other subsidiaries i.e. HMT Watches Limited, HMT Chinar Watches Limited, HMT International Limited, HMT Bearings Limited. The holding company, HMT Limited, retains and directly operates the Tractors Business. The Machine Tools Subsidiary, head-quartered at Bangalore, initially had 5 manufacturing units located at Bangalore (Karnataka), Kalamassery (Kerala), Hyderabad (Andhra Pradesh), Ajmer (Rajastan) and Pinjore (Haryana). Later, Praga Tools Limited (PTL), Hyderabad, which was another subsidiary of HMT Limited, was merged with HMT Machine Tools Limited (HMTMTL), and became the 6th Manufacturing Unit of the latter. These units are named as MBX , MTK , MTH , MTA , MTP , PTH. 1.5 Corporate Structure Fig. no. 1.1 corporate structure 1.6 Organisation Fig. no. 1.2 organisation 1.7 Corporate Vision: To Be a Manufacturing Solution Provider of international Repute, Offering Best of Products & Services With Contemporary Technologies for Customers’ ultimate delight. 1.8 Corporate Mission: To be a key source of :Technology for Excellence" in the field of metal cutting / metal forming. To provide 'High quality cost competitive solution' for entire manufacturing Industry on 'One stop shop' basis. To provide sustained support to all of strategic sectors. To exceed customers’ expectations through continuous innovation. To provide leadership & direction in the manufacturing sector for the overall industrial growth of nation. 1.9 Corporate Objectives : To achieve a growth percentage above the industrial average of machine tool sectors with in 5 years. Focus and aim for achieving positive gross margin in year 2013-14. To achieve sustained growth in the earnings of the company on behalf of shareholders. Focus on to achieve 80% capacity utilisation of facilities and resources by 2017-18 from present level of 61%. Introduce at least one new product by each unit every year with contemporary technologies through In-house R & D, Joint Partnerships, Sourcing and Acquisitions. Achieve higher productivity through upgradation modernization, reduction in rejection & rework, value engineering, waste elimination, developing alternative source and Effective Financial Planning and Control. To achieve a sales turnover of per employee from Rs 6.67 L (2011-12) to Rs 26 L by 2017-18. 1.10 Corporate Goals : To be a Rs 1000 Cr. Company by 2020 with Miniratna status 1.11 Quality Policy: To maintain quality leadership in all our products & services. Total Customer Satisfaction through Quality Goods and Services. Commitment of management to Quality. To create a culture amongst all employees towards total quality concepts. 1.12 Major Projects / Execution Domestic Wheel & Axle Plant Project for Indian Railways Flexible Machining Cell with 8 CNC Turning Centers, each with 2-axes gantry loader & Automatic Guided Vehicle (AGV) for pallet transfer. Automatic Shell Forging Line Machining Line for Cylinder Blocks, Tata Cummins Ltd., Jamshedpur, India Flexible Machining System (FMS) with large size Machining Centers linked by Rail Guided Vehicle (RGV), area tool gantry and host computer for manufacture of IC Engine Components, (JWA with Rino Berardi, Italy) FMS with 2 Machining Centers linked by Rail Guided Vehicle and host computer for manufacture of tractor components, HMT Tractor Plant, Pinjore, India Mechanical 10-station Transferline for manufacture of engine case, Bajaj Auto Limited, Pune, India Flexible Turning Cell SBCNC 60 with Gantry Automation. Press Line for manufacture of automobile panel forming, Jai Bharat Maruthi Udyog Limited, India Bilateral Master-Slave Servo Manipulators, Rugged Duty Manipulators, 3-Piece Master-Slave Manipulators for material handling. International NMT, Nigeria: Joint venture for manufacture of machine tools in Nigeria. Maintenance-cum-Machine Tool Reconditioning Shop, SNVI/ CVT, Algeria. Sonelgaz, Algeria Turnkey project for manufacture of Gas Meters/Water Meters and Regulators. Engineering Design & Fabrication Centre, Federal Institute of Industrial Research, Nigeria. Tool Rooms Training & Development Centers Project Consultancy Alloy Steel Foundry for Alloy Steel Castings, Kenya. GLS Lamp Manufacturing Unit, CEILMAC, Tanzania. Welding Electrode Manufacturing Unit, Kenya 1.12 Major Collaborations TURNING Year Collaborator Country Product 1949-66 Oerlikon Switzerland High precision Centre Lathes 1959-66 ErnaultBatignolles France Production Centre Lathes (LB) 1964-74 Haut Rhin France Single Spindle Automatics 1966-74 Gildemeister FRG Multispindle Bar & Chucking Automatics 1966-74 Haut Rhin France Single Spindle Automatics 1966-77 Ernault Somua France Copying Lathes (S. Pilote) 1966-71 Jones & Lamson DivisionWaterburyFarrel USA FAY Automatic Lathes 1966-71 Gildemeister FRG Drum Type Turret Lathes 1969-74 Oerlikon Switzerland Multipurpose Lathes (DA) 1970-75 American Tool Works USA Heavy Duty Engine Lathes & Machining Centres for Drilling Milling & Boring Operations 1971-78 Petermann Switzerland Sliding Headstock Automatics 1984-92 Gildemeister FRG MultispindleAutomatics (GF, GS) 1986-91 Gildemeister FRG GDM Series Chuckers Table no.1.1 MACHINING CENTERS & MILLING MACHINES Year Collaborator Country Product 1957-63 Fritz Werner FRG Milling Machines (M2 & M3) 1963-70 Fritz Werner FRG Milling Machines(Electrically Controlled) 1966-77 Ernault Somua France Copying Lathes (S. Pilote) 1970-77 Fritz Werner FRG Ram Bed Type Milling Machines 1970-75 American Tool Works USA Heavy Duty Engine Lathes & Machining Centres for Drilling Milling & Boring Operations 1971-78 Fritz Werner FRG Unit Assembled Bed Type Milling Machines 1983-91 KTM UK CNC Machining Centres Table no.1.2 GRINDING Year Collaborator Country Product 1959-66 Olivette Italy Cylindrical Grinding Machines 1961-71 Limex GDR Hydraulic Surface Grinding Machines (SFW) 1985-93 Buderus FRG Precision Internal Grinding Machines Table no.1.3 GEAR CUTTING Year Collaborator Country Product 1963-70 Drummond Brothers UK Gear Shapers(Maricut 2A & 3A) 1964-71 Liebherr FRG Gear Hobbing Machines(L series) 1976-79 Cross USA Gear Chamfering Machines 1983-91 Liebherr FRG Heavy Duty Gear Hobbers 1983-91 Liebherr FRG High Speed Gear Shapers (WS1) Table no. 1.4 METAL FORMING Year Collaborator Country Product 1969-79 Interfonda Switzerland Diecasting Plastic Injection Moulding Machines 1969-79 Verson USA Presses & Press Brakes – Hydraulic & Mechanical 1982 Interfonda Switzerland Diecasting Dies 1981-89 Reissenhauser FRG Plastic Extrusion Machines 1982-89 Verson UK Presses 1996-98 Clearing-Niagara USA Presses Table no. 1.5 SPECIAL PURPOSE MACHINES Year Collaborator Country Product 1961-68 Renault France Special Purpose Machines 1970-77 Fritz Werner FRG Ram Bed Type Milling Machines 1971-78 Fritz Werner FRG Unit Assembled Bed Type Milling Machines 1976-79 Cross USA SPMs 1980-87 Pegard Belgium Horizontal Boring Machine Table no. 1.6 GENERAL PURPOSE MACHINES & OTHERS Year Collaborator Country Product 1958-65 Hermann Kolb FRG Radial Drilling Machines (RM) 1967-77 Oswald Forst FRG Broaching Machines – Horizontal & Vertical (Internal & External) 1968-73 Fin Motil Switzerland Clamping Chucks 1969-76 Ateliers GSP France Drilling & Boring Machines 1982-90 Oswald Forst FRG Surface Broaching Machines 1984-90 Carl Zeiss Jena GDR Ballscrews 1984-94 Siemens FRG CNC Control Systems Table no. 1.7 1.14 Major Manufacturing Facilities Experienced design & development facilities Facilities to produce machine tool grade meehanite castings including Pattern shop Centralised sand conditioning plant Metallurgical/Material Testing Laboratory Assorted production facilities including Precision machines (jig boring, gear grinding, etc.) Special purpose machines CNC Machines Heavy duty machines (like Waldrich Coburg, etc.) Advanced and sophisticated Tool Room Precision measuring & inspection facilities Fabrication shop to build huge structures with stress relieving facilities Heat treatment facilities Material testing laboratory Facilities for calibration of measuring & testing equipments 1.15 Corporate Strength Fig no. 1.3 corporate strength 1.16 Technology and R&D HMT Machine Tools has imbibed a wide range of technologies as a result of its diversification strategies, to be a truly multi-technology company. The list includes, though not limited to, the following technologies: High Speed Machining Hard Parts Turning Precision Machining Computer Numeric Controls Computer Integrated Manufacture Flexible Manufacturing Systems/ Modules/Cells Metal Forming including Die casting & Plastic processing Fig. no.1.4 diff. Model R&D efforts in these technology areas are a continuous and ongoing process at the Design & Development C enters of all HMT Machine Tools’ manufacturing units. In each area of HMT Machine Tools’ business domain, well-established research & testing facilities with experienced engineers to man them are in position. Extensive use is made of in-house CAD facilities for designing products. The R & D efforts include the design and development of over a 100 new types / variants of machine tools HMT Machine Tools’ R&D is committed to provide the best to the customer in terms of contemporary technology and contemporary designs at competitive prices. 1.17 Manufacturing Network Fig. no. 1.5 manufacturing network 1.18 HMT Centers With Their Year Of Establishment YEAR UNITS/DIVISION LOCATION STATE 1953 1961 1962 1963 1965 1967 1971 1971 1972 1972 1973 1975 1975 1975 1978 1981 1981 1982 1983 1985 1986 1991 Machine Tools I Machine Tools II Watch Factory I Machine Tools III Machine Tools IV Machine Tools V Tractor Division Die Casting Division Printing Machine Division Watch Factory II Precision Machine Division Machine Tools VI HMT (International) Ltd. Watch Factory III Watch Factory IV HMT Bearing Ltd. Quartz Analog Watches Watch Factory V Stepper Motor Division Ball Screw Division CNC System Division Central Re-Conditioning Banglore Banglore Banglore Pinjore Kalamessery Hyderabad Pinjore Banglore Kalamessery Banglore Banglore Ajmer Banglore Sri Nagar Tumkur Hyderabad Banglore Ranibagh Tumkur Banglore Banglore Banglore Karnataka Karnataka Karnataka Haryana Kerala Andhra Pradesh Haryana Karnataka Kerala Karnataka Karnataka Rajasthan Karnataka Jammu & Kashmir Karnataka Andhra Pradesh Karnataka Uttar Pradesh Karnataka Karnataka Karnataka Karnataka Table no. 1.8 1.19 Pinjore Complex Fig. no. 1.6 pinjore complex Machine Tools Division (MTP), Pinjore 134 101. Dist. Panchkula Telephone 91-1733-263 825-29 Fax 91-1733-264 114 Email mtpsales[at]hmtmachinetools.com | mtp[at]hmtmachinetools.com Inception 1963 Managing Director M D SreeKumar Unit Chief Mr. R.N. Lakshminarasimha - General Manager Telephone 91-1733-264 372, (+91) 93154 44816 Sales Chief S.P Sharma -Joint General Manager(S) Telephone 91-1733-264 073, (+91) 93154 44812 1.20 Major Manufacturing Facilities Machining facilities for major structures and critical components of machines Captive foundry of capacity 2040 MT per annum – Size of Grey Cast Iron casting up to 4 MT Assembly Facilities Spindle balancing machine Clean room for spindle assembly Assembly rigs for sub assemblies Testing rigs for sub assemblies Pattern shop Tool room with latest facilities Latest inspection facilities like CMM (carl & Zelss), Laser equipment (H.P & Renishaw), Sine Bar System (Renishaw) Table no.1.9 1.21 Collaboration / Technical Tie-ups MACHINING CENTERS & MILLING MACHINES Year Collaborator Country Product 1957-63 Fritz Werner FRG Milling Machines (M2 & M3) 1963-70 Fritz Werner FRG Milling Machines(Electrically Controlled) Table no 1.10 GENERAL PURPOSE MACHINES & OTHERS Year Collaborator Country Product 1967-77 Oswald Frost FRG Broaching Machines – Horizontal & Vertical (Internal & External) 1982-90 Oswald Frost FRG Surface Broaching Machines Table no. 1.11 1.22 Major Projects Executed / Achieved Design, development, manufacture and commissioning of fully automatic Flexible Machining Module Line First to develop horizontal and vertical machining centers in the country First in the country to manufacture High Speed Machining Center (with integral spindle) Special machines for line production in Auto Sector Machines exported to Europe, America, Middle East and Russia Table no.1.12 1.23 Awards of Excellence 1982–83 National Productivity Council Award for Productivity 1985-86 FIE Foundation Award for Excellence in Design at IMTEX 86 SNC–H & SNC–V 1991–92 National Productivity Council Award for Productivity 1992–93 National Productivity Council Award for Productivity 1994–95 FIE Foundation Award for Excellence in Design at IMTEX 95 for HMC 320H 1997-98 FIE Foundation Award for Excellence in Design at IMTEX 98 for HMC 400E Table no.1.13 1.24 Products Range Machining Centers Centers HMC 320M HMC 400M HMC 500 / HMC 500M HSM 400 HMC 630 HMC 800 Vertical Machining Centers VMC 400M VMC 600M VMC 5SM VMC 800M VMC 1000 VMC 1200M Tool Room Machining Center VMC (TC) Table no.1.14 Milling Machines Milling Machines FN2 (H,U,V) Tool Room Milling Machine TRM 3V/5V Table no. 1.15 Broaching Machines Broaching Machine - Horizontal RW 5/16/25 Broaching Machine - Vertical RISZ 10x1250 RISZ 16x1250 RISZ 25x1600 Table no. 1.16 1.25 Machine Tool Marketing Division Wide marketing network manned by qualified & trained sales & service engineers Service outlet at customer doorsteps in major industrial locations. Customer training programs on Mechatronics in addition to regular machine-oriented training for machine tools. Manufacturing Units supplement customer support for tooled-up and high technology machine tools. Specialised components, jigs & fixtures to suit customers’ specific/ special application needs. Fig. no.1.7 marketing division 1.26 Sales & Service Network Fig. no.1.8 sale and service network 1.27 Products Discription 1.27.1. Horizontal Machining Center HMC 800/1000/1250/1500 /HMC 320/400, HSM400/500, HMC 500M HMC 630 Fig no.1.9 HMC 1.27.1.1 Salient Features : » Make up a range that satisfy the needs of any metalworking shopm machining a variety of components » Offered with 40/60 tool ATC and twin pallet shuttle » Continuous rotary table as fourth axis B 1.27.1.2 Specifications : HMC 800 HMC 1000 HMC 1250 HMC 1500 Table size mm 800x800 1000x1000 1250x1250 1500x1500 Table longitudinal traverse - X mm 1300 1750 2000 2000 Headstock vertical traverse - Y mm 1000 1000 1500 1500 Column cross traverse - Z mm 1000 1000 1500 1500 Spindle power kW 15/22 15/22 30 37 Spindle taper ISO 50 ISO 50 ISO 50 ISO 50 Speed range (1 rpm increment) rpm 20-3600 20-3600 20-3600 20-3600 Table no.1.17 1.27.2. Vertical Machining Center VMC 800M Fig. no.1.10 VMC 1.27.2. 1 Salient Features : » Bed type machine configuration » Preloaded linear recirculating guideway system » AC Spindle motor » AC Servomotors for feed drive of all axes. » Automatic cyclic lubrication system for ballscrews and guideway system. » Chip collection arrangement with chip conveyor. » Guideway protection through telescopic covers/bellow covers. » Machine work lighting. » Cam driven high speed armless auto tool changer. » External coolant » Head counter balance 1.27.2.2 Specifications : Table size mm 860 x 460 Traverses X, Y & Z axes mm 760 x 500 x 450 Rapid rate m/min 12 (standard), 20/32 (optional) Positioning accuracy mm ± 0.005 Repeatability mm ± 0.003 Spindle taper BT-40/ISO 40 Spindle speed rpm 60-6000, 60-8000 Spindle power kW 5.7 / 7.5 ATC Capacity 12 / 20 Max. tool weight kg 8 Max. tool dia. mm 80, 125 (alternate pocket empty) Tool change time sec 10 CNC System Fanuc/Siemens Table no 1.18 1.27.3. TRM 3V / 5V Fig. no.1.11 TRM 3V /5V Versatile milling machine for milling, drilling and boring operations with precision and speed 1.27.3. 1 Salient Features : » Versatile ram type milling machine that can perform milling, drilling and boring operations with precision and speed. All these operations can be performed vertically or at an angle at any point on the table surface. » Can easily be converted in to Horizontal Milling Machine with horizontal milling attachment. » Solid locking of drilling/milling/boring head in spite of many planes of articulation. » Heavy milling with speed reduction can utilise the full capacity of the motor. » Single shot lubrication pump for lubrication to lead screws and guideways in X, Y & Z axes. » Grease packed drive arrangement ensures maintenance-free enhanced life to the infinitely variable speed milling head. 1.27.3. 2 Specifications : 3V 5V Table mm 1070x230 Table Clamping Area mm 900x230 Travel-(Manual-X/Y/Z/Ram/Quill) mm 760 /305 / 400 / 305 / 127 Spindle taper ISO 30 (without face mounting facility) ISO 40 Quill feed rates (3 nos.) mm 0.038, 0.076, 0.150 Motor power HP 3 5 Spindle speed Infinitely variable Speed range 50 c/s 60 c/s rpmn rpm 50-3500 60-4200 Swivel of milling head degree 45 either side in X- and Y- planes 45 either side in X-plane Swivel of ram degree 360 Machine Dimension (LxBxH) mm 1525x1650x1000 Net Weight kg 900 1000 Table no. 1.19 1.27.4. Knee Type Milling Machine FN2/FN3 Fig. no.1.12 FN2H Fig no. 1.13 FN3V 1.27.4.1 Salient Features : » Streamlined construction, rugged and vibration free. » 7.5/5l5 kW Motor for heavy stock removal. » Power operated feeds and rapid traverses in all directions. » Independent main drive and feed drive motors. » Wide range of spindle speeds and feeds. » Instantaneous braking of spindle and table drives through electromagnetic clutches. » High rate of rapid traverses. » Light fingertip push button controls. » Inching push button for speed and feed drives 1.27.4.2 Specifications : FN3/FN3E (H & V) FN3/FN3E (U) FN2/FN2E (H,U,V) Overall dimensions (LxW) mm 2050x355 2060x300 1520x310 Clamping area (LxW) mm 1600x355 1600x300 1350x310 Power operated table traverses Longitudinal Cross Vertical mm mm mm 1200 320 425 950 320 375 800 265 400 Max. safe weight on table kg 600 400 350(H&V), 250(U) Number of speeds 18 18 18 Speed range rpm 25.5-1800 35.5-1800 35.5-1800 Main Motor kW/rpm 7.5/1500 7.5/1500 5.5/1500 Feed Motor kW/rpm 3.7/3000 3.7/3000 1.5/1500 Space required (LxBxH) mm 386x253x214(H) 386x206x217(W) 345x253x209 255x250x207(H) 255x196x197(V) 255x313x201 U) Packing Case (LxWxH) cm 260x245x230 260x245x230 230x195x210 Weight-Net / Gross kg 3600 / 4500 (H) 3700 / 4600 (V) 3700 / 4600 2400 / 3200 (H) 2500 / 3300 (V&U) Table no. 1.20 1.27.5. Broaching Machine Fig no.1.14 broaching machine 1.27.5.1 Salient Features : » Rugged construction. » Hydraulic system gives infinitely variable cutting speeds. » Dead constant draw speeds ensure optimum tool life and fine surface finish 1.27.5.2 Specifications: HORIZONTAL VERTICAL RW 5 RW 16 RISZ 10 RISZ 16 RISZ 25 Max. tractive force kg 5000 16000 10000 16000 25000 Max. stroke mm 1320 1600 1250 1250 or 1600 1600 Cutting speed m/min 1-10 1-6.25 Up to 7.5 Up to 7.5 Up to 7.5 Power kW 6.5 30 15 22 or 30 37 Table no.1.21 1.28 Major customer of HMT Automobile sectors Bajaj Auto, Ashok Leyland, Hero Honda, Maruti, Mahindra &Mahindra. Bearing industries Timken India, SKF Bearing, NEI, KCI Bearing, HMT Bearing. Defence Ordnance Factory Ambernath, Khamaria, Ambajari, Katni, Kanpur,V.F.& GCF Jabalpur, Nuclear Fuel Complex (NFC), H.V.F. Avadi, A.H.Q, Base Repair Depot (BRD), HAL, Army Base Workshops (ABW). Railways ICF (Chennai), C & W (Amritsar), DMW (Patiala),C & W (Jagadhari), DLW (Varanasi). Others Educational Sector (Engg. Colleges, Polytechnics, ITI’s etc.) Power Sector (BHEL, NTPC, State Electricity Boards etc.) Refractory Industries (TATA Refractory, Bharat Refractory etc.) Tool Rooms and Training Centers. 1.29 Diagrammatic Representation of Hierarchy in the Organization Fig no. 1.15 hierarchy in organisation Chapter 2 Pattern Shop and Foundry, Material testing 2.1 PATTERN SHOP A pattern may be defined as a replica or facsimile model of the desired casting which, when packed or embedded in a suitable moulding material, produces a cavity called mould. This cavity, when filled with molten metal, produces the desired casting after solidification of the poured metal. Since it is a direct duplication, the pattern very closely conforms to the shape and size of the desired casting, except for a few variations due to the necessary allowances. The most commonly used pattern materials in the industry are 1) wood (e.g. teak, deodar etc.), 2) metal (e.g. aluminium, cast iron, bronze etc.), 3) thermocol, 4)rubber, 5)epoxy resin. Wood: Wood are used for pattern making are of either teak or deodar or both of them. When both of them are used, then teak is generally used on the inner sides because teak is harder and retains it’s shape for longer times as compared to deodar which secretes a resign that on solidification can effect the shape of the pattern which when used gives defective casting. Comparison of Teak and Deodar: 1. Teak is easier to work in milling operation. 2. Teak is harder in comparison with deodar. Teak has longer life so it is used in making patterns of those tools which are to be manufactured in large numbers. Thermocol: Its main advantage is that it’s cheap and is lighter in weight as compared to wood or aluminium. Aluminium: It is lighter as compared with wood and also it’s rigidness and smooth finishing gives better casting. Also it retains its shape for longer times with almost no effect of water on it as compared to wood, which is very sensitive The following factors affect the choice of a pattern. (i) Number of Castings to be produced. (ii) Size and complexity of the shape and size of casting (iii) Type of molding and castings method to be used. (iv) Machining operation (v) Characteristics of castings 2.1.1 Different types of patterns The common types of patterns are: 1) Single piece pattern 2) Split piece pattern 3) Loose piece pattern 4) Gated pattern 5) Match pattern 6) Sweep pattern 7) Cope and drag pattern 8) Skeleton pattern 9) Shell pattern 10) Follow board pattern Fig. no.2.1: Single piece, Split, Match-plate, Cope and Drag Pattern Single piece pattern:This is the simplest type of pattern, exactly like the desired casting. For making a mould, the pattern is accommodated either in cope or drag. Used for producing a few large castings, for example, stuffing box of steam engine. Split pattern:These patterns are split along the parting plane (which may be flat or irregular surface) to facilitate the extraction of the patternout of the mould before the pouring operation. For a more complex casting, the pattern may be split in more than two parts. Loose piece pattern:When a one piece solid pattern has projections or back drafts which lie above or below the parting plane, it is impossible to with drawit from the mould. With such patterns, the projections are made with the help of loose pieces. One drawback of loose feces is that their shifting is possible during ramming. Fig. no.2.2: Loose piece pattern Gated pattern:A gated pattern is simply one or more loose patterns having attached gates and runners.Because of their higher cost, these patterns are used for producing small castings in mass production systems and on molding machines. Fig. no.2.3: Gated pattern Match plate pattern:A match plate pattern is a split pattern having the cope and drags portions mounted on opposite sides of a plate (usually metallic), called the "match plate" that conforms to the contour of the parting surface. The gates and runners are also mounted on the match plate, so that very little hand work is required. This results in higher productivity. This type of pattern is used for a large number of castings.Piston rings of I.C. engines are produced by this process. Sweep pattern:A sweep is a section or board (wooden) of proper contour that is rotated about one edge to shape mould cavities having shapes of rotational symmetry. This type of pattern is used when a casting of large size is to be produced in a short time. Large kettles of C.I. are made by sweeppatterns. Fig. no.2.4: Sweep pattern Cope and drag pattern:A cope and drag pattern is a split pattern having thecope and drag portions each mounted on separate match plates. These patterns are used when in the production of large castings; the complete moulds are too heavy and unwieldy to be handled by a single worker. Skeleton pattern:For large castings having simple geometrical shapes, skeleton patterns are used. Just like sweep patterns, these are simple wooden frames that outline the shape of the part to be cast and are also used as guides by the molder in the hand shaping of the mould. This type of pattern is also used in pit or floor molding process. Fig. no.2.5: Skeleton pattern Shell pattern: Fig. no.2.6: Shell pattern Follow board pattern:A follow board is not a pattern but is a device (wooden board) used for various purposes. Fig. no.2.7 : Follow board pattern 2.1.2 Machinery Machines used in pattern shop are:- i. Blade sharping machine. ii. Bend saw machine. iii. Wood planner . iv. Circular saw . v. Wood milling machine 2.1.3 Shrinkage Allowance Metal Pattern Oversize Factor* Finish Allowance* Win Wall mm/(in) Aluminum 1.08 – 1.12 0.5 to 1.0% 4.75 (0.187) Copper Alloys 1.05 - 1.06 0.5 to 1.0% 2.3 (0.094) Gray Cast Iron 1.10 0.4 to 1.6% 3.0 (0.125) Nickel Alloys 1.05 0.5 to 1.0% N/A Steel 1.05 – 1.10 0.5 to 2% 5 (0.20) Magnesium Alloys 1.07 – 1.10 0.5 to 1.0% 4.0 (0.157) Malleable Irons 1.06 – 1.19 0.6 to 1.6% 3.0 (0.125) Table no 2.1 2.2 FOUNDARY SHOP HMT’s foundary shop comprises of two units: • One is the captive foundary, meant for the small production of casting having weight upto 4 tonnes. The capacity of this foundary is 1000 MT per annum. • And the other is meant for mass production of comparatively smaller tractor and machine components. The capacity of this foundary is 2000 MT per annum. 2.2.1 Melting Department: The process of melting in HMT is carried out in induction furnaces at a temperature of about 1400°-1450° C Process:At first the induction furnaces are coated with fine cement clay. Now metal scrap is inserted in the furnace and slag coagulant is added to it. The requisite amount of coke is added to it. The current is supplied to copper coils provided in the furnace which induce current in the metal scrap and the scrap gets heated up, when the melting temperature is reached the molten metal is collected in ladles and taken to the pouring zone. When this process is being carried out the copper coils are regularly cooled with coolant (water) so that the coils do’not melt due to the high temperature generated in the coils. The foundary of HMT has three furnaces, two, each having capacity of 3MT and one of 1.5MT. The two types of induction furnaces are:- • Main frequency Induction Furnace(50Hz) • Medium frequency Induction Furnace(250Hz) Melting of metal ion medium frequency furnaces are faster than the main frequency furnaces. 2.2.2 Induction Furnace Induction Furnace is used for melting the metal. There is tilting head in furnace for pour out the melting metal. To get more special properties following metal is added. Ferro Manganese. Ferro Silicon. Ferro chromium. Carbon (as required). To remove slag from the melting metal silica sand is mixed in the furnace. To get more fluidity of metal elino cline mixed in the melted metal. Fig. no.2.8 Induction Furnace Melting Process of Cast Iron 2.2.3 Specifications of 1.5 tonne capacity furnace:- Line Voltage : 11000 Volts Primary Voltage : 440 Volts Power Voltage : 440 KW Power Rating : 5 KA Melting Power : 1 tonne per hour Frequency : 50 Hz Lining Thickness : 95 mm Power Factor : 0.9 After the melting process is complete, the molten metal is carried quickly to the moulds to prevent solidification. The inversion of Induction Furnaces is carried out by hydraulic lifts fitted just below the whole apparatus. 2.2.4 FOUNDRY TOOLS AND EQUIPMENTS There are large number of tools and equipments used in foundry shop for carrying out different operations such as sand preparation, molding, melting, pouring and casting. They can be broadly classified as hand tools, sand conditioning tool, flasks, power operated equipments, metal melting equipments and fettling and finishing equipments. Different kinds of hand toolsare used by molder in mold making operations. Sand conditioning tools are basically used forpreparing the various types of molding sands and core sand. Flasks are commonly used forpreparing sand moulds and keeping molten metal and also for handling the same from place to place. Power operated equipments are used for mechanizing processes in foundries. Theyinclude various types of molding machines, power riddles, sand mixers and conveyors, grindersetc. Metal melting equipment includes various types of melting furnaces such as cupola, pitfurnace, crucible furnaces etc. Fettling and finishing equipments are also used in foundry work for cleaning and finishing the casting. General tools and equipment are used in foundry are discussed as under. 2.2.5 HAND TOOLS USED IN FOUNDRY DEPARTMENT The hand tools used in foundry department are given below:- Hand riddle. Shovel. Rammers (Hand, Peen, Floor & Pneumatic Rammers.). Sprue pin. Strike off bar. Mallet. Draw spike. Vent rod. Lifters. Trowels. Slicks. Smoothers. Swab. Spirit level. Gate cutter. Gaggers. Spray-gun. Nails & wire pieces. Bellows. Clamps, cotters & wedges. 2.2.6 FLASKS The common flasks are also called as containers which are used in foundry department as moldboxes, crucibles and ladles. 2.2.7 MOULDING BOXES Moulding boxes are used in sand maulding following two types:- Open moulding boxes. Closed moulding boxes. 2.2.8 CRUCIBLE Crucibles are made from graphite or steel shell lined with suitable refractory material like fire clay. They are commonly named as metal melting pots. The raw material or charge is broken into small pieces and placed in them. They are then placed in pit furnaces which are coke-fired. In oil- fired tilting furnaces, they form an integral part of the furnace itself and the charge is put into them while they are in position. After melting of metals in crucibles, they are taken out and received in crucible handle. Pouring of molten is generally done directly by them instead of transferring the molten metal to ladles. But in the case of an oilfired furnace, the molten metal is first received in a ladle and then poured into the molds. Fig. no.2.9 crucible use Fig. no.2.10 crucible sketch 2.2.9 LADDLE It is similar in shape to the crucible which is also made from graphite or steel shell lined with suitable refractory material like fire clay. It is commonly used to receive molten metal from the melting furnace and pour the same into the mold cavity. Its size is designated by its capacity. Small hand shank ladles are used by a single foundry personal and are provided with only one handle. It may be available in different capacities up to 20 kg. Medium and large size ladles are provided with handles on both sides to be handled by two foundry personals. They are available in various sizes with their capacity varying from 30 kg to 150 kg. Extremely large sizes, with capacities ranging from 250 kg to 1000 kg, are found in crane ladles. Geared crane ladles can hold even more than 1000 kg of molten metal. The handling of ladles can be mechanized for good pouring control and ensuring better safety for foundry personals workers. All the ladles consist of an outer casing made of steel or plate bent in proper shape and then welded. Inside this casing, a refractory lining is provided. At its top, the casing is shaped to have a controlled and well directed flow of molten metal. They are commonly used to transport molten metal from furnace to mold. Fig. no.2.11 geared laddle 2.2.10 POWER OPERATED EQUIPMENTS Power operated equipments used in foundary department are given below:- Moulding Machines. Sand Slingers. Core making & core baking equipments. Power riddles. Mechanical conveyors. Sand Mixers. Material Handling Equipments. 2.2.11 Moulding and Core Making: In HMT due to complex structure of components (such as gear box) are produced with the help of master pattern. Here core is first made with the help of master pattern after which the core is allowed to be baked. The core is made with the help of sand such as • Rigid coated sand in shell core machining. • Air setting sand or no bake sand. • Green sand. Here the gear box is made with no bake/air setting sand which is prepared by mixing different constituents. Here the prepared core (made from master pattern) is allowed to solidify. Smaller core is baked with the help of shell core machine, which has a box containing rigid coated sand. When allowed to operate the front assembly rotates and the box moves upward from which the sand falls in the die (die used according to shape of core required) here die can be changed. Now the core is put in cope, drag and the molten metal is poured after which pattern can be easily obtained. Fig. no.2.12 mould making machine 2.2.12 The process of creating a shell mold consists of six steps 1. Fine silica sand that is covered in a thin (3–6%) thermosetting phenolic resin and liquid catalyst is dumped, blown, or shot onto a hot pattern. The pattern is usually made from cast iron and is heated to 230 to 315 °C (450 to 600 °F). The sand is allowed to sit on the pattern for a few minutes to allow the sand to partially cure. 2. The pattern and sand are then inverted so the excess sand drops free of the pattern, leaving just the "shell". Depending on the time and temperature of the pattern the thickness of the shell is 10 to 20 mm (0.4 to 0.8 in). 3. The pattern and shell together are placed in an oven to finish curing the sand. The shell now has a tensile strength of 350 to 450 psi (2.4 to 3.1 MPa). 4. The hardened shell is then stripped from the pattern. 5. Two or more shells are then combined, via clamping or gluing using a thermoset adhesive, to form a mold. This finished mold can then be used immediately or stored almost indefinitely. 6. For casting the shell mold is placed inside a flask and surrounded with shot, sand, or gravel to reinforce the shell. The machine that is used for this process is called a shell molding machine. It heats the pattern, applies the sand mixture, and bakes the shell. fig. no.2.13 shell moulding process 2.2.13 Chaplets These are small metal supports that bridge the gap between the mold surface and the core, but because of this become part of the casting. As such, the chaplets must be of the same or similar material as the metal being cast. Moreover, their design must be optimized because if they are too small they will completely melt and allow the core to move, but if they are too big then their whole surface cannot melt and fuse with the poured metal. Their use should also be minimized because they can cause casting defects or create a weak spot in the casting. It is usually more critical to ensure the upper chaplets are stronger than the lower ones because the core will want to float up in the molten metal Fig. no.2.14 chaplets usage Fig.no.2.15 types of chaplets 2.2.14 Basic process of casting There are six steps in this process 1. Place a pattern in sand to create a mold. 2. Incorporate the pattern and sand in a gating system. 3. Remove the pattern. 4. Fill the mold cavity with molten metal. 5. Allow the metal to cool. 6. Break away the sand mold and remove the casting Fig. no.2.16 process of casting 2.2.15 Green sand These expendable molds are made of wet sands that are used to make the mold's shape. The name comes from the fact that wet sands are used in the molding process. Green sand is not green in color, but "green" in the sense that it is used in a wet state (akin to green wood). Unlike the name suggests, "green sand" is not a type of sand on its own, but is rather a mixture of: • silica sand (SiO2), or chromite sand (FeCr2O), or zircon sand (ZrSiO4), 75 to 85%, or olivine, or staurolite, or graphite. • bentonite (clay), 5 to 11% • water, 2 to 4% • inert sludge 3 to 5% • anthracite (0 to 1%) 2.2.16 Fettling Fettling is the process by which the pattern obtained is given the desired finish by various processes. Before fettling, the casting obtained is subjected to removal of projections, chips, core, runner, riser etc. by the following processes: • Decoring • Chipping • Shot blasting (for heavy pattern) • Wheel abrasion (for small pattern) Decoringecoring is the process of removing the fused sand. Chipping:Chipping is the process of removing the runner, riser etc. Shot Blasting & Wheel Abrasion:Shot blasting or wheel abrasion is used for removing the sand particles by the usage of air. After this fettling is done by the following process: • Pneumatic gun- to remove corner sand. • Angle grinder- to give corner finish. • Die grinder- to give finish to inner portion. • Pedestal grinder- to give surface finish. While making casting for gears, surface finish is not required because gear has to be cut on it with the help of milling machine after which it is grinded. 2.2.17 PRIMING & PAINTING: After clean and fettling, the casting is subjected to priming and painting to prevent corrosion 2.3 MATERIAL TESTING 2.3.1.UNIVERSAL TESTING MACHINE It has component load scale, oil pump, hydraulic press, main piston, fixed cross head, & movable cross head. It has range according to load applied: a) 0-1 tons b) 0-4 tons c) 0-10 tons It is generally used to determine: Proportional & elastic limit Yield point Ultimate tensile strength Percentage elongation & reduction of area Working:It is generally used to perform tensile test which is widely used in the design of material for structure & other purposes. Here, test piece is pulled out at a constant rate gradually increasing the axial pull, till the rupture take place. The tensile test for ductile material is generally, carried out with the help of a Universal Testing Machine on the specimen made from material to be tested. Fig.no.2.17 UTM 2.3.2. SPECTROSCOPE: It is a method of qualitative analysis of material with the help of electricity. Argon gas is being used as it prevents oxidizing of piece. Here piece is not destroyed. This is used for chromium, ammonium, nickel, tungsten, manganese, zinc, tin, lead etc. the spectrum is directly compared with a chart as it is moved by caliper & is then compared. It is used to find what materials are present. Fig.no.2.18 spectroscope 2.3.3.SPRING TESTING MACHINE: In this machine, spring test is done. We will find out compression or extension of spring & the load applied which is noted from load indicator. Then we calculate spring stiffness. Fig. no.2.19 STM 2.3.4.POLISHING MACHINE: In this machine polishing of material is done. In this belts are present on which abrasive powder is applied. In this machine belt is passed over two pulleys & which is driven by motor. Fig no.2.20 polishing machine 2.3.5.MAGNETIC CRACKING TEST: In this method, magnetic crack test machine is used. It is to check cracks b/w two pieces. We take two pieces which are magnetized followed by spraying the iron chips. The ultra violet light marked & fluorescent color is produced. Then Iron piece is glows due to ultra violet light. Fig. no.2.21 magneting cracking test 2.3.6.SPECTOMETER: It is basically computerized control program in which material is kept under observation than software is there which give composition of each element present in the material. Fig.no.2.22 spectometer 2.3.7.PORTABLE MICROSCOPE: It is a method used for analysis of the structure without cutting. And also it is used for determining the composition of element present in the material. It is used for the analysis of the structure. Fig. no.2.23 portable microscope 2.3.8.CARBON TESTING APPRATUS: It is chemical method of analysis of the material. In this, we take test sample of 1gm of carbon in the silica boat which is put in silica pipe. This is now passed through furnace which is at 1000 deg Celsius. Now oxygen gas is passed & then carbon dioxide (CO2) is formed which dissolves in alkaline solution than value is raised to corresponding exhaust temperature. Then carbon content is determined as: CARBON CONTENT = 0.3×CORRECTION FACTOR×VOLUME READING Fig. no.2.24 carbon testing appratus 2.3.9.ROCKWELL HARDNESS TEST: The Rockwell hardness test is generally performed when quick & direct reading is desirable. This test is also performed when the material have hardness beyond the range of Brinell hardness test. In this test the load for making indent are smaller & thus make smaller shallower indent. It is because of this reason that the Rockwell hardness test is widely used in industry. This test has nine scales of hardness (A to H & K). But B & C scales are widely used. The ball indenters are generally made of hardened tool steel or tungsten carbide. During the test, the specimen is placed on anvil, & raised till it comes in contact with indenter. A minor load of 100 KN is applied on the specimen & the small pointer indicates set. Now the main pointer is also brought to the set position. The major load is then applied & is allowed to continue for one second. The depth of indentation in mm is read from the smaller pointer. Fig. no.2.25 rockwell hardness test 2.3.10.VICKER HARDNESS TEST: The Vicker Hardness Test is the most accurate test which has a fairly continuous scale of hardness. The test makes the use of a diamond square based pyramid indenter. A piston & a dashpot of oils used for controlling the rate & duration of the loading. The test is performed by placing the specimen on an anvil & raised till it is close to the indenter point. The load is then gradually applied to the indenter & then removed. This test is very suitable for testing polished & hardened material or nitride surface due to small impression made on the test specimen. Fig. no.2.26 vicker hardness test 2.3.11 PRECAUTION: • The indenter & anvil should be clean & well placed. The surface of the specimen should be flat, clean, dry, & smooth &should be placed perpendicular to the indenter Chapter 3 Machine design 3.1 Introduction to Machine Design Machine Design is the innovation of new and effective machines and improving the existing ones. A new or effective machine is one which is more economical in the overall cost of production and operation. The design is to formulate a plan for the satisfaction of a human need. In designing a machine component, it is necessary to have a good knowledge of many subjects such as Mathematics, Engineering Mechanics, Strength of Materials, Theory of Machines, Workshop Processes and Engineering Drawing. 3.2 Classifications of Machine Design The machine design may be classified as follows: 1. Adaptive design: In this the designer’s work is concerned with adaptation of existing designs. The designer only makes minor alternation or modification in the existing designs of the product. 2. Development design: This type of design needs scientific training and design ability in order to modify the existing designs into a new idea by adopting a new material or different method of manufacture. 3. New design: This type of design needs lot of research, technical ability and creative thinking. Only those designers who have personal qualities of a sufficiently high order can take up the work of a new design. 4. Rational design: This type of design depends upon mathematical formulae of principle of mechanics. 5. Empirical design: This type of design depends upon empirical formulaebased on the practice and past experience. 6. Industrial design: This type of design depends upon the production aspects to manufacture any machine component in the industry. 7. Optimum design: It is the best design for the given objective function under the specified constraints. It may be achieved by minimizing the undesirable effects. 8. System design: It is the design of any complex mechanical system like a motor car. 9. Element design: It is the design of any element of the mechanical system like piston, crankshaft, connecting rod, etc. 10. Computer aided design: This type of design depends upon the use of computer systems to assist in the creation, modification, analysis and optimization of a design. 3.3 General Procedure in Machine Design In designing a machine component, there is no rigidrule. The problem may be attempted in several ways. However, the general procedure to solve a design problem is as follows: Fig. no.3.1 procedure of MD 1. Need or Aim: First of all, make a complete statement of the problem, indicating the need, aim or purpose for which the machine is to be designed. 2. Synthesis (Mechanisms): Select the possible mechanism or group of mechanisms which will give the desired motion. 3. Analysis of forces: Find the forces acting on each member of the machine and the energy transmitted by each member. 4. Material selection: Select the material best suited for each member of the machine. 5. Design of elements (Size and Stresses): Find the size of each member of the machine by considering the forceacting on the member and the permissible stresses for the material used. It should be kept in mind that each member should not deflect or deform than the permissible limit. 6. Modification: Modify the size of the member to agree with the past experience and judgment to facilitate manufacture. The modification may also be necessary by consideration of manufacturing to reduce overall cost. 7. Detailed drawing: Draw the detailed drawing of each component and the assembly of the machine with complete specification for the manufacturing processes suggested. 8. Production: The component, as per the drawing, is manufactured in the workshop. 3.4 Design and Manufacturing A machine element, after design, requires to be manufactured to give it a shape of a product. Therefore, in addition to standard design practices like, selection of proper material, ensuring proper strength and dimension toguard against failure, a designer should have knowledge of basic manufacturing aspects. First and foremost is assigning proper size to a machine element from manufacturing view point. As for example, a shaft may be designed to diameter of, say, 40 mm. This means, the nominal diameter of the shaft is 40 mm, but theactual size will be slightly different, because it is impossible to manufacture a shaft of exactly 40 mm diameter, no matter what machine is used. In case the machine element is a mating part with another one, then dimensions of both the parts become important, because they dictate the nature of assembly. The allowable variation in size for the mating parts is called limits and the nature of assembly due to such variation in size is known as fits. 3.4 .1 Limits Below Fig. explains the terminologies used in defining tolerance and limit. The zero line, shown in the figure, is the basic size or the nominal siz e. The definition of the terminologies is given below. For the convenience, shaft and hole are chosen to be two mating components. Fig. no.3.2 limits Allowance: It is the difference of dimension between two mating parts. Upper deviation: It is the difference of dimension between the maximum possible size of the component and its nominal size. Lower deviation: Similarly, it is the difference of dimension between the minimum possible size of the component and its nominal size. Fundamental deviation: It defines the location of the tolerance zone with respect to the nominal size. For that matter, either of the deviations may be considered. 3.4 .2 Tolerance Tolerance is the difference between maximum and minimum dimensions of a component, i.e. between upper limit and lower limit. Depending on the type of application, the permissible variation of dimension is set as per available standard grades. Tolerance is of two types, bilateral and unilateral. When tolerance is present on both sides of nominal size, it is termed as bilateral; unilateralhas tolerance only on one side Fig. no.3.3 tolerance 3.4 .3 Fits The degree of tightness or looseness between the two coupling parts is known as a fit of the parts. The nature of fit is characterized by the presence and size of clearance and interference. The clearance is the amount by which the actual size ofthe shaft is less than the actual size of the mating hole in an assembly as shown in Fig. In other words, the clearance is the difference between the sizes of the hole and the shaft before assembly. The difference must be positive. The interference is the a