final project
TRANSCRIPT
1. INTRODUCTION TO THE COMPANY
Mahindra and Mahindra Ltd., a premier Organization since 1945, is the flagship company of the U.S. $3 billion Mahindra group, which has a significant presence in key sectors of the Indian economy. A consistently high performer, M&M is one of the most respected companies in the country today. It is the 10th largest company in the Indian private sector. It is the 4th largest in tractors and 27th in vehicles globally. It has the largest sales distribution network in India.
The two main operating divisions of M&M are:-The Automotive Division manufactures utility vehicles, light commercial vehicles and three wheelers. The Company has entered into a JV with Renault of France for the manufacture of a mid-sized sedan, the Logan, and with International Truck & Engine Corporation, USA, for manufacture of trucks and buses in India.
The J.D. Power Asia Pacific 2007 India Initial Quality Study ranked the Logan as the ‘Best Entry Midsize Car in Initial Quality’, which is the ultimate measure in quality. The Logan received the lowest score of 65 PP100, i.e. problems per 100 vehicles, indicating a high level of satisfaction experienced by customers.
End-November 2007 saw M&M launching the Scorpio V-series – a new line-up of India’s leading SUV with the introduction of the Scorpio VLX. The new VLX edition is equipped with the powerful mHawk engine and a wide array of smart features like the mode lever on the steering wheel for conveniently switching radio stations or changing the music volume, without taking hands off the steering wheel or eyes off the road; and a cruise control button that takes over while the driver sits back and relaxes, advanced features are a sophisticated measuring system that indicates the exact air pressure and temperature of each tyre, intelligent headlamps that sense changes in ambient light and automatically turn on or off; and smart windshield wipers that start as soon as they sense a certain amount of rain, with the wiping frequency changing according to the intensity of rain.
The Tractor (Farm Equipment) Division makes agricultural tractors and implements that are used in conjunction with tractors, and has also ventured into manufacturing of industrial engines. The Tractor Division has won the coveted Deming Application Prize 2003, making
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it the only tractor manufacturing company in the world to secure this prize.
The prestigious ‘Golden Peacock National Quality Award – 2007’ for Excellence in Quality was conferred on FES after rigorous evaluation by independent examiners. FES has now won three Golden Peacock Awards; two for Quality and one for Occupational Health and Safety
1.1 Automotive Division Profile
The Company was incorporated in 1945 and was originally formed to manufacture utility vehicles for the Indian market, initially by importing and assembling Willys Jeep kits. The manufacture of utility vehicles commenced in 1954 in collaboration with Willys Overland Corporation and its successors, Kaiser Jeep Corporation and American Motor Corporation (now part of the DaimlerChrysler group). The Company commenced manufacturing Light Commercial Vehicles (LCV) in 1965. The Company has now also entered the three-wheeler market.
Over the years, the Mahindra brands of vehicles have come to represent high quality, ruggedness, durability, reliability, easy maintenance and operational economy. These are the qualities that have endeared the vehicle to individuals as well as institutions like the Indian armed forces. M&M is the leader in the MUV business in the country since inception.
M&M has comprehensive manufacturing facilities with high level of vertical integration. M&M's automotive division has four manufacturing plants, three in the state of Maharashtra and one in Andhra Pradesh. In Maharashtra, its plants in Mumbai and Nasik manufacture multi-utility vehicles, and engines are produced at the Igatpuri plant. Light commercial vehicles and three-wheelers are manufactured at the Company's plant in Zaheerabad in Andhra Pradesh.
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M&M has a strong Research & Development set-up, with over 300 engineers in the automotive division. Cross-functional and concurrent engineering teams are working on Integrated Design & Manufacturing (IDAM) to design a product to suit specific requirements of the customers through quick product development. The Company's technical prowess is proven by negligible import content in the vehicle and by the design and development of a totally, new contemporary SUV - Scorpio, from ground up.
Currently the Export focus of Mahindra is on the African, the South American, the South Asian and the Middle East Markets, where the need and use of vehicles is akin to India.
The division's marketing efforts are supported by a network of more than 275 dealers across the country, which are managed by 20 sales offices. Additionally, the division has a national network of authorized service stations and stockiest to meet customer needs for servicing and spare parts. M&M's automotive division also exports its products to several countries in Africa, Asia and European & Latin American countries.
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1.2 Products of the Automotive Division of Mahindra and Mahindra
Bolero Range BoleroBolero Camper
Pickup Range Utility Pick-Up NC 640DP Pick-Up CBC
MaXX Range MaXX MaXX-LX
CL Range 500/550MDI MMRange 540/550 DP
540/550 XDB 550 PE
Commander Range 650 DI 750 ST 750 DI Long
Hard Top Range Economy Marshall DI 775 XDB 3/5 Door Marshall Deluxe Marshall Royale
LCV Range CabKing 576 FJ470-DS4 High Roof OmnibusDI 3200 FJ MinibusTourister Cabking 576DI Loadking DI
Three Wheeler Range Champion DX Champion
Alternative Fuel RangeCNG Bijlee FJ CNG Minibus
Army Range Rakshak550 XD
Export Range Single Cab Double Cab 4WD MM-775Classic
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2. ORIENTATION AT THE KANDIVLI PLANT
This plant, is one of the most functionally sound of all the plants, and oozes with the brilliance and dedication put into it.The Mumbai- based M&M Auto Sector manufacturing plant at Kandivli, received the QS (Quality-system) 9000 Certificate in the year 2000. It is also ISO 14001 certified by RWTuV in the year 2002.The Mumbai plant has received the TPM excellence award from Japanese Institute of Plant Maintenance (JIPM) in the year 2003. It is also a member of the Mumbai Hazardous Waste Management Limited for the safe disposal of waste. The plant adheres to all safety standards in efforts to achieve zero accidents. M&M is the first Automobile Company to be recommended for TS 16949 certification by RWTuV in the year 2003. The Kandivli plant has also received the first place in the ‘National Energy Conservation Award’, for the automobile sector given by the Union Ministry of Power in 2003.
The layout of Mahindra & Mahindra Automotive sector along with a rough process layout of the plant is shown as follows in fig 1 :-
Fig. 1: Layout of the Automotive Sector Kandivli plant
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Fig. 2 : Schematic process flow of Automotive Sector Kandivli plant
The concept of PU`s (Product Unit) was evolved by the BPR to
systematize the processes of receiving vendor supplies, machining
and assembly of distinct parts of the vehicle. The major Product Units
(P.U) under the Automotive Sector is(ref. fig. 2) :
1. BODY P.U.2. AXLE P.U.3. TRANSMISSION P.U.4. ENGINE P.U.5. VEHICLE P.U.6. FOUNDRY P.U.
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2.1. Body Product Unit (Body P.U.)
Fig. 3: Body P.U Process Flow Chart
1. Press ShopThe press shop manufactures the sheet metal components, which form the body shell and the chassis of the Jeep. Imported MS sheets of thickness varying from 1mm to 5mm are used as the raw material.
The press shop has various presses with varying tonnage capacity, maximum 1200 M.T. The shop carries out various operations like cutting, forming, blocking, punching, embossing, etc with various high and low tonnage presses like:
Universal Guillotine Machine Single column hydraulic press Gordon press Fukui machinery Pvt. Ltd HMT press USI press.
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Raw Material Sheets
Press Shop
Body Shop
Accessories
Paint Shop
Finished Body shell to Trim Shop
The Press Shop includes:1. High Bay Section: Having presses with tonnage more than
150 tones.2. Low Bay Section: Having presses with tonnage less than 150
tones.3. Shearing Section: For cutting sheets to proper size.4. Bending Section: For bending sheets to precise angle.
2. Body ShopIt is subdivided into:1. Single CAB assembly area.2. CL/CDR assembly area.3. CO2 Welding area.
Here everything related to joining of the various pressed parts into nearly the final shape is done. The welding done here is majorly by
Resistance Welding Spot welding. Projection Welding.
3. Paint Shop Here the assembled body gets painted. It is a high risk area and very few people are allowed to enter. The stages are:
1. Pretreatment.a. Degreasing (at about 500C-650C).b. Water Rinsing.c. Activation (For best and dense coating).d. Phosphating (by using zinc phosphate).e. Water rinsing.
2. Red Primer coating.3. Heating. 4. Unicoat.5. Heating.6. Top coat.7. Heating.
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The purpose of painting is three fold To increase the aesthetic appeal. To create a shield between the surface and atmosphere to
avoid rusting. To hide minor defects like scratches, weld marks etc.
There is also a 3-D Coordinate Measuring Machine (CMM) for inspection.
2.2. Axle Product Unit (Axle P.U.)
Fig. 4: Axle P.U. process flow chart
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Raw Material Forgings
Raw Material Castings
Raw Material Castings
Raw Material Castings
Hypoid Cell Machining
Differential Case
Machining
Gear Carrier Machining
Hub Cell Machining
Heat Treatment
Pair Making
Gear Carrier Assembly Line
Axle Assembly Line
Final Axles to Vehicle PU Line
Differential Case
Machining
Pair Making
Gear Carrier Assembly Line
Axle Assembly Line
Final Axles to Vehicle PU Line
In Axle Production Unit of Mahindra there are following type of cells(fig.4) :-
1. Hypoid cell.2. Heat Treatment.3. Differential Case Machining line.4. Hub Cell.5. Gear Carrier Machining line.6. Gear Carrier Assembly line.7. Axle Assembly.
1. Hypoid CellIn Hypoid cell Ring gears, Hypoid pinions, Side gears & Pinion mates are manufactured from raw material that is forged one. The following are the sequence of operations for:
RING GEARa. Facing & Turning.b. Drilling and tapping of holes which are used for assembly.c. Gear cutting (rough).d. Gear cutting (finish). e. De-burring.
PINION a. Facing and Turning.b. Grinding dia. which is critical for bearing. c. Spline cut.d. Pinion cutting.e. Pinion Finish (Forward stage & Reverse Stage).
SIDE AND PINION MATESThese side gears and pinion mates are manufactured by using gear cutting machines. These gears are used in assembly of differential case.
2. Heat TreatmentNow after machining, these gears are heat treated to improve their strength, wear resistance, hardness etc. This stage is carried out in Heat Treatment cell. After the Heat treatment is done the gears and pinions are ground and then tested. After this stage the ring gear and pinion are paired so that the differential case assembly will be with proper set of gears.
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3. Differential Case Machining LineIn this cell the differential case is machined from the casting that is obtained from the vendor. The following are the various steps involved:1. Axle bore, Counter bore of rib and non-rib side.2. Rib and non-rib diameters turning.3. Spot facing of 10 holes.4. Bore of cross bore holes.5. Rough and Finish of Spherical radius.6. Drill and ream of pin hole.7. Final inspection.8. Washing.After this the case is sent to the assembly stage.
4. Hub CellIn this cell the Hub is machined. Most of the operations of Hub are carried out on the MURATHA CNC LATHE. The machine has two sides L.H.S. & R.H.S. On L.H.S. the operations that are carried are:1. Rough facing & turning.2. Rough boring of oil seals.3. Finish of seal bore. 4. Drum dia. finish.On R.H.S. the operations that are carried on are 1. Rough facing & turning.2. Rough taper side boring.3. Padding.4. Taper side finish boring.5. Bolt side boring finish.6. Locator diameters finish.Now this hub is carried on to the assembly line.
5. Gear Carrier Machining LineHere the case of the gear carrier is machined in the following stages:-1. Cover face milling.2. Locate hole drilling & boring.3. Bearing seat milling.4. Rough pinion boring.5. Rough tube boring.6. Drain plug hole drill.
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7. Cover face & bearing cap seat 14 hole drilling & tapping.
6. Gear Carrier Assembly LineHere all the parts of the gear carrier are assembled in following stages:-1. Bearing chuck.2. Pinion positioning.3. Spacer selection. 4. Pinion pressing stage.5. Shim cell.6. Bearing fitment with differential case.7. Inspection.
7. Axle AssemblyHere the front and rear axle assembled at different places.FRONT AXLE ASSEMBLY STAGE
1. Placing of different parts on the trolley2. Pressing of the tubes to the axle 3. Welding of tube & gear carrier 4. Brake shoe assembly5. Rear shoe plate & hub assembly6. Hand brake assembly7. Cable fitment & play checking8. Drum fitment & oil filling9. Painting
REAR AXLE ASSEMBLY1. 4WD OEY pressing 2. Welding the gap3. Cable fitment 4. Play checking 5. Painting.
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2.3. Transmission Product Unit (Transmission P.U.)
Fig. 5: Transmission P.U. process flow chart
Transmission product unit involves manufacturing of the transmission drives e.g. gear box. It deals with the production of transmission case, transfer case, through different sections (fig.5).
The two of the latest transmission units for the 5-speed gearboxes of Mahindra & Mahindra are NGT 530 and NGT 520 (NGT stands for NEW GENERATION TRANSMISSION) are manufactured in the transmission product unit.
NGT 530 stands for New Gear Transmission cell producing 5-speed gearbox giving an output of 30 N/m torque. The NGT 530 is the assembly line producing transmission boxes for M&M models like Scorpio and Bolero. The assembly is of Nagara type, wherein a single worker does the complete assembly of a unit. The main advantage of the Nagara system is the time required to produce a unit is less and the worker is alone responsible for the loss in
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Raw Material Forging Blank
Raw Material Forging
Raw Material Casting
Gear Machining
Heat Treatment
Grinding
Shaft Machining Transmission
Case Machining
Heat Treatment
Grinding
Transmission Assembly
Finished Transmission Case Assembly transferred to Vehicle P.U.
production, which can be used as a data for the analysis of the productivity loss or gain.
The general procedure of the assembly done in NGT 530 of Scorpio is as follows:
1. Arrangement of the gear shafts, gear and housing to be assembled.
2. Fitting of the housing.3. Mounting clutch housing.4. Inter rear mounting is assembled.5. Mounting of the gears in between the forks.6. Mounting inter rear cover. 7. Fitting of the gear change lever attachment.8. Air leak test is done wherein the transmission case is first
charged with air, balanced and measured.9. The final testing is done for the gear shifting (starting with
reverse) for specific load and speed.
NGT 520 stands for New Gear Transmission cell producing 5-speed gearbox giving an output of 20 N/m torque. The NGT 520 is the assembly line producing transmission boxes for CL models. The assembly is of Line type, wherein the complete assembly is done in stages and by different workers at different workstations. The main advantage of the Line system is flexibility during high production demand, unlike in the Nagara system in NGT 530 assembly line.The NGT 530 can be distinguished from NGT 520 by the following unique features:
Feature NGT 530 NGT 520
Assembly line Nagara System Line Type
Housing Split HousingTunnel type (closed)
Torque Transmitted
30 N-m 20 N-m
Cost High cost Low cost
VehiclesBolero and Scorpio
Max Pick-up
Table 1.1: Difference between NGT 530 & NGT 520 transmissions
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1. TTC Machining Line
The TTC machine line is the production line on which the transmission case of the 4 speed gear box is machined. The various stages involved to convert the casting into finished case are mentioned on the following page.
Operation Description Machine1. Facing, drilling, chamfering and reaming
VA 5 0
2. Straddle milling of facesCincinnati duplex milling m/c
3. Pad milling HMT FN 344. Rough Boring of 2 holes XLR – R Boring5. Finish Boring XLR – R Boring6. Drain plug hole drilling and tapping
HMT radial drill
7. Finish milling and boring Makino A55 HMC8. Drilling, tapping and chamfering HMT radial drill9. Gang drilling HMT Multi drill10. Cover face and pad holes tapping
Batliboi radial drilling machine
11. Tapping on Bell housing and top case
Batliboi radial drilling machine
12. Cleaning machine
Table 1.2: Transmission Case Machining Sequence of operations
2. Gear and Shaft Line (GSL)Spur and helical gears and transmission shafts required for the 5-speed and 4-speed gear boxes are machined here.
The various machines and processes studied here are as follows:1. CNC Turning (WASINO Lathe).2. Gear Hobbing (HMT LIEBHERR & COOPER PFAUTER
hobbing machines).3. Gear Shaping (HMT & HURTH shaping machines).
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4. Gear Tooth Rounding & Chamfering (HURTH & HEY machines).
5. Gear Shaving (RED RING & FELLOWS shavers). 6. Gear Deburring (SAMPUTENSELLI).
3. Gear GrindingAfter the last operation in gear cutting the gears are sent to heat treatment cell then they are ground. The gear grinding operations are as follows:
1. Bore gear grinding of ID, front face, back face and conical grinding.
2. 5th driving gear grinding of work diameter, internal diameter.3. Output shaft grinding of outside diameter, face.4. Main drive gear grinding of outside diameter and internal
diameter.The gears are then sent for noise testing.
4. Heat TreatmentAfter machining of gears they are sent to heat treatment cell. There are two types of heat treatment carried out. They are case hardening and carbonitriding.The sequence of flow of material is as follows:
1. Washing.2. Drying.3. Heating in furnace.4. Carburizing.5. Hardening.6. Post wash.7. Tempering.8. Inspection is done by gear roller tester.
5. 4 Speed Gear Box AssemblyThe sequence in the assembly of 4 speed gear box is as follows:
1. Fitting of studs & pin & number punching2. Fitting of main & counter gear shaft in casing.3. Main gear drive & front bearing retainer assembly4. Control housing assembly fitment on transmission case5. Lever & shift rail fitment6. Installation of outer casing 7. Final testing for noise during gear shifting.
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2.4. Engine Product Unit (Engine P.U.)
Fig. 6: Engine P.U. process flow chart.The heart of the vehicle is the engine. The product unit is involved in different activities to manufacture the engine. The engine manufactured is diesel engine MDI 3000 and also different engines as per the BS standards, BS I and BS II. MDI stands for Mahindra Direct Injection and 3000 is the rated rpm of the engine. The objective is achieved by dividing the product unit into different sections as follows:
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Raw MaterialCasting
Raw MaterialCasting
Cylinder Head machining
Crankcase machining
Engine Assembly
Supply Module
Engine Testing
Engine Dispatch to Vehicle assembly and other plants
1. Crank Case Line MachiningThe crankcase casting of spheroid gray iron is moulded in the foundry at M&M or procured from Menon Foundries in semi-finished condition and then machined in this shop. Machining crankcase is the most complex of all the processing operations.
The various machines and processes in this line are as follows: Boring of crankshaft and camshaft (HMT Cam & Crank Borer). Drilling of oil gallery hole (HMT Deep Hole Drilling M/c). Drilling of holes on the side face (HMT Horizontal Multidrill). Drilling and Reaming of various other holes (HMT Radial
Driller). Plano milling of top face (Sunstrand Milling M/c). Boring of cylinder bore (WIDMA Cylinder Borer).
2. Cylinder head machining lineThe cylinder head, made up of grey cast iron is moulded at the M&M Foundry Product Unit. Cylinder head machining is carried out in this line. Cylinder head houses the valves, valve guides, valve springs fuel injectors, rocker arms, rocker arm supports and a recessed area called as the ‘combustion chamber’. The principal machining processes in this line are:Plano Milling of sides (HMT Plano milling m/c).Drilling and Reaming of various holes (HMT radial drilling m/c).
3. Engine assembly and testingThree types of DI engines are assembled and then tested in this assembly line viz. MDI 2500 B, MDI 3000 and MDI 3150. The following procedure is done for 4stroke, 8valve, 4cylinder diesel engine:
1. Washing of crankcase & cylinder head.2. O-ring, liner, Plummer block & bearing seal Fitment.3. Crank shaft mounting.4. Fitting of foundation bracket, studs & thrust bearings.5. Camshaft assembly.6. Fitting of camshaft, idler shaft & idler gear.7. Piston assembly mounting inside liner.8. Fuel Injection Pump mounting.9. Timers, oil pump, crank pulley, oil sump, oil seal retainer, fly
wheel & water pump mounting.10. Cylinder head assembly & its mounting.
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11. Rotation testing of pulley.12. Push rod placement in tappets.13. Rocker arm assembly & its mounting.14. Various pipes, belts & fan mounting.15. Covers mounting & oil filling
4. Engine TestingThe engines after assembly they are sent for testing in the testing room. In engine testing at a time 25 no. of engines can be tested. There are different parameters, such as load, torque, fuel consumption, smoke, etc., which are tested before the engine is sent for dispatch.
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2.5. Vehicle Product Unit (Vehicle P.U.)
Fig. 7: Vehicle P.U. process flow chart.
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Chassis Chassis preparation Body shell &
accessories from
Body P.U.
Trim shop
Axle assembly from
Axle P.U.
Axle drop
Engine assembly from
Engine P.U.
Engine drop
P.D.I.
Tyre fitting
Oil filling
Body drop
Dispatch
This assembly plant has the following sub-sections.
1. Trim shopHere, head canopy, seat covers, and other small items like straps etc. are made. The complete trimming of windshield assembly of the vehicle is also done her
2. Final assembly
At this sub-section, the final assembly of the vehicle is done on a single moving conveyor. The general assembly procedure of a vehicle is:
a. Chassis assembly: Mounting of fuel tank, steering gear box, shock absorber and spare wheel bracket mounting.
b. Axle assembly: Tie rod and brake pipe is fixed to the front axle and leaf spring fitted to each end of the axle.
c. Axle and chassis assembly: Leaf spring along with the axles is fitted to the chassis, tie rod is fixed to the steering gear box, stabilizer bar mounted, steering damper mounted and attached to the tie rod with the help of a bracket, propeller shaft connected to the differential gear box, silencer mounted and wiring for brake lights and fuel position.
d. Engine and transmission box assembly: Engine and transmission box assembled and attached together on the chassis, propeller shaft attached to transmission box whereas exhaust pipe to the engine. Hand brake connections provided along with axle greasing, gearbox oil filling and other lubrication.
e. Body trim cell: Fitment of doors, window glass, dashboard and its electrical connections, mounting of floor pads and various pedals.
f. Body assembly: Body is attached to the chassis, steering column attached to the steering gear box and various electrical and hydraulic connections made. Number plate, front grill and fenders attached to main body.
g. Tyre assembly: Computerized static balancing of each tyre is carried out and then fitted to the hub using bolts. Reflector and tail lights are fixed.
h. Accessories assembly: Steering wheel mounting, wiper fitting, battery placed in position, fuel and oil filters mounted, bonnet fixed and all electric connections checked.
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i. Testing of accessories: Wheel alignment done with respect to steering wheel positions, door alignment, mirrors fitment and testing of head lights.
j. Brake testing: Computerized brake testing is carried out to indicate the weight of the vehicle on front and rear axle, and efficiency of front, back brakes and hand brake.
k. Vehicle roller testing: Front and rear pairs of tyre are made to rest on individual rollers and made to rotate on them to test for:
Smooth clutch operation and gear engagement. Maximum speed achieved on each gear. Gear noise and clutch noise. Acceleration, deceleration & Speedometer checks. Engine noise and vibration & Emission test.
Finally the vehicle is then inspected from the bottom side, by lifting it, for any loose connections, cracks or leakage. It is then sent to RFI (Ready for Inspection) department where dynamic testing of the vehicle is done along with thorough inspection of the vehicle.
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2.6. Foundry Product Unit (Foundry P.U.)
Fig. 8: Foundry P.U. process flow chart
Foundry P.U. is mainly concerned with gray cast iron components. The various components casted are as follows:
1. Cylinder Block.2. Cylinder Head. 3. Rear axle carrier.4. Front axle support.
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Sand Mixing
Sand Receivable
Core Making
Sand Receiving
Mould Making
Melting & Pouring
Fettling
Shot Blasting
Dispatch
Inspection
The main sections of this shop are as follows:
1. Sand Mixing (Preparation of Molding Sand)Green sand with hot strength, permeability etc. is mixed with water, Bentonite powder, Bentacol oil & saw dust and is mulled to have proper sand mixing. The various stages are as follows:
a. Shakeout machine.b. Rotary screen.c. Storage bunkers.d. Mixed sand elevator.e. Panel board.f. Blended sand elevator.
2. Core Making, Baking & AssemblyThe three types of sand are used here is as follows:-
Hot box sand-made in-house. Shell sand-procured. Oil sand-made in-house:-for non critical parts.
Also they follow two types of core making.a) Hand or manual core making and then baking in Oven.b) Core making machine or core-shooter machine.
Predominantly Shell Sand is the sand that is used for core making. Here hot box sand & oil sand core mixtures contain sand, resins, catalyst, and water when required. Heated core is then painted with Alumina silicate water based paint. Assembly takes place by gluing with sodium silicate based glue
3. Mould Bays I & IIThe process of casting is carried out on 2 bays. Mould bay I is for heavier castings like cylinder block etc. while Mould bay II is meant for lighter casting. The general sequence for making the molding box is as follows:
1. Aluminum Pattern fitting on ramming machine intended for drag.
2. Ramming.3. Coating.4. Baking.5. Fitting cores.6. Fitting Chaplets.
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7. Fitting cope (which is already prepared in the mean time when the above operations are being carried out).
8. Pouring.9. Allowing it to cool down.
4. MeltingThe melting is carried out in a Cupola furnace & in an underground electric furnace. Also there is a three ton capacity Induction furnace. The various charges that are put in the cupola are as follows:
Pig iron
Steel
Cast iron scrap
Coal + Silicon [ 4 – 4.5 kg ]
Lime stone [ 34 kg]
Sodium [ 1 kg]
Potassium + Manganese [1 kg.]
This charge is heated up in the furnace & is thus converted into the
molten metal. This molten metal is poured into the mould. The
induction furnace bath temperature is 14800C-15000C.
5. FettlingIn the fettling section the so produced castings are processed for their
final dispatch to the other product units for their machining. Fettling is
done due to the following reasons:
For the removing the runners and the in gates.
Removing the sand that has failed to fall off, during the shake
out.
Short blasting of the casting which is done by striking fine metal
balls on these castings.
Air cleaning.
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6. GrindingIn the grinding section, unwanted projections on casting are removed using swing type grinder.
After all this, the parts are checked for final hardness, microstructure, cracks, distortion, etc. Various equipments like Brinell Hardness Tester, Microscope, Magnetic Particle Inspector, Liquid Dye Penetrate Tester, etc. is used for inspection of various components.
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3. INTRODUCTION TO THE ENGINE PRODUCT UNIT
The Engine Production Unit as the name suggest is involved in the production of the engines used in the utility vehicles. Its immediate customer is the Vehicle P.U., where the finished engines are sent for vehicle assembly.(ref. fig. 9)
Fig. 9: Final Assembly of an Engine
MISSION STATEMENT
“TO MANUFACTURE ENGINES TO MEET CUSTOMER EXPECTATION OF FUEL EFFICIENCY AND DURABILITY AT LOW COST.”
A daily schedule is provided to the unit by the PPC cell, which includes the type and number of engines to be manufactured.
The Engine P.U has the following divisions:1. Supply module.2. Crank case machining line.3. Cylinder head machining line.4. Engine assembly.
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3.1. Supply moduleThe supply module’s function is to provide continuous supply of parts required by the Engine P.U. by maintaining optimum inventory levels. The supply module makes use of ABC analysis for segregating different parts into critical and non-critical components.
Example:A type: Oil Pumps, Turbo Chargers, Alternator.B type: Crankcases, Flywheels, Rocker arms.C type: Washers, Shims, Spacers, Bolts and nuts.
Classification of the Engine P.U. products is done into:Runner - daily manufactured product.Repeater - produced once in 3-4 weeks.Stranger - produced once in 5-6 months or once a year.
The supply module uses a 2-bin KanBan system for replenishing the inventory at each cell. The 2 bin systems follow FIFO method of material utilization.A typical KanBan card consists of the following details.1. Type of KanBan card.2. Order quantity.3. Part number.4. Part description.5. Storage location.6. Lead time.7. Buyer.
3.2. Crank Case Machining LineThe Crankcase casting of Spheroidal gray (SG) iron is moulded in foundry at M&M or procured from other foundries in semi-finished condition and then machined in this shop. Machining crank case is the most complex of all the processing operations.
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The various machining processes and machines in this line are as follows.
Boring of crankshaft and camshaft holes (HMT cam and crank borer).
Drilling of oil gallery hole (HMT deep hole drilling m/c). Drilling and reaming of various other holes (HMT multi-drill). Plano-milling of top faces (Sunstrand milling m/c). Boring of cylinder bore (WIDMA cylinder borer).
3.3. Cylinder Head Machining LineThe cylinder head machining line consist of the following major operations:
Plano milling of side( HMT Plano-mill machine) Drilling and reaming of various holes (HMT radial drilling and
Borer)
The detailed steps are as follows1. Top face finish milling.2. Joint face milling.3. Drilling of cooling and oil holes.4. Intake and exhaust face milling.5. Front face milling.6. 8 valve guide holes, 4 rocker arm holes, temperature plug hole.7. 8 push rod holes.8. 14 bolt hole drilling.9. Counter-bore top weld plug.10. Joint face finish milling.11. Spring seat, Welch plug, angular hole drill (universal mill m/c).12. Drill intake, exhaust, front face and water hole.13. Intake mounting extra holes (2) drill and spherical mill on joint face
side.14. All sides tapping with turbo tapping.15. Injector mounting, counter-bore, chamfer and tap & notch mill and
finish bore.16. Rough counter-bore, part valve seat, finish mill and ream valve
guide hole.17. Finish valve seat bore.18. Pressing intake & exhaust valve seat (chilled bushes used for
easing press fit).19. Press valve guide.20. Finish valve seat bore and valve seat guide.
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21. Washing of the cylinder head.22. Washing of head after jacket.23. Rework, de-burring and plug fitment-rear, top and angular plugs.24. Water testing.25. Dispatch to engine assembly.
3.4. Engine assembly stageThe engine P.U. produces 2 types of DI engines namely: MDI 3000 and MDI 3150 which are then tested after assembly. After punching serial numbers on the cylinder head and crank case the engine assembly is carried out.
The following sequence is followed.1. Sleeve/ liner fitment in crank case.2. Crank shaft fitment.3. Filter fitted, bolts tightened (Pokayoke: shows number of bolts
left to be tightened).4. On the main conveyor.5. Foundation bracket fitted.6. Camshaft.7. Head Mtg. dowel and piston assembly.8. Idler gear.9. Rotary pump assembly.
10. Rotary pump setting and checking.11. Crank pulley FIP gear and CCF cover.12. Flywheel assembly.13. Cylinder head gasket assembly and water pump
assembly.14. Cylinder head sub assembly.15. Valves fitted.16. Fuel injection plug.17. Leakage testing for valve.18. Air intake manifold.19. Rocker arm assembly.20. Cylinder and rocker arm assembly and push rods.21. Rocker arm and shaft over pipe assembly thermostat housing.22. Oil sump assembly.23. High pressure pipe and water pump inlet hose, thermostat
hose.24. Alternator and fan belt assembly.
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25. Maxim 32 engine oil filled (Pokayoke: checks if 5lt. Of oil is filled).
26. Engine pre-lubrication and rocker arm cover assembly with dipstick.
27. Turbo charger and exhaust manifold assembly.
3.5. Engine TestingThe engines after assembly are sent for testing in the testing room. In the engine testing room, we can at a time test 25 engines. There are different parameters which are being tested such as load test, fuel consumption, smoke, lowest r.p.m. maximum r.p.m. and oil pressure tests are conducted before the engine is sent for dispatched. Some of the general checks are as follows:
vii. General checks Oil supply to rocker arm. Water traces in oil. Water leakage. Oil leakage. Fuel leakage. Abnormal noise.
In the month of January’08, Engine P.U. won the Best P.U. in Electricity Consumption Competition for the year 2007, which was conducted among various PU’s of M&M.(ref. fig. 10.1,10.2,10.3).
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Fig. 10.1: Best P.U. Trophy
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Fig. 10.2: Best TPM process award in Automotive Sector
Fig. 10.3: Best Productivity award in Kandivli plant
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4. INTRODUCTION TO DEPARTMENT
As we were been given our Product Unit (P U), after orientation in our P U we I was allotted my department and i.e. ‘maintenance’ department Here I am been kept as a trainee under the supervision of Mr. Vijay Rokade. Who is the manager of this maintenance mod. Under whose guidelines I was to work. As engine is the heart of the vehicle without which the vehicle cannot run, similarly a factory with lots of machines in it cannot run without ‘maintenance’ department. Basically the main aspects with what maintenance is concerned are:-
1. Breakdown maintenance 2. Preventive maintenance 3. Improvement of the machines
4.1 BREAKDOWN OF MACHINES
Breakdown generally is defined as “stoppage of the equipment for more than 15 minutes due to failure/damage of the equipment element which needs to be either replaced or repaired so as to start the equipment.”
As the machines are been continuously used for the whole day some of the machine parts get damaged, overloaded ,wear out etc; due to this machines stop and the production rate hampers, henceforth; maintenance people are been sent for, for the breakdown repair. So a maintenance person is supposed to have a through knowledge of machines (whatsoever the concern may be). When breakdown occur we (maintenance people) are been sent for to look into the problem & tackle it skillfully. The first thing what we do at the site is to make the ‘Why? Why? Analysis’ with which we get into the root cause of the problem and hence the cause of the problem is founded and repaired and the machine is handed over to the shop people. After that we make a detailed documented analysis of the breakdown with what we make the classification of breakdown. The path followed is as:-
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Why? why?
Root cause
Classification
4.2 CLASSIFICATION OF BREAKDOWNS Depending on the time interval of the breakdown we classify them
as :-
Minor breakdown. Medium breakdown Major breakdown
MINOR BREAKDOWN
Equipment stoppage is more than 15 mins. And less than 30 mins. Than it’s called as Minor breakdown.
MEDIUM BREAKDOWN Equipment stoppage is more than or equal to 30 mins. And less than 2 hours. Than it is called as Medium breakdown.
MAJOR BREAKDOWN
Equipment stoppage is more than 2 hours than it is called as Major breakdown.
4.3 PREVENTIVE MAINTENANCE
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Preventive maintenance is generally defined as the “prior maintenance of the machine to keep them away from stoppages/breakdown.” When preventive maintenance is to be done it requires prior planning of what and how (when) to be done. WHAT - Basically what prevention is to be taken is decided on the life span of the machine parts which requires to be replaced before their expiry period for prevention. This life span of equipment is known to us by the manufacturer of the machine or in some cases by the experience of the machine. E.g:- Gears of the spindle gear box needs to be replaced after a period of 10 years. So planning is to be made that on this date this machine’s spindle gear box is to be changed.
4.4 Improvement of the machines
Improvement of machines is a very important factor to be considered in an organization to improve & enhance the productivity. Basically it is the improvement of constitution of machine, this term deals with each & every person of the organization under the activity of Total Productive maintenance.
Improvement of constitution of machine:
making the existing equipment efficient by improving its
constitution
Normal set and life cycle cost design for the equipment.
Improving the constitution of the machine
How maintenance department do Improvement?
Our role is to eliminate the recurring breakdowns by modifying
design or by some other means. This is done by the why? Why?
analysis of breakdown and finding its root cause and then making
modification on it i.e KAIZEN (continuous improvement).
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5. PROJECTS
5.1 TOTAL PRODUCTIVE MAINTENANCE (TPM)
DEFINITION OF TPM The Preventive maintenance through the ”PARTICIPATION OF
EVERYBODY” which is abbreviated as TPM has been defined, as
follows by the JAPANESE INSTITUTE OF PLANT
MAINTENANCE(JIPM), It is the activity in which the improvement of
the equipment efficiency to the maximum is set as the objective,
Where a total system considering the overall life of the equipment is
established.
The activity spreads to different divisions such as planning
division, division where the material or the product is to be used the
maintenance division….etc.
All the employees from the top to the front line operation
participate and
The TPM is promoted through properly boosting the morale by the
self-initiated small group activity.
Considering different trends the, JIPM gave a new definition of TPM
in 1989.
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New definition for the company wide TPM
Company wide TPM is an activity through which the construction of new enterprise constitution to pursue the ultimate production efficiency system is aimed at.
A mechanism by observing actual phenomenon and actual
item to check different types of losses, in other words aiming at zero
accident, zero defects and zero breakdown beforehand by taking into
consideration the life cycle of the total system in the production
system is constructed.
All the different sections from production to development, sales and
management are covered. All the employees from the top to the front
ranking operators participate. Zero loss is achieved through
overlapping small group activities.
The TOTAL here refers to three meanings.
1. Total improvement of total efficiency.
2. Total in total system of the production department
3. TOTAL of participation from all the different sections of production
to development, sales and management; all employees from the
top to the front ranking operators.
4. The improvement of constitution of man.
5. To groom the man to meet the requirements of the FACTORY
AUTOMATION era.
6. Operator self initiated maintenance capability. Maintenance man
capability to maintain the equipment
7. Production engineer plans the equipment of high reliability.
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Improvement of constitution of machine:
making the existing equipment efficient by improving its
constitution
Normal set and LIFE CYCLE COST design for the
equipment.
Improving the constitution of the machine
16 Major Losses identified by TPM
1. Breakdown Loss :
Loss generated when machine has stopped on its own due to
component failure e.g. breakage of V belt on a machine , etc
For calculation of OVERALL EQUIPMENT EFFICIENCY (OEE), a
part of breakdown, which has resulted in loss of opportunity of
production, shall be considered.
All repairs that are not part of planned maintenance (based on
annual plan) are part of breakdown loss.
2. Planned Shutdown Loss:
Loss generated when equipment is stopped in planned
manner. The activity that is pre-decided (annual calendar) with a
realistic estimate .E.g. In the year F2K, spare parts of the machines
will be replaced with a specific predetermined periodicity, irrespective
of the life left / failure occurred due to the spare part in question (Time
bound maintenance). It will also include specific predetermined
overhaul program.
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3. Set up And Adjustment Loss:
The loss attributed to change of setup from one
component to other component. Note: It shall include time for
removal, fixing, and adjustment/repair. Setting is complete when 1st
job is as per specifications.
E.g. Change of Jigs & fixture (as applicable in machining area),
Change of die (as applicable in stamping area & foundry).
4. Tool change Loss:
Tool change loss is defined as a loss occurred while changing tools &
tooling in running production till 1st ok part is produced.
Note: Time lost in changing drills, bushes, dressing wheels, etc.
5. Start up Loss:
The time required for the equipment to attain optimal operating
condition.
E.g. Paint shop - oven temperature is expected to reach X oC
before baking can start.
Heat Treatment - Furnace should attain Y oC before charge is put
inside.
Foundry PU - Die is heated to Z oC before start of production.
6. Minor Stops:
It is a performance-related loss (usually less than a minute) that
results in stoppage of material movement.
E.g. Limit switch is manually operated to restore operating condition,
Component has stuck to die while stamping - it is removed by one
touch.
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7. Speed Loss :
Loss due to increase in on line and/or auto cycle time due to
reduction in speed, feed.
E.g. Cycle time of Widma Borer has gone up from 6.5 min to 9.5 min
due to feed variation.
8. Defects Loss :
Number of parts that are not confirming to specification.
E.g. Rework, Rejection.
9. Management Loss :
Loss due to wrong planning.
E.g. Tools, Material, Instructions are not available.
10. Operating Motion Loss :
Loss that reduces human efficiency.
E.g. Walking of operator is more because of inefficient layout,
Operator's motion economy is violated due to skill difference,
operator is wasting some time in searching tools/tooling etc.,
operator's morale is low, and it affects his performance.
11. Design and Development Loss :
Loss that is generated at mass production stage due to design
problems.
E.g : Delay for commissioning of any m/c .
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12. Inventory Loss :
Loss generated due to inventory carrying cost
13. Logistics Loss :
Loss due to non-availability of material.
E.g. Finished & Accepted CrankCases are ready but not sent to
assembly line due to some reason, which results in loss of Engine
Assembly.
14. Yield Loss :
Loss of raw material in any form.
E.g. Blanks generated in stamping operation, Chips generated in
machining operation, Slurry of paint, runners/risers in foundry
application.
15. Energy Loss :
Loss of energy in the form of heat, powers, air, water, fuels due to
leakage and or overload. It is to be measured by consumption.
16. Die & Tool Loss :
Loss resulting from manufacturing and repair of tools & tooling. It also
includes consumption of FOS items and sand.
17. Process Trouble Loss :
Loss generated when equipment stops fro more than 10 mins. but no
machine component is damaged or stopped due to Quality
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issue/Speed loss.
E.g : Serve alarm on CNC m/c(machine) due to loosening of
wires /cards .
18. Consumable Loss :
Loss generated due to over consumption of FOS(Factory Operating
Services).
E.g : More consumption of cutting oil / coolant on m/c due to leakage.
19. Man Power Loss :
Loss generated when more man man power is deployed then
required due to line imbalance or other value added activity.
20. Office TPM Loss :
Loss generated due to inefficient use of manpower, extra
consumption of consumable and higher information expenses.
21. Cash outflow Loss :
Loss that is generated due to lack of exploring various ingeneous
ways to save cash outflow without capital investment .
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To achieve the objectives of TPM the following pillars of TPM are
formed.The different pillar of TPM and their activities are shown
below
Activities of each committee at work place:-
1.)JISHU HOZEN
Clean the machine thoroughly.Identify abnormalit ies by putt ing tags.
Identify Sources of contamination.
Identify areas diff icult to clean, inspect, lubricate.
Take Countermeasures against sources of forced
deterioration.
Remove abnormalit ies for taking corrective actions.
Make areas easy to clean, inspect and lubricate.
Prepare visual controls on machine.
2) KOBATSU KAIZEN
Identify losses on machine & Prepare loss cost matrix.
Identify Productivity, related Kaizens & implement.
Horizontal Deployment of them in other areas.
3) PLANNED MAINTENANCE
Preventive and Corrective Maintenance of machines
through Time. Based Maintenance and Condit ion Based
Maintenance.
4) HINSHITSU HOZEN
Quality Maintenance with condit ion sett ing.
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5) OFFICE TPM
Cost reduction through Office TPM.
Job and work f low analysis in Off ice area.
6) EDUCATION & TRAINING
Imparting education and training to enhance
knowledge and skil l at various levels of employees.
7) TOOL SUB-COMMITTEE
Ensuring availabil i ty of required tools at al l t imes.
Reduce tooling cost and inventory.
8) IN FLOW CONTROL
Lower life cycle cost of equipment by incorporating TPM concept
at the time of ordering of machine.
CALCULATION THE PERFORMANCE OF A MACHINE
OVERALL ALL EQUIOPMENT EFFICIENCY is taken into account while calculating the over all equipment efficiency of a machine. Calculatiion of the over all equipment efficiency involves consideration of the various losses.
The over all equipment efficiency depends upon
1. availability
2. performance rate
3. quality product rate.
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AVAILABILITY
The availability stands for the ratio of actual operating time to the load time. It is expressed as:
AVAILABILITY =LOAD TIME –STOPPAGE TIME/(LOAD TIME )
Load time =total operating time-stoppage time in production planning-scheduled maintenance time-time daily morning management
PERFORMANCE RATE:
Performance rate comprises of speed performance rate and net operating rate.
Speed performance rate = standard cycle time /actual cycle time*100
Net operating rate shows whether it is operating at a constant speed within a unit time
Net operating rate=no op pieces produced-bad products /no of pieces produced
Performance rate = speed performance rate*net operating rate
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OVER ALL EQUIPMENT EFFECTIVENESS
Over all equipment effectiveness = availability*performance rate*quality product rate
OEE CALCULATION (EXAMPLE):OEE CALCULATION (EXAMPLE):1. 1. AVAILABILITYAVAILABILITYA. Total Available Time : A. Total Available Time : 480 min480 min
B. Planned Downtime : B. Planned Downtime : 50min 50min
C. Net Available Time : C. Net Available Time : (Total Avail. Time -- Planned Downtime) (A--B) (Total Avail. Time -- Planned Downtime) (A--B) 430min430min
D. Downtime D. Downtime Mins LostMins Lost
No of breakdowns 4 10No of breakdowns 4 10
No of Setups and Adjustments 5 20No of Setups and Adjustments 5 20
No of Minor Stoppages 12 30 No of Minor Stoppages 12 30 D. Downtime = 60 mins.D. Downtime = 60 mins.
E. Operating Time :E. Operating Time : (Net Available Time - Downtime) (C--D) (Net Available Time - Downtime) (C--D) 370 min370 min
F. Equipment Availability :F. Equipment Availability :
(Operating Time/Net Available Time) X 100 (E/C)x100 (Operating Time/Net Available Time) X 100 (E/C)x100 86 %86 %
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OEE CALCULATION (EXAMPLE):OEE CALCULATION (EXAMPLE):
1.1. PERFORMANCE EFFICIENCYPERFORMANCE EFFICIENCY
G. Total Parts Run :G. Total Parts Run : (Good and bad parts) (Good and bad parts) 400 parts400 parts
H. Ideal Cycle Time : mins/part H. Ideal Cycle Time : mins/part 0.50.5
J. Performance Efficiency :J. Performance Efficiency : (Ideal Cycle Time x Total Parts Run)(Ideal Cycle Time x Total Parts Run) x 100 x 100 54 % 54 % Operating TimeOperating Time
OEE CALCULATION (EXAMPLE):OEE CALCULATION (EXAMPLE):
3.3. QUALITY RATE. QUALITY RATE. K. Total Defects (Rejects & Scrap) : K. Total Defects (Rejects & Scrap) : 20 parts20 parts
L. Quality Rate : (G--K)/G x100L. Quality Rate : (G--K)/G x100 (Total Parts Run -- Total defects) (Total Parts Run -- Total defects) x 100 = 95%x 100 = 95% Total Parts Run Total Parts Run
2.2. OVERALL EQUIPMENT EFFECTIVENESS –OEEOVERALL EQUIPMENT EFFECTIVENESS –OEE
M. OEE = (Availability x Performance Efficiency x Quality Rate) x M. OEE = (Availability x Performance Efficiency x Quality Rate) x 100 100
(F x J x L) x 100 44%
GOALS OF TPM
Increase effective utilization of equipment upto 85% over a period of three to five years thereby reducing the requirement of additional resources for increased production and reducing manufacturing costs of the product. Thus bringing machine breakdown to zero besides reducing maintenance costs increased inventory turns through speedier material flow and achievement of zero accidents.
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THE SEVEN STEPS FOR THE EXPANSION OF SELF INITIATED MAINTENACE
STEP 1
INITIAL CLEANING
Details of activity: Removal of dust and dirt in one operation especially form main body of the machine. (Remove unnecessary parts also)Guidance and assistance by the manager/supervisory staff: Educate the workers about the relationship between dirt and dust
and deterioration of the machines and their maintainability. Teach workers about the important parts to be cleaned and the
importance of cleaning, oiling and tightening Teach the meaning of “Cleaning is checking”.
Detail STEP 2TAKE THE COUNTER MEASURES AGAINST THE ROOT CAUSES AND MODIFY DIFFICULT TO REACH AREAS
Details of activity: The root causes of formation of the dirt and dust they’re scattering are taken off; improve the areas where oiling is difficult, to shorten the time required for cleaning and oiling.
Guidance and assistance by the manager/supervisory staff:
Appreciate the ideas for improvements and give hints for practical application of such ideas.
Execute commissioned work speedily. Give guidance on management with the help of visual aids like
marks to be aligned, oil level indicators etc.
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STEP 3
PREPARATIONS OF DRAFT STANDADRS FOR SELF INITIATED MAINTENANACE
Details of activity: Prepare standard procedures for activities like cleaning, oiling, tightening of nuts and bolts etc. so that such work can be done with certainty and in a short time (it is important to indicate time frames that can be normally employed on a routine basis)
Guidance and assistance by the manager/supervisory staff:
Provide hints about the format and method of preparation of cleaning standards.
Provide technical assistance in preparation of oiling standards.
STEP 4
GENERAL INSPECTION
Details of activity: Training for teaching inspection techniques through the use of inspection manual, identification of microdefects in the machine through general inspection and taking remedial action for restoration of the machine. Improving the machine to make it easier to inspect.
Guidance and assistance by the staff manager/supervisory staff:
Prepare a general inspection manual and a history of problems, and educate and train the leaders for inspection.
Prepare inspection schedules. Quickly process the commissioned work after the problem has
been identified. Teach simple methods of addressing the problems through
practical demonstrations. Improve the ease of inspection (visual management ) Give guidance in data collection and analysis. Involve the leaders in drafting of maintenance plans.
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STEP 5
SELF INSPECTION
Details of activity preparation of self initiated inspection checklists (the cleaning standard, oiling standard and checking standard should be well matched so that these activities can be done efficiently)
Improvement of the reliability of the operation
Guidance and assistance of the manager /supervisory staff
Provide hints ,including tips on how to understand data and about which are the important parts to inspect thoroughly and how often Provide hints about the form and method of writing inspection
sheets.
STEP 6
STANDARDIZATION
Details of activity
Standardize the items to be managed at the site in order to improve the efficiency of the work and to maintain quality and safety
Improve the procedures and reduce inventory of unfinished goods Standardize the methods of data recording Set management standards for spares ,unfinished
materials ,products , moulds and toolsGuidance and assistance of the manager /supervisory staff
Provide technical assistance in standardization in response to request from the group and department
Carry out PM analysis
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STEP 7
ENFORCEMENT OF SELF INITIATED MANAGEMENT
Details of activity
Expand the company policy and objectives and make improvements a routine activity record the result f MTBF analysis unfailingly and analyze and carry out improvements in the machines
Guidance and assistance by the manager /supervisory staff
Provide technical assistance for improving the machine Provide training in repair work Take part in discussion on improving the machine, and promote
improvements in them along with the members of the group Standardize the particulars of improvements.
PROJECTS
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5.2. Elimination of breakdown and cost reduction
ESTIMATION OF BREAKDOWN
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Previous Breakdown = 1 pin per eight days and after 2 pins per day
Total pins broken in 4 months = 36 pins Pins broken per month = 9 pins per month Cost of 1 pin = 52 Rs per pin Pins broken per year = 108 pins per year Cost saving due to kaizen = 468 Rs per month /
5616 Rs per year .
5.3. SAFETY KAIZEN ON MZCHINE NO. 1927.
5.4. KAIZEN NAME –
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MODIFICATION OF LOADING CYLINDER FROM PNEUMATIC TO HYDRAULIC ON M/C NO. 7069.
Fig.11a fig.11b
PROBLEM – Continuous break down Unsafe condition .
The loading pneumatic cylinder which loads the cylinder head on the machine table gets struck up sometimes due to some obstruction to the cylinder head from the machine conveyor and the machine gets stopped.Due to this breakdown occurs and the productive time is lost, this breakdown occurs normally six to eight times a day which hampers a lot to the production time. When the maintenance people are called for the problem and when they shake the job the cylinder bangs the job hardly due to the huge pressure developed inside the cylinder as the air is compressible. This is an unsafe condition for the maintenance people as they put their hands in the machine and the job may hurt their hands.
ACTION TO BE TAKEN
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To eliminate this unsafe condition and the continuous breakdown the remedy founded out is that the pneumatic cylinder (fig11b) should be changed to hydraulic and should be given hydraulic power pack connections. As the hydraulic fluid is almost incompressible and can withstand large amount of load hence when the cylinder head (job) gets obstruction it can go continuously with the hydraulic cylinder which has a constant feed rate.
Difference between Pneumatic and Hydraulics.
Pneumatics HydraulicsAir is compressible Hydraulic is almost
incompressible They have no constant feed rate They have a constant feed rate Speed varies according to the load
Speed doesn’t varies with the load .
ESTIMATION OF BREAKDOWN.
Previous breakdown – 6 to 8 times a day
Loss of time – 15 mins. Per breakdown
Total time loss per day = 6 x 15 =90 mins.
Time taken to complete one job = 1mins. and 8 secs.
Reduced loss of job = 79 jobs per day
RESULT
Increased the production of the job by 79 jobs per day. Increased the time period between two breakdowns. 5.5. KAIZEN NAME –
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REDUCTION IN BREAKDOWN BY CHANGING THE DESIGN OF THE CLAMP ON MACHINE NO. 7134.
Fig12a
PROBLEM
CONTINUOUS BREAKDOWN The clamps that are used for clamping the cylinder head, were earlier fixed to the clamping rod with the help of grub screw and a dimple on the rod. The rod had a dimple onto which the grub screw of the clamp use to fit for the locking of the clamp to the rod. As the dimple was small and due to the continuous clamping and declamping of the clamp it use to get jerk and hence the grub screw use to loosens up and pops out of the dimple, thus the clamp position use to change and the breakdown occurs
ACTION TAKEN
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To eliminate this breakdown the remedy that is founded out is that a through hole is drilled through the clamp and the rod for the provision of bolt and nut so that it dosent loosens up (fig 12b). Here the bolt and nut are tightened up with a spring washer in it and thus though the clamp gets the jerk the bolt dosent gets loosens up
Fig 12b
ESTIMATION OF BREAKDOWN.
Previous breakdown – 2 to 3 times a day
Loss of time – 30 mins. Per breakdown
Total time loss per day = 2 x 30 =60 mins.
Time taken to complete one job = 2mins. and 3 secs.
Reduced loss of job = 29 jobs per day
RESULT
Reduced breakdown. Increased the production of the job by 29 jobs per day.
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6 . ASSIGNMENTS
6.1. STUDY OF ENCODER.
A rotary encoder, also called a shaft encoder, is an electro-mechanical device used to convert the angular position of a shaft or axle to an analog or digital code, making it an angle transducer (fig. 13). These devices are used in industrial controls, robotics, in top-of-the-line photographic lenses, in computer input devices (such as optomechanical mice )
There are two main types: absolute and incremental (relative).
Absolute rotary encoder
Fig. 13Absolute rotary encoder
Construction
The absolute digital type produces a unique digital code for each distinct angle of the shaft. They come in two basic types: optical and mechanical.
Mechanical Absolute Encoders
A metal disc containing a set of concentric rings of openings is affixed to an insulating disc, which is rigidly fixed to the shaft. A row of sliding contacts is fixed to a stationary object so that each contact wipes against the metal disc at a different distance from the shaft. As the disc rotates with the shaft, some of the contacts touch metal, while others fall in the gaps where the metal has been cut out. The metal sheet is connected to a source of electric current, and each contact is connected to a separate electrical sensor. The metal pattern is designed so that each possible position of the axle creates a unique
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binary code in which some of the contacts are connected to the current source (i.e. switched on) and others are not (i.e. switched off).
Optical Absolute Encoders
The optical encoder's disc is made of glass with transparent and opaque areas. A light source and photo detector array reads the optical pattern that results from the disc's position at any one time.
This code can be read by a controlling device, such as a microprocessor, to determine the angle of the shaft.
The absolute analog type produces a unique dual analog code that can be translated into an absolute angle of the shaft (by using a special algorithm)..
Standard binary encoding
Rotary encoder for angle-measuring devices marked in 3-bit binary. The inner ring corresponds to Contact 1 in the table. Black sectors are "on". Zero degrees is on the right-hand side, with angle increasing anticlockwise.
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An example of a binary code, in an extremely simplified encoder with only three contacts, is shown below.
Standard Binary Encoding
Sector Contact 1 Contact 2 Contact 3 Angle
1 off off off 0° to 45°
2 off off on 45° to 90°
3 off on off 90° to 135°
4 off on on 135° to 180°
5 on off off 180° to 225°
6 on off on 225° to 270°
7 on on off 270° to 315°
8 on on on 315° to 360°
.
In the above example, the contacts produce a standard binary count as the disc rotates. However, this has the drawback that if the disc stops between two adjacent sectors, or the contacts are not perfectly aligned, it can be impossible to determine the angle of the shaft. To illustrate this problem, consider what happens when the shaft angle changes from 179.9° to 180.1° (from sector 4 to sector 5). At some instant, according to the above table, the contact pattern will change
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from off-on-on to on-off-off. However, this is not what happens in reality. In a practical device, the contacts are never perfectly aligned, and so each one will switch at a different moment. If contact 1 switches first, followed by contact 3 and then contact 2, for example, the actual sequence of codes will be
off-on-on (starting position) on-on-on (first, contact 1 switches on) on-on-off (next, contact 3 switches off) on-off-off (finally, contact 2 switches off)
Now look at the sectors corresponding to these codes in the table. In order, they are 4, 8, 7 and then 5. So, from the sequence of codes produced, the shaft appears to have jumped from sector 4 to sector 8, and then gone backwards to sector 7, then backwards again to sector 5, which is where we expected to find it. In many situations, this behavior is undesirable and could cause the system to fail. For example, if the encoder were used in a robot arm, the controller would think that the arm was in the wrong position, and try to correct the error by turning it through 180°, perhaps causing damage to the arm.
Gray encoding
Rotary encoder for angle-measuring devices marked in 3-bit binary-reflected Gray code (BRGC). The inner ring corresponds to Contact 1 in the table. Black sectors are "on". Zero degree is on the right-hand side, with angle increasing anticlockwise.
To avoid the above problem, Gray encoding is used. This is a system of binary counting in which two adjacent codes differ in only one position. For the three-contact example
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Given above, the Gray-coded version would be as follows.
Gray Coding
Sector Contact 1 Contact 2 Contact 3 Angle
1 off off off 0° to 45°
2 off off on 45° to 90°
3 off on on 90° to 135°
4 off on off 135° to 180°
5 on on off 180° to 225°
6 on on on 225° to 270°
7 on off on 270° to 315°
8 on off off 315° to 360°
In this example, the transition from sector 4 to sector 5, like all other transitions, involves only one of the contacts changing its state from on to off or vice versa. This means that the sequence of incorrect codes shown in the previous illustration cannot happen here.
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Encoder output formats
In commercial absolute encoders there are several formats for transmission of absolute encoder data, including parallel binary, SSI, ISI, Profibus, CAN DeviceNet, CANopen, Endat and Hiperface, depending on the manufacturer of the device
Incremental rotary encoder
An incremental rotary encoder, also known as a quadrature encoder or a relative rotary encoder, has two outputs called quadrature outputs. They can be either mechanical or optical. In the optical type there are two gray coded tracks, while the mechanical type has two contacts that are actuated by cams on the rotating shaft. The mechanical types require debouncing and are typically used as digital potentiometers on equipment including consumer devices. Most modern home and car stereos use mechanical rotary encoders for volume. Due to the fact the mechanical switches require debouncing, the mechanical type are limited in the rotational speeds they can handle. The incremental rotary encoder is the most widely used of all rotary encoders due to its low cost: only two sensors are required.
The fact that incremental encoders use only two sensors does not compromise their accuracy. One can find in the market incremental encoders with up to 10,000 counts per revolution, or more.
There can be an optional third output: reference, which happens once every turn. This is used when there is the need of an absolute reference, such as positioning systems.
The optical type is used when higher RPM's are encountered or a higher degree of precision is required.
Incremental encoders are used to track motion and can be used to determine position and velocity. This can be either linear or rotary motion. Because the direction can be determined, very accurate measurements can be made.
They employ two outputs called A & B which are called quadrature outputs as they are 90 degrees out of phase.
The state diagram:
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Gray coding forclockwise rotation
Phase A B
1 0 0
2 0 1
3 1 1
4 1 0
Gray coding forcounter-clockwise
rotation
Phase A B
1 1 0
2 1 1
3 0 1
4 0 0
Two square waves in quadrature (clockwise rotation).
The two output wave forms are 90 degrees out of phase, which is all that the quadrature term means. These signals are decoded to produce a count up pulse or a count down pulse. For decoding in software, the A & B outputs are read by software, either via an interrupt on any edge or polling, and the above table is used to decode the direction. For example if the last value was 00 and the current value is 01, the device has moved one half step in the clockwise direction. The mechanical types would be debounced first by requiring that the same (valid) value be read a certain number of times before recognizing a state change.
If the encoder is turning too fast, an invalid transition may occur, such as 00->11. There is no way to know which way the encoder turned; if it was 00->01->11, or 00->10->11.
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If the encoder is turning even faster, a backward count may occur. Example: consider the 00->01->11->10 transition (3 steps forward). If the encoder is turning too fast, the system might read only the 00 and then the 10, which yields a 00->10 transition (1 step backward).
This same principle is used in old ball mice to track whether the mouse is moving to the right/left or forward/backward.
Optical tachometer (no quadrature output)
Rotary sensors with a single output are not encoders and cannot sense direction, but can sense RPM. They are thus called tachometer sensors.
6.2. STUDY OF CONTACTORS
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CONTACTORS
Fig. 14 contactor
A contactor previously fitted in an elevator control system.
A contactor is an electrically controlled switch (relay) used for switching a power circuit. A contactor is activated by a control input which is a lower voltage / current than that which the contactor is switching. Contactors come in many forms with varying capacities and features. Unlike a circuit breaker a contactor is not intended to interrupt a short circuit current(fig.14).
Contactors range from having a breaking current of several amps and 110 volts to thousands of amps and many kilovolts. The physical size of contactors ranges from a few inches to the size of a small car.
Contactors are used to control electric motors, lighting, heating, capacitor banks, and other electrical loads.
Construction
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Fig 15 contactor
A contactor is composed of three different systems. The contact system is the current carrying part of the contactor. This includes Power Contacts, Auxiliary Contacts, and Contact Springs. The electromagnet system provides the driving force to close the contacts. The enclosure system is a frame housing the contact and the electromagnet. Enclosures are made of insulating materials like Bakelite, Nylon 6, and thermosetting plastics to protect and insulate the contacts and to provide some measure of protection against personnel touching the contacts. Open-frame contactors may have a further enclosure to protect against dust, oil, explosion hazards and weather.
Contactors used for starting electric motors are commonly fitted with overload protection to prevent damage to their loads. When an overload is detected the contactor is tripped, removing power downstream from the contactor.
Some contactors are motor driven rather than relay driven and high voltage contactors (greater than 1000 volts) often have arc suppression systems fitted (such as a vacuum or an inert gas surrounding the contacts).
Magnetic blowouts are sometimes used to increase the amount of current a contactor can successfully break. The magnetic field produced by the blowout coils force the electric arc to lengthen and move away from the contacts. The magnetic blowouts in the pictured
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Albright contactor more than double the current it can break from 600 Amps to 1500 Amps.
Sometimes an Economizer circuit is also installed to reduce the power required to keep a contactor closed. A somewhat greater amount of power is required to initially close a contactor than is required to keep it closed thereafter. Such a circuit can save a substantial amount of power and allow the energized coil to stay cooler. Economizer circuits are nearly always applied on direct-current contactor coils and on large alternating current contactor coils.
Contactors are often used to provide central control of large lighting installations, such as an office building or retail building. To reduce power consumption in the contactor coils, two coil latching contactors are used. One coil, momentarily energized, closes the power circuit contacts; the second opens the contacts.
A basic contactor will have a coil input (which may be driven by either an AC or DC supply depending on the contactor design) and generally a minimum of two poles which are controlled.
Operating Principle
Unlike general-purpose relays, contactors are designed to be directly connected to high-current load devices, not other control devices. Relays tend to be of much lower capacity and are usually designed for both Normally Closed and Normally Open applications. Devices switching more than 15 amperes or in circuits rated more than a few kilowatts are usually called contactors. Apart from optional auxiliary low current contacts, contactors are almost exclusively fitted with Normally Open contacts.
When current passes through the electromagnet, a magnetic field is produced which attracts ferrous objects, in this case the moving core of the contactor is attracted to the stationary core. Since there is an air gap initially, the electromagnet coil draws more current initially until the cores meet and reduct the gap, increasing the inductive impedance of the circuit.
For contactors energized with alternating current, a small part of the core is surrounded with a shading coil, which slightly delays the magnetic flux in the core. The effect is to average out the alternating pull of the magnetic field and so prevent the core from buzzing at twice line frequency.
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Most motor control contactors at low voltages (600 volts and less) are "air break" contactors, since ordinary air surrounds the contacts and extinguishes the arc when interrupting the circuit. Modern medium-voltage motor controllers use vacuum contactors.
Motor controls contactors can be fitted with short-circuit protection (fuses or circuit breakers), disconnecting means, overload relays and an enclosure to make a combination starter. In large industrial plants many contactors may be assembled in motor control centers.
Ratings
Contactors are rated by designed load current per contact (pole),
[maximum fault withstand current, duty cycle, voltage, and coil voltage. A general purpose motor control contactor may be suitable for heavy starting duty on large motors; so-called "definite purpose" contactors are carefully adapted to such applications as air-conditioning compressor motor starting. North American and European ratings for contactors follow different philosophies, with North American contactors generally emphasizing simplicity of application while European rating philosophy emphasizes design for the intended life cycle of the application. A contactor basically consists of two parts; signaling and actual.
A motor rated contactor (AC3) would be better than a relay (AC1) because of arc suppression design for inductive loads. Relays generally don't have arc suppression (arcing plates). That is what pitting on the contact surface is caused by. For arduous starting conditions, use AC4 ratings.
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7. ROLE IN DEPARTMENT
As I was been placed in maintenance department the first thing they told me to do to get handful of information about TPM and get started.
The first work I was given was the office TPM of maintenance office i.e. 1S and 2S – 1S means scrapping unwanted materials and 2S means keeping the needed materials at their proper place. Than as some days paced on I was handed over with the Jaishu hozen work which includes the following things to be done
Clean the machine thoroughly. Identify abnormalit ies by putt ing tags.
Identify Sources of contamination.
Identify areas diff icult to clean, inspect, lubricate.
Take Countermeasures against sources of forced
deterioration.
Remove abnormalit ies for taking corrective actions.
Make areas easy to clean, inspect and lubricate.
Prepare visual controls on machine.
7.1. For doing these things it needs mere observation,
observing the machine and f inding the abnormalit ies
and registering them down.
This becomes the init ial step of my role.
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So my roles are:-
1. Observation and f inding abnormalit ies.
2. Planning for the removal of abnormalit ies.
3. Acting as a coordinator between workers and off icers
for removal of abnormalit ies.
4. Giving detailed information about the abnormalit ies
found and removed to the TPM manager.
5. Acting as a trainee off icer when there are no off icers
in the department.
7.2. PLANNING FOR REMOVAL OF ABNORMALITIES
The next thing I got to do is to make the planning
with the maintenance executive about how and when
those abnormalit ies are to be removed.
7.3. ACTING AS A CO-ORDINATOR BETWEEN
WORKER AND OFFICER.
What abnormalit ies are l isted down needs to be
shown to the workers physically by going on the
machines sites. Then for removing abnormalit ies what
things are needed are to be requested from the central
store with the permission of the off icer.
e.g:- a taff lon tape for arresting air leakage or an air
exhaust si lencer or some tie cl ips for rerouting wires,
etc.
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7.4.GIVING DETAILED INFORMATION ABOUT THE
ABNORMALITIES FOUND AND REMOVED TO THE TPM
MANAGER.
I have to give the detailed record of al l the
abnormalit ies l isted in the register and how many of
them are removed from each of the cell to the TPM
manager Mr. Ajit Soundatt i .
For this I need to sort al l the abnormalit ies according to
their types (red tags or white tags).
RED TAGS – red tags are those tags which are to
be removed by the maintenance people as they
require some special ski l ls or equipments to get r id
of
WHITE TAGS – white tags are those which can be removed by the ordinary
people as no manipulation is needed to remove them.
Ce l lTags pu t Tags removed
Red Wh i te To ta l Red Wh i te To ta l
DCCL 281 178 459 252 150 402
DHL/ T /A 1024 429 1453 847 362 1209
ASSLY 203 139 342 171 127 298
TESTING 353 102 455 346 100 446
TOTAL 1861 848 2709 1616 739 2355
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Then they are needed to be classif ied according to
their types
i .e,-Minor defects, Source of contamination, Basic
condit ion, Hard to access, Unwanted slow moving
objects, Unsafe points, Quality defects.
This information is to be updated everyday as a
soft copy on the PC and monthly to be updated on the
Jaishu Hozen board of the Product Unit.
Ce l l
M ino r
de fec t
Sou rce o f
cond i t i on
Bas i c
cond i t i on
Hard to
access
Unwan ted
ob jec t s
Unsa fe
po in t s
Qua l i t y
de fec t s
Pu t Rem Put Rem Put Rem Put Rem Put Rem Put Rem Put Rem
DCCL 26 23 104 90 190 161 5 5 31 30 97 89 6 4
DHL/
T /A6 5 309 220 792 707 40 32 59 57 246 187 1 1
ASSLY 4 4 36 24 191 166 4 4 31 29 75 60 1 1
TEST 20 20 61 58 227 222 18 18 48 48 79 78 2 2
7.5. ACTING AS A TRAINEE OFFICER WHEN THERE ARE NO OFFICERS IN THE DEPARTMENT.
Being in the maintenance department I learnt some important
skills as the every day job work like Loading people Making decisions Answering to the head of the department
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LOADING PEOPLE
Like how and where the workers are to be loaded whether on to breakdown or on to the preventive maintenance work or for the improvement work.
MAKIING DECISIONS
Like which breakdown is to be attended first if a lot of breakdown comes at a time, i.e, what thing is to be given first priority.
ANSWERING TO THE HEAD OF DEPARTMENT
At the end of the day a report is to be given to the head of department in short about what breakdowns occurred? and why? what was the down time? And why?
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8. CONCLUSION
In the six months of training at Mahindra & Mahindra Auto
Sector, Kandivali. I have learnt many lessons about how an industry
works, lessons which will be invaluable for me throughout my career
and life. I am very fortunate to have studied in a sandwich course
which has given me a taste of professional life even before I
graduate.
Training at Mahindra & Mahindra has given me a great
opportunity to learn not only an automotive company works, but also
the ways and methods of work which is carried out.
My regular work at Mahindra & Mahindra was related to TPM
such as solving problems and defects related machine breakdown
etc. along with TPM work during audit time which energized me to
learn lots of things with practical approaches. This cycle of thoughts
has improved my ways of thinking immensely and I am confident that
it will help me to take better decisions in every aspect of life in the
professional carrier.
Since project requires active involvement of many different
people from the department, project also honed my skills of dealing
with people in a professional manner. Moreover, I felt that this training
has helped me understand the practicalities an engineer has to face.
Thus, I conclude by saying that I have truly benefited spending
this period of my education in Mahindra & Mahindra.
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