bottle neck operation through critical path method
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The document provides details about the author's industrial training at Mahindra & Mahindra (Swaraj Division). It includes: 1) An overview of Swaraj Division and its various product lines and departments. 2) Descriptions of key manufacturing processes like light machine shop, heat treatment, and assembly of components like the differential, engine, and gearbox. 3) Time studies conducted using Critical Path Method to identify bottlenecks in the assembly of differential sub-assembly, rear cover, engine sub-assembly, and gearbox sub-assembly. The analyses identified specific activities as bottlenecks in each assembly process.
bottle neck operation through critical path method
- 1. REPORT OF INDUSTRIAL TRAINING AT MAHINDRA & MAHINDRA (SWARAJ DIVISION) SUBMITTED TO: SUBMITTED BY DEPPT. OF MECHANICAL ENGG. KANWALDEEP SINGH SG12927 MECHANICAL 8TH SEM
- 2. INTRODUTION • Established on 27th of June 1970. • PTL started with an annual capacity of 5000 tractors and with a capital of Rs. 3.7 cr. • IN 2007 M&M (the leaders in domestic tractor industry) acquires majority stake in PTL. • IN 2012 Swaraj becomes the second tractor company in the world to win the prestigious DEMING Prize. • IN 2013 Swaraj Division Plant 1 and Plant 2 Won TPM Excellence Award From JIPM.
- 3. VARIOUS DIVISION OF SWARAJ GROUP:- Swaraj consists of SIX divisions: • Swaraj Tractors Division. • Swaraj Mazda Ltd. • Swaraj Combine Ltd. • Swaraj Automotive Ltd. • Swaraj Foundry Division. • Swaraj Engines Ltd. VARIOUS MODLES OF SWARAJ TRACTORS DIVISION • Swaraj 735 with 35 HP. • Swaraj 744 with 44 HP. • Swaraj 855 with 55 HP. • Swaraj 960 with 40 HP.
- 4. VARIOUS DEPARTMENT IN SWARAJ TRACTOR DIVISION • PPC: Production planning & control • R&D :Research & Development • H.R :Human Resource
- 5. LIGHT MACHINE SHOP (L.M.S) L M S is the largest section of the factory. All transmission components like shafts and gears used in tractors are manufactured here. L.M.S comprises of 117 machines. • FUNCTION OF THE DEPARTMENT • Gear manufacture and grinding. • Machining of bull gears. • Bevel gear cutting of all rounds on power hacksaws. • Facing and centering. • All type of grinding inner and outer gears. • Hobbing and broaching machine. • Gear shaving gear deburring machine. • Drilling of all gears reporting system. • Number of workmen shifts operations.
- 6. DIFFERENT MANUFACUFACTURING OPERATIONS IN LMS • Facing • Rough Turning • Finish Turning • Grooving • Drilling • Boring • Grinding • Hobbing • BROACHING
- 7. HEAVY MACHINE SHOP (H.M.S) • All heavy casting of tractors is machined in this shop with the help of variety of special machine. • Facilities of this shop include general-purpose turning, drilling and milling machines COMPONENTS MACHINED IN THE HMS 1. GEAR BOX HOUSING 2. DIFFERENTIAL HOUSING
- 8. 3. REAR COVER 4. TRUMPET HOUSING 5. BRAKE HOUSING
- 9. HEAT TREATMENT SHOP • In automobile industry all the gear and shafts need to be heat treated to impart desired strength and increase life of the component. • The H.T shop at PTL is equipped with several gas carbonizing furnaces, quenching tanks, induction hardening machines and shot blasting furnaces. Heating of the metal to pre-determined temperature. Soaking of the metal at that temp. until the structure becomes uniform throughout the mass. Cooling of the metal at some pre-determined rate to cause the formation of desirable structures within the metal/alloy for the desired purpose.
- 10. PURPOSE OF THE HEAT TREATMENT • Improve machinability. • Relieve internal stresses. • Improve mechanical properties such as ductility, strength, hardness, toughness etc. • Change in grain size. • Increase resistance to heat and corrosion.
- 11. ASSEMBLY SHOP (ASSEMBLY OF SWARAJ TRACTOR) • ASSEMBLY: The process of joining various constituents to form a final product. Assembly of the tractor is divided into five sections: a) Differential Sub assy. b) Engine Sub assy. c) Hydraulic rear cover Sub Assy. d) Gearbox Sub Assy. e) Main line Assy.
- 12. DIFFERENTIAL SUB ASSEMBLY • FUNCTION: When the vehicle takes turns , a device is necessary which make the wheels move at different speed and equal speed on straight path To accomplished this purpose a system of gear called “ Differential System “ is provided.
- 13. • PARTS IN DIFFERNTIAL SUB ASSEMBLY: • CAGE • CROSS • BEVEL WHEEL • SUN GEAR • PLANET GEAR • TAIL PINION SHAFT • BULL PINION SHAFT • BULL GEAR • SUCTION STRAINER • PTO SHIFTER • PTO SHAFT • TRUMPET LAY OUT OF DIFF. SUB ASSY. • BRAKES CAGE ASSEMBLY CAGE , BULL GEAR &BRAKES FIITTED PTO SHIFTER & SUCTIO N STRAINER ASSY BRAKE PEDAL ,TAIL PINION SHAFT FITTED GEAR BOX COUPLING
- 14. ENGINE SUB ASSEMBLY • PARTS ATTACHED IN ENGINE SUB ASSEMBLY: • ALTERNATOR • HYD. PUMP • STARTING MOTOR • CLUTCH PLATE • PRESSURE PLATE • FRONT AXLE BEAM(FAB) • KPSA(KING PIN STUB AXLE)
- 15. LAY OUT OF ENGINE SUB ASSY HYD PUMP ASSEMBLY CLUTCH PLATE & PRESSURE PLATE FITMENT ALTERNATOR,STARTING MOTOR FITMENT FRONT AXLE BEAM ASSEMBLY KING PIN STUB AXLE ASSEMBLY FRONT AXLE BEAM FITMENT
- 16. REAR COVER SUB ASSEMBLY • It is the device which is used to control the hydraulic lift attached behind the tractor . • Hydraulic lift capacity of tractor can be up to 3000kg. PARTS IN REAR COVER SUB ASSEMBLY: • CONTROL SECTOR • RAM ARM • COUPLER • SENSOR TUBE • CYLINDER • PISTON • CONTROL VALVE
- 17. LAYOUT OF REAR COVER ASSEMBLY Rear Cover Casting loaded on assy line Control sector assy., Cylinder Assembly, Coupler assembly Control Valve Assembly Response Valve Assembly Sensor Tube ,cylinder, control sector & valve attached Testing Of Rear Cover For Any Leakage
- 18. GEARBOX SUB ASSEMBLY PRINCIPLE: • As we know that horsepower developed by any engine is directly proportional to product of torque and rotational speed. FUNCTION: • Most modern GEARBOXES are used to increase torque while reducing the speed of a prime mover output shaft (e.g. a motor crankshaft). • This means that the output shaft of a GEARBOX rotates at a slower rate than the input shaft, and this reduction in speed produces a mechanical advantage, increasing torque. TYPES OF GEAR BOX: • Sliding mesh gear box • Constant mesh gear box.
- 19. • PARTS IN GEAR BOX SUB : • IDLER CLUSTER • INTERMEDIATE SHAFT • LAY SHAFT • BEARING HOLDER • PLANET CARRIER • STEERING • SHIFTER ROD LAY OUT OF GEAR SUB ASSEMBLY IDLER CLUSTER,LAY SHAFT,INTERMEDIATE ASSY. LAY SHAFT& INTERMEDIATE SHAFT ATTACHED BEARING HOLDER& CA GUIDE , PLANET CARRIER ASSY ABOVE PARTS ATTACHED STEERING FIITEDTESTING
- 20. PAINT SHOP • Paint shop is the place where the different sheet metal components are painted. • They are made to pass through various chemicals before they are actually painted. • The painting methods operated is that of Spray painting. NEED FOR PAINTING:- • Long Life. • Rust Resistance. • Better Look
- 21. The various operation performed in paint shop are • Surface Preparation (Pre Treatment Cell) – carried out for sheets and rims. • Painting JOSH 1(dash board, rear frame ,front shield ,top bonnet), JOSH 2(fenders, side panel), CHASSIS BOOTH (washing, primer, washing zones), FINAL TOUCH UP. • Inspection. • Rejection (Reprocessing) for sheets and rims. • NEED FOR SURFACE PREPERATION:- • For removing Organic compounds (oil, grease) • Inorganic compounds (oxides, peroxides) • Better paint adhesion. • Elimination chances of reoccurring of dust.
- 22. NEED FOR SURFACE PREPERATION:- • For removing Organic compounds (oil, grease) • Inorganic compounds (oxides, peroxides) • Better paint adhesion. • Elimination chances of reoccurring of dust. CHEMICAL PROCESS Degreasing. Water Rinsing De-rusting Rinsing Surface activation Phosphating Water Rinsing Passivation Drying
- 23. • PAINTING • The process (sheet and rim painting) includes: • Full primer+ one coat of paint (30-40 microns). • Flash off. • Baking. • Rubbing. • Cleaning with tag rag. • Final painting. • Flash off. REASONS FOR REJECTION:- • Flow. • Less paint. • Pin hole. • Crow footing. • Shade variation.
- 24. TESTING
- 25. PROJECT WORK TIME STUDY TO FIND BOTTLE NECK PROBLEM USING CRITICAL PATH METHOD
- 26. Bottleneck PROBLEM • Bottleneck • Schroeder defines bottleneck as, “a work centre whose capacity is less than the demand placed on it and less than the capacities of all other resources. A bottleneck resource will constrain the capacity of the entire shop and an hour added to the bottleneck will add an hour of capacity to the entire factory. An hour added to the non- bottleneck work center will not help the schedule at all since the excess capacity exists there.” • A bottleneck station determines the capacity of the whole production system; in a balanced assembly line, if 5 minutes’ of work is added to the tasks of a station, all the following stations will have to wait for 5 minutes for all assembled products. This shows that, in fact each operator on the line is a bottleneck for the line and it is of crucial importance to eliminate the balance losses for maximizing line capacity.
- 27. What is CPM? The Critical Path Method or Critical Path Analysis, is a • mathematically based algorithm for scheduling a set of project activities • It is an important tool for effective project management • Commonly used with all forms of projects, including • construction, software development, research projects, product • development, engineering, and plant maintenance, among others • Any project with interdependent activities can apply this method of scheduling
- 28. DIFFERENTIAL TIME STUDY TIME STUDY ACTIVITY TASK OBSERVED TIME AVG. TIME PRECEDENCE ACTIVITY 1 2 3 A CAGE ASSEMBLY 4:17.1 4:12.2 4:15.1 4:14.81 ----- B TRUMPET ASSEMBLY 1:16.6 1:07.7 1:11.2 1:11.83 ----- C TAIL PINION SHAFT ASSEMBLY 2:52.3 3:04.8 3:15.9 3:04.2 ----- D PTO SHIFTER ASSEMBLY 1:13.3 1:16.5 1:26.4 1:15.4 ----- E PTO SHAFT ASSEMBLY 00:57.8 1:05.48 1:06.8 1:03.3 ------ F SUCTION STRAINER ASSEMBLY 00:46.11 00:49.8 00:58.0 00:51.3 ----- G ATTACHMENT OF ABOVE PARTS 33:54.7 24:59.7 30:13.0 29:43.2 A,B,C,D,E,F H IDEAL TIME 2:11.0 6:00.9 3:33.1 3:54.8 G I GEAR BOX COUPLING 2:31.8 2:45.1 3:15.5 2:50.3 H
- 29. NETWORK DIAGRAM OF DIFFERENIAL SUB ASSEMBLY • CRITICAL PATH:A+G+H+I=40:41.4 • BOTTLE NECK PROBLEM : Activity (A):Cage Assembly
- 30. REAR COVER TIME STUDY TIME STUDY ACTIVITY TASK OBSERVED TIME AVG. TIME PRECEDENCE 1 2 3 A CONTROL SECTOR SUB ASSEMBLY 1:56.2 1:42.4 2:05.1 1:54.5 ------ B CYLINDER SUB ASSEMBLY 1:39.05 1:30.3 1:37.74 1:35.71 ------- C SENSOR TUBE 00:50.3 00:50.15 00:54.8 00:51.75 ------ D RAM ARM ASSEMBLY 00:12.9 00:16.68 00:19.9 00:16.9 ------- E DRAFT ROD 00:25.29 00:40.3 00:47.8 00:37.79 ------- F POSITION ROD 00:30.47 00:52.6 00:48.1 00:43.72 ------ G COUPLER SUB ASSEMBLY 00:30.2 00:25.9 00:34.8 00:30.3 E,F H ATTACHMENT OF THE ABOVE PARTS 25:20.5 24:26.2 26:42.8 25:29.3 A,B,C,D,G I TEST RIG 2:04.5 2:20.8 2:35.9 2:19.74 H
- 31. NETWORK DIAGRAM OF DIFFERENIAL SUB ASSEMBLY • CRITICAL PATH:A+H+I=28:42.3 • BOTTLE NECK PROBLEM:ACTIVITY (A):CONTROL SECTOR
- 32. ENGINE SUB ASSEMBLY TIME STUDY TIME STUDY ACTIVIT Y TASK OBSERVED TIME AVG. TIME PRECEDENC E1 2 3 A HYD. PUMP SUB ASSEMBLY 1:34.18 1:32.02 1:33.56 1:33.2 ---- B KPSA SUB ASSEMBLY 1:45.0 1:30.6 1:32.0 1:35.8 ---- C FRONT AXLE BEAM ASSEMBLY 3:12.0 3:19.0 3:35.3 3:22.2 ---- D KPSA & TIE ROD FITMENT 1:26.2 1:27.8 1:20.4 1:24.8 C E FAB FITMENT 2:20.4 2:06.4 2:45.0 2:23.6 D F VARIOUS OTHER PARTS 30:43.8 22:43.4 25:48.9 26:24.75 A,B,E G IDEAL TIME 10:21.6 15:00.3 12:16.9 12:32.39 F
- 33. NETWORK DIAGRAM OF ENGINE SUB ASSEMBLY • CRITICAL PATH:C+D+E+F=33:53.91 • BOTTLE NECK PROBLEM:C,D,E
- 34. GEAR BOX SUB ASSEMBLY TIME STUDY TIME STUDY ACTIVITY TASK OBSERVED TIME AVG. TIME PRECEDENCE 1 2 3 A IDLER CLUSTER ASSEMBLY 00:54.5 1:06.9 1:12.6 1:04.6 ------ B PLANET CARRIER ASSEMBLY 1:40.2 1:43.9 1:48.3 1:44.1 ------ C STEERING SUB ASSEMBLY 2:16.8 2:20.5 2:31.9 2:23.07 ----- D ALL PART FITMENT 32:44.5 32:52.0 33:37.1 33:04.5 A,B,C E TESTING 1:02.7 1:35.8 1:44.9 1:27.8 D
- 35. NETWORK DIAGRAM OF ENGINE SUB ASSEMBLY • CRITICAL PATH: C+D+E:36:54.20 • BOTTLE NECK PROBLEM:Activity (C);Steering sub assembly
- 36. MAIN LINE ASSEMBLY TIME STUDY TIME STUDY ACTIVITY TASK OBSERVED TIME AVG. TIME PRECEDENCE 1 2 3 A Sound check 1:01.3 1:14.1 1:10.3 1:17.5 ----- B Rear cover fitment 2:07.9 1:47.4 1:38.7 1:50.7 A C Engine coupling 4:54.8 4:20.9 4:44.3 4:39.4 A D Hydraulic lift parts attachment 5:54.5 5:25.8 5:39.4 5:39.39 B E Pre whipping station 1:56.5 2:10.9 1:59.2 2:01.72 D,C F Paint 20:56.89 21:56.5 20:45.2 21:12.65 E G Front tyre fitment 1:33.6 1:46.4 1:20.9 1:33.06 F H Fender fitment 2:27.3 2:40.6 3:05.1 2:44:03 F I Rear tyre fitment 3:17.6 3:25.8 3:16.8 3:19.40 H J Radiator fitment 02:17.0 2:16.6 2:12.9 2:15.05 F K Various other parts 12:25.7 14:28.7 15:23.6 14:05.4 J,G,I L Testing 4:50.6 5:24.4 5:27.9 5:13.73 K M Light testing 4:25.9 4:50.4 4:40.1 4:38.38 L
- 37. NETWORK DIAGRAM OF ENGINE SUB ASSEMBLY • CRITICAL PATH;A+B+D+E+F+H+I+K+L+M=61:58.2
- 38. NET WORK DIAGRAM
- 39. CONCLUSION • A bottle neck resource will constrain the capacity of the entire shop and an hour added to the bottle neck will add an hour of capacity to the entire factory. An hour added to the non bottleneck work center will not help the schedule at all since the excess capacity exists there. • A bottle neck station determines the capacity of the whole production system; in a balanced assembly line , if 5 minutes of work is added to tasks of a station all the following station swill have to wait for all assembled products. • This shows that , in fact each operator on the line is a bottleneck for the line and it is of crucial importance to eliminate the balance losses for maximizing line capacity. • The ultimate bottle neck problem , I found is Differential sub Assembly , and further in Differential assembly ,I found that Cage assembly is the bottle neck problem . • By increasing the no. of workers or operators and by giving more automation to assembly line , we can increase the production.