The document discusses push and pull production control systems. A push system like MRP initiates production based on forecasts, while a pull system like JIT initiates production based on current demand. MRP involves gathering demand data, determining planned order releases using explosion calculus, and developing shop floor schedules. Lot sizing algorithms aim to balance setup and holding costs. Capacity constraints and improvement steps can further optimize production planning.

1. Chapter 7 Push and Pull Production Control Systems MRP and JIT

5. Schematic of the Productive System Fig. 7-1

10. The Three Major Control Phases of the Productive System Fig. 7-2

12. Typical Product Structure Diagram Fig. 7-3

13. Trumpet and Subassemblies Fig. 7-4

14. Product Structure Diagram for Harmon Trumpet Fig. 7-5

16. 38 76 14 45 112 26 12 32 42 42 Net demand Expect 23 in inventory at the end of week 7 9 6 12 Scheduled Receipts Returns 38 76 14 45 112 26 21 38 42 77 Demand 17 16 15 14 13 12 11 10 9 8 Week

17. MRP calculations for Bell assembly 38 76 14 45 112 26 12 32 42 42 Planned order release (lot for lot) 38 76 14 45 112 26 12 32 42 42 Time-phased Net Reqts 38 76 14 45 112 26 12 32 42 42 Lead time Net Reqts 38 76 14 45 112 26 12 32 42 42 Gross Reqts 17 16 15 14 13 12 11 10 9 8 7 6 Week

18. MRP calculations for the valves 30 60 186 On-hand Inv. 96 Scheduled Receipts 114 228 42 135 336 78 36 66 Planned order release (lot for lot) 114 228 42 135 336 78 36 66 Time-phased Net Reqts 114 228 42 135 336 78 36 66 0 0 Net Reqts 114 228 42 135 336 78 36 96 126 126 Gross Reqts 13 12 11 10 9 8 7 6 5 4 3 2 Week

20. Starting in week 4 C(1)=132 C(2)=[132+0.6(42)]/2=78.6 C(3)=[132+0.6(42+2(32))]/3=65.2 C(4)=[132+0.6(42+2(32)+3(12))]/4=54.3 C(5)=[132+0.6(42+2(32)+3(12)+4(26))]/5=55.92  y 4 = 42+42+32+12=128 38 76 14 45 112 26 12 32 42 42 Time-phased net reqts . 13 12 11 10 9 8 7 6 5 4 Week

21. Starting in week 8: C(1)=132 C(2)=[132+0.6(112)]/2=99.6 C(3)=[112+0.6(112+2(45))]/3=84.4 C(4)=[112+0.6(112+2(45)+3(14))]/4=69.6 C(5)=[112+0.6(112+2(45)+3(14)+4(76))]/5=92.16  y 8 = 26+112+45+14=197 38 76 14 45 112 26 12 32 42 42 Time-phased net reqts. 13 12 11 10 9 8 7 6 5 4 Week

22. Starting in week 12: C(1)=132 C(2)=[132+0.6(38)]/2=77.4  y 12 = 76+38=114 Week 4 5 6 7 8 9 10 11 12 13 Pon 128 0 0 0 197 0 0 0 114 0 38 76 14 45 112 26 12 32 42 42 Time-phased net reqts. 13 12 11 10 9 8 7 6 5 4 Week

24. Order horizon total holding cost 1 0 2 0.6(42)=25.2 3 0.6(42+2(32))=64.8 4 0.6(42+2(32)+3(12))=86.4 5 0.6(42+2(32)+3(12)+4(26))=148.8 > 132 Since 148.8 is closer to 132 than 86.4 the order horizon is 5 periods _________________________________________________________ 1 0 2 0.6(45)=27=27 3 0.6(45+2(14))=43.8 4 0.6(45+2(14)+3(76))=180.6 > 132 Since 121.2 is closer to 132 than 151.2 the order horizon is 3 periods _________________________________________________________ 38 76 14 45 112 26 12 32 42 42 Time-phased net reqts . 13 12 11 10 9 8 7 6 5 4 Week

25. MRP calculations for valve casing Inv Del Ord Net Reqt 0 38 0 14 59 171 0 12 44 86 128 42 4 12 0 114 0 0 0 197 0 0 0 128 0 114 0 0 0 197 0 0 0 38 76 14 45 112 26 32 42 38 76 14 45 112 26 12 32 42 42 17 16 15 14 13 12 11 10 9 8 7 6 5

27. Lower level of valve casing (valves) SM Orders 198 0 0 0 495 0 0 0 342 0 0 0 0 Time-Phased Net Reqts OH inv Receipts Gross Rqts. 0 0 0 0 342 0 0 0 495 0 0 0 198 1 0 342 0 0 0 495 0 0 0 198 0 96 96 96 0 186 96 0 342 0 0 0 591 0 0 0 384 13 12 11 10 9 8 7 6 5 4 3 2

31. Calculations of the improvement step 0 0 0 0 272 295 0 91 20 Excess capacity 242 192 30 50 120 50 28 105 200 109 100 y 0 0 58 108 30 50 120 50 300 400 200 200 120 c 30 50 120 50 28 105 200 109 100 r’ 9 8 7 6 5 4 3 2 1 Period

32. Calculations continued 0 0 0 0 192 295 0 91 20 Excess capacity 142 0 0 120 50 108 105 200 109 100 y 0 158 30 50 120 50 300 400 200 200 120 c 30 50 120 50 28 105 200 109 100 r’ 9 8 7 6 5 4 3 2 1 Period

33. 0 0 0 0 142 295 0 91 20 Excess capacity 300 137 0 0 120 0 158 105 200 109 100 y 0 263 30 50 120 50 300 400 200 200 120 c 30 50 120 50 28 105 200 109 100 r’ 9 8 7 6 5 4 3 2 1 Period

34. 0 0 0 0 300 137 0 91 20 Excess capacity 0 0 120 0 0 263 200 109 100 y 30 50 120 50 300 400 200 200 120 c 30 50 120 50 28 105 200 109 100 r’ 9 8 7 6 5 4 3 2 1 Period