Mechanical Engineering 101

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1 Mechanical Engineering 101 University of alifornia, Berkeley Lecture #17 1

2 Today s lecture apacity planning Kanban intro 2

3 MRP Last lecture: MRP scheduling Materials Requirements Planning: MRP This lecture: apacity planning Manufacturing Resources Planning : MRP II 3

4 Lot for lot MPS plan from last lecturelast time X period POR MPS for B? B: lead time = 1 period GR SR I NR POR B X 1 each A 1 ea 1 ea 1 ea 4

5 Manufacturing Resources Planning Standard MRP scheduling ignores workstation capacity assumes infinite! apacity planning Rough cut capacity planning (RP) apacity requirements planning (RP) 5

6 Rough cut capacity planning resource profile graphically shows precedence, lead times annotated with work center (W), time per unit purchased F Op# hr/unit E Op#2 D 0.20 hr/unit A W hr/unit Week Askin fig

7 RP period (week) POR(A) Op# hr/unit E Op#2 D 0.20 hr/unit A W hr/unit Week 7

8 Op# hr/unit E Op#2 D 0.20 hr/unit A W hr/unit W 300 example, week 3 capacity req s: resource profiles for the relevant weeks Op# hr/unit E Op#2 D 0.20 hr/unit A W hr/unit Op# hr/unit E Op#2 D 0.20 hr/unit A W hr/unit

9 25* Op# hr/unit E 25* Op#2 D 0.20 hr/unit A W hr/unit W 300 example 50* Op# hr/unit E 50* Op#2 D 0.20 hr/unit A W hr/unit 200* Op# hr/unit E 200* Op#2 D 0.20 hr/unit A W hr/unit Q A3 =25 Q A4 =50 Q A5 = 200 9

10 RP r ijk = resources (time) per unit of end item i in work center j in k th period before i completed r A,100,0 =? hrs none of the above Op# hr/unit E Week Op#2 D 0.20 hr/unit A W hr/unit 10

11 RP r ijk = resources (time) per unit of end item i in work center j in k th period before i completed r A,200,2 =? hrs none of the above Op# hr/unit E Week Op#2 D 0.20 hr/unit A W hr/unit 12

12 Resource profile r A,j,k is for single end item A work-content/work-center/period for A period work center Op# hr/unit E Op#2 D 0.20 hr/unit A W hr/unit Week 14

13 RP period (week) POR(A) period work center Op# hr/unit E Op#2 D 0.20 hr/unit A W hr/unit Week 15

14 Work center load r ijk = resources (time) per unit of end item i in work center j in k th period before i completed Q it = production quantity end item i in period t from MPS 16

15 Work center load r ijk = resources (time) per unit of end item i in work center j in k th period before i completed Q it = production quantity end item i in period t from MPS w jt = load (time) on work center j in period t make sure it s w/in capacity limits! n T w jt ri, j, k t i 1 k t Q ik 17

16 .Work center load W 300 Example period POR(A) ra period work center k=3: r A,300,3-3 = 0.0, Q A3 = 25 k=4: r A,300,4-3 =.15, Q A4 = 50 k=5: r A,300,5-3 =.15, Q A5 = 200 k=6: r A,300,6-3 = 0.0, Q A6 = 0 n T w jt ri, j, k t i 1 k t w 300,3... Q ik 18

17 25* Op# hr/unit E 25* Op#2 D 0.20 hr/unit A W hr/unit. W 300 Example 50* Op# hr/unit E 50* Op#2 D 0.20 hr/unit A W hr/unit 200* Op# hr/unit E 200* Op#2 D 0.20 hr/unit A W hr/unit Q A3 =25 Q A4 =50 Q A5 =

18 Work center load period POR(A) ra period work center <=w 200,2 <5 2. 5<=w 200,2 < <=w 200,2 < <=w 200,2 < <=w 200,2 <25 w 6. 25<=w 200,2 < <=w 200,2 < <=w 200,2 < <=w 200,2 < <=w 200,2 n T w jt ri, j, k t i 1 k t 200,2...? Q ik 22

19 75* Op# hr/unit E 75* Op#2 D 0.20 hr/unit A W hr/unit. W 200 Example 25* Op# hr/unit E 25* Op#2 D 0.20 hr/unit A W hr/unit 50* Op# hr/unit E 50* Op#2 D 0.20 hr/unit A W hr/unit Q A2 = 75 Q A3 =25 Q A4 =50 24

20 Announcements HW6 late deadline 4pm Friday! So all can be graded and returned next Tuesday Midterm next Thursday 10/25 HW 1-6, movies, lecture material through this week Try the posted samples!!! Review section Monday 6 pm 1165 Etcheverry Bring: 3x5 inch card of notes, handwritten, one side only alculator Hewlett Packard: The HP 33s and HP 35s models, but no others. Texas Instruments: All TI-30X and TI-36X models. asio: All fx-115 models. 26

21 apacity Requirements Planning What does RP ignore? inventory setup times larger batch production of components w/ POQ RP looks at detailed production plans add capacity resources in MRP explosion as additional components inventory = stored capacity not flexible capacity, though! 27

22 Work center load report available capacity available capacity Hours Hours Late Time period Time period planned order releases open shop orders 28

23 MRP II links additional modules to traditional MRP scheduling: capacity planning BOM processor EO management customer order entry financial planning forecasting inventory & warehouse management purchasing 2-way communication between modules 29

24 Enterprise Resources Planning (ERP) beyond individual company whole supplier-producer-customer network use electronic data interchange (EDI) 30

25 MRP assumptions known, constant lead times dependent demand adequate capacity accurate BOM good demand forecasts predictable scrap rates accurate inventory records 31

26 Ensuring accurate inventory data Why off? scrap not recorded correctly parts cannibalized just plain lost One solution: hire cycle counter given list of part numbers to count find and count on shop floor, in storage update electronic record 32

27 EOs Engineering hange Orders lag existing inventory implementation of process change vendor qualification coordination purchasing manufacturing engineering: testing, analyzing 33

28 Today s lecture apacity planning Kanban intro 34

29 Product Design: Push vs. Pull Market oriented (pull system) ustomer defines product ompetency Exceptional service Low cost Variety of choices and features Technology oriented (push system) Technology defines product ompetency Scientific research Unique product with market niche , McMains,, Min ME 101 lecture 19 35

30 Production Systems: Push vs. Pull Push: build inventory based on forecasts promotions to sell off the green cars Pull: just-in-time (JIT) systems replace inventory only as needed p.36 fig 2.12 Askin (mis-keyed in Askin) , McMains,, Min ME 101 lecture 19 36

31 Production Systems: Push vs. Pull Push: build inventory based on forecasts promotions to sell off the green cars Pull: just-in-time (JIT) systems replace inventory only as it is removed , McMains,, Min ME 101 lecture 19 37

32 Production Systems: Push vs. Pull Push: build inventory based on forecasts promotions to sell off the green cars Pull: just-in-time (JIT) systems replace inventory only as needed smaller buffers, no stockrooms, little WIP specific production orders generated when mfg start time nears , McMains,, Min ME 101 lecture 19 38

33 JIT benefits reduced inventory sizes reduced lot size inventories reduced buffer inventories reduced finished goods inventories reduced inventory costs less inventory space less equipment to handle inventories less inventory accounting less inventory control effort reduced impact of forecasting errors reduced scrap and rework , McMains,, Min ME 101 lecture 19 39

34 Kanban: a method for controlling pull system Japanese roughly translated as card used for production authorization each kanban includes info on part type number of units authorized possible additional info often used together with transport container possibly color-coded to match empty container pulls parts / triggers production kanban card is work order transfer lot size = container size , McMains,, Min ME 101 lecture 19 40

35 Kanban Step N supplier Step N manufacturer Z Z kanban card (and empty container) = request to supplier to make a container of Z and deliver ASAP send request when remaining WIP/material just covers lead time for replenishment , McMains,, Min ME 101 lecture 19 41

36 Kanban example [Mahoney] one-card kanban low mix/high volume environment products X and Z each has 3 steps performed at same 3 stations A,B, one worker per station (aka Point Of Use, POU) storage after each station Process A Process A+B Process A+B , McMains,, Min ME 101 lecture 19 42

37 Kanban card for example X 1 card located with product throughout the system X Model number Replenishment quantity 1 X product: Z product: , McMains,, Min ME 101 lecture 19 43

38 LMHV Location after process A Product X after process A Product specific one-card kanban system product X kanban card Finished product X Product Z after process A Finished product Z Process A Process B Process Process A Process A+B Process A+B , McMains,, Min ME 101 lecture 19 44

39 Signals from parts and cards Authorizes another product Z to be started Product Z Kanban card put up at Z 1 Product Z removed from FGI , McMains,, Min ME 101 lecture 19 45

40 More details process B & Z 1 Z 1 removes partially completed Z from input buffer Z kanban put up at B to schedule production of another Z product ompleted Z after process goes with card to FGI , McMains,, Min ME 101 lecture 19 Z 1 46

41 Moving further upstream. Z 1 Z 1 B removes partially completed Z from input buffer Z kanban put up at A to schedule production of another Z product ompleted Z after process B goes with card to output buffer , McMains,, Min ME 101 lecture 19 47

42 Last step... process step A creates product Z Z and kanban card placed in step A output buffer , McMains,, Min ME 101 lecture 19 48

43 Idle state no kanban cards at any process stage no production occurs removing an X or Z from FGI would restart process , McMains,, Min ME 101 lecture 19 49

44 Homework 7 (due after midterm) Reading Askin , Askin (watch your lead times!) 8.14 (LFL) 8.15 (POQ) 8.21 (LFL, then RP) turn in 2 print-outs of your spreadsheet output for each With formulas (or matlab code, but Excel highly recommended) With values Referring to the article Piecing Together a Supply hain : a) What happened to scheduled receipts of mass air flow sensors that G.M. had already ordered earlier in March? b) Hypothesize how you think their planned order releases for this part (mass air flow sensors) changed. c) How did their planned order releases for build orders for vehicles that used this part change? Be sure to use the bold-faced MRP terminology in each answer. 50

Dennis Bricker Dept of Mechanical & Industrial Engineering The University of Iowa. JIT --Intro 02/11/03 page 1 of 28

Dennis Bricker Dept of Mechanical & Industrial Engineering The University of Iowa JIT --Intro 02/11/03 page 1 of 28 Pull/Push Systems Pull system: System for moving work where a workstation pulls output