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© 2003‐2012, McMains, DornfeldME 101 lecture 17 1
Mechanical Engineering 101
University of California, Berkeley
Lecture #17
© 2003‐2012, McMains, Dornfeld ME 101 lecture 17 2
Today’s lecture
• Capacity planning• Kanban intro
© 2003‐2012, McMains, Dornfeld ME 101 lecture 17 3
MRP
• Last lecture: MRP scheduling– Materials Requirements Planning: MRP
• This lecture: Capacity planning– Manufacturing Resources Planning : MRP II
© 2003‐2012, McMains, Dornfeld ME 101 lecture 17 4
B: lead time = 1period 0 1 2 3 4 5 6GR 1000 1000 1000 1500SRI 1106 106NR 894 1000 0 0 1500POR 894 1000 0 0 1500 0
Lot‐for‐lot MPS plan from last lecturelast time
• MPS for B?
Xperiod 0 1 2 3 4 5 6POR 1000 1000 1000 1500
X
B A
C
1 each
1 ea 1 ea
1 ea
© 2003‐2012, McMains, Dornfeld ME 101 lecture 17 5
Manufacturing Resources Planning
• Standard MRP scheduling ignores workstation capacity– assumes infinite!
• Capacity planning– Rough cut capacity planning (RCCP)– Capacity requirements planning (CRP)
© 2003‐2012, McMains, Dornfeld ME 101 lecture 17 6
Rough cut capacity planning
– resource profile• graphically shows precedence, lead times• annotated with work center (WC), time per unit
Week-5 -4 -3 -2 -1 -0
E
C C
A
D
Op#1WC200
0.10 hr/unit
Op#2WC300
0.15 hr/unitWC100
0.05 hr/unitWC3000.15 hr/unit
WC2000.20 hr/unit
Fpurchased
Askin fig. 8.10
© 2003‐2012, McMains, Dornfeld ME 101 lecture 17 7
RCCP
Week-5 -4 -3 -2 -1 -0
period (week)1 2 3 4 5 6
POR(A) 50 75 25 50 200
E
C C
A
D
Op#1WC200
0.10 hr/unit
Op#2WC300
0.15 hr/unitWC100
0.05 hr/unitWC3000.15 hr/unit
WC2000.20 hr/unit
© 2003‐2012, McMains, Dornfeld ME 101 lecture 17 8
E
C C
A
D
Op#1WC200
0.10 hr/unit
Op#2WC300
0.15 hr/unitWC100
0.05 hr/unitWC3000.15 hr/unit
WC2000.20 hr/unit
E
C C
A
D
Op#1WC200
0.10 hr/unit
Op#2WC300
0.15 hr/unitWC100
0.05 hr/unitWC3000.15 hr/unit
WC2000.20 hr/unit
E
C C
A
D
Op#1WC200
0.10 hr/unit
Op#2WC300
0.15 hr/unitWC100
0.05 hr/unitWC3000.15 hr/unit
WC2000.20 hr/unit
1 2 3 4 5 6
WC 300 example,week 3 capacity req’s:resource profiles for therelevant weeks
© 2003‐2012, McMains, Dornfeld ME 101 lecture 17 9
E
C C
A
D
Op#1WC200
0.10 hr/unit
Op#2WC300
0.15 hr/unitWC100
0.05 hr/unitWC3000.15 hr/unit
WC2000.20 hr/unit
50 75 QA3=25 QA4=50 QA5= 200
E
C C
A
D
Op#1WC200
0.10 hr/unit
Op#2WC300
0.15 hr/unitWC100
0.05 hr/unitWC3000.15 hr/unit
WC2000.20 hr/unit
E
C C
A
D
Op#1WC200
0.10 hr/unit
Op#2WC300
0.15 hr/unitWC100
0.05 hr/unitWC3000.15 hr/unit
WC2000.20 hr/unit
200*
200*
50*
50*
25*
25*
WC 300 example
© 2003‐2012, McMains, Dornfeld ME 101 lecture 17 10
RCCP
• rijk = resources (time) per unit of end item i in work center j in kth period before i completed
• rA,100,0 = ? hrs1. 02. .053. .104. .15 5. .20 6. .257. .308. .359. .4010. none of the above Week
-3 -2 -1 -0
E
C C
A
D
Op#1WC200
0.10 hr/unit
Op#2WC300
0.15 hr/unitWC100
0.05 hr/unitWC3000.15 hr/unit
WC2000.20 hr/unit
© 2003‐2012, McMains, Dornfeld ME 101 lecture 17 12
RCCP
• rijk = resources (time) per unit of end item i in work center j in kth period before i completed
• rA,200,2 = ? hrs1. 02. .053. .104. .15 5. .20 6. .257. .308. .359. .4010. none of the above Week
-3 -2 -1 -0
E
C C
A
D
Op#1WC200
0.10 hr/unit
Op#2WC300
0.15 hr/unitWC100
0.05 hr/unitWC3000.15 hr/unit
WC2000.20 hr/unit
© 2003‐2012, McMains, Dornfeld ME 101 lecture 17 14
Resource profile
• rA,j,k is for single end item A work-content/work-center/period for A
Week-5 -4 -3 -2 -1 -0
E
C C
A
D
Op#1WC200
0.10 hr/unit
Op#2WC300
0.15 hr/unitWC100
0.05 hr/unitWC3000.15 hr/unit
WC2000.20 hr/unit
periodwork center 0 -1 -2
100 0.05200 0.2 0.1300 0.15 0.15
© 2003‐2012, McMains, Dornfeld ME 101 lecture 17 15
RCCP
Week-5 -4 -3 -2 -1 -0
period (week)1 2 3 4 5 6
POR(A) 50 75 25 50 200
E
C C
A
D
Op#1WC200
0.10 hr/unit
Op#2WC300
0.15 hr/unitWC100
0.05 hr/unitWC3000.15 hr/unit
WC2000.20 hr/unit
periodwork center 0 -1 -2
100 0.05200 0.2 0.1300 0.15 0.15
© 2003‐2012, McMains, Dornfeld ME 101 lecture 17 16
Work center load
• rijk = resources (time) per unit of end item i in work center j in kth period before i completed
• Qit = production quantity end item i in period t– from MPS
© 2003‐2012, McMains, Dornfeld ME 101 lecture 17 17
Work center load
• rijk = resources (time) per unit of end item i in work center j in kth period before i completed
• Qit = production quantity end item i in period t– from MPS
• wjt = load (time) on work center j in period t– make sure it’s w/in capacity limits!
ik
T
tktkji
n
ijt Qrw
,,1
© 2003‐2012, McMains, Dornfeld ME 101 lecture 17 18
.Work center load
• k=3: rA,300,3-3 = 0.0 , QA3 = 25• k=4: rA,300,4-3 = .15 , QA4 = 50• k=5: rA,300,5-3 = .15 , QA5 = 200• k=6: rA,300,6-3 = 0.0 , QA6 = 0
rA periodwork center 0 -1 -2
100 0.05200 0.2 0.1300 0.15 0.15
period1 2 3 4 5 6
POR(A) 50 75 25 50 200
ik
T
tktkji
n
ijt Qrw
,,1
...3,300w
WC 300 Example
© 2003‐2012, McMains, Dornfeld ME 101 lecture 17 20
E
C C
A
D
Op#1WC200
0.10 hr/unit
Op#2WC300
0.15 hr/unitWC100
0.05 hr/unitWC3000.15 hr/unit
WC2000.20 hr/unit
50 75 QA3=25 QA4=50 QA5= 200
E
C C
A
D
Op#1WC200
0.10 hr/unit
Op#2WC300
0.15 hr/unitWC100
0.05 hr/unitWC3000.15 hr/unit
WC2000.20 hr/unit
E
C C
A
D
Op#1WC200
0.10 hr/unit
Op#2WC300
0.15 hr/unitWC100
0.05 hr/unitWC3000.15 hr/unit
WC2000.20 hr/unit
200*
200*
50*
50*
25*
25*
. WC 300 Example
© 2003‐2012, McMains, Dornfeld ME 101 lecture 17 22
Work center load
rA periodwork center 0 -1 -2
100 0.05200 0.2 0.1300 0.15 0.15
period1 2 3 4 5 6
POR(A) 50 75 25 50 200
ik
T
tktkji
n
ijt Qrw
,,1
?...2,200 w
1. 0<=w200,2<52. 5<=w200,2<103. 10<=w200,2<154. 15<=w200,2<205. 20<=w200,2<25
6. 25<=w200,2<307. 30<=w200,2<358. 35<=w200,2<409. 40<=w200,2<4510. 45<=w200,2
© 2003‐2012, McMains, Dornfeld ME 101 lecture 17 24
E
C C
A
D
Op#1WC200
0.10 hr/unit
Op#2WC300
0.15 hr/unitWC100
0.05 hr/unitWC3000.15 hr/unit
WC2000.20 hr/unit
E
C C
A
D
Op#1WC200
0.10 hr/unit
Op#2WC300
0.15 hr/unitWC100
0.05 hr/unitWC3000.15 hr/unit
WC2000.20 hr/unit
E
C C
A
D
Op#1WC200
0.10 hr/unit
Op#2WC300
0.15 hr/unitWC100
0.05 hr/unitWC3000.15 hr/unit
WC2000.20 hr/unit
50*
50*
25*
25*
75*
75*
50 75 QA2= 75 QA3=25 QA4=50
. WC 200 Example
© 2003‐2012, McMains, Dornfeld ME 101 lecture 17 26
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 EtcheverryBring:– 3x5 inch card of notes, handwritten, one side only – Calculator
• Hewlett Packard: The HP 33s and HP 35s models, but no others.
• Texas Instruments: All TI-30X and TI-36X models.• Casio: All fx-115 models.
© 2003‐2012, McMains, Dornfeld ME 101 lecture 17 27
Capacity Requirements Planning
• What does RCCP ignore?– inventory– setup times– larger batch production of components w/ POQ
• CRP looks at detailed production plans– add capacity resources in MRP explosion as
additional “components” – inventory = stored capacity
• not flexible capacity, though!
© 2003‐2012, McMains, Dornfeld ME 101 lecture 17 28
Work center load report
planned order releases
open shop orders
Time periodLate 1 2 3 4
Hou
rs
70
60
50
40
30
20
10
available capacity
Time period1 2 3 4
70
60
50
40
30
20
10
available capacity
Hou
rs
© 2003‐2012, McMains, Dornfeld ME 101 lecture 17 29
MRP II
• links additional modules to traditional MRP scheduling:– capacity planning– BOM processor– ECO management– customer order entry– financial planning– forecasting– inventory & warehouse management– purchasing
• 2-way communication between modules
© 2003‐2012, McMains, Dornfeld ME 101 lecture 17 30
Enterprise Resources Planning (ERP)
• beyond individual company– whole supplier-producer-customer network
• use electronic data interchange (EDI)
© 2003‐2012, McMains, Dornfeld ME 101 lecture 17 31
MRP assumptions
• known, constant lead times• dependent demand• adequate capacity• accurate BOM• good demand forecasts• predictable scrap rates• accurate inventory records
© 2003‐2012, McMains, Dornfeld ME 101 lecture 17 32
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
© 2003‐2012, McMains, Dornfeld ME 101 lecture 17 33
ECOs
• Engineering Change Orders• lag
– existing inventory– implementation of process change– vendor qualification
• coordination– purchasing– manufacturing– engineering: testing, analyzing
© 2003‐2012, McMains, Dornfeld ME 101 lecture 17 34
Today’s lecture
• Capacity planning• Kanban intro
© 2003‐2011, McMains, Dornfeld, Min ME 101 lecture 19 35
Product Design: Push vs. Pull• Market oriented (pull system)
– Customer defines product– Competency
• Exceptional service• Low cost• Variety of choices and features
• Technology oriented (push system)– Technology defines product– Competency
• Scientific research• Unique product with market niche
© 2003‐2011, McMains, Dornfeld, Min ME 101 lecture 19 36
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)
© 2003‐2011, McMains, Dornfeld, Min ME 101 lecture 19 37
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
© 2003‐2011, McMains, Dornfeld, Min ME 101 lecture 19 38
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
© 2003‐2011, McMains, Dornfeld, Min ME 101 lecture 19 39
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
© 2003‐2011, McMains, Dornfeld, Min ME 101 lecture 19 40
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
© 2003‐2011, McMains, Dornfeld, Min ME 101 lecture 19 41
Kanban
Z
Step N manufacturer
• 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
Z
Step N supplier
© 2003‐2011, McMains, Dornfeld, Min ME 101 lecture 19 42
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,C
– one worker per station (aka Point Of Use, POU)
– storage after each station
Process A+B+CProcess A+BProcess A
© 2003‐2011, McMains, Dornfeld, Min ME 101 lecture 19 43
Model number
Replenishment quantity
X
1
X1
“Z” product:
Kanban card for example
“X” product:
card located with product throughout the system
© 2003‐2011, McMains, Dornfeld, Min ME 101 lecture 19 44
Product specific one-card kanban system
Product Zafter process A
Process AProcess BProcess C
Process A+B+CProcess A+B
Finished product X
Product Xafter process A
Finished product Z
product X kanban card
Process A
LMHV
Location after process A
© 2003‐2011, McMains, Dornfeld, Min ME 101 lecture 19 45
Signals from parts and cards
Product Z removed from FGI
Product Z Kanban card put up at C
Z1
Authorizes another product Z to be started
© 2003‐2011, McMains, Dornfeld, Min ME 101 lecture 19 46
More details……process B & C
Z1Completed Z after process C goes with card to FGI
Z1
Z1
Z kanban put up at B to schedule production of another Z product
C removes partially completed Z from input buffer
© 2003‐2011, McMains, Dornfeld, Min ME 101 lecture 19 47
Moving further upstream….
Completed Z after process B goes with card to output buffer
Z1
Z kanban put up at A to schedule production of another Z product
Z1
B removes partially completed Z from input buffer
© 2003‐2011, McMains, Dornfeld, Min ME 101 lecture 19 48
Last step……...
Z and kanban card placed in step A output buffer
process step A creates product Z
© 2003‐2011, McMains, Dornfeld, Min ME 101 lecture 19 49
Idle state
• no kanban cards at any process stage– no production occurs– removing an X or Z from FGI would restart process
50
Homework 7 (due after midterm)• Reading
– Askin 269-291, 299-307• Askin (watch your lead times!)
– 8.14 (LFL)– 8.15 (POQ)– 8.21 (LFL, then CRP)– 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 Chain”:
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. © 2003‐2012, McMains, Dornfeld ME 101 lecture 17