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# By: Prof. Y. Peter Chiu - PowerPoint PPT Presentation

Chapter 7 ~ HOMEWORK SOLUTION ~. By: Prof. Y. Peter Chiu. What is the MRP Calculations for the slide assemblies ? ( 3 slide assemblies for each valve casing ). Lead Time = 2 weeks. Assume On-hand inventory of 270 slide assemblies at the end of week

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~ HOMEWORK SOLUTION ~

By: Prof. Y. Peter Chiu

• Lead Time = 2 weeks

• Assume On-hand inventory of 270 slide assemblies at the end of week

3 & Scheduled receipts of 78 & 63 at the beginning of week 5 & 7

• Solution to MRP Calculations for the slide assemblies

2 3 4 5 6 7 8 9 10 11 12 13

Week

Gross

Requirements

126 126 96 36 78 336 135 42 228 114

78 63

Scheduled Receipts

On-hand inventory

270 144 96 0 27

Net

Requirements

0 0 0 051336 135 42 228 114

Time-Phased

Net Requirements

51 336 135 42 228 114

Planned Order

Release (lot for lot)

51 336 135 42 228 114

#4(a) MPS for the computers

(b)

Week

27 28 29 30 31 32 33 34 35

MPS-end item

165 180 300 220 200 240

Component B (P.O.R)

330 360 600 440 400 480

Component F

330 360 600 440 400 480

-Net. Req.

Time Phased Net. Req.

330 360 600 440 400 480

Ans. →Planned Order Release

330 360 600 440 400 480

(c)

Week

21 22 23 24 25 26 27 28 29 30 31 32 33 34 35

165 180 300 220 200 240

MPS-end item

P.O.R –Comp. B

330 360 600 440 400 480

330 360 600 440 400 480

Net Req. –Comp. E

330 360 600 440 400 480

Time Phased –Net Req.

P.O.R – Comp. E

330 360 600 440 400 480

660 720 1200 880 800 960

Net Req. –Comp. G

660 720 1200 880 800 960

Time Phased –Net Req.

P.O.R –Comp. G

660 720 1200 880 800 960

660 720 1200 880 800 960

Net Req. –Comp. I

660 720 1200 880 800 960

Time Phased –Net Req.

Ans. → P.O.R –Comp. I

660 720 1200 880 800 960

(d)

1980 2160 3600 2640 2400 2880

Net Req. –Comp. H

Time Phased –Net Req.

1980 2160 36002640 2400 2880

Ans. → P.O.R –comp. H

1980 2160 36002640 2400 2880

Month

1 2 3 4 5 6 7 8 9 10 11 12

Demand

6 12 4 8 15 25 20 5 10 20 5 12

• Current Inventory : 4

• An ending Inventory should be : 8

• h = \$ 1

• k = \$ 40

Month

1 2 3 4 5 6 7 8 9 10 11 12

Net. Demand

212 4 8 15 25 20 5 10 20 5 20

(a) Silver-Meal

• Starting in Period 1 :

C(1) = 40

C(2) = (40+12)/2 = 26

C(3) = [40+12+2(4)] /3 = 20

C(4) = [40+12+2(4)+3(8)] /4= 21 <stop>

(a) Silver-Meal

C(1) = 40

C(2) = [40+15]/2 = 27.5

C(3) = [40+15+2(25)] /3 = 35 <stop>

• Starting in Period 4 :

• Starting in Period 6 :

C(1) = 40

C(2) = [40+20]/2 = 30

C(3) = [40+20+2(5)] /3 = 23.3

C(4) = [40+20+2(5)+3(10)] /4 = 25 <stop>

• Starting in Period 9 :

C(1) = 40

C(2) = [40+20]/2 = 30

C(3) = [40+20+2(5)] /3 =23.3

C(4) = [40+20+2(5)+3(20)] /4 = 32.5 <stop>

∴ Using Silver- Meal ; y = [ 18 , 0 , 0 , 23 , 0 , 50 , 0 , 0 , 35 , 0 , 0 , 20 ]

(b) LUC

• Starting in Period 1 :

C(1) = 40 /2 = 20

C(2) = 52 /14 = 3.71

C(3) = 60 /18 = 3.33

C(4) = 84 /26 = 3.23

C(5) = (84+60) /41 = 3.51 <stop>

• Starting in Period 5 :

C(1) = 40 /15 = 2.67

C(2) = 65 /40 = 1.63

C(3) = [65+2(20)] /60 = 1.75 <stop>

• Starting in Period 7 :

C(1) = 40 /20 = 2

C(2) = (40+5) /25 = 1.80

C(3) = [40+5+2(10)] /35 = 1.86 <stop>

(b) LUC

• Starting in Period 9 :

C(1) = 40 /10 = 4

C(2) = 60 /30 = 2

C(3) = [60+2(5)] /35 = 2

C(4) = [70+60] /55 = 2.36 <stop>

∴ Using LUC ; y = [ 26 , 0 , 0 , 0 ,40 , 0 , 25 , 0 , 35 , 0 , 0 , 20 ]

(C) PPB

Period

Holding cost

• Starting in Period 1 :

1* (12) = 12

12+2(4) = 20

20+3(8) = 44

2

3

4

K = \$40

Closer to period 4

Period

Holding cost

• Starting in Period 5 :

1

2

3

0

25

25+2(20) = 65

K = \$40

Closer to period 2

Period

Holding cost

• Starting in Period 7 :

2

3

4

5

5+2(10) = 25

25+3(20) = 85

K = \$40

Closer to period 3

Period

Holding cost

• Starting in Period 10 :

2

3

5

5+2(12) = 29

K = \$40

∴ Using PPB ; y = [ 26 , 0 , 0 , 0 ,40 , 0 , 35 , 0 , 0 , 45 , 0 , 0 ]

1 2 3 4 5 6 7 8 9 10 11 12

SM

18 0 0 23 0 50 0 0 35 0 0 20

LUC

26 0 0 0 40 0 25 0 35 0 0 20

PPB

26 0 0 0 40 0 35 0 0 45 0 0

Demand

2 12 4 8 15 25 20 5 10 20 5 20

Inv. SM

Σ = 95

16 4 0 15 0 25 5 0 25 5 0 0

24 12 8 0 25 0 5 0 25 5 0 0

Inv. LUC

Σ = 104

Inv. PPB

24 12 8 0 25 0 15 10 0 25 20 0

Σ = 139

Cost of S.M. (\$40*5)+(\$1*95) = \$295

Cost of LUC (\$40*5)+(\$1*104) = \$304

Cost of PPB (\$40*4)+(\$1*139) = \$299

∴ Silver Meal Method is the least expensive one !

#17

#18 (cont’d)

The End