Lesson 18 MRP Solutions Solved Problem #1: See textbook Solved Problem #2: See textbook #1: Given the following diagram for a product, determine the quantity of each component required to assemble one unit of the finished product.

E

F (2) G H

J (2) D (4) L (2) J (2) A (4) D (3)

Answer the following questions.

a. Determine the quantity of each subcomponent to produce 1 end item E. Show your answer in the table below.

F 2 G 1 H 1 J 6 D 10 L 2 A 4

b. Determine the quantity of each subcomponent to produce 200 E’s. Show your answer in the table

below.

F 400 G 200 H 200 J 1200D 2000L 400 A 800

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#2: Draw a product structure tree diagram for a stapler, where

Item Components Stapler Top Assembly, Base Assembly Top Assembly Cover, Spring, Slide Assembly Slide Assembly Slide, Spring Base Assembly Base, Strike Plate, Rubber Pad (2)

Stapler

Top Assembly Base Assembly

Cover Spring Base Strike Plate Slide Assembly

Slide

Spring

Rubber Pad (2)

#3: The following product structure tree shows the subcomponents for an end item. Also, the lead times and the quantity on hand are given.

End Item

B (2) C D (3)

E (2) F (3) G (2) E (2) H (4) E (2)

Item End B C D E F G H LT (wk) 1 2 3 3 1 2 1 2 Amount on hand 0 10 10 25 12 30 5 0 Answer the following questions. This problem must be done manually.

a. If 20 units of the end item are to be assembled, how many additional units of E are needed?

138

b. A order for the end item is scheduled to be shipped at the start of week 11. What is the latest week that the order can be started and still be ready to ship on time.

The beginning of week 5

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#4: A table (T) is assembled using 3 components: wood sections (WS), braces (B) and legs (L). The product structure tree is shown below:

T

WS (2) B (3) L (4)

The company wants to ship 100 units at the beginning of day 4, 150 units at the beginning of day 5, and 200 units at the beginning of day 7. Receipts of 100 wood sections scheduled at the beginning of day 2. There are 120 legs and 60 braces on hand. 200 legs are scheduled for receipt at the beginning of day 2. 150 braces are scheduled for receipt at the beginning of day 3. The lead times in days are as follows: assembly time for tables – 1 day; wood sections – 2 days for braces; and 1 day for legs. Prepare the material requirements plan for braces and legs as requested in the following.

a. Prepare a material requirements plan for braces using lot-for-lot ordering. Complete the table below. You do not need to enter values of 0.

Week Number 1 2 3 4 5 6 7 8 9

Demand 300 450 600 Gross requirements 300 450 600 OH/ SR 60 150 Projected on hand 60 60 210 0 0 Net requirements 90 450 600 Planned-order receipts 90 450 600 Planned-order releases 90 450 600

b. Prepare a material requirements plan for legs using a lot size of 60. Complete the table below. You do not need to enter values of 0.

Week Number 1 2 3 4 5 6 7 8 9

Demand 400 600 800 Gross requirements 400 600 800 OH/ SR 120 200 Projected on hand 120 320 320 40 40 40 20 20 20 Net requirements 80 560 760 Planned-order receipts 120 600 780 Planned-order releases 120 600 780

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#5: End item P is composed of three subassemblies: K, L, and W. K is assembled using 3 G’s and 4 H’s. L is made of 2 M’s and 2 N’s. W is made of 3 Z’s. On hand inventories are 20 L’s, 40 G’s, and 200 H’s. Scheduled receipts are 10 K’s at the start of week 3, 30 K’s at the start of week 6, and 200 W’s at the start of Week 3. One hundred P’s will be shipped at the start of week 6 and another 100 at the start of week 7. Lead times are two weeks for subassemblies, and one week for components, G, H, M, N and Z. Final assembly of P requires one week.

a. Develop a product structure tree for P.

P

K L W

G (3) H (4) M (2) N (2) Z (3)

b. Complete the following table. Item P K L W G H M N Z

Lead Time (wk) 1 2 2 2 1 1 1 1 1 Amount on hand 20 40 200

c. Prepare a master schedule and MRP for P using lot-for-lot ordering by completing the table below. You do not need to enter values of 0.

Week Number 1 2 3 4 5 6 7 8 9

Demand 100 100 Gross requirements 100 100 OH/ SR Projected on hand Net requirements 100 100 Planned-order receipts 100 100 Planned-order releases 100 100

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d. Prepare an MRP for K using lot-for-lot ordering by completing the table below. You do not need to enter values of 0.

Week Number 1 2 3 4 5 6 7 8 9

Demand 100 100 Gross requirements 100 100 OH/ SR 10 30 Projected on hand 10 10 10 30 Net requirements 90 70 Planned-order receipts 90 70 Planned-order releases 90 70

e. Prepare an MRP for G using a lot size of 70 by completing the table below. You do not need to enter values of 0.

Week Number 1 2 3 4 5 6 7 8 9

Demand 270 210 Gross requirements 270 210 OH/ SR 40 Projected on hand 40 40 40 50 50 50 50 50 50 Net requirements 230 160 Planned-order receipts 280 210 Planned-order releases 280 210

f. Prepare an MRP for H using a lot size of 100 by completing the table below. You do not need to enter values of 0.

Week Number 1 2 3 4 5 6 7 8 9

Demand 360 280 Gross requirements 360 280 OH/ SR 200 Projected on hand 200 200 200 40 60 60 60 60 60 Net requirements 160 240 Planned-order receipts 200 300 Planned-order releases 200 300

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#6: A company which makes electric golf carts has just received an order for 200 carts, which must be ready for delivery at the end of week 8. Information concerning the product structure, lead times, and quantities on hand are shown in the following table. There are no scheduled receipts.

Parts List for Electric Golf Cart

Lead Time

Quantity on Hand

(GC) Electric Golf Cart 1 0 (T) Top 1 40 (B) Base 1 20 (T) Top (S) Supports (4) 1 200 (CV) Cover 1 0 (B) Base (M) Motor 2 300 (BO) Body 3 50 (SE) Seats (2) 2 120 (BO) Body (F) Frame 1 35 (CN) Controls 1 0 (WA) Wheel Assemblies (4) 1 240

Use this information to answer the following questions.

a. Develop a product structure tree for the GC.

GC Electric Golf Cart

T Top

B Base

S (4) Supports

CV Cover

M Motor

BO Body

SE (2) Seats

F Frame

CN Controls

WA (4) Wheel Assemblies

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b. For this problem disregard the quantities on hand, and determine the Bill of Material quantities for each subassembly and components that are required to produce 200 golf carts. Show your answers in the table below.

GC 200 T 200 S 800

CV 200 B 200 M 200

BO 200 SE 400 F 200

CN 200 WA 800

Prepare an MRP for GC, B, BO, and WA using lot-for-lot ordering in the following questions.

c. Show the MRP for GC by completing the table below. You do not need to enter values of 0. Week Number 1 2 3 4 5 6 7 8 9

Demand 200 Gross requirements 200 OH/ SR Projected on hand Net requirements 200 Planned-order receipts 200 Planned-order releases 200

d. Show the MRP for B by completing the table below. You do not need to enter values of 0. Week Number 1 2 3 4 5 6 7 8 9

Demand 200 Gross requirements 200 OH/ SR 20 Projected on hand 20 20 20 20 20 20 20 Net requirements 180 Planned-order receipts 180 Planned-order releases 180

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e. Show the MRP for BO by completing the table below. You do not need to enter values of 0. Week Number 1 2 3 4 5 6 7 8 9

Demand 180 Gross requirements 180 OH/ SR 50 Projected on hand 50 50 50 50 50 50 Net requirements 130 Planned-order receipts 130 Planned-order releases 130

f. Show the MRP for WA by completing the table below. You do not need to enter values of 0. Week Number 1 2 3 4 5 6 7 8 9

Demand 520 Gross requirements 520 OH/ SR 240 Projected on hand 240 240 240 Net requirements 280 Planned-order receipts 280 Planned-order releases 280 0

g. Show the assembly time chart for GC – BO – B – WA. What is the lead time for this assembly sequence?

Assemblly Time Chart

WA BO B GC0123456789

-1 0 1 2 3 4 5 6 7

The assembly sequence GC – BO – B – WA lead time is 6 weeks.

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