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)
J (2)
G
D (4)
L (2)
H
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
G
H
J
D
L
A
b.
2
1
1
6
10
2
4
Determine the quantity of each subcomponent to produce 200 E’s. Show your answer in the table
below.
F
G
H
J
D
L
A
400
200
200
1200
2000
400
800
1
#2: Draw a product structure tree diagram for a stapler, where
Item
Stapler
Top Assembly
Slide Assembly
Base Assembly
Components
Top Assembly, Base Assembly
Cover, Spring, Slide Assembly
Slide, Spring
Base, Strike Plate, Rubber Pad (2)
Stapler
Base
Assembly
Top Assembly
Cover
Slide
Assembly
Spring
Base
Rubber Pad
(2)
Strike Plate
Slide
Spring
#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)
E (2)
Item
LT (wk)
Amount on hand
C
F (3)
End
1
0
G (2)
B
2
10
D (3)
E (2)
C
3
10
D
3
25
H (4)
E
1
12
F
2
30
E (2)
G
1
5
H
2
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
2
#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
Demand
Gross requirements
OH/ SR
60
Projected on hand
60
60
Net requirements
Planned-order receipts
Planned-order releases
b.
4
300
300
150
210
90
90
450
450
600
600
0
450
450
600
0
600
600
90 450
5
6
7
8
9
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
Demand
Gross requirements
OH/ SR
3
120
Projected on hand
Net requirements
Planned-order receipts
Planned-order releases
1
2
3
4
400 600
400 600
5
6
7
8
9
800
800
200
120 320 320 40 40 40 20 20 20
80 560
760
120 600
780
120 600
780
3
#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
G (3)
b.
H (4)
W
M (2)
N (2)
Z (3)
Complete the following table.
Item
P
K
L
W
G
H
M
N
Z
Lead Time (wk)
1
2
2
20
2
1
40
1
200
1
1
1
Amount on hand
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
Demand
Gross requirements
1
2
3
4
5
6
7
8
9
100 100
100 100
OH/ SR
Projected on hand
Net requirements
Planned-order receipts
Planned-order releases
100 100
100 100
100 100
4
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
Demand
Gross requirements
10
10
OH/ SR
Projected on hand
Net requirements
Planned-order receipts
90
Planned-order releases
e.
1
2
Gross requirements
8
9
100 100
100 100
30
10 10 30
90 70
90 70
70
3
4
5
6
7
8
9
50
50
50
50
40
Projected on hand
40
Net requirements
Planned-order receipts
Planned-order releases
40
40 50 50
230 160
280 210
280 210
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
Demand
Gross requirements
OH/ SR
7
270 210
270 210
Demand
f.
6
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
OH/ SR
5
1
2
3
4
5
6
7
8
9
60
60
60
60
360 280
360 280
200
Projected on hand
Net requirements
Planned-order receipts
Planned-order releases
200 200 200 40 60
160 240
200 300
200 300
5
#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
(GC) Electric Golf Cart
(T) Top
(B) Base
(T) Top
(S) Supports (4)
(CV) Cover
(B) Base
(M) Motor
(BO) Body
(SE) Seats (2)
(BO) Body
(F) Frame
(CN) Controls
(WA) Wheel Assemblies (4)
Quantity on
Hand
1
1
1
0
40
20
1
1
200
0
2
3
2
300
50
120
1
1
1
35
0
240
Use this information to answer the following questions.
a.
Develop a product structure tree for the GC.
GC
Electric Golf Cart
T
Top
S (4)
Supports
B
Base
CV
Cover
M
Motor
BO
Body
SE (2)
Seats
F
Frame
CN
Controls
WA (4)
Wheel Assemblies
6
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.
200
200
800
200
200
200
200
400
200
200
800
GC
T
S
CV
B
M
BO
SE
F
CN
WA
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
200
200
Demand
Gross requirements
OH/ SR
Projected on hand
200
200
Net requirements
Planned-order receipts
200
Planned-order releases
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
8
9
200
200
Demand
Gross requirements
OH/ SR
7
20
Projected on hand
20
20
20
20
20
20
Net requirements
Planned-order receipts
Planned-order releases
20
180
180
180
7
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
Gross requirements
9
50
OH/ SR
Projected on hand
50
50
50
50
50
50
130
130
Net requirements
Planned-order receipts
130
Planned-order releases
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
520
520
Demand
Gross requirements
240
OH/ SR
Projected on hand
Net requirements
Planned-order receipts
Planned-order releases
g.
8
180
180
Demand
f.
7
240 240 240
280
280
280 0
Show the assembly time chart for GC – BO – B – WA. What is the lead time for this assembly
sequence?
Assem blly Tim e Chart
-1
0
1
2
3
4
5
6
7
0
1
WA
BO
B
GC
2
3
4
5
6
7
8
9
The assembly sequence GC – BO – B – WA lead time is 6 weeks.
8