MS 401, Spring 09-10
Recitation #7
MPS and MRP
Question 1. The MPS planer at Murphy Motors uses MPS time-phased records for planning end
item production. The planner is currently working on a schedule for P24, one of the Murphy’s topselling motors. The planner uses a production lot size of 70 and a safety stock of 5 for the P24 motor.
Period
1
2
3
4
5
6
7
8
Forecast
30
30
30
40
40
40
45
45
Orders
13
8
4
Available
60
30
70
30
60
20
45
70
ATP
39
1
40
70
70
70
70
70
70
70
MPS
On hand = 20
a) Complete the MPS time-phased record for product P24.
b) Can Murphy accept the following orders? Update the MPS time-phased record for accepted
orders.
New customer orders:
40 units, customer order number 4704 due in week 4.
30 units, customer order number 4709 due in week 6.
30 units, customer order number 4747 due in week 2.
25 units, customer order number 4747 due in week 3.
Question 2: The Spencer Optics Company produces an inexpensive line of sunglasses. The company
is interested in using material requirements planning to schedule its operations for one particular
popular model. The forecast for this model is 100 orders per week for the next 10 weeks. Spencer has
customer orders of 110 units, 80 units, 50 units, and 20 units in weeks 1, 2, 3, and 4 respectively. The
sunglasses are assembled in batches of 300. Presently, three production batches are scheduled: one in
week 2, one in week 5, and one in week 8. Complete the following time-phased record.
WEEKS
5
6
100
100
7
100
8
100
9
100
10
100
230
30
230
130
30
Forecast
1
100
2
100
3
100
4
100
Orders
110
80
50
20
30
230
130
30
30
150
300
300
300
300
300
Available
ATP
MPS
140
130
Question 3.
(a) Generate the relevant Bill of Material (BOM) diagrams using the following information:

A and B are final products

One unit of A requires one unit of C and one unit of D

One unit of D requires two units of E and one unit of F

One unit of B requires one unit of C and two units of F
(b) Generate the MRP output for items A, B, D and F, using the BOMs you identified in part (a), and
the following demand and inventory data. Use the MRP record tables provided in the following page.
Week
1
2
3
4
5
6
7
8
9
10
Demand (A)
21
25
75
30
35
80
75
19
22
25
Demand (B)
0
0
10
15
15
15
25
25
30
30
Item
Amount
on Hand
Scheduled
Receipts
Arrival
on week
Lead Time
(Weeks)
Lot Sizing Rule
Safety
Stock
A
60
70
3
2
Lot-for-lot
5
B
30
0
N/A
3
Lot-for-lot
0
D
50
0
N/A
1
Multiple of 30
0
F
30
100
100
1
3
1
Multiple of 50
20
Item A, LT=2
now
Gross Requirements
1
2
3
4
5
6
7
8
9
10
21
25
75
30
35
80
75
19
22
25
5
5
Scheduled Receipts
Projected Avl. Balance
70
60
39
14
9
5
5
5
5
5
26
35
80
75
19
22
25
1
2
3
4
5
6
7
8
9
10
0
0
10
15
15
15
25
25
30
30
30
30
20
5
0
0
0
0
0
0
10
15
25
25
30
30
Planned Order Releases
Item B, LT=3
now
Gross Requirements
Scheduled Receipts
Projected Avl. Balance
Planned Order Releases
30
Item D, LT=1
now
1
2
3
4
5
6
7
8
0
26
35
80
75
19
22
25
50
24
19
29
14
25
3
30
90
60
30
1
2
3
4
5
6
Gross Requirements
0
50
120
110
80
Scheduled Receipts
100
60
50
100
50
Gross Requirements
9
10
8
8
8
7
8
9
10
60
90
0
0
0
20
60
20
20
20
20
100
50
Scheduled Receipts
Projected Avl. Balance
50
Planned Order Releases
Item F, LT=1
Projected Avl. Balance
now
30
Planned Order Releases
130
30
100
80
Question 4. Suppose you are an IE in a company that makes stools. You have collected the
following data related to the production process:
Part Name
Components
Lot Sizing Rule
Planned Lead Time
Part Name
Components
Lot Sizing Rule
Planned Lead Time
Part Name
Components
Lot Sizing Rule
Planned Lead Time
Part Name
Components
Lot Sizing Rule
Planned Lead Time
Part Name
Components
Lot Sizing Rule
Planned Lead Time
Stool (end item)
1 Base, 1 Seat, and 2 Bolts
Period Order Quantity
1 week
Base
3 Legs, 3 Bolts
Lot for lot
2 weeks
Seat
None
Lot for lot
1 week
Leg
None
Lot for lot
2 weeks
Bolt
None
Lot for lot
1 week
Suppose that ordering cost is $10 per order and holding cost is $0.28 per unit per week.
a) Draw a bill of diagram for the end item “Stool”. Show LLCs (Low level codes) and other
necessary details.
b) Complete the following MRP tables for stool, base, legs and bolts.
This row indicates when a planned order release will be received (that
is, “leadtime” periods after a planned order release)
Stool (LT = 1)
Gross Requirements
Scheduled Receipts
Projected Ending Inv
Net requirements
Planned order receipts
Planned order releases
Base (LT = 2)
Gross Requirements
Scheduled Receipts
Projected Ending Inv.
Net requirements
Planned order receipts
Planned order releases
Leg (LT = 2)
Gross Requirements
Scheduled Receipts
Projected Ending Inv.
Net requirements
Planned order receipts
Planned order releases
Bolt (LT = 1)
Gross Requirements
Scheduled Receipts
Projected Ending Inv.
Net requirements
Planned order receipts
Planned order releases
0
1
10
2
20
3
15
4
20
5
15
6
40
30
20
0
0
0
0
0
0
35
20
15
35
0
0
0
0
55
40
15
55
0
0
0
10
10
10
0
1
0
40
60
2
35
3
0
4
55
5
0
6
10
7
0
25
25
0
30
30
10
0
0
0
10
10
0
0
0
0
20
7
10
0
30
0
0
1
0
2
90
4
30
5
0
6
0
7
0
20
20
0
70
70
10
3
0
20
20
0
10
10
0
0
0
0
1
0
3
0
4
140
5
0
6
20
7
0
40
40
2
160
100
0
20
20
0
0
140
140
0
0
20
20
70
20
140
20
c) Determine the holding and ordering costs for each week only for the stool. Compare your
findings with the ones that you would incur if L4L rule was used instead of the Period Order
Quantity rule.