Question

Materials Requirements Planning

QUESTION

An MRP exercise is being implemented over an 8-week period and the following relevant information is provided:

One (1) unit of A is made of two (2) units of B and three (3) units of C. One (1) unit of B is made up of three (3) units of D and two (2) units of E. One(1) unit of C is made up of two (2) units of B and two (2) units of D. Items A, C and E have one (1) week lead time. Items B and D have lead times of two (2) weeks. Assume that lot-for-lot (L4L) lot sizing is used for Items A, C and E and a lot size of 100 is used for items B and D. Items A and D have beginning inventories of twenty (20) and forty ( 40) units respectively; all other items have zero beginning inventory. We are scheduled to receive ten (10) units of item B in week two (2) and twenty (20) units of item D in week one (1). There are no other scheduled receipts.

1. Draw the product structure tree with low level coding. [5 marks]
2. Draw the corresponding time-phased diagram showing lead times to scale. [5 marks]
3. If fifty (50) units of A are required in Week eight (8), determine the necessary planned order releases for all components {five(5) schedules} [15 marks]

Answer 1

(a)

(b)

(c)

Item:	A	Week		1	2	3	4	5	6	7	8
OH =	20	Gross requirements		0	0	0	0	0	0	0	50
LT =	1	Scheduled receipts		0	0	0	0	0	0	0	0
Q =	L4L	Projected ending inventory	20	20	20	20	20	20	20	20	0
		Net requirements		0	0	0	0	0	0	0	30
		Planned receipts		0	0	0	0	0	0	0	30
		Planned orders		0	0	0	0	0	0	30	0
Item:	B	Week		1	2	3	4	5	6	7	8
OH =	0	Gross requirements		0	0	0	0	0	0	240	0
LT =	2	Scheduled receipts		0	10	0	0	0	0	0	0
Q =	100*	Projected ending inventory	0	0	10	10	10	10	10	70	70
		Net requirements		0	0	0	0	0	0	230	0
		Planned receipts		0	0	0	0	0	0	300	0
		Planned orders		0	0	0	0	300	0	0	0
Item:	C	Week		1	2	3	4	5	6	7	8
OH =	0	Gross requirements		0	0	0	0	0	0	90	0
LT =	1	Scheduled receipts		0	0	0	0	0	0	0	0
Q =	L4L	Projected ending inventory	0	0	0	0	0	0	0	0	0
		Net requirements		0	0	0	0	0	0	90	0
		Planned receipts		0	0	0	0	0	0	90	0
		Planned orders		0	0	0	0	0	90	0	0
Item:	D	Week		1	2	3	4	5	6	7	8
OH =	40	Gross requirements		0	0	0	0	900	180	0	0
LT =	2	Scheduled receipts		20	0	0	0	0	0	0	0
Q =	100*	Projected ending inventory	40	60	60	60	60	60	80	80	80
		Net requirements		0	0	0	0	840	120	0	0
		Planned receipts		0	0	0	0	900	200	0	0
		Planned orders		0	0	900	200	0	0	0	0
Item:	E	Week		1	2	3	4	5	6	7	8
OH =	0	Gross requirements		0	0	0	0	600	0	0	0
LT =	1	Scheduled receipts		0	0	0	0	0	0	0	0
Q =	L4L	Projected ending inventory	0	0	0	0	0	0	0	0	0
		Net requirements		0	0	0	0	600	0	0	0
		Planned receipts		0	0	0	0	600	0	0	0
		Planned orders		0	0	0	600	0	0	0	0