6.7. Micro Castings Limited has an order for its final assembly A, which is assembled using B1 and B2. B1 is made of C l, C2, and C3. B2 is made of C2 and C3. Material is available for all parts. Following are the description and standard time taken for each operation. Using a piece of graph paper, draw a backward schedule based on the given data. When should an order be released for C3 if the 100 As are needed by day 7?

Assume no inventory on hand.

a. Only one machine is assigned to each operation.

b. The factory works one 8-hour shift, 5 days a week.

c. All parts move in one lot of 100.

Part Standard Time (days)

C l 3 C2 3 C3 3 B1 2 B2 2 A 1