A furniture maker has received an order for 100 units of its kitchen table to be delivered in six workdays. The table consists of one top and four legs, made from purchased lumber (2" by 6" by 6'). Each top is made from 1.5 units of lumber, and each leg is made from 1/6 unit of the lumber. Tops and legs can be made independently in two different workstations, and manufacturing time for one top is expected to be 12 minutes and for one leg is two minutes. All 100 tops and 400 legs should be made before any tables are assembled, and final assembly of one table is expected to take four minutes. The shop works eight hours a day, Monday to Friday. Currently, the company has 20 units of lumber in stock, and purchase lead time for lumber is one workday.

a. Calculate the manufacturing lead time for each operation (round up) and draw the product structure tree.

b. Perform material requirements planning for this order. What action should be taken now?

c. How would your answer for lumber change:

i. If the safety stock for lumber is 20 units?

ii. If lumber is purchased in batch size of 250 units?

iii. If 250 units are scheduled to be received on the next workday?