Consider the magazine rack and its pieces shown on the following page. The raw material is 1 inch by 6 inches by 6 feet long planks of oak lumber. The 6 rails and handle are made from one plank of lumber, but to make tire 2 ends and bottom, first two planks have to be glued together side-by-side.

The product structure tree below shows that one kit of 6 rails and a handle is made from one plank of lumber, and one kit of 2 ends and a bottom is made from one side-by-side glued piece of lumber which, in turn, is made of 2 planks of lumber. The cutting time of one plank of lumber into one kit of 6 rails and a handle will be 5 minutes. The glue time of 2 planks of lumber will be 5 minutes (assume that the glue will dry overnight). The cutting and router time (for the grooves) of one side-by-side glued piece of lumber into one kit of 2 ends and a bottom will be 10 minutes. Finally, tire assembly of one kit of 6 rails and a handle and one kit of 2 ends and a bottom will take 15 minutes. The shop works eight hours a day, five days a week. The purchase lead time for lumber is one work day. The shop has just sold 80 magazine racks to a customer to be delivered on Tuesday, March 31. Assume that each operation is performed by a different operator and each batch should be completed before it is moved to the next operation.
a. Calculate the manufacturing lead time for each operation to make this order.
b. Complete MRP tables for each item. Suppose we currently have 100 planks of lumber in stock. Assume lot-for-lot ordering for all Items except lumber, which is purchased in lots of 200 planks.
c. What action should we take now?