Information systems have long been an important part of the

manufacturing environment. In the 1960s, manufacturers

developed Material Requirements Planning (MRP). According to

the American Production and Inventory Control Society,

Inc. (APICS), MRP is a set of techniques that uses bill of

material data, inventory data, and the master production

schedule to calculate requirements for materials. It makes

recommendations to reorder materials. Furthermore, because it

is time-phased, it makes recommendations to reschedule open

orders when due dates and need dates are not in phase.

Time-phased MRP begins with the items listed on the Master

Production Schedule and determines the quantity of all

components and materials required to fabricate those items and

the date that the components and material are required.

Time-phased MRP is accomplished by exploding the bill of

material, adjusting for inventory quantities on hand or on

order and offsetting the net requirements by the appropriate

lead times.