Net Change Material Requirements Planning

Defined and evaluated are concepts and characteristics of net change, a method that facilitates replanning and provides timely response to chunge in a transaction-oriented system. (MRP) entail an inherent massive data-handling task. Consequently , batch-oriented MRP systems tend to be untimely in their response to change since replanning can be done only periodically at best, probably once a week. A method of continuous replanning that minimizes the number of accesses to inventory records and bills of material at any given time is presented in this paper. Called net change, this approach offers the user the ability to replan at high frequency, or continuously in a transaction driven system. The COPICS manuals describe a system that is based on net change material requirements planning.' The purpose of this paper is to provide insight to the concepts of net change and to define the essential characteristics of an MRP system that is designed to utilize these concepts. Because net change is a variation on a theme, this theme of conventional material requirements planning, one of the two principal approaches to manufacturing inventory management, is described first, so as to establish proper perspective for the reader. There are two alternate fundamental approaches, and two sets of techniques that a manufacturing enterprise may employ in the management of inventories. They are: Statistical inventory control (also called order-point tech