Page 334 - Orlicky's Material Requirements Planning

CHAPTER 18 Process Industry Application 313

constraint in the process industry and is planned first in the planning cycle. The first MRP
systems were developed for the job shop to manage the complex flow of raw materials
through variable capacity. The priority plan initially assumes that there is infinite capac-
ity. Capacity planning is used to validate the priority plan in the discrete enterprise.
The process industry accomplishes its planning exactly in reverse. Capacity is
planned first, and then the priority plan is determined. Materials are ordered based on
the availability of capacity rather than the other way around. Therefore, it is not surpris-
ing that these traditional systems do not fit the process industry well and Orlicky posed
his question in the first edition of this book. Unique scheduling tools are used for process
industries, including process-flow scheduling. The MRP system must have these unique
functions to allow this integrated system to best fit the process enterprise. Using the right
tools for the right job makes the job much easier. Attempting to use the same tools to
solve every problem is asking for disaster. Successful MRP implementation in the process
industry is the ability to know the difference.