Capacity Planning in a Discrete Item Manufacturing Environment

Capacity planning is a medium-to-long- term production planning tool that enables management to better understand how the demand of its customers have and will affect the available capacity planning. For a successful production and planning control system, management needs to consider the availability of not only the materials and component, but also the required manufacturing capacity. Several capacity planning techniques that deal with capacity planning in a discrete item manufacturing (job shop environment) are discussed in this report. These are Resource Requirement Planning, Rough Cut Capacity Planning, Capacity Requirement Planning, Operation Sequence, Input Output, and Simulation. A computerized capacity planning system for the IBM Microcomputer family is developed and presented in this report. The system maintains the profile of the job shop in a data base along with data pertinent to various products that can be manufactured in the shop. Projected orders for the planning period are input to the system with their associated quantities and delivery dates. The system has its own data base management component which is used in creating, updating, and reviewing the data base contents. The capacity planning algorithm uses information retrieved from the data base, and the user’s input (loading rule and planning horizon) to simulate the behavior of the shop work centers along the planning horizon. The process involves loading (accumulating) the various elements of each order in its pertinent work center using a specified loading rule (currently it uses forward and backward loading). The system uses the loading policies in generating the scenarios, and the user is consulted in the selection of the policy to apply. Other scenarios may be tried by “splitting” the orders with various ratios to meet the delivery dates by the current capacity. The system will enable the user to select a course of action such as acquiring more resources, shift work loads, increase work shifts of specific work center for certain time periods, and/or subcontracting for some orders. Efficiency figures, based on a number of criteria, are produced along with the resource allocation for the planning period to guide the user in his/her selection of the proper scenario. Various reports that are generated by the system should aid the planner (Industrial Engineer) in making a complete analysis of the required future capacity and in identifying bottlenecks. The system is designed to encompass the best technique in operation and communicate with the user. The system will facilitate the future research in the capacity planning problem such as the development and testing of efficiency factors that can be used to compare various loading rules and the development of a heuristical procedure for leveling the required capacity of each work center along the planning horizon. Future expansion of the system might include: addition of subroutine that will change the normal calendar dates to working days, calendar and vice versa, priority rules for processing the orders, and/or capacity leveling subroutine. The system also might be modified to produce a list of all jobs (orders) that are needed to be processed at each work center per planning period (time bucket) along the planning horizon