A simulation-based backward planning approach for order-release

Abstract

The problem of order release planning for a make-toorder production facility is addressed. Traditionally, order-release planning in a multi-stage shop is performed with material requirements planning (MRP) logic. MRP assumes infinite resource capacity and component lead times that are estimated using historical data, past experience, and rules-of-thumb. These assumptions often result in infeasible plans that make the task of scheduling difficult. An approach to order release planning termed qRP (resource planning based on queuing simulation) is discussed. qRP generates order release plans via a backward bill of material explosion logic similar to MRP except that a queuing simulation model of the facility is used. The simulation model captures the appropriate level of detail to provide a more realistic picture for planning. Component lead times are time-based (dependent on the current state of the shop) and may change from period to period. Automatic factory and simulation model generators are developed to compare this dynamic lead time approach with the static approach offered by MRP. Generalizations are made for key manufacturing attributes.