Work release strategies in a dual resource constrained job shop

Abstract

One of the basic assumptions in past job shop research is that arriving jobs are immediately released to the shop floor for processing regardless of available job and shop information. In practice, jobs arriving at the shop are usually collected into a backlog file. Jobs are then released by some mechanism so that they can be processed within the time available before the due date. This study examines the effects of several release mechanisms on the performance of a dual resource constrained job shop. The release mechanisms differ in the amount and types of information used to make release decisions. Four release mechanisms are tested in conjunction with two dynamic, due date oriented dispatching rules, Modified Operation Due Date and Critical Ratio. The job shop environment is specified by two levels of due date tightness. A labor and machine limited job shop model was used to simulate the shop performance.