A Look-Ahead Routing Procedure for Machine Selection in a Highly Informative Manufacturing System

Many dispatching rules have been developed for the on-line control of product flow in a job shop. The introduction of a highly informative manufacturing system (HIMS) has added a new requirement to a classical job-shop control problem: the selection of machines by parts of different types. An HIMS can keep a great deal of information on the status of the system, such as information on what is scheduled in the near future with great accuracy, which can be used for shop floor control. For example, the knowledge of the time when the next parts arrive at the machines can be used for better routing. This article tests the effect of the use of this knowledge for part routing on the part's flow time and tardiness under a look-ahead routing procedure (LARP). LARP assigns a new part to a machine so that the assignment minimizes the flow time or tardiness of the current part and the next N parts arriving after the current part. A test shows that the reduction of part flow time is up to 11% and the reduction of tardiness is up to 21% for the cases with this procedure.