AN INNOVATIVE APPROACH FOR JOB PRE-ALLOCATION TO PARALLEL UNRELATED MACHINES IN THE CASE OF A BATCH SEQUENCE-DEPENDENT MANUFACTURING ENVIRONMENT

The problem of allocating jobs to a set of parallel unrelated machines in a make to stock manufacturingsystem is studied. The items are subdivided into families of similar products. Sequence-dependent setupsarise when products belonging both to the same family and to different families are sequenced. Restrictionson the number of available setups should be considered. The availability of planning batch production exists.Nevertheless, batch size is not known a priori. Hence, a solving approach considering both a preassignmentprocedure and a scheduling algorithm is proposed. Specifically, the focus of the paper is on thepre-assignment methodology: a pre-assignment model (solved by a commercial solver) and two heuristicsare presented and compared, in order to minimize the average idle residual capacity during the planninghorizon, while considering pejorative factors related with the split volumes of the same product on differentmachines, unsatisfied demand along with demand produced in advance in each time period. The applicationto a case study is finally described in order to assess the performance of the proposed approach.