A study of the selection of types of pieces for short term production planning in an FMS

This research compares seven approaches found in the literature on the selection of types of pieces for simultaneous production in a time horizon. A flexible approach for the selection of types of pieces and a simultaneous determination of mixing relations, as well as of work load balancing to aggregated machines, is presented. Simulation studies in detailed and realistic models are developed, together with flexible flow systems (FFS) configured as combined machines of equal size. The simulation scenarios are built to evaluate the impact of factors such as blockade, transportation, use of reserves, accessories requirements and constraints of various types. This paper attempts to relegate an artificial constraint-which consists in only allowing changes in tools between batches-for those cases in which it is adequate. For other cases of FMS, the use of batches may be more adequate. The results show that the use of a flexible approach allows an increase in the utilization of the system. It was also observed that batching approaches tend to need more accessories of every type than flexible approaches.