Loading problem with alternative operations in FMS

Abstract

The purpose of this thesis is to study a method of loading a set of tools to machining centers in a flexible manufacturing system (FMS). It is assumed that each part to be manufactured is allowed to visit only one machining center for its entire processes. Thus during operations, any tool which is required by unavailable for the processing of a part must be borrowed after some waiting, if necessary, from other machining center or tool room. We also consider alternative operation (tool) and impose time penalty if tools are used for other than their primary operation. The above problem is formulated as a integer program (IP) whose objective is to simultaneously determine the part group and set of tools for each machining center which gives the minimum number of tool transfers among the machining centers. For the IP, a heuristic solution procedure is proposed utilizing the similarity coefficient. The validity of the procedure is examined through the simulation of hypothetical problems. The test results are compared with those from an existing solution procedure in terms of the makespan and the number of the tools transfered.