Material handling and machine loading in a flexible manufacturing system

Decisions on material handling, machine loading, and sequencing in a Flexible Manufacturing System (FMS) are made much more complex by the fact that many FMSs or automated job shops are characterized by machine cells with multiple, functionally similar machines that differ in performance due to age, model, and make. If poorly planned, material handling time in a FMS could constitute a high percentage of the total production time of a job. To facilitate material transfer, flexible material handling systems are normally used to link the machines or cells. Furthermore, to improve production, batch jobs are usually split into sublots or unit loads for handling between machines. Thus, coordinating the movement of the sublots and the assignment of the sublots to machines within a cell is a critical decision factor which, if poorly made, can significantly affect the production efficiency of the shop in terms of batch completion times. In this research, the problems of material handling, machine loading, and sequencing in a FMS with heterogeneous but functionally similar machines are addressed. The research pursues the development of a methodology to assign unit loads to machines, determine move times for unit loads, and assign unit load movement to material handling equipment. The solution to the problems are obtained through the use of mathematical programming technique and heuristic algorithm.