Planning and control models to analyze problems of flexible manufacturing

The design and use of flexible manufacturing systems (FMSs) involves some intricate operations research problems. Such a system consists of an integrated set of computer numerically controlled machine tools, interconnected by an automated material handling system, all under the control of one or more computers. An FMS is capable of the simultaneous manufacture of several different part types in batches of size one. Various mathematical models that have been used in the design, planning, scheduling, and control of these systems will be discussed. These models have been used in the design of an FMS to determine, for example, the appropriate number of machine tools of each type, the capacity of the material handling system, or the size of buffers. They have also been used in the planning, or set up, of an FMS to determine which parts should be simultaneously machined, the optimal partition of machines into groups, allocations of pallets and fixtures to part types, and the assignment of operations and associated cutting tools among the limitedcapacity tool magazines of the machine tools. Mathematical models have been used in the scheduling of an FMS to determine the optimal input sequence of parts and an optimal sequence at each machine tool given the current part mix.