Procedures to determine part mix ratios for independent demands in flexible manufacturing systems

The problem of determining the part mix ratios at which a set of part types should be produced over the next production period is addressed. Integer programming is used to solve this problem, with computations based on machine utilizations. Several objectives are discussed, each applicable in different FMS situations. One objective balancing machine workload to eliminate bottlenecks, is illustrated. The ratios provide input into more detailed models that can be used to evaluate these part mix ratios. Three complementary models are suggested: a stochastic, multiclass, closed queuing network model, providing pessimistic, aggregate, and steady-state performance evaluation results: a deterministic, timed Petri net model, and its associated algebraic representation, which provides optimistic results: simulation, which provides the detailed modeling capabilities necessary to evaluate the performance of the ratios for research purposes. Either of the first two models is adequate to evaluate the ratios in practice. The part mix ratios can help solve other planning and operating problems