A practical approach for parts scheduling with alternative process plans in automated manufacturing systems

A set of parts with alternative process plans to be scheduled in an automated manufacturing system is considered in this paper. For each process plan, the part may require specific types of tool and auxiliary devices such as fixtures, grippers and feeders. The system objective is to schedule the set of parts with the minimum operation cost. The operation cost includes the process plan cost and the Hamming distance cost. The Hamming distance cost measures the dissimilarity between process plans for successive parts. A new mathematic model and a dynamic programming (DP) approach are presented to solve the problem optimally. Dominant properties of the problem are also identified such that the DP approach can be more efficiently applied. However, owing to the complexity of the problem, heuristic approaches are provided to solve the problem in practical sizes, and experimental results are discussed.