Models and solution approaches for part movement minimization and load balancing in FMS with machine, tool and process plan flexibilities

The paper addresses a generalized loading problem with the objective of part movement minimization in an FMS with machine, tool and process plan flexibilities. The three flexibilities refer to the ability of machines to perform a variety of operations, ability of tools to perform several operations, and the availability of alternate process plans for a part type, respectively. The resulting problem of integrated process plan selection and operation-tool-machine assignment is formulated as a 0-1 quadratic programming problem. The part movement minimization is achieved by assigning the maximum possible number of successive operations of a part type to the same machine subject to several system configuration and operational constraints. A two-stage heuristic exploiting the special structure of the problem is suggested as solution methodology. Numerical examples are solved to illustrate various steps of the proposed heuristics and to study its computational performance in comparison with Hyper Lindo. The problem is further extended to take into consideration the objective of workload balancing.