Set-up times in cyclic and acyclic Group Technology Scheduling systems

The formation of production part-families by the application of Group Technology opens the way for more efficient manufacture. One area for improvement is reduction in manufacturing set-up times. Particular opportunities exist for minimizing total set-up time for the part-family when the set-up times for parts in the family are dependent on which part has been made immediately previously. Where the production of an entire family is to be repeated sequentially, the problem is that of cyclic scheduling, and a solution can be sought by Travelling Salesman methods. Where only selected parts from a family are to be made, and the family not repeated, the problem is acyclic. In this paper, an efficient technique is presented for determining the optimum part sequence in such an acyclic case, and the technique is illustrated by a specific industrial scheduling example.