ABSTRACT
An important contribution to manufacturing is the concept of group technology (GT) which has now found wide acceptance in real-life workshops. The following advantages are obtained by applying GT to production scheduling. The total production time is reduced by setting a group setup for a parts family included in a group. The material-flow pattern can be of flow type by establishing GT layout. Hence, with GT operations scheduling can be simplified as flow-shop scheduling; it is called group scheduling. The optimal solutions for group scheduling—the optimal sequences for groups and for jobs included in each group under the minimum-time criterion—are determined through the branch-and-bound technique. However, this procedure is not practical because of a huge consumption of computer time, especially as the number of jobs and the number of stages increase. This is recognised as an NP-hard problem. Hence a heuristic approach—the Petrov method—is applied to this problem.
