Models for the process planning problem in flexible manufacturing systems

Two levels of the process planning problem may be distinguished: the local problem, i.e. the production of a single part, and the global problem concerned with the interdependence of a group of parts to be manufactured. At the local level, one is faced with the completeness and the proper sequencing of the required operations. This may be related to the set covering problem and to topological sorting, respectively. The global problem is more involved and two important models are discussed: the process selection model and the FMS scheduling model. The process selection model is formulated as a clique problem. The FMS scheduling model is described as a constrained travelling salesman problem, and for its decomposition cluster analysis is applied.