Clamps positioning and optimal holding positions in a DNC punch press

A process planning problem typically encounted in flexible manufacturing systems (FMS) treating laminated material (e.g. metal sheets) is modeled and solved. In such production systems, computer-controlled clamps hold the material on a work table. Sheet repositioning represents an important proportion of the processing time. Models are developed that give, under various operational conditions, a minimal set of repositionings. The first formulation of the model calls for a medium-size mixed-integer programming problem. In a subsequent reformulation, the real-life problem is reduced to a set of simpler linear programming problems. Illustrations of the method, as currently implemented on a FMS, are provided