An optimization model for trim loss minimization in an automotive glass plant

This paper deals with glass cutting in an Italian plant producing parts for the automotive market. Glass cutting is basically organised in two phases: first, large rectangular sheets of the same type are obtained from a ribbon of flat glass and sent to warehouse; then, sheets of various types are taken from the warehouse and cut into small rectangular parts of various sizes according to demand. In both phases, trim loss is generated. A problem then arises of fulfilling the demand of small parts using a limited assortment of large sheets and minimizing the total trim loss. In this paper we describe a heuristic algorithm based on a p-median model with additional constraints that take into account all the relevant shop floor requirements. A computational study conducted on real instances provided by the plant is presented and discussed.