An application of constraint programming to a specific production scheduling problem

This paper presents an application of constraint-based programming to a specific scheduling problem. The problem consists of scheduling batches of molded parts in a three-machine shop according to a wide variety of constraints including machine capabilities, cast-iron availability, minimal and maximal batch sizes, as well as constraints on operation preemption. The paper explains how the constraint programming tools Ilog Solver and Ilog Schedule have been used to develop a scheduling algorithm for the targeted problem. The usefulness of a scheduling library and the importance of its ‘extensibility’, i.e. of the possibility for the user of the library to develop specific types of constraints and specific problem-solving procedures, are discussed.