Scheduling injection molding operations with multiple resource constraints and sequence dependent setup times and costs

This paper addresses a production scheduling problem in an injection molding facility. It appears to be the first attempt to schedule parallel machines for multiple items in presence of multiple capacitated resource constraints with sequence-dependent setup costs and times. The objective is to meet customer demands while minimizing the total inventory holding costs, backlogging costs and setup costs. We present a mathematical formulation of the problem. The computational complexity associated with the formulation makes it difficult for standard solvers address industrial-dimensioned problems in reasonable solution time. To overcome this, a two-phase workcenter-based decomposition scheme has been developed in this paper. The computational results for different problem sizes demonstrate that this scheme is able to solve industrial-dimensioned problems within reasonable time and accuracy.