Minimizing the sum of earliness/tardiness in identical parallel machines schedule with incompatible job families: An improved MIP approach

This research considers the problem of scheduling jobs on a set of identical parallel machines, with distinct due dates, process time and early due date restrictions. Further more, the jobs originate from incompatible product families, making it a sequence-dependent setup every time a job is switched from one family to another. Based on the policy that discourages both jobs being early as well as late, we focus on minimizing the sum of earliness/tardiness in the presence of setups. We developed a mixed integer programming formulation model to deal with such scheduling problems. The model can provide optimal solutions for up to 18 jobs that originate from up to four incompatible families.