Hybrid stage shop scheduling

The proposed hybrid stage shop scheduling (HSSS) model, inspired from a real case in the high-fashion industry, aims to fully exploit the potential of parallel resources, splitting and overlapping concurrent operations among teams of multifunctional machines and operators on the same job. The HSSS formally extends mixed shop scheduling (a combination of flowshop and open shop), which is able to model routing flexibility, and hybrid shop scheduling, which provides resource flexibility. To also include operational flexibility through alternative plans obtained by reordering operations linked by undefined or arbitrary (immaterial) precedence constraints, the proposed model integrates process planning and group shop scheduling. A mixed integer linear programming model and a theory based on disjunctive graphs have been proposed to explore the composite relations between nodes involving immaterial relations and deploying their routing rules. A constructive O(resources x jobs(2)) algorithm to generate a feasible plan/schedule in the most general case has been developed and applied to a case study.