Formula selection and scheduling for precast concrete with double layer production

Abstract

This paper considers the precast production process with double layer production. To produce precast elements, multiple processes must be completed inthe same mold for each job. Processing times are constant except thecuring time, which depends on mixing formula.Normally, a cheaper formula requires a longer curing time than the more expensive ones.Each process requires an additional resource, which must be shared among the molds.Given base production plan, this paper proposes the mathematical model and heuristic to obtainthe maximumnumber of double layer jobs, select their concrete formulas and schedule jobs to satisfy the due date whileminimize the total production cost. The results demonstrate that the MIP model is suitable for small problems while the proposed heuristics is suitable for the more complicated problems.The heuristics provides less than 17%maximum difference from the MIP in term of the objective function value.Keywords : Formula selection, Scheduling, Heuristics, Precast production process with double layer production