A Bi-objective Model for a Flowshop Scheduling Problem with Availability Constraint of Machines

Abstract

This paper presents a new bi-objective mathematical model for a permutation flowshop scheduling problem with availability constraint in case of preventive maintenance operations on machines. In this paper, preventive maintenance is flexible and there is not a certain time for the maintenance operation; however, time between two consecutive maintenance operations for each machine should not be greater than a given time. The model has two objectives; (1) minimizing the makespan (i.e., <em>C_max</em>) and, (2) minimizing the sum of earliness and tardiness simultaneously. This study reports the results obtained by the Reservation Level Tchebycheff Procedure (RLTP) and the <em>ε</em>-constraint method for solving a case study problem. The results show high quality of reached solutions from RLTP in comparison with the <em>ε</em>-constraint method.