Solving Re-entrant No-wait Flowshop Scheduling Problem

In this study, we consider the production environment of no-wait reentrant flow shop with the objective of minimizing makespan of the jobs. In a reentrant flow shop, at least one job should visit at least one of the machines more than once. In a no-wait flowshop scheduling problem, when the process of a specific job begins on the first machine, it should constantly be processed without waiting in the line of any machine until its processing is completed on the last one. Integration of the properties of both of these environments, which is applied in many industries such as robotic industries, is not investigated separately. First, we develop a mathematical model for the problem and then we present three methods to solve it. Therefore, we construct simulated annealing (SA), genetic algorithm (GA) and a bottleneck based heuristic (BB) algorithms that solve the problem. Finally, the efficiency of the proposed methods is numerically analyzed.