Minimizing makespan on an mm-machine re-entrant flowshop

This paper focuses on an mm-machine re-entrant flowshop scheduling problem with the objective of minimizing makespan. In the re-entrant flowshop considered here, routes of all jobs are identical as in ordinary flowshops, but the jobs must be processed multiple times on the machines. We present heuristic algorithms, which are modified from well-known existing algorithms for the general mm-machine flowshop problem or newly developed in this research. For evaluation of the performance of the algorithms, computational experiments are performed on randomly generated test problems and results are reported.