This paper deals with a real-life two machine scheduling problem for the side frame press shop in a truck manufacturing company. The shop consists of two machines where only the first machine, press machine, has separable, external and sequence dependent setup times. Moreover all the jobs require processing by the press machine more than once in their operation sequences with re-entrant work flows. Redefining the job elements, the problem is transformed into a general two machine flow shop problem which has a set of job-element precedence constraints. To solve the problem, an ant colony optimization (ACO) algorithm with the objective of the minimum makespan is developed. We investigate performance of the proposed ACO algorithm through the comparative study. Experiment results show that the proposed algorithm is more effective than existing method for the problem.
A FPTAS for a two-stage hybrid flow shop problem and optimal algorithms for identical jobs
