A case study of a hybrid flow shop with no-wait and limited idle time to minimize material waste

This paper deals with a new configuration of scheduling problem inspired from a real industrial case which is pasta production. It could be defined as maximal-idle time (limited idle time) and no-wait hybrid flow shop with dedicated machines. Machines on the first stage have a limited idle time interval constraint. To the best of our knowledge, this is the first paper to study constraint of maximal idle time simultaneously with machine set-up for hybrid flow shop problems. The objective is to minimize waste of materials due to machine idle time exceeding α unit. Two mixed integer linear programming models (MIP) with two different objectives are proposed. Using numerical experiments, we compare the results of the first MIP according to makespan minimization and waste minimization.