Abstract
With the increasing demand for customization, flow shop scheduling tends
to process multi-variety small batch products. Thus, there are frequent
switches between batches. Frequent switchovers between different sets
are required during batch changeover, where machine setups may be
necessary. This paper investigates scheduling optimization and
work-in-process inventory optimization problems in a hybrid flow shop
with rolling processing requirements. Developing continuous processing
conditions to meet rolling processing requirements presents a
significant challenge. In this work, continuous processing conditions
are derived. Subsequently, a linear programming model is designed to
find an optimal solution for this scheduling problem. Formulas for
calculating work-in-process inventory are presented. To enhance
work-in-process storage, a greedy algorithm with bubble sort and a
Q-learning algorithm with a modified ε-policy are proposed to
find an optimized product sequence and reduce work-in-process inventory,
respectively. Numerical experiments evaluate the effectiveness and
efficiency of the proposed methods.