A hierarchical mathematical modelling approach for production scheduling in ring spinning operations

Globalized world markets, highly automated production technologies and increasing capital investment costs have made it impossible to compete solely on low labor costs. In this study, a new scheduling approach has been developed for the spinnig operation, which is the most critical bottleneck stage in yarn production. The investigated scheduling problem considers sequence-dependent setup times and machine-dependent operation times to meet the due dates of the orders. Due to computational complexity of the problem, the overall problem is divided into three interrelated hierarchical stages. The first stage is devoted to the selection of the orders that would be scheduled for the current period (usually a month) under due date and capacity constraints. Assignment of the selected orders into the spinning machine groups is carried out at the second stage. Finally, the last stage schedules the orders within each spinning machine group independently. Key Words : Production Scheduling, Mathematical Programming, Yarn Production II