Optimization of Sole Production Scheduling

Mathematics In Industry Reports, (2024),
10.33774/miir-2024-zhmg5

This report addresses a challenge proposed at the 174th European Study Group in Industry to develop an algorithm to optimize processes on rubber soles manufacturing. The objective is to create an order distribution plan that maximizes efficiency, reduces setup times synchronizing molds changing, ensuring that delivery dates are met. This problem can be classified as a parallel machines scheduling problem with sequence dependent setup times. This work presents an heuristic that minimizes the makespan, accounting for the sequence dependent setup times, divided into two steps: (i) a client’s order will be partitioned into sets corresponding to the assigned slots; (ii) reorder the molds within each position of the press, so that setup times are simultaneous. We find solutions for real data, for cases with double and triple molds for a given size. Results show that synchronization of setup times due to heating and mold changes decrease significantly the makespan.