A tire production scheduling system for Solideal

A TIRE PRODUCTION SCHEDULING SYSTEM FOR SOLIDEAL Zeger Degraeve Raf Jans Solideal is an international industrial tire manufacturer. The tires are built in molds and are produced in heaters in large series production runs. Some tires can be cured in two different types of heaters. Preparing a heater for a specific tire type requires a set up which typically only takes place during the morning shift. Therefore, the company employs to a discrete production policy. The resulting scheduling problem is a capacitated, multi-item lot sizing problem with set up times and multiple non-identical alternative machines. The objective is the minimization of the total costs for set up, backlog and inventory. Management opted for a fast algorithm that could produce various alternative high quality solutions. The problem is solved using a column generation scheme where the master is solved approximately using Lagrange relaxation. During the column generation process, various heuristic integer solutions are created from which the schedulers can then choose one to implement. We present computational results on real life data with up to 30 products and 30 periods.