A priori reformulations for joint rolling-horizon scheduling of materials processing and lot-sizing problem

In a previous paper (Araujo et al. 2007), the authors proposed a lot sizing and sequencing model for a production process where a key material is prepared and then transformed into different final items. The lot sizing decisions concern not only the production of final items, but also that of the prepared material in order to take account of their sequence-dependent setup costs and times. The number of articles published in recent years shows the relevance of this problem in various industrial settings. In this paper, facility location reformulation and strengthening contraints are newly applied to improve the quality and computing time of the solution. Three alternative metaheuristics are used to fix the setup variables, resulting in much improved performance over previous research, especially regarding the use of the metaheuristics for larger instances.