Heuristic approaches to solve a two-stage lot sizing and scheduling problem

This paper addresses the two-stage lot sizing and scheduling problem considering the production environment with parallel machines. The aim of this problem is to ensure the synchrony between the stages through of the integrated lot sizing and scheduling decisions. In addition, we consider the presence of a buffer between the production stages with minimum and maximum time lags of the items. Reprocessing, discarding and acceleration costs are considered when the permanence times of the items in the buffer are not respected. Two mathematical models and several heuristics strategies based on decomposition of the problem are presented to solve real data adapted instances. The results showed that our heuristic strategies can achieve competitive solutions in short computational time, outperforming the solutions provided by the optimization solver.