A decision support system for aggregate production planning based on MILP: A case study from the automotive industry

The aggregate production planning (APP) problem is concerned with determining the optimum production, work force, and inventory levels for each period of the planning horizon. The aggregate production planning problem is a multiple objective one; that involves many functional areas to create. This paper addresses an implementation of a Decision Support System that supports an aggregate production planning problem. The case study covers a real engine assembler serving from their local premises to clients all over the world, with variable demands and calendars. The core of the global tool is a set of MILP model which calculates working calendars for six different sections of a factory, taking into account production rates defined by the company, its internal and external suppliers working calendars and the union requirements. Moreover, the real system had requirements that are not usually considered on APP literature. The model has been designed and calibrated in a prototype-validation iterative process and has been optimized to calculate scenarios with an acceptable computational time within planners' expectative. The system has been developed using free-software and its interfaces have been designed to require the minimum possible interaction from users. The time cost due to the use of non-commercial software has been assessed.