Gestão de estoques de produtos siderúrgicos semi-acabados utilizando uma abordagem híbrida de otimização e simulação

Abstract

The inventory management is a vital subject witch frequently absorbs substantial part of the budget of an organization. As they do not add value to the product, as less inventories a productive system use more efficient it will be. However the current competitive environment, with the strong presence of global payers, forces the operational costs reduction, represented her for the inventories, and the development of attract mechanisms and defense or increasing of market-share. On this context eminent trend is get in touch with supply requirements of the customers and develop manufacturing strategies to fill these necessities with the less possible operational cost. The concept witch drives this project is that strategically placed inventories of the right semi- finished products in the right quantities and mix can e used to achieve shorter, reliable deliveries while at the same time preserving production efficiencies, witch is crucial for the capital intensive industries such as steelmaking. The concept of OPP order penetration point and its variations is widely discussed through the evaluation of its importance and the various factors that influence on its positioning. The few practical application of these concepts in the steel industry nowadays is analyzed in comparison with the models already developed. This paper proposes three different manufacturing approaches to three customers. These approaches complies the position of semi-finished inventories for two customers and maintain a pure Make-to-order system for one. We also develop a mixed optimization-simulation model to evaluate the performance of this proposal in the management of semi-finished stocks. The model consist of two simulation modules and optimization module. The simulation modules are responsible for demand generation and shop-floor simulation. The optimization module works as a lot sizing witch solve the production plan for the first equipment on the production flow. Several operational parameters (utilization level, reserve capacity) and demand patterns are changed to create several different scenarios for analysis