Planejamento da aquisição de materiais para manutenção preventiva de vagões de carga geral

Abstract

This work presents a tool for optimizating the inventory used for preventive maintenance of general cargo freight cars. This approach has two objective functions: the first one is focused on minimizing the purchase cost of materials, and the second one is to minimize the risk cost of stopping freight cars due to material shortages. The objective of this tool is to aim cost reduction with inventory at the same time that freight cars stop risk is controlled. These two objectives define a trade-off, which must be analyzed in the choice of a solution based on how much risk one wants to assume to reduce the inventory costs. A list of all materials to be purchased in each period of the maintenance cycle is presented for each Pareto-optimal solution. It makes possible to identify which materials are being prioritized in each solution. A real data set from a transport railway company, focusing on the maintenance cycle of general cargo freight cars over a one year period, was used to test the tool. Another test performed was the comparison between the solutions generated through the scrapping rates calculated forthe previous cycle (2017) and the results achieved using the real scrapping rates of the 2018 cycle. This analysis allowed to estimate the risk gap between predicted and ideal solutions, which made possible to indicate points of improvement in the processes of the company in question.