Balanceamento da linha final de carroceria de uma fábrica de veículos utilitários com o uso de programação linear inteira mista e validação através de simulação

Abstract

The proposal of this project is to accomplish the best balance possible of the metal line of the body-shop sector at an automobile industry in the metropolitan area of Curitiba. In this factory are made three car models, and each one of them has its varieties some of them take longer than others to produce. For this work it was considered five varieties, three of them being vans, one is a pick-up and the last one is a hatch. The reason for choosing the metal line is that this part of the body-shop is the bottleneck of this sector and there are some difficulties for adapting and performance problems. These issues usually happen when a rise of the productive capacity, or a change in the mix of products, or a reduction in the number of operators or even the inclusion of some tasks are needed. Aware of that the main goal of the project was set as finding a tool that indicates the best settings for the metal line depending on the situation. The costs of the production losses caused by unbalanced line justify this project. After studying the process and analyzing the documents of the metal line was possible to make a precedence graph for the tasks and create a mathematical model using Mixed Integer Linear Programming with the software GAMS. This model simplifies the metal line characteristics, with restrictions for balancing. The results obtained after the resolution of the mathematical model were tested and validated using the software Witness, a simulation program. After the analysis of the results was possible to notice that there is a big gain in the metal line productivity with the line balanced. Besides that, it is important to highlight that the mix also influences in the productivity. The validation of the mathematical models by using simulation models was confirmed, but only for the condition of having always a car available in the entrance of the metal line. Because otherwise the metal line can stop being the bottleneck of the body-shop sector. This condition can be assured by building a buffer in the beginning of the metal line or with a greater production capacity from the lines that provide the cars to the metal line. This way the goals that were set at the beginning of the project were accomplished.