Modelo térmico para a solução de problemas inversos em transferência de calor com aplicação em um processo de usinagem por torneamento

Abstract

This work proposes the determination of the high temperatures generated, during machining, in the region of the tool cutting edge. These temperatures have a controlling influence on the rate of wear of the cutting tool and on the friction between the chip and the tool. However, direct measurement of temperature using contact type sensors at the tool-work interface is difficult to implement due to the movement of the workpiece and the presence of the chip. In these sense, these work proposes the development of a computational code to solve numerically the three-dimensional thermal transient equation using finite volumes technique, irregular and co-located mesh. For the solution of the inverse problem were tested the following inverse techniques: Golden Section, Simulated Annealing, Function Specification and Dynamic Observers based on Green´s Function. The software is validated by controlled experiments and qualitative analyses. Several tests were realized and some improvements were implemented in the algorithm with the objective of guaranteeing the energy conservation during the thermal analysis of complex geometries. This work applies the software called INV3D to determine the thermal fields during machining of free cutting steel with high speed steel tool. It is also presented the influence of the parameters of cut - feed rate, depth of cut, cutting speed - in the temperature of the chip-tool interface. It is pointed out that the temperatures for each cutting condition are compared to the tool-work thermocouple technique. Finally, an error analysis of the results is presented.