Estudo da minimização do custo de usinagem de aço duro usando a metodologia de superfície de resposta

Abstract

This paper presents a study about the utilization of Response Surface Methodology (RSM) in costs stochastic modeling by a turning process of a hardned steel SAE/ABNT 52100. In function of the random nature of the tool life (T) and the superficial finishing quality, could be established mathematical models for this functions since a planed experiment. Thus, taking full quadratic models for the tool life (T) and the surface roughness (Ra), written in terms of the cutting speed, feed rate and depth of cut, it can get a similar model for the process cost. The minimization of this non-linear objective function is implemented by the GRG algorithm, taking into account spherical and finishing constraints. Considering the influence of the finishing constraint over the obtained minimum, successive variations in the bounds of constraints are made what allows the gradual relaxing of the nonlinear constraint and its influence over the cost behavior. The results show that the minimization of cost function is achieved with the adoption of higher levels of cutting speed, for a band of superficial finishing constraints variation between 0,3 and 0,65 μm, beyond to provide a great material removing rate.