Residual compressive stress prediction determined by cutting-edge radius and feed rate during milling of thin-walled parts

Abstract

Abstract

Residual compressive stress can effectively improve fatigue the life of aerospace thin-walled parts. In this study, residual compressive stress control is taken as the target. Firstly, a surface residual stress prediction model is proposed, which considers both machining parameters and milling force heat. The model of the relationship between milling force, thermal load, and residual stress is established, which quantifies the effects of mechanical and thermal loads on the formation of residual compressive stresses. The results show that the feed rate of each tooth and the cutting-edge radius play an important role in the residual compressive stress of the milling surface. The prediction models of surface residual stress for thermal load, mechanical load, feed per tooth, and radius are established. Secondly, the ratio α of the feed rate per tooth f_z to the cutting-edge radius r is quantified. When α_xx = 0.42–0.65 and α_yy = 0.36–0.7, the surface residual compressive stress in the x and y directions of the workpiece reaches the maximum value. Thus, the ratio of the feed rate per tooth f_z to the cutting-edge radius r is optimized to control the mechanical and thermal load quantization. It realizes active control of residual compressive stress on the workpiece surface.