Study on the surface grain state, residual stress and their influence on the deformation of thin-walled parts under ultra-precision cutting

Abstract

Thin-wall parts have the advantages of light weight and high structural strength and are widely used in industrial fields. As the increasing requirements for the form accuracy and surface quality, ultra-precision cutting has been increasingly used to manufacture thin-walled parts. However, due to the small effect range (less than 10 [Formula: see text]m) of residual stress caused by ultra-precision cutting, it cannot be accurately measured by the conventional methods. Therefore, the research on the residual stress and deformation of thin-walled parts under ultra-precision cutting are currently restricted. In this paper, we first introduced the GIXRD method to solve the technology absence for measuring the ultra-precision cutting conducted residual stress. Based on GIXRD, TEM and dynamic interferometer measurement, the relationship between grain state, residual stress and deformation of thin-walled parts was established. The research works had shown that reducing the cutting depth within a certain range was beneficial to reduce residual stress and deformation. However, there was an extreme point of the cutting parameter. If this extreme point was exceeded, the cutting action would gradually transform from shearing to pressing and pushing, resulting in an increase in residual stress. Therefore, there was an extremely small cutting parameter that minimized residual stress and deformation of the thin-walled member. The results were helpful to understand the mechanism of deformation of thin-walled parts from the perspective of grain size and residual stress, and accordingly established a deformation control method.