Effects of tool diameters on the residual stress and distortion induced by milling of thin-walled part

摘要

Residual stress has a sustained impact on the deformation of thin-walled parts after processing, raising the strict restrictions required in their using procedure. In general, with regard to thin-walled parts, different processing parameters will affect the distortion and residual stress generation of the workpiece, which play the key role in the machining. However, controlling the material removal rate is also quite critical to machining of thin-walled parts. In order to reach these goals, based on the relation between residual stress and uncut chip thickness (UCT), a method is proposed by optimizing the milling tool diameters. The research finding reveals that, by improving the tool diameter, at the same circular position, smaller UCT can be achieved. In addition, take 6 and 12 mm tool diameter as analysis cases; larger tool diameter can reduce the residual tensile stress distribution significantly (the ratio ranges from 13.9 to 34.7%) and improve the material removal rate. Moreover, a typical thin-walled part is evaluated using different tool diameters (6 and 12 mm) by experiments, as the final distortion can be decreased by 60% with 12-mm tool diameter. The distribution of machined surface and subsurface residual stress is turning to be more uniform. Hence, it proves that, under the goals of maintaining machining accuracy and material removal rate, also improving the distribution of residual stress, it is possible to achieve by controlling the UCT (tool diameters) in the processing of thin-walled. All these findings can help to enhance the milling precision of thin-walled parts, as well as control and optimize the residual stress distribution.