Surface integrity under diamond tool wear effects in ultra-precision raster milling of a Zn–Al–Cu alloy

Abstract

In ultra-precision raster milling, the material removal process determines surface integrity. In this study, surface integrity was discussed under diamond tool wear effects in ultra-precision raster milling of a Zn–Al–Cu alloy. The results firstly showed that under high speed cutting in ultra-precision raster milling, quenching took place with phase decomposition (namely twin phase changes) with a deformation thickness of even less than 100 nm. Flank wear enhanced phase changes, promoted surface hardening, degraded surface quality, and increased deformation thickness, but crater wear gave better surface integrity. The intrinsic reason is that flank wear caused more external stress but crater wear was reverse, well supported by finite element simulation in orthogonal cutting. Significantly, it provides a further insight into diamond tool wear effects on surface integrity in ultra-precision raster milling of a Zn–Al–Cu alloy.