Study on improving the surface integrity and wear resistance of CVD α-Al2O3 coated tool by a combined blasting process

The surface integrity of coated tools plays a critical role in determining their wear resistance and service life during machining. To improve surface integrity and enhance wear resistance, this study adopts a novel composite post-treatment process that integrates wet sandblasting (WB) and low-angle rotary micro-blasting (LRM) for chemical vapor deposition (CVD) coatings. Three post-treatment methods applied to CVD-TiN/TiCN/TiN/α-Al₂O₃/TiN composite-coated tools are compared: (1) WB combined with LRM, (2) WB combined with sprayed abrasives polishing (SAP), and (3) conventional WB. Key evaluation parameters include surface morphology, cutting edge morphology, surface roughness, edge roughness, phase structure, coating thickness, cutting edge radius, shape factor (K value), wear characteristics, tool life, and machining performance. The results demonstrate that the WB and LRM composite process offers superior performance. It produced the lowest surface roughness values:158.8 nm on the rake face, 133.4 nm on the flank face, and 176 nm at the cutting edge. In cutting tests, the WB and LRM-treated tools exhibited a tool life of 6.5 min, comparable to that of the WB and SAP method, and representing an 18.18 % improvement over conventional WB. Among the three techniques, WB and LRM consistently produced the smoothest surfaces, with an average surface roughness of 769.4 nm maintained over the entire cutting lifespan. This method not only results in enhanced surface smoothness and wear resistance but also ensures optimal machined surface quality, while preserving the cutting edge radius, K value, and coating thickness across the rake face, flank face, and cutting edge, at levels comparable to the other post-treatment methods.