Machining performance and wear mechanism of CVD diamond-coated micro-grinding tools in micro-grinding of fused silica

Abstract

This paper investigates the fabrication and application of chemical vapor deposition (CVD) diamond-coated micro-grinding tools in machining fused silica. The study innovatively fabricated four diamond-coated micro-grinding tools (10,000#, 6000#, 3000#, 1500#) using hot filament chemical vapor deposition and explored their formation mechanism, grinding performance, as well as wear and failure mechanism. The results revealed that a larger grain size leads to a flatter film surface with prominent planar features, columnar growth characteristics, and fewer internal defects. Machining experiments revealed that the grinding quality increases with increasing feed rate and grinding depth. On the other hand, it decreases with increasing spindle speed. Nevertheless, the dominant failure mechanism of 1500# and 3000# micro-grinding tools is primarily brittle fracture. Meanwhile, 6000# micro-grinding tools are featured with both brittle fracture and ductile domain removal. Micro-grinding tools with grind size 10,000# are featured with ductile domain removal and demonstrated the best machining quality. The results showed that crack generation and extension caused by abrasive and bonded wear are the leading causes of diamond film failure in micro-grinding tools, and the larger the average grain size, the better the wear resistance. This research provides new insight into the wear mechanism of diamond-coated micro-grinding tools and contributes to developing CVD diamond-coated micro-grinding tools for precision machining hard and brittle materials.