Experimental research on the performance of micro-textured CVD diamond-coated abrasive tools in longitudinal-torsional ultrasonic grinding of die steel

Abstract

Precision grinding employs the micro-cutting action of abrasive micro-edges to achieve high accuracy and low roughness in machined surfaces. However, the extremely high hardness and wear resistance of diamond abrasive grains present a significant challenge in generating micro-cutting edges on the surface through grinding wheel dressing. Therefore, diamond abrasive tools with micro-edges were prepared by the hot filament chemical vapor deposition (HFCVD) method in this paper. Firstly, the cemented carbide was pretreated, that is, Square and concentric circles micro-textures were prepared on the surface of the cemented carbide by laser technology. Secondly, the concentric circle groove micro-texture boron-doped micro-nano (CCGMT-BDMN) and square groove micro-textured boron-doped micro-nano (SGMT-BDMN) diamond abrasive tools were prepared by HFCVD. The surface morphology, quality and adhesion strength of the textured diamond films were characterized by scanning electron microscopy (SEM), Raman spectroscopy and Rockwell hardness tester. Results indicate incomplete filling of the groove textures with diamond particles, leading to sloping sidewalls at the texture edges. The coating exhibited significant residual stress, which diminished away from the texture edge. Micro-texturing with square grooves enhanced outer edge diamond quality and bond strength, resulting in superior adhesion of SGMT-BDMN abrasive tools. Longitudinal-torsional ultrasonic vibration-assisted grinding (LTUVAG) was evaluated to mitigate diffusion wear between diamond and die steel. Compared to conventional grinding (CG), LTUVAG achieves circumferential intermittent cutting, which reduces grinding forces, suppresses carbon atom diffusion wear on the abrasive tool surface, significantly minimizes adhesive wear, and extends the service life of diamond abrasive tools. Furthermore, the impact of various processing parameters on surface quality was examined. Within specific ranges, enhancing ultrasonic amplitude and grinding speed, while reducing feed speed, positively influences surface quality improvement.