Microgroove grinding of monocrystalline diamond using medium-frequency vibration-assisted grinding with self-sensing grinding force technique

This study presents an approach to extra-hard material removal using “medium-frequency vibration-assisted grinding with self-sensing grinding force” for producing a microgroove array on monocrystalline diamond (MCD). Vibration mode at nano-amplitude is employed to vibrate the MCD workpiece against the polycrystalline composite diamond (PCD) wheel-tool during grinding. This approach is used to break the covalent atomic bonds of diamond, creating a “nanocracked subsurface layer” thereby reducing grinding resistance during material removal. The PZT stage's grinding system is designed with a low center of gravity, bilateral symmetry, and an in-situ co-shaft grinding devise. This setup provides a well-defined nanoscale depth of grinding. Expentmental results show that a highly consistent, smooth crisscross microgroove array can be successfully produced on MCD with no apparent burrs and chipping. It is confirmed that “medium-frequency vibration-assisted grinding with self-sensing grinding force” remarkably reduces grinding resistance and improves the surface finish on a MCD workpiece. In addition, these experiements prove that diamond's innate charateristic of “thin-brittle resistance” self-generates a “nanocrack growth resistance boundary” stopping further crack expansion. Using a “self-sensing grinding force” design allows the system to determine whether the “nanocracked subsurface layer” has been completely removed. This ensures high quality grinding, which produces a flat, solid microgroove surface on MCD. Furthermore, detailed discussions are conducted for the following aspects: effects of dressing using spark erosion, influences of amplitude and grinding mode, geometry and topography of microgrooves, PCD wheel tool wear, and an assesment criterion for available nasal-tip radius.