WEAR AND SELF-SHARPENING OF VITRIFIED BOND DIAMOND WHEELS DURING SAPPHIRE GRINDING

Vitrified bond diamond wheels were tested during grinding of single cr ystal sapphire on a precision CNC grinding platform. Self-sharpening, evidenced by the occurrence of cyclic behavior in the machine deflecti on (grinding force), was observed for wheels made with one bond/ diamo nd composition. These wheels could remove large volumes of sapphire wi thout re-dressing. The self-sharpening effect was reproducible but sho wed considerable variability in terms of the detailed cycle shape. Whe el failure eventually occurred due to a loss of the self-sharpening ac tion (overloading) or stall-out of the spindle. Process conditions pro ducing increased wheel wear enhanced the self-sharpening action. (C) 1 998 Elsevier Science S.A. All rights reserved.