Wheel Life and Cutting-Edge Wear in Mirror-Grinding Using a Coarse-Grained cBN Wheel Treated by Microdressing

This paper presents the wheel life and wear behavior of the cutting edges of a coarse-grained, microdressed cubic boron nitride (cBN) wheel used in mirror-grinding of hardened roll-steel. Many grain-cutting edges with smooth, ductile-mode cut surfaces and numerous brittle-mode-fractured micro dents are formed on the wheel’s working surface after microdressing with a fine-grained diamond dresser. Cylindrical mirror-grinding experiments are conducted using a metal-bonded cBN wheel with a mesh size of #140 (Average grain sizeda=105 μm). A mirror surface with a roughness below 0.2 μmRzcan be efficiently formed with the wheel surface treated by the abovementioned microdressing method. This wheel surface can perform mirror-grinding with precision for more than nine hours. A flat plane formed via attritious wear of the cutting edge gradually extends with increasing accumulated stock removal, and simultaneously, the unevenness due to wear streaks on this flat plane increases. This increase in the unevenness of the worn flat plane is the main factor causing an increase in the roughness of the mirror surface.

Research on Formation Mechanism of Grinding Wheel Oxide Film in ELID Ultra Precision Mirror Grinding

The characteristics, structural characteristics and composition of the grinding wheel oxide film is revealed by the theoretical analysis and simulating test in pre-dressing process of the ELID ultra precision mirror grinding, and the validity of oxide film formation mechanism analysis is verified by ELID experiments. Mirror grinding of hard brittle materials can be realized by on-line real-time control of the thickness of the oxide film.

Mirror Grinding Process Parameter Selection and Design

Mirror grinding mainly depends on the precision of the machine tool, cutting and grinding amount and wheel selection and dressing. This paper mainly studies the MG1432 high-precision universal cylindrical grinder, exploring the impact on the workpiece roughness through selection and design of various process parameters in grinding, such as changing work table speed in dressing the grinding wheel and grinding, workpiece linear velocity and excessive feeding. The experimental conditions were: Using resin binder white corundum graphite grinding wheels, workpiece: GCr15 (HRC60); dressing tool: sharp single particle diamond correction pen, and ultimately achieving mirror grinding process results.