Microgrinding of Ceramic Materials.

Abstract

Ceramic micro-components are becoming increasingly important in various industrial fields, as they not only allow manufacturers to reduce product size, but also provide many attractive properties, such as good chemical stability, high hardness and strength. Featured with high machining flexibility, miniature tool-based microgrinding is a new technology to manufacture ceramic micro-components, but it lacks comparable knowledge-based research that can be drawn on to optimize the process. This research addresses this barrier through conducting fundamental studies in ceramic microgrinding in the grinding force prediction, surface generation modeling and tool wear mechanism study. Grinding force prediction is important for improving the dimensional accuracy in microgrinding of ceramic materials. Based on cohesive zone finite element analysis, this study investigates grinding force modeling and prediction in ceramic microgrinding by modeling the actual chip generation process. The chip generation is explicitly simulated based on actual diamond cutting edge profile. It was observed that the tool stiffness has a significant influence on the grinding force prediction. In grinding of ceramic materials, surface texture is generated by both ductile material flow and surface chipping. By considering these two mechanisms, this study proposes a surface generation model for microgrinding of ceramic materials. It was observed that the predicted surface roughness matches well with the experiment results. At high feed rates and depths of cut, the vibration effect could result in more prediction error. To understand the influence of tool wear in microgrinding of ceramic materials, individual diamonds on a microgrinding tool were tracked for their detail wear process. It was observed that their wear mechanisms have specific influences on the surface generation, and attrition wear is dominant when the grinding process is stable. By applying water based coolant, the microgrinding tool wear can be reduced. It was also observed that the process signals in microgrinding are influence by both tool wear and tool deflection due to the low tool stiffness.