Intermittent turning performance of ceramic tools with surface micro-geometry designed considering fluid-like behavior of chip

This work was performed to study the intermittent turning performance of ceramic tools with surface micro-geometry designed considering fluid-like behavior of chip. Quantitative analysis of the fluid-like behavior of chip was conducted for different cutting length ratios. Ceramic tools with different patterns of miro-textures on the rake face were designed on the basis of the fluid-like behavior of the chip and the skins of dung beetle and shark. An assessment indicator of tool performance was proposed covering external loads and tool microscopic mechanical property. The optimum pattern of miro-texture was distinguished based on the tool performance indicator. Tool lives obtained from turning tests and the values of indicator acquired at varying combinations of miro-texture pattern and cutting length ratio were compared to validate the assessment indicator of tool performance and the design method of tool surface micro-geometry. It was found that the similarity between chip and Newtonian fluid decreased as the chip flowed across tool rake face or the intermittence in turning process became higher. Assessment indicator of tool performance was put forward as the ratio of tool material fracture toughness to the maximum stress intensity factor on the cutting tool. Larger value of the indicator indicated better tool performance. Miro-texture pattern designed with the fluid-like behaviors of different chip zones considered was most efficient in enhancing the tool performance indicator. Experimental results of tool lives demonstrated the correctness of the assessment indicator of tool performance and the effectiveness of the design method of tool surface micro-geometry.