超硬微结构表面模具的精密磨削加工技术

Investigation of Precision Grinding Process on Superhard Molds with Microstructured Surface

针对超硬模具材料,研究磨削方式(顺磨和逆磨)、进给率和主轴转速等磨削参数对磨削后微结构表面的表面粗糙度和尖锐部分完整性的影响规律。基于磨削结果,对微结构表面质量不均一现象以及微结构表面磨削过程中的砂轮磨损分布进行研究。试验结果表明磨削后的微结构侧表面粗糙度小于底面粗糙度。采用逆磨可以获得更低的粗糙度和更加完整、锋利的尖锐部分。磨削后的表面粗糙度随着进给率的降低而减小,当进给率为0.2 mm.min–1时,微结构底面平均表面粗糙度Ra89 nm,侧面为Ra 60 nm。磨削后,尖锐部分圆弧半径随进给率的降低呈现减小趋势,当进给率为0.5 mm.min–1时,其平均圆弧半径最小,为0.67μm。主轴转速对表面粗糙度和尖锐部分圆弧半径的影响不大。由阶梯光栅表面结构性引起的,相对于其各个表面的磨削轨迹不相同,是导致磨削后阶梯光栅表面质量不均一现象主要原因。在微结构表面的磨削加工过程中,相对于砂轮的径向和轴向磨损,砂轮的形貌磨损更为严重。

The primary objective is to find the influence factors on inhomogeneous surface quality,and to optimize machining parameters（such as grinding mode,feed rate and spindle speed） to generate good microstructures surface and sharp edges in the precision grinding on superhard microstructured molds.The experiment results show that the better surface quality and sharper edges are obtained by using up-cut grinding mode.Reducing the tool feed rate do necessarily help to improve the surface roughness and edges of structures.The smallest average Ra values of 60 nm（side） and 89 nm（bottom） are obtained by feed rate of 0.2 mm？ min–1.The smallest average radius 0.67 μm of edge values is obtained by feed rate of 0.5 mm？min–1.Compare with feed rate,the influences of spindle speed on the surface quality and edges are not significant.The surface roughness of side surface is always smaller than that of bottom surface.The variety of grinding tracks due to surface＇s microstructures is the main factor for inhomogeneous surface quality.In addition,the wheel wear is dominated by profile wear.