结构化砂轮磨削蓝宝石微沟槽底面质量的研究

Research on Quality of Bottom Surface of Sapphire Micro-grooves Ground by Structured Grinding Wheels

针对蓝宝石这类超硬材料表面微结构难加工的问题,提出一种基于结构化砂轮的磨削表面微结构方法.采用电火花线切割(Wire Electrical Discharge Machining,WEDM)技术对砂轮表面进行结构化修整,利用修整后的结构化砂轮磨削蓝宝石表面微结构,研究顺磨和逆磨方式下,结构化砂轮磨削速度、磨削深度和进给速度对蓝宝石微沟槽底部表面粗糙度的影响规律.研究结果表明,结构化砂轮磨削蓝宝石表面微沟槽形貌基本完整,且相对120µm的加工深度,尺寸误差仅为1.4µm,微沟槽的垂直度较好,垂直度偏差仅为4.9°;顺、逆磨方式下,随着磨削速度增大,磨削深度和进给速度减小,都可以减小蓝宝石微沟槽底部表面粗糙度;相较于逆磨方式,顺磨方式下微沟槽底面微坑较小,底面质量更优;在较优加工参数砂轮磨削速度35m/s、磨削深度1µm、工件进给速度200mm/min下,表面粗糙度从4.487µm降低至2.923µm.

Aiming at the problem of difficult machining of micro-structured surfaces of super-hard materials such as sapphire,a microstructure technology for grinding surfaces based on structured grinding wheels is proposed.In this paper,the surface of the grinding wheel is structured through Wire Electrical Discharge Machining(WEDM)technology,and the structurally dressed wheel was utilized to grind the microstructure of the sapphire surface.The influence law of structured wheel grinding speed,grinding depth,and feed rate on the surface roughness at the bottom of sapphire microgrooves in both down and up grinding modes was carried out.The results show that the microgroove morphology of the sapphire surface ground by the structured wheel is basically complete,the dimensional error is only 1.4µm relative to the cutting depth of 120µm,and the perpendicularity of the microgrooves is better,with a perpendicularity deviation of only 4.9°;The surface roughness at the bottom of the sapphire microgroove can be reduced by increasing the grinding speed and decreasing the grinding depth and feed rate in both down and up grinding modes;Compared with the up-grinding method,the micro-pits on the bottom surface of the micro-groove are smaller,and the bottom surface quality is better in the down-grinding method.The bottom surface roughness is reduced from 4.487µm to 2.923µm under the better machining parameters of grinding speed of 35 m/s,grinding depth of 1µm,and workpiece feed speed of 200 mm/min.