基于预制孔的SiCf/SiC复合材料微小孔超声振动辅助钻削加工研究

Research on Micro-hole Drilling of SiC_f/SiC CMCs Via Ultrasonic Vibration Based on Prefabricated Holes

SiCf/SiC复合材料是典型的硬脆性难加工材料。为解决SiCf/SiC复合材料微小孔(<1 mm)加工难题,提高加工精度和改善加工质量,先采用脉冲激光预制SiCf/SiC微小孔,再在不同预制孔尺寸和加工参数下开展直径0.5 mm的SiCf/SiC微小孔超声振动辅助钻削加工试验,最终确定了合适的激光预制孔尺寸及超声振动辅助钻削加工参数域。结果表明:脉冲激光预制孔时存在的较大热影响区和微裂纹等缺陷,会明显影响后续超声辅助钻削微小孔的入、出口质量,推荐的预制孔直径为0.3 mm;超声振动辅助钻削加工时,选择主轴转速为11000~15000 r/min、进给速度为2~10mm/min,可获得加工质量较好的SiCf/SiC微小孔。

SiC_f/SiC ceramic matrix composites are typical hard and brittle difficult-to-machine materials.To solve the problems of machining micro-holes(<1 mm)in SiC_f/SiC ceramic matrix composites,improve the machining accuracy and quality,pulse laser is first used to prefabricate SiC_f/SiC micro-holes,and then ultrasonic vibration assisted drilling experiments ofΦ0.5 mm micro-holes in SiC_f/SiC ceramic matrix composites are carried out under different prefabricated hole sizes and machining parameters to determine the appropriate laser prefabricated hole size and ultrasonic vibration assisted drilling parameter domain.The results show that the defects such as large heat-affected zone and micro-cracks in pulse laser processing of prefabricated holes can significantly affect the quality of the inlet and outlet of micro-holes drilled by the subsequent ultrasonic-assisted drilling,the prefabricated hole size is recommended to beΦ0.3 mm.When using ultrasonic vibration assisted drilling,selecting a spindle speed of 11000~15000 r/min and a feed rate of 2~10 mm/min can obtain SiC_f/SiC ceramic matrix composites micro-holes with good machining quality.