Huang Weiqing, Huang Kaijie, Zhong Qunyou, Wu Jialun, An Dawei
School of Mechanical and Electrical Engineering, Guangzhou University, Guangzhou 510006, China.
Micromachines (Basel). 2025 Mar 30;16(4):408. doi: 10.3390/mi16040408.
Due to the high hardness and brittleness of sapphire, traditional machining methods are prone to surface scratches and microcracks. As an advanced processing technique, ultrasonic machining can reduce damage to hard-brittle materials and improve surface quality. In this study, an integrated ultrasonic longitudinal-torsional vibration system consisting of both a horn and a tool was designed. The resonant frequency and output amplitude of the horn were simulated and tested. The results indicated that the resonant frequency was 19.857 kHz, the longitudinal amplitude at the tool end was 4.2 µm, and the torsional amplitude was 1.8 µm. Experiments were then carried out to investigate the effects of various machining parameters on the reduction of sapphire surface roughness (Ra) and material removal rate (MRR). A comparative experiment was then conducted to evaluate the effects of ultrasonic longitudinal and longitudinal-torsional vibration on sapphire grinding. The ultrasonic longitudinal-torsional grinding experiments showed that the surface roughness of the sapphire workpiece was reduced from 960.6 nm to 82.6 nm, and the surface flatness was improved to 84.3 nm. Compared with longitudinal ultrasonic vibration, longitudinal torsional grinding reduced the surface roughness of sapphire workpieces by 48% and increased the surface flatness by 88.3%. The results of this study provide specific guidance for the longitudinal-torsional composite ultrasonic machining of hard-brittle materials.
由于蓝宝石具有高硬度和脆性，传统加工方法容易产生表面划痕和微裂纹。作为一种先进的加工技术，超声加工可以减少对硬脆材料的损伤并提高表面质量。在本研究中，设计了一种由变幅杆和工具组成的集成超声纵扭振动系统。对变幅杆的共振频率和输出振幅进行了模拟和测试。结果表明，共振频率为19.857kHz，工具端的纵向振幅为4.2μm，扭转振幅为1.8μm。然后进行实验，研究各种加工参数对降低蓝宝石表面粗糙度（Ra）和材料去除率（MRR）的影响。随后进行了对比实验，以评估超声纵向振动和纵扭振动对蓝宝石磨削的影响。超声纵扭磨削实验表明，蓝宝石工件的表面粗糙度从960.6nm降低到82.6nm，表面平整度提高到84.3nm。与纵向超声振动相比，纵扭磨削使蓝宝石工件的表面粗糙度降低了48%，表面平整度提高了88.3%。本研究结果为硬脆材料的纵扭复合超声加工提供了具体指导。
