Clarification of the Mechanism of Pulse Laser Grinding of Nanosecond Lasers Using High-Speed Camera Imaging
Clarification of the Mechanism of Pulse Laser Grinding of Nanosecond Lasers Using High-Speed Camera Imaging
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DOI：
10.3390/machines10030196
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发表时间：
2022-03
期刊：
影响因子：
2.6
通讯作者：
Xiaoxu Liu;Xianlong Ni;O. Konda;Hiroko Furuhashi;S. Maegawa;F. Itoigawa
中科院分区：
文献类型：
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作者：
Xiaoxu Liu;Xianlong Ni;O. Konda;Hiroko Furuhashi;S. Maegawa;F. Itoigawa
脉冲激光磨削（PLG）作为一种刀具加工方法，不仅可以实现高精度的刃磨，还可以产生表面修饰。例如，通过PLG加工的多晶立方氮化硼（PCBN）工具可以显示出由于缺陷减少而增加的硬度。然而，在PLG加工下边缘形成的机制尚不清楚。在本研究中，通过使用高速摄像机观察加工过程中产生的等离子体，可视化了PLG过程中每个激光脉冲的基本过程。等离子体发光先后经历了多点发光、均匀发光、发心向下运动和微弱发光四个阶段。通过对比三种不同激光脉冲间距（0.2、2和20 μm）的结果，发现脉冲间距对PLG的加工方式有显著影响。当脉冲节距过小时，侧壁效应容易导致局部多余加工。较大的脉冲间距导致被加工表面不能被激光照射完全覆盖，因此最好随后去除减小阈值。因此，中等脉冲螺距条件下的加工表面优于其他条件。
Pulse laser grinding (PLG), as a cutting tool processing method, can not only achieve edge sharpening with high precision, but it can also produce surface modification. For example, polycrystalline cubic boron nitride (PCBN) tools processed by PLG can show increased hardness due to the reduction in defects. However, the mechanism of edge formation under PLG processing remains unclear. In this study, by observing the plasma generated during processing using a high-speed camera, the elementary process for each laser pulse of the PLG process was visualized. The plasma luminescence moved successively through four stages: multipoint luminescence, uniform luminescence, the downward movement of the luminous center, and faint luminescence. By comparing the results of three different laser pulse pitches (0.2, 2, and 20 μm), it was found that the pulse pitch had a significant influence on the PLG processing mode. When the pulse pitch was too small, the sidewall effect was likely to lead to local excess machining. The large pulse pitch resulted in processed surfaces that could not be fully covered by laser irradiation, and it was preferred to remove the decrease threshold subsequently. Thus, the moderate pulse pitch condition showed a superior processed surface compared to the others.