超快激光旋光钻孔孔径和锥度的控制  

Controlling of Diameter and Taper in Ultrafast Laser Helical Drilling

作　　者：阿占文 陈灵灵 吴影 杜荣葆 白海林[1] 邹贵生[1] A Zhanwen;Chen Lingling;Wu Ying;Du Rongbao;Bai Hailin;Zou Guisheng(Department of Mechanical Engineering,Tsinghua University,Beijing 100084,China;School of Mechanical Engineering,Qinghai University,Xining,Qinghai 810016,China)

机构地区：[1]清华大学机械工程系,北京100084 [2]青海大学机械工程学院,青海西宁810016

出　　处：《中国激光》2021年第8期188-195,共8页Chinese Journal of Lasers

基　　金：国家重点研发计划(2017YFB1104900);国家自然科学基金(51775299,52075287);国家自然科学基金国际(地区)合作与交流项目(51520105007)。

摘　　要：孔径和锥度的控制是超快激光微孔加工面临的难点之一,旋光钻孔是控制孔径和锥度的有效手段。因此,针对道威棱镜旋光钻孔系统,首先,从几何光学的角度研究了聚焦后激光出射角度和光斑旋转直径与可平移反射镜位置、楔形棱镜旋转角之间的关系。然后,利用CCD相机分别测量实际光斑在焦平面、焦平面上下±250μm处的旋转直径,并在厚度为0.5 mm的黄铜板上进行钻孔实验,得到深径比为6∶1、锥度为-2.6°~2.3°的微孔。对比实验得到的微孔出入口直径与CCD相机的测量结果,得到孔径、锥度与光束旋转角之间的关系。结果表明,孔径主要由楔形棱镜旋转角决定,调整可平移反射镜的位置可得到不同锥度的微孔;激光能量的变化会影响材料的去除,因此,焦点位置、激光平均功率以及光斑重叠率也会在小范围内影响孔径和锥度。Objective Taper-free or negative conical micro-holes with a diameter of tens to few hundreds of microns are of great interest in a variety of industries.Conventional methods,such as electro-discharge drilling,mechanical drilling,electrochemical drilling,and continuous or pulsed laser drilling,have their limitations,including poor accuracy,low efficiency,as well as they are incapable of drilling in non-conductive materials,such as glass.Although ultrafast laser is believed to be a reliable tool for drilling processes due to its unique characteristics,the control of the diameter and taper of micro-holes is one of the greatest challenges encountered in the process.At present,the diameter and taper of micro-holes can be controlled using a 5-axis Galvano scanner,but the equipment is expensive,and a complex drilling strategy is required.Ultrafast laser helical drilling technology is an effective and simple way to adjust the taper and diameter of micro-holes since the laser spot is rotated at a high speed,and the roundness of the holes can be improved in the meantime.However,the taper and diameter are affected by several factors in helical drilling,and these factors vary with material,aspect ratio,laser characteristics,and drilling strategy.Hence,it is important and necessary to investigate the relationship between the diameter,taper,and beam rotation of micro-holes and to show the control mechanism of the diameter and taper in ultrafast laser helical drilling.Methods With the ultrafast laser focused in the middle of a 0.5 mm thick copper plate,various micro-holes with different diameters and taper are drilled by adjusting the angle of the focused beam and rotation diameter of the laser spot.Then the rotation diameter of the laser spot at a focal plane,±250μm above and below the focal plane,is in situ monitored by a CCD.The diameters of the micro-holes in the entrance and exit are compared with the CCD measurement results at±250μm above and below the focal plane,respectively.The dependence of the spot rotation diame

关 键 词：激光技术 超快光学 旋光微孔加工 道威棱镜 孔径 锥度 

分 类 号：O439[机械工程—光学工程]