In order to solve the problems of microcracks in high pulse energy femtosecond laser drilling,a trepanning method with femtosecond laser was proposed.The femtosecond laser with pulse width of 120 fs was used to trepan 304 stainless steel with 0.5 mm thickness.The effect of defocusing amount and relative deflection angle of double wedge on the micro-hole diameter and the effect of defocusing amount on the micro-hole conicity are studied by the experi-ments.The results show that the diameters of micro-holes increases with the increasing of the defocusing amount,but the conicity first decreases and then increases.When the defocusing amount is zero,the minimum conicity is 3.5° .Micro-hole diameter increases with relative deflection angle increase of double wedge.Nanometer periodic stripes are found on the sidewalls of micro-holes trepanned by femtosecond laser,while there are microcracks on the sidewalls of micro-holes through percussion drilling.%为了解决飞秒激光高脉冲能量冲击打孔中时存在微裂纹等问题，提出了飞秒激光旋切加工方法。本文利用脉宽为120 fs 的飞秒激光，选择0．5 mm 厚度的304不锈钢进行旋切打孔实验。实验研究了激光旋切加工中离焦量和光楔的相对偏转角对孔直径的影响，以及激光离焦量对微孔锥度的影响。结果表明，随着离焦量的增大，孔径增大，同时锥度会减小后增加，当离焦量为0时，锥度最小为3．5°；微孔直径随之双光楔相对转角的增大而增大。此外实验发现冲击打孔孔壁出现微裂纹而旋切微孔的孔壁出现了纳米周期性条纹。
展开▼
