为了研究超短脉冲激光对钢箔微孔加工的影响,利用脉宽为400 fs的超短脉冲激光在130 μm厚的06Cr19Ni10不锈钢箔上进行了一系列微孔加工实验.利用光学显微镜,对基模激光打孔效果和超短脉冲激光“冷加工”效果进行观测,发现基模激光光斑的光强分布会影响打孔效果,而“冷加工”的效果使得打孔精度很高,而且重铸层和热影响区都可以忽略不计.实验中发现微孔的锥度比较大,通过理论分析认为孔内的激光能量耦合,光致等离子体的屏蔽作用和圆锥辐射现象都是微孔锥度过大的主要原因.通过同时使用变焦平面法和FP旋光模组进行激光打孔,可以在一定程度上改善微孔的锥度问题,从19°左右减少至10°左右.

In order to research the influence of steel drilling by ultra short laser,using the 400 fs ultra short laser to drill on the 130 μm-thick stainless steel foil. The effects of fundamental mode laser drilling and cold working of ultra short laser are detected by optical microscope .The distribution of light intensity of laser spot will impact the results of drilling. The re-cast layer and the heat affected zone of ultra short laser drilling can be neglected because of cold working. Experiments and theories find that the energy coupling,plasma shielding and conical emission are main origins of the taper in micro-pores. Applying variable focal plane and FP module simultaneously is the improvements to reduce the taper in holes. As a consequence,the average taper in holes changes from 19°to 10°.