激光偏振特性在微尺度工件激光弯曲成形中的作用

Experimental Study on Laser Polarization Properties in Laser Micro-Bending Processes

根据激光的偏振特性影响金属材料对激光的吸收这一特点,通过改变激光扫描工件表面的入射角,提高了金属表面对CO2激光能量的吸收率,使厚度为0.1 mm的微尺度不锈钢工件在未进行黑化处理的情况下获得了弯曲变形.实验结果表明,在采用线偏振激光对具有吸收层的工件进行多次扫描时,由于变形部分入射角增大引起激光吸收率提高,以及光斑面积增大引起激光功率下降,从而导致作用于工件表面的激光能量因素改变,这是弯曲角度发生变化的主要原因.

The influence of the beam polarization in laser bending process is experimentally investigate. With the beam polarization of laser, the laser absorption of the metallic specimen can be enhanced by increasing the incident angle. The bend angles are achieved in stainless foil specimens without absorptive coatings, and larger bend angles can be obtained by single laser scanning with higher incident angles. Multi-pass laser bending experiments are also carried out on the same material with graphite coatings. The results show that the bend angle per pass is affected obviously by the beam polarization, and the bend angle per pass increases significantly while the total bend angle gets big enough. Using polarized light, the laser beam distortion and laser absorption change induced by the variation of the absorptive coatings and laser incident angle are the two main factors affecting the coupled laser energy. The bending rule is the synthesis effect of the above two factors.