Mahrle Achim, Borkmann Madlen, Pfohl Peer
Fraunhofer IWS Dresden, Winterbergstraße 28, D-01277 Dresden, Germany.
Institute of Manufacturing Science and Engineering, TU Dresden, D-01062 Dresden, Germany.
Materials (Basel). 2021 May 19;14(10):2669. doi: 10.3390/ma14102669.
Factorial Design-of-Experiment analyses were applied for conventional and beam oscillation fiber laser cutting of 10 mm thick AISI 304 stainless steel. Considered factors in case of the conventional process with a static beam involve both laser and cutting gas parameters, in particular the laser power, the focal plane position, the cutting gas pressure, the nozzle stand-off distance as well as the nozzle diameter. The conducted trials were evaluated with respect to the achievable cutting speed, the cut kerf geometry and the cut edge roughness. Noticeable correlations between cut edge roughness and cut kerf geometry stimulated the development of a corresponding Computational Fluid Dynamics (CFD) model of the cutting gas flow through the kerf. A specific approach of data synchronization revealed that the experimentally determined roughness values do well correlate with numerically computed values of the backward directed component of the gas-induced shear stress and that the cut kerf geometry as internal process-inherent boundary condition influences relevant cutting characteristics more than controllable external cutting gas parameters. Finally, effects of circular beam oscillation were investigated by an additional factorial analysis considering the laser power, the focal plane position, the oscillation frequency and the oscillation amplitude as factors. The results demonstrate the potential of beam oscillation techniques for quality improvements in laser cutting.
采用析因实验设计分析方法，对10毫米厚的AISI 304不锈钢进行常规激光切割和光束振荡光纤激光切割。在传统的静态光束切割过程中，考虑的因素包括激光和切割气体参数，特别是激光功率、焦平面位置、切割气体压力、喷嘴与工件的距离以及喷嘴直径。通过可达到的切割速度、切割缝几何形状和切割边缘粗糙度对所进行的试验进行评估。切割边缘粗糙度与切割缝几何形状之间显著的相关性促使人们开发了一种相应的计算流体动力学（CFD）模型，用于模拟切割气体通过切割缝的流动。一种特定的数据同步方法表明，实验测定的粗糙度值与气体诱导剪切应力向后分量的数值计算值具有良好的相关性，并且切割缝几何形状作为内部固有工艺边界条件，对相关切割特性的影响大于可控的外部切割气体参数。最后，通过额外的析因分析，研究了以激光功率、焦平面位置、振荡频率和振荡幅度为因素的圆形光束振荡的影响。结果证明了光束振荡技术在改善激光切割质量方面的潜力。
