Process optimization of laser fusion cutting of multilayer stacks of electrical sheets

To increase the productivity for laser fusion cutting of electrical sheets, pre-baked multilayer stacks are laser-cut by using fiber lasers. In this study, the electrical sheets cut consist of the material denoted as M270-35A with an individual thickness of 0.35 mm. In a comparative study, both a 500-W single-mode fiber laser and a 1-kW multimode fiber laser are employed for the cutting process. The objective of this study is to optimize the maximum achievable cutting speed for a burr-free laser cut. The optimization is based on a design of experiments approach, extended by one-factor-at-a-time method and digital modulation of the laser source. The findings confirm that, in general, the cutting speed can be improved for a three-layer stack as compared to three single sheets, e.g., by up to 120 % for the multimode fiber laser system, while maintaining a high cutting quality. The increase of the productivity depends on the dynamic of the linear drives of the cutting machine and beam propagation characteristics of the used single-mode or multimode laser system.