Improving the efficiency of laser bending forming using circularly oscillating laser beam

Laser bending forming techniques commonly utilize point lasers，which have a limited maximum bending angle of approximately 3° due to the temperature gradient mechanism. To increase the bending angle and improve the forming efficiency of point laser bending，this study explored the feasibility of applying the circular oscillation mode to enhance the bending angle in the bending process of stainless steel 304 sheets. Additionally，the dynamic response of the workpiece during circular oscillation laser bending forming was measured using a three-dimensional vision sensor to investigate the bending deformation mechanism from the perspective of thermal effect，variation in absorption，etc. The comparative experimental results show that the circular oscillation mode significantly improves the bending angle of the workpiece，with a growth rate of approximately 60% when the laser has a higher energy density. At the same time，the measurement results from the three-dimensional vision sensor reveal the complex deformation and angle changes of the workpiece during the forming process：plastic deformation occurs in both the length and width directions of the workpiece，with the length-width deformation ratio is about 10：1；the growth of the bending angle during a single scan exhibits different growth curves；and the distribution of bending angles in multiple scans is uneven. In addition，the thickness of the plate also gradually increases，and the micro-grains in the heat-affected zone are refined. These experimental findings provide support for a better understanding of the process and mechanism of circular oscillation laser bending forming. © 2024 Chinese Academy of Sciences. All rights reserved.