An experimental study of laser bending for sheet metals

In this paper, changes in the bending angle with process parameters have been studied for the laser bending of sheet metals. These parameters may be divided into three kinds: laser energy parameters; material parameters; and sheet geometric parameters. The laser energy parameters include laser power, path feed-rate, beam spot diameter and feed number. The tests show that the bending angle is, generally, in direct proportion to the laser power and feed number, and in inverse proportion to the path feed-rate and beam spot diameter. The material parameters mainly relate to a thermal-effect index, which can be shown as R=αth/ρcp, i.e. the coefficient of thermal expansion divided by the factor of the density multiplied by the specific heat. The bending angle increases with increase in the index R. There is no significant influence of the strength at room temperature on the bending angle. Among the sheet geometric parameters only, there is greater influence of the sheet thickness on the bending angle, which decreases sharply with increase in the sheet thickness.