Laser bending of high strength alloys

Abstract

Laser bending has emerged as a candidate process for bending sheet metal. The dimensional accuracy of parts produced by bending processes is a topical issue. As the dimensions of a laser bent part depend on the temperature field induced in the workpiece, the correct laser processing parameters are essential. This work reports on an investigation into the factors influencing the dimensions of laser formed thin plates of an α - β titanium and an AlCuMg aluminum alloy. The influence of the energy input on the bend angle is examined empirically and compared with an analytical model. Results show that the plastic strain is critically dependent on the energy supplied to the workpiece surface. The decreasing bend rate with increasing irradiations over the same track is evident. This is attributed to an increase in the sample section modulus due to the thickening of the material along the bending edge. Edge effects are apparent in the samples. These effects can be minimized by varying the line energy supplied to the plate surface with the in plate location. The conclusions drawn are that the dimensions of the final part and the rate of bending can be controlled primarily from the temperature field. In addition, the increase in the section modulus and the edge effects influence the dimensional accuracy.