Experimental and Numerical Investigation of Effective Parameters and Optimization of Bending Angle by Response Surface Method in Laser Bending of Aluminum Sheets using Pulsed Nd: YAG Laser

In optimization of laser bending process, the parameters are often selected without considering their significance, while the correct selection of parameters in the optimization stage is important to achieve the optimal bending angle. In this paper, a novel approach is proposed to identify and select effective parameters in the optimization of laser bending process. Using this method, due to disregarding ineffective parameters in the pre-optimization stage, the number of required tests is reduced. Eight parameters including laser power, scan velocity, beam diameter, pass number, step time, sheet length, sheet width, and sheet thickness were selected. Furthermore, the Response Surface Methodo (RSM) was used to investigate the effect of parameters and to optimize the process. The repeatability of the process along with accuracy and validation of the simulation by accurate measurement of the bending angle were examined by experiments. All experiments were performed by a laser machine with a maximum power of 400 W on AA 6061 sheets with a thickness of 2 mm. Results showed that the utilization of parameters screening, leads to a 20% reduction in time and costs of experiments in the optimization stage. In addition, among the eight parameters studied in the screening stage, five parameters were selected as effective parameters for the optimization stage. Results after parameters screening indicated that the maximum bending angle was achieved when sheet thickness (2.5 mm), beam diameter (2 mm), and scan velocity (18 mm/s) were at their low level, and that pass number (9) and laser power (450 W) were at their high level.