Laser beam forming: Experimental investigation and statistical analysis of the effects of parameters on bending angle

Laser Beam Forming (LBF), a non-contact manufacturing process has become a viable manufacturing process for shaping of metallic components. The capability of LBF and bending demands more on experimental studies to identify optimized parameter settings and also establish the probable influence of process parameters on the response i.e. the resulting bending angles in the present work. The experiments on laser forming process of 3 mm steel plate were conducted using a 4.4 kW Nd: YAG laser (Rofin DY 044), at the Council for Science and Industrial Research - National Laser Centre (CSIR-NLC), Pretoria, South Africa. This paper investigates the effects of five important process parameters such as namely laser power, beam diameter, number of scan tracks, scan velocity and cooling effect on the resulting formed sample curvature. Statistical tools combined with the Taguchi robust Design of Experiment, based on the L-27 Taguchi Orthogonal array (TOA) have been used. The samples were successfully formed to different curvatures following the experimental design. Both the Taguchi analysis and Analysis of Variance (ANOVA) established that the number of scan irradiation had the maximum effect while cooling effect coolant flow had the least contribution on the bending angle of formed components. Regression analysis was also conducted on the experimental data and a linear model relating all the influencing parameters was developed with an R-square value of around 98% showing the goodness of fit of the model. The regression model confirms that the experimentally measured bending angles were in good agreement with the model predicted values. This model can ultimately be used to estimate the bending angle in LBF of 3 mm steel plate within the study range of parameters.