Prediction of weld strength and seam width for laser transmission welding of thermoplastic using response surface methodology

In the present work, a study is made to investigate the effects of process parameters, namely, laser power, welding speed, size of the laser beam and clamp pressure, on the lap-shear strength and weld-seam width for laser transmission welding of acrylic (polymethyl methacrylate), using a diode laser system. Response surface methodology (RSM) is employed to develop mathematical relationships between the welding process parameters and the output variables of the weld joint to determine the welding input parameters that lead to the desired weld quality. In addition, using response surface plots, the interaction effects of process parameters on the responses are analyzed and discussed. The statistical software Design-Expert v7 is used to establish the design matrix and to obtain the regression equations. The developed mathematical models are tested by analysis-of-variance (ANOVA) method to check their adequacy. Finally, a comparison is made between measured and calculated results, which are in good agreement. This indicates that the developed models can predict the responses adequately within the limits of welding parameters being used. (C) 2009 Elsevier Ltd. All rights reserved.