Laser transmission welding of polycarbonates: experiments, modeling, and sensitivity analysis

Abstract

An experimental investigation on laser transmission welding of polycarbonate is presented in this paper. Instead of concentrating on the well-known effects of process parameters, the present study focuses on the sensitivity analysis of process parameters to identify the critical parameters and to assess their relative impact on the variation in output quality. Curvilinear regression models are developed using the independently controllable design variables like laser power (W), welding speed (mm/s), standoff distance (mm), and clamp pressure (MPa). Selected weld quality characteristics, namely the weld strength (N/mm), which is calculated based on failure load per unit length and weld width (mm), are used to set the objective functions. Parametric sensitivity analyses are performed using the developed models. It is observed from the results of sensitivity analysis that the weld strength is more sensitive to welding speed (sensitivity of 8.4 N/mm per unit welding speed) and laser power (sensitivity of 3.08 N/mm per unit laser power), whereas weld width is more sensitive to welding speed (sensitivity of 0.37 mm per unit welding speed) and standoff distance (sensitivity of 0.11 mm per unit standoff distance), respectively. These are the critical parameters for the respective quality characteristics, and a small variation of these parameters causes relatively higher deviation in weld quality.