A new laser welding method of two transparent plastic parts based on reflector assisted method

Abstract

It is a challenging work to joint two transparent plastic parts using traditional laser welding because the absorptivity of transparent plastic on short wavelength (800–1000 nm) laser energy is very low. During the laser welding of two transparent plastic parts, although laser absorber and long wavelength (1600–2000 nm) laser can obtain the high-strength weld joint, the problems of unattractive weld joint or pollution will occur when laser absorber is used, and the laser energy utilization coefficient is about 70% when long wavelength laser energy is used. To address this issue, this paper proposes a new production method for the absorber-free laser welding of two transparent plastic parts based on reflector assisted method. From three-dimensional thermal model, it can be found that the simulation data of the modified Gauss cylindrical body heat source show better agreement with the experimental result than those of Gauss surface heat source and Rotary-Gauss body heat source. In addition, for the same the weld joint width on the contact surface, the reflector assisted laser welding method can decrease the laser energy consumption by about 20%. Moreover, the maximum shear force of weld joint can be up to 1315 N. Under the same process parameters, the reflector assisted method can increase the shear strength of weld joint by 15.3%. Hence, the reflector assisted method has good application and promotion value in laser welding two transparent plastic parts.