Investigating laser intensity profile and light scattering effects in the transmission laser welding process of 3D printed parts

Transmission Laser Welding (TLW) is a promising technique for joining thermoplastic and composite components, especially those produced through additive manufacturing or 3D printing processes. However, achieving optimal welding quality and efficiency in TLW of 3D printed parts is challenging due to the presence of highly heterogeneous and anisotropic materials, which introduce light scattering and absorption issues. Light scattering is caused by the refraction phenomenon. These phenomena significantly impact the laser intensity profile within the materials and at the welding interface, thereby affecting the energy required for successful welding and the mechanical strength of the final assembly. In this paper, we present an in-depth investigation into the laser intensity profile and the effects of laser-matter interaction on the welding of 3D-printed parts. Our approach combines experimental measurements using a heat flux sensor and an analytical inverse model to measure the laser intensity distribution within the materials at the welding interface. The results obtained from the experimental measurements and numerical identification are compared and analyzed, providing insights into the laser intensity profile in TLW of 3D printed parts.