Laser transmission welding of carbon fiber reinforced thermoplastic using filler material—A fundamental study

In the automotive industry, the increasing environmental awareness is reflected through consistent lightweight construction. Especially, the use of carbon fiber reinforced thermoplastic plays an increasingly important role. Accordingly, to the material substitution, the demand for adequate joining technologies is growing. Therefore, laser transmission welding using filler material provides a way to combine two opaque joining partners by using the process specific advantages of the laser transmission welding process. After introducing the new joining technology and the applied experimental setup, this paper will investigate the process itself and the conditions for a stable process. Fundamental studies of the absorption characteristics of the applied carbon reinforced thermoplastic and the heat distribution within the surface due to laser impact are performed. To analyze the resulting weld seam quality and to investigate the influence on the process parameters and the welding process itself, lap shear tests are carried out. After all, a thermal model for the joining process is generated and presented in this paper.