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

Abstract

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.

Mechanical Strength of Thermoplastic Polyamide Welded by Nd:YAG Laser

“…Additionally, laser welding has also been used to successfully join fiber-reinforced thermoplastic composites [12,13,14,15,16]. More recently, the influence of laser welding process parameters on the weld bead quality of thermoplastic composites with high moisture content has also been studied [17].…”

Laser welding of thermoplastics: An overview on lasers, materials, processes and quality

“…This penetration is larger in amorphous polymers than in semi-crystalline polymers. There are available several reports that mention the use of Nd:YAG laser operating at 1064 nm to make welded joints using thermoplastics such as polyethylene, [11], polyamide [12,13] and epoxy resin [39]. Pereira et al [13] first used a pulsed Nd:YAG laser, instead of the continuous wave laser commonly used, to perform welding of thermoplastics.…”

“…low absorption) in the range 400-1600 nm. The laser radiation from laser sources operating within this range are mainly transmitted by the polymer and so, they can only be used for laser transmission Welding (LTW) [10,11,12,13]. In this case, an absorber must be added to one of the parts to be welded.…”

Laser transmission welding of PEKK: Influence of material properties and process parameters on the weld strength

“…Although, the bottom substrate can be rendered absorbent by different methods. The first one is filling the polymer with an absorbing additive, like colorants [2,3] or reinforcements [4,5]. And the other and much less studied option is to increase the degree of crystallinity of the lower substrate to modify its optical properties.…”