Today, fiber reinforced materials are present in a wide field of industrial applications. Short glass fiber reinforced composites are mainly used in automotive, aerospace and medical sectors. In recent years, endless fiber reinforced thermoplastics have gained importance as construction material, especially for lightweight assembly. There are different methods of joining thermoplastic materials such as vibration, resistance and induction welding. Another process is laser transmission welding, which can be characterized by its excellent reproducibility, high flexibility and potential for automation. Typically, laser transmission welding can be applied for joining unreinforced or glass fiber reinforced thermoplastic parts. This welding process was now adapted to heat conduction welding for joining thermoplastic CFRP to itself. The goal of these investigations was to determine the influence of the matrix material on the weld seam quality. The experiments were conducted with a carbon fiber fabric reinforced polyphenylene sulfide with natural matrix material as well as containing carbon black. In the first step, the temperature distribution at the upper joining member, where the heat generation occurred, was evaluated. The heat affected width was determined and correlated to the process temperatures in order to develop a process model. In a next step, lap shear samples were welded and tested. These results were then correlated with previous results.
An adequate use of finite resources is one of the greatest challenges of our times. To address this, lightweight concepts based on continuously fiber reinforced composites (FRC) are already being adapted for the transportation industry, especially within the automotive and the aerospace sectors. In order to broaden the use of lightweight composite structures and components, suitable processing, monitoring and control techniques are required for a variety of materials, constituting a prerequisite for economic, flexible and automated high volume production. In this regard, photonic technologies can provide valuable solutions. In this presentation, the latest developments within the field of FRC laser machining are summarized. For the processing of large structures such as resin transfer molding parts, combinations of galvo scanners with robots or axis systems are of particular interest. For this purpose, both high brightness cw fiber lasers and pulsed systems are used. Within the repair chain for valuable FRC parts, pulsed UV and NIR lasers are used for the precise removal of fiber layers in order to generate a defined scarfing. For both applications, disintegration of the fiber matrix interconnection due to thermal impact has to be avoided. Thermoplastic composites are becoming increasingly important for many industrial applications. In contrast to thermoset systems, welding techniques are particularly applicable. In this context, laser welding is not limited to the joining of transparent-absorbing-combinations, as it is required for conventional laser transmission welding processes but can be extended to the welding of structural parts consisting of high-performance carbon fiber reinforcements.
Conference Committee Involvement (2)
High-Power Laser Materials Processing: Applications, Diagnostics, and Systems IX
5 February 2020 | San Francisco, California, United States
High-Power Laser Materials Processing: Applications, Diagnostics, and Systems VIII
6 February 2019 | San Francisco, California, United States