Description

Carbon fiber reinforced plastics (CFRP) have become standard in the lightweight industry due to their high strength-to-weight ratio. CFRP with a thermoplastic matrix material is more attractive for many applications because it offers new possibilities for repairs. Due to the high amount of resources required for the production of CFRP parts in combination with high production costs, there is an interest in repairing components instead of replacing them completely. At the moment, the repair process is mostly done manually. In order to reduce repair costs, an automated, reliable and fast process is needed. Therefore, a repair procedure has been developed at LZH using laser welding technique.

For the repair process, first a scarf joint is prepared in a CFRP laminate with thermoplastic matrix material. After that, a CFRP patch with the same matrix material is ​​laser welded on it. The test material was a 4-layer CFRP laminate with polyphenylene sulfide matrix. Heat conduction welding was used to join the components. In this process, the laser radiation is absorbed on the top of the material and the generated heat is transported through the part by heat conduction. The laser system used was a diode laser with a maximum power of PL = 300 W and a wavelength of λ = 940 nm. A homogenizer optic was used to generate a tophat intensity distribution such that the laser beam geometry has a dimension of A = 11 x 43 mm². In order to develop a suitable parameter set for a high joining quality, the surface temperature, holding time and joining pressure were varied by using design of experiment. For the analysis of the joining quality, overlap samples with a joining area of ​​A = 11 x 20 mm² were prepared in order to determine the tensile strength. As well, cross sections were analyzed. Finally, the measured results were correlated with the process parameters to optimized the weld seam quality.

Contributing Authors

Track: Laser Materials Macroprocessing
Session: Non-metal Processing
Day of Week: Tuesday
Date/Time:
Location:

Keywords

  • 98E7B75E-E7C0-44A8-A08E-77254Cf1E5B6
  • Hirt
  • Presenter
  • S.hirt@Lzh.de
  • Simon