The Fraunhofer Institute for Laser Technology ILT has developed an ultrafast laser processing method that selectively removes the outer layers of composite materials.
Using ultrashort pulsed lasers, the matrix material – which usually consists of epoxy resin – can be processed and removed with local and depth-selective ablation. An adapted process control allows this to be done without damaging the adjacent fibres. ‘This is achieved through a local and selective adjustment of laser power and beam guidance,’ explained Christian Hördemann, scientist at Fraunhofer ILT. ‘As a result, even complex geometries and 3D components can be processed with the laser.’
This ability to process surfaces without disturbing the load-oriented processed fibres is especially interesting for the aerospace industry.
The new method could potentially be used in the preparation of a solid joint between composite materials and adjacent components. Following this, heterogeneous plastics could be sprayed directly onto the exposed fibre structure, where they would surround the fibres and combine in a form-closed joint.
The method is also suitable for subsequent work steps using adhesion. For certain applications, carbon fibre reinforced polymers and other plastic components must be coated with conductive layers.
Working with Fraunhofer IST, Fraunhofer ILT developed the method so that plastic components can be supplied with a well-bonded copper layer without using toxic Cr(VI) chemicals. A direct metallisation is also possible. The method is used for highly loaded antenna bodies as well as for chrome plating of decorative lightweight components.