In the IGF project LIBS-OF, an ultraviolet (UV) laser with a wavelength of 193 nanometers is used for particularly effective cleaning. This short wavelength makes it possible to break bonds between carbon and silicon atoms. This allows even stubborn contaminants - such as silicone release agents - to be removed, where conventional cleaning methods reach their limits. In addition, the plastic surface is chemically functionalized under the influence of atmospheric oxygen. This creates -OH or other polar groups, for example, which are firmly anchored to the surface. This activation ensures that subsequent processes such as bonding or coating can be carried out directly after the laser LIBS treatment.
Avoid over- and under-treatment of fiber composites
Treating surfaces with high-energy lasers carries the risk of over-treatment. Over-intensive treatment can be particularly problematic in fiber composite technology: If the reinforcing fiber is exposed on the surface - for example in carbon fiber reinforced plastic (CFRP) components - there is a risk of oxidative damage. In order to avoid both under- and over-treatment, the cleaning and activation process is monitored inline using laser-induced plasma spectroscopy. The analysis results control the process parameters in real time. In this way, a high cleaning performance is achieved, over-treatment is avoided and process time is saved at the same time.