Laser technology for surface treatments

Laser technology offers a wide range of possibilities for cleaning and modifying surfaces. For example, metal surfaces can be made more resistant to corrosion, the adhesion of a paint or adhesive can be improved, or storage-capable and liquid-transporting layers can be created. The laser process can be used for both large scale area and local, maskless treatments and is characterized by an environmentally friendly and resource-efficient process technology. Fraunhofer IFAM has been developing customized laser processes for cleaning and functionalizing a wide variety of surfaces for many years.

Laser - what is that actually?

Laser is an acronym for "light amplification by stimulated emission of radiation" and refers to both the process and the systems used to generate the corresponding radiation. Put simply, a laser beam is very intense light that is focused on and scans a surface as if under a magnifying glass. The laser radiation has a fixed wavelength depending on the laser source, which produces different effects on the irradiated surface. Depending on which properties are to be produced and which class of material - metal, plastic, composite material, ceramics, etc. - is being processed, different laser sources are available. They can be used, for example, to cut or weld surfaces, introducing high temperatures into the material. In contrast, pulsed lasers are often used for surface treatments. Their interaction is close to the surface (a few 10 nm to a few µm in depth) and does not affect the base material.

Wide range of possibilities for cleaning and designing surfaces

The potential of laser technology is optimally exploited in surface pretreatment. Due to their high energy, the short laser pulses can vaporize and remove contaminants, release agent residues, unstable top layers or oxides in fractions of a second. The vaporized ablation products can be removed by simple suction directly at the point of generation. In addition, depending on the choice of laser system and process parameters, the surface chemistry and topography are adjusted. Slight smoothing effects are possible on metals, as is the introduction of targeted structures that lead to various functional properties, e.g. an improvement in adhesive strength of paints or adhesives. Comparable effects are also possible on polymers or composites. In addition, existing metal oxides can be made thicker and denser and thus more resistant, or they can be reduced. With suitable process control, various effects can be achieved with just a single process step.

Examples of possible applications of laser for surface treatment are:

• Improved adhesion and aging resistance of adhesive joints and coatings.
• Cleaning and decoating
• Influencing the wetting behavior
• Visual and optical design (e.g., color, reflectance)
• Fluid transport and storage or release
• Improved biological compatibility (e.g., for medical applications)

Sustainability in focus

Industrial laser sources enable quality-assured and environmentally friendly processing of material surfaces. In contrast to many wet-chemical and mechanical methods, the use of laser technology completely avoids chemicals and by-products that are partly hazardous to the environment and health. As a result, only very small amounts of waste are produced, resulting in a positive effect on the environment and reducing the costs of disposal. In addition, relevant component areas can be treated locally and selectively, resulting in time and cost savings. In addition to hand-guided systems, primarily inline and / or robot-assisted process control is used.

Your competent partner for laser treatment of surfaces

Fraunhofer IFAM has decades of experience in the field of laser technology. We are there for you with the following offers:

• Commercial laser systems for different treatment effects and material classes
• Selection of suitable laser types depending on the requirements profile
• In-depth knowledge of laser-substrate interactions, process control and management
• Consultations for developments / process introductions as well as for the design of laser treatment cells
• Broad network of partner companies for possible implementations

Surface technology is a core competence of Fraunhofer IFAM. The "Laser Technology" working group develops processes for the surface treatment of a wide range of materials based on industrially established or available system components. The fields of application range from automotive engineering, aircraft manufacturing and consumer electronics to medical technology.