Surface decoating by laser

As an ablative process, the laser is ideally suited to remove coatings from surfaces and preparing them directly for recoating. This saves time and money, especially in the case of local repair, as the laser can be guided in a very defined way, resulting in an ablation with sharp edges without a mask. Depending on the material combinations and the laser parameters used, a coating can be selectively removed or stripped down to the base substrate while maintaining virtually the same surface quality.

Applications and obstacles in coating removal

If a coating, usually a paint consisting of one or more layers, adheres well, that's basically a great thing. However, there are also cases where a layer needs to be removed locally or over the entire surface for various reasons. Exemplary, if electrical contacts or a grounding has to be locally realized, for example in the case of a coated component in an electric drive. Or if a recoating is required in the maritime sector for reasons of corrosion protection. In the second case, this is often accompanied by residues, for example caused by corrosion.

Mechanical cleaning processes require blasting or abrasive media and are only suitable for local and selective removal to a limited extent. In addition, the abrasive media must be collected and disposed of, which is increasingly being questioned in the course of an industry aiming at resource efficiency.

Environmentally friendly and selective ablation with laser

Laser technology circumvents these difficulties by providing an abrasive-free removal process. The laser beam can be guided over the surface in a targeted and edge-sharp manner and, depending on the coating composition and the laser parameters, enables selective, layer-by-layer ablation. Thereby, e.g., a top coat can be removed, whereas the underlying primer can only be ablated in the border area and directly recoated. In the case of complete coating removal, the process can be adjusted in such way that the underlying surface quality is largely maintained or readjusted. Contamination, such as corrosion residues, can also be removed directly. This saves time and costs, as otherwise necessary subsequent process steps can be avoided.

Automated or hand-guided laser technology

The high flexibility of laser technology and the associated systems allows the ablation of a wide variety of coating systems, including metallic coatings such as zinc or nickel and various polymers and paints. Depending on the materials used, both automatable, robot- or gantry-guided systems and hand-guided laser optics can be applied. The latter are even commercially available as mobile systems or backpack systems for high user flexibility. The ablated coatings are largely vaporized and can be removed by suction.

Your competent partner for resource-efficient decoating of surfaces

Fraunhofer IFAM has many years of experience in the field of laser technology. This is complemented by sound in-house expertise in the field of paint technology. We therefore offer our customers:

• Commercial laser systems for the removal of a wide range of coating materials
• Selection of suitable laser types depending on the requirements profile
• In-depth knowledge of laser-substrate interactions
• Technical coating tests (in-house)
• Consultations for developments / process introductions
• Wide range 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. In the "Plasma Technology and Surfaces" department, the group has comprehensive know-how, analysis methods, and complementary surface treatment processes.