Laser focus on surface structures Lasers are an important tool in industrial materials processing, enabling scientists to modify the surfaces of materials and tailor their properties. Researchers in the FemtoSurf project are developing a new system to treat large curved surface areas of metals, work which holds interest to several areas of industry, as Femtika CEO Vidmantas Sakalys explains.
A large number
of lasers with pulse durations in the nanosecond (10 -9 of a second) range have been developed over recent years, but researchers are continuing to push the boundaries of technology and strive for further improvements. As Project Leader of the EU-funded FemtoSurf project, Vidmantas Sakalys is now leading a team of worldclass scientists and engineers to develop a femtosecond (10 -15 of a second) laser based surface modification machine. “One of the project targets is to create a very powerful - about 2 kilowatts - femtosecond laser,” he explains. This work could be relevant to a wide range of industrial sectors. “Our main targets in the project are shipbuilding, healthcare, aerospace, and heavy industry,” says V. Sakalys. “For example, with shipbuilding, we can use surface structuring to make the propellers anti-fouling.” This could have a significant impact on the performance of a vessel and greatly improve efficiency. A ship’s propellers are often rapidly clogged up after a period out on the water as a result of fouling, which V. Sakalys says has a detrimental impact on its overall performance. “Fouling usually causes about a 5 percent increase in fuel consumption, and the ship has to be taken in for cleaning on a regular basis,” he outlines. By modifying the surface of the structure, researchers aim to improve performance and reduce maintenance costs. “If we can make it easier to clean the ship’s propellers, then it would really drastically reduce the costs of using it,” points out V. Sakalys. “The surface of a metal can also be structured in such a way to reduce friction and corrosion.”
Different surface micro-textures resulting in different properties and contact angles between water drop and the surface.
metal can change its behaviour. “Some nanoripples and micro-patterns are formed on the surface of a metal,” explains V. Sakalys. Researchers in the project are working to develop a system to structure the surface of a metal, which V. Sakalys says represents a route to introducing certain interesting properties.
“We can make the surface hydrophobic for example, so that it repels water, or hydrophilic, the opposite. It’s also possible to make surfaces anti-microbial,” he says. A major challenge at the moment is the insufficient power of femtosecond lasers, an issue that V. Sakalys and his colleagues are
Surface structures The idea in the project is to develop a laser based micro-fabrication machine to structure relatively big and curvy surfaces, with dimensions in the order of several square metres, all within a reasonable and cost effective timeframe. Applying a laser beam with a femtosecond pulse to the surface of a
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Water drops on the textured water-repellent surface.
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