Project examines lasers as replacement for hull coatings

Malcolm Latarche

Malcolm Latarche · 04 February 2020

ShipInsight


Laser-engraved hulls could replace traditional marine coatings if work on a new project proves the concept viable.

The scientists behind the three-year European laser project MultiFlex expect the specially-designed structures on steel ship hulls helping to reduce fuel consumption and replace toxic ship paints and varnishes that are harmful to the environment.

MultiFlex is supported by the European Commission in the framework of the EU Horizon 2020 ICT programme with a grant of €4.7 million under the Photonics Public Private Partnership.

The European consortium consists of the Fraunhofer laser technology research institute ILT and the Chair for Technology of Optical Systems of RWTH Aachen University from Germany, Amplitude Systèmes, LASEA France, AA OptoElectronic from France, and LASEA from Belgium as industrial research and development partners.

Anti-fouling, ‘hydrophobic’ metal or plastic surfaces, engraved by a new laser technology being developed by the project partenrs, could soon replace the toxic varnishes used in ship coatings to stop algae or barnacles sticking to hulls - reducing maintenance costs, fuel bills and CO2 emissions.

Harnessing new photonics technology a high-power (1 kW) ‘dot matrix’ ultrafast laser system carves flow-optimised metal or plastic surfaces that can reduce drag by imitating the incredibly efficient skin from sharks.

Etching microscopic ‘spike’ structures onto sheet metal or plastic, the laser creates a rough surface that reduces drag to inhibit the growth of bacteria, algae or even barnacles.

Shark's flesh, covered in millions of microscopic denticles - or tiny protruding scales - reduces drag to make it a highly efficient swimmer. Similarly, engraved metal or plastic surfaces can have 'anti-fouling' properties that prevent contaminants or microorganisms from clinging on.

Dr Johannes Finger, coordinator of the MultiFlex project, said, “Laser-fabricated surface structures have the potential to reduce friction and to prevent the growth of plants and algae. This could significantly reduce ship repair, maintenance, CO2 emissions and fuel bills while providing an alternative to harmful coatings that are toxic to the environment.”

“Besides maritime components, application fields can be found in aircraft and turbomachinery. Here, surface structures might inhibit cavitation and thus improve lifetimes of propellers of propulsion systems or water turbines.

“Our photonics system can also create design textures or ‘microcavities’. Here the environment benefits by replacing environmental problematic technologies like chemical etching,” said Dr Finger.

Ultrashort Pulsed (USP) or 'Ultrafast' lasers can ablate any material without damaging it. Surfaces cut with a USP are smooth, on a micron-scale and ideal for many industries where hard materials need to be processed with the highest precision.

Developed by the MultiFlex project, the material is structured by the world's first 'dot matrix' laser. In the same way that an old-fashioned dot matrix printer uses a moving head, printing in a line by line motion, the laser sends super-fast pulses of concentrated energy to ablate - or cut - materials that are notoriously difficult to work with.

Resembling a giant chessboard, the system splits a single beam into a grid of 64 ‘beamlets’, where every single ray can be turned on, off, positioned, and individually ‘tuned’.

“Existing ultrafast lasers are known for their precise ablation and cutting results. Unfortunately, processing large parts with such lasers can take weeks. Our system will ablate more than 150 mm³ in one minute, therefore making it hundreds of times faster than existing technologies,” said Dr Finger.

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