Euro Consortium Developing Better Laser Surfacing

The objective of ultraSURFACE is to develop equipment that will reduce surface processing time to a tenth of conventional approaches—and costs by half.

It’s called the “ultraSURFACE” project, with its full name being “Ultra Dynamic Optical Systems for High Throughput Laser Surface Processing.” This research program is addressing one aspect of laser surface processing techniques (e.g., structuring, which can make structures as small as the micrometer scale via the use of ultra-short pulsed lasers); polishing, which can remelt a surface so that it can go from a roughness of Ra = 1 to 10 μm to RA = 0.1 to 0.5 μm; and thin-film processing, which is a two-step process in which a film is deposited on a surface then hardened with a laser) that is something of a constraint: throughput.

So the ultraSURFACE project is working on increasing throughput by a factor of 10 without having any reductions in process quality. The plan is to achieve this through the use of two different optical processes. In one, there is a flexible beam-shaping approach that uses piezo-deformable mirrors (PDMs) that can adjust the beam to specific intensity distributions such that there is a significant increase in feed speed and track offset. The other approach is to use beam splitting so that there is simultaneous processing with multiple beams.

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The research program is being conducted with the participation of research organizations, equipment suppliers, and end users, including Fraunhofer Institute for Laser Technology ILT (ilt.fraunhofer.de), RWTH Aachen University Chair for Technology of Optical Systems TOS (rwth-aachen.de), Unitechnologies SA (unitechnologies.com), Pulsar Photonics GmbH (pulsar-photonics.de), Newson NV (newson.be), Flexible Optical BV (OKO Tech; okotech.com), HOLO/OR Ltd. (holoor.co.il), Schaeffler Technologies GmbH & Co. KG (schaeffler.de), Procter & Gamble Manufacturing GmbH (pg.com), and GEMÜ Gebr. Müller Apparatebau GmbH & Co. KG (gemu-group.com).

In the first approach, there are switching intervals of less than five milliseconds. Explains Judith Kumstel, a laser polishing expert at Fraunhofer ILT, “The laser beam is reshaped depending on the angle of incidence so that its projection on the workpiece surface always has the same shape and the intensity remains constant.” This assures consistency of processing, even should the processing be performed on complex shapes. The PDMs allow this to happen.

Then there is the multi-beam approach for laser structuring. In this case, there is a diffractive optical element used that takes the laser beam and splits it into four square parallel beams. While beam splitting is not new, apparently in traditional systems the focusing optics and the shape of the components being processed can lead to distortion of the beam. In this case, a system has been developed that allows each individual beam to be positionally adjusted in milliseconds so that there is always a square beam produced.

The ultraSURFACE participants have developed two compact optical modules for these two approaches and a laser system is being produced by Unitechnologies to test the concept. This industrial-grade machine will be capable of polishing, structuring and coating.

Kumstel says, “With the concepts developed in this project, surfaces will soon be processed just as well as with conventional systems. Thanks to the new optics and the new machine, processing will be ten times faster than before, so that laser-based surface finishing will offer a cost-effective alternative to conventional surface finishing for many companies from various industries – even for small job shops.”

It is expected that through the development of these technologies processing costs will be reduced by at least half and production time will be decreased by as much as 70 percent compared with conventional techniques. Consequently, it should be commercially viable.

In addition to which, by using the laser for surface processing there are health and environmental benefits, as well, including the reduction of noise in the factory; reduced amounts of dust, including heavy metals; no chemical solutions; and a reduction of CO2 emissions up to 80 percent.