11 Apr 2022
Diode lasers with 10kW+ outputs offer new solutions for laser cladding – to be presented at Laser World of Photonics.
Together with industrial partners, the Fraunhofer Institute for Material and Beam Technology (IWS) has developed applications for this class of laser to industry readiness under the brand HICLAD®. The Dresden-based institute and its project partner Laserline will present some of these at Laser World of Photonics in Munich, Germany, at the end of April.
The IWS has been developing the HICLAD process range for laser cladding for several years now to enable customized solutions for productive coating processes using high power diode lasers. To this end, the researchers are, among other things, fine-tuning the parameters of energy distribution, speed and feeding rate in such a way that wide process windows become possible.
“We are once again pushing the limits of applying high-power lasers,” commented Dr. Maria Barbosa, who heads the Thermal Coating Department at IWS. HICLAD enables “sustainable functional coatings that ultimately improve the durability, wear resistance and lifetime of the components so processed,” she said. “We look at the functionalization of component surfaces holistically and with the goal of still achieving resilient as well as industry-ready results with minimal material use and short cycle times,” she said.
The researchers say that a key component is measurement and control hardware, some of which has been developed in-house, that enables them to monitor and regulate the complex process and control its quality.
HICLAD is deployed, for example, for the laser-based hardfacing coating of brake discs, hydraulic cylinders and plain bearings. In the future, says IWS, large components for the oil, gas and paper industries and many other sectors may also be coated efficiently in this way.
For many years, IWS has pioneered the use of high power lasers with steadily increasing power classes – especially for laser cladding. Based on this experience, the institute and Laserline have now achieved and surpassed deposition rates with 20kW diode lasers which were previously only feasible using Plasma Transferred-Arc processes.
The partners have also made considerable progress compared to existing laser-based solutions: Depending on the specific material and the nozzle selected, HICLAD achieves deposition rates of 18 kilograms per hour in industrial use.
For an Inconel 625 nickel alloy, for example, productivity can be roughly tripled compared to a solution using a conventional nine-kilowatt laser. The exact values depend on the specific application scenario. Compared to competing solutions with high-power lasers, the IWS process is considered more robust.
In contrast to powder-based laser cladding, wire-based processes were previously limited to a maximum of 6kW. COAXquattro now enables laser powers up to 20kW to be used in the combination of wire and powder. This can play a decisive role in multi-material development, for example of novel alloys.
Different materials can be fed as required through each of four wire and powder channels. In addition, the comparatively short processing times shrink expenditures for staff, shielding gases and other operating costs. In general, the system is designed for particularly efficient material utilization as well as very robust and flexible process control with high quality.
“Together with IWS, we have succeeded in opening up concrete applications for a new class of high-power lasers to industry,” said cladding and additive manufacturing expert Dr. Sörn Ocylok from Laserline.
“Currently, we are already testing the further scalability of the processes by using a higher diode laser power class with up to 45kW output power in test runs – aiming at potential industrial application in the near future,” said Ocylok.
The IWS will present HICLAD, the laser nozzle COAXquattro, and show a high power laser-welded plain bearing. In addition to a 45-kilowatt diode laser, Laserline will also present brake discs coated by high-power laser cladding. These cause less abrasion and may thus help to reduce fine dust pollution.