Due to introduction of new EURO 7 standard the by cars emitted fine dust particles must be reduced significantly. The by tires and brake discs emitted fine dust particles contribute to approx. 30-35% of the overall fine dust emission by gas or diesel driven cars. Since the total fine dust emission must be reduced by more than 90% (in comparison to EURO6) the coating of brake discs will become critical for gas or diesel driven cars. Even for electrified vehicles fine dust will be produced by brakes discs if the vehicle must come to a complete and safe stop. Further development of the High-Speed Laser Metal Deposition (abrev. HS-LMD) process has made this coating technology even more attractive for the automotive industry. High-Speed Laser Metal Deposition is already used for a broad range of applications: wear resistant layers on small valves, corrosion resistant coatings for very long shafts used in hydraulic systems, etc. Even additive manufacturing of rotational symmetric geometries – such as seal lips or a shoulder on a shaft – are feasible. For automotive industry HS-LMD are already being investigated for a broad range of applications. Using HS-LMD, a laser beam is melting powder particles, which are fed coaxially into the laser beam, before these particles hit the substrate. Using a laser as heat source, heat input into workpiece can be minimized and fast thermo cycles can be achieved. This allows for a very low dilution of additive into workpiece – typically < 10µm – and high feed rates between 100-500 m/min. Layers generated by this process can be locally adjusted in thickness between 50-300 µm per layer. Since each layer is metallurgically bonded to the substrate or the layer before, multi layers or multi-material approaches are feasible. This feature can be used to achieve functionally graded material or to apply metallurgically bond coatings on hard-to-weld alloys such as cast iron. In this paper we will show recent results of the development of HS-LMD, which will make the process even more robust for such highly innovative mass production applications. At the same time the productivity has been scaled towards high productivity. These new developments involve new laser-based systems technology that also utilizes beam shaping for the first time.
TRUMPF Laser- und Systemtechnik GmbH: Mr. Marco Göbel, Ms. Sabrina Vogt, Mr. Tim Hesse, Mr. Nicolai Speker, Mr. Sautter Björn