ADVANCED MATERIALS & PROCESSES | MARCH 2024 1 7 Extreme high-speed laser application (EHLA) is a groundbreaking material deposition process that is disrupting the status quo and reshaping the way industry thinks about coatings technologies. Evolving from laser cladding (also known by other terms such as laser metal deposition (LMD), or laser beam-directed energy deposition (LB-DED), and laser engineered net shaping (LENS)), EHLA operates at speeds 10-100 times faster than prevailing methods. As a sustainable alternative to chrome plating, EHLA excels in material integrity, efficiency, and performance, while rapidly reducing costs compared to thermal spray and conventional laser cladding. This addresses many sustainability concerns within the manufacturing sector. EHLA operates by feeding powder from a specially designed nozzle that creates an optimized powder-gas jet stream. The particles coincide with the path of a laser beam and melt in flight, before reaching the substrate. Most of the laser energy is absorbed by the powder, but a small percentage (approximately 20%) reaches the substrate, creating a shallow molten pool, enabling a metallurgical bonding of the deposited powder to the substrate (Fig. 1). The energy and heat transferred to the substrate is low and therefore the impact is significantly less compared to conventional fusion processes such as arc weld overlay and conventional laser cladding. Without the dependency of forming a conventional meltpool, the process can therefore be sped up. There has yet to be found a limit to this besides appropriate machine technology to match, with current developments working up to deposition speeds of around 300-500 m/min. The EHLA technology was initially developed for coating rotationally symmetric components, such as hydraulic shafts and gate valve seats, utilizing the simplicity of turning the component at high speeds to create the effective surface deposition speed. Unlike the conventional laser cladding process, EHLA creates unprecedented low dilution and small heat affected zones for a fusion based process, with dilution depths as low as 5-10 µm. This allows the generation of thin coatings with desired chemistry, which can rival other fast coating processes, e.g., thermal spray, but offers stronger bonding interface and material adhesion (Fig. 2). TECHNICAL SPOTLIGHT EXTREME HIGH SPEED LASER APPLICATION: A REVOLUTION IN COATING AND REPAIR TECHNOLOGY A new process offers efficient deposition of high-performance materials in aerospace manufacturing, providing key advantages compared to conventional laser cladding. Combatting Euro 7 and China 7 emission regulations: EHLA hardfacing coated rotor produced quickly and efficiently, to reduce the wear and emissions of particulates.
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