Fri, 24 January, 2020
TWI Yorkshire has acquired the UK’s first EHLA system from Hornet Laser Cladding BV. Scheduled to be delivered to TWI Technology Centre Yorkshire in February 2020, the system has been undergoing factory acceptance tests in The Netherlands before installation. In addition, TWI staff have been trained on operating the system.
Hornet Laser Cladding BV is the first system integrator to successfully implement the EHLA process (Extreme High-speed Laser Application).
Additionally, the system is supplied with a 4kW Laserline diode laser and will be an interesting addition to TWI's existing Disk and CO2 beam sources.
The EHLA technique was developed by Fraunhofer ILT Institute in Aachen, Germany and is capable of speeds 10 times faster than traditional LMD (laser metal deposition) for surface coverage rate.
The EHLA process has proven capable of coating speeds above 300m/min and surface coverage rates of 250-1000cm2/min for rotationally systematical components. The short production cycle is also helped by the layer thickness being between 25 μm and 400 μm per layer, as compared to a minimum thickness of 500 μm for conventional LMD. The EHLA process differs from LMD by melting powder in flight before it reaches the substrate, significantly reducing the laser energy absorbed into the substrate and subsequently the depth of the dilution.
Being able to apply layers of coating in a resource efficient way has opened up new opportunities for material pairings and additive manufacturing. EHLA also acts as an economically viable alternative to hard chrome plating and thermal spray technologies for corrosion and wear protection. The coating is metallurgically bonded via the fusion process to the base layers, meaning that it will not chip, peel, or delaminate and, due to being non-porous, it offers more efficient protection than competitive techniques.
EHLA, when compared to thermal spraying, has been found to be more efficient in its use of materials. Because EHLA does not require multiple layers to mitigate against porosity and has a higher capture efficiency, there are examples of 90% feedstock material savings thermal spray.
The EHLA process is also superior in applying high-quality coatings to components than traditional LMD/laser cladding. This is due to EHLA’s ability to cover large components quickly with similar integrity and material characteristics to LMD.
You can find out more about the EHLA process at the Fraunhofer ILT Institute website.