Extreme High-Speed Directed Energy Deposition (EHLA) is a modified variant of the laser based Directed Energy Deposition (DED-LB) and is being applied as an efficient coating process for rotational symmetric components. Characteristic for EHLA processes are feed rates of up to 200 m/min which result in smaller weld bead deposition and thinner layer thicknesses compared to conventional DED-LB. When transferred to Additive Manufacturing (AM) this characteristic utilizes the potential of depositing thin-walled filigree structures at deposition rates which are comparable to typical DED-LB processes (EHLA3D).
Due to the high feed rates typical EHLA handlings are lathe type machines which realize the relative movement by rotating the rotational symmetric component. During the recent years the transfer to AM processes were demonstrated on a tripod machine developed by ponticon GmbH in collaboration with Fraunhofer ILT. The results of this work were achieved with a modified CNC-type machine which is capable of feed rates of up to 30 m/min.
In this work process parameters were developed for the deposition of thin-walled filigree structures with the Ni-based superalloy IN718. Single tracks with constant feed rates and variation of beam diameter and powder mass flow were deposited and analysed regarding the resulting weld bead dimension. Then process parameters were selected and transferred to the deposition of thin walls and guidelines of the parameter adaption towards thin-walled deposition were defined. Depending on the developed parameter sets wall thicknesses between 300 µm – 500 µm are achieved.