Increase in Surface Strength by Hammering and Solid Rolling of Volumes Produced by Means of Extreme High-Speed Laser Material Deposition

Abstract In the field of additive manufacturing, the demand for Extreme High-Speed Laser Material Deposition (EHLA) is increasing due to its unique process characteristics, economic efficiency as well as its great resource efficiency. The process is currently mostly used for surface functionalization through coating, by means of corrosion and wear protection. Thereby, almost all materials can be processed and nearly all material combinations can be created. The layers produced are dense and metallurgical bonded, and furthermore the surface roughness produced is low, so that only 20-100 μm has to be removed to produce a finished surface. However, it can also be used for the generation of 3D geometries. The greatest cost factor in the production is the coating material. With increasing requirements, for example in wear protection, cost-intensive special alloys or materials must be used. An opportunity to increase the areas of application in the field of wear resistance as well as increasing material efficiency is offered by combining EHLA with the innovative post-processing methods of hammering, solid as well as smooth rolling. Using these processes, the surface roughness can be reduced to a value of Rz 1-3 μm on the one hand and the surface hardness can be increased on the other hand. The hammering and solid rolling processes differ in their depth of impact. In the case of hammering, the impact depth can be a few millimeters and in the case of solid rolling only a few tenths of a millimeter. So far, the influence of hammering or solid rolling of additive manufactured volumes or surfaces has not been investigated. In the context of this study, the influence of hammering and solid rolling on a volume produced with EHLA is investigated. For this purpose, an EHLA produced volume of IN718 is built up and the influence of hammering as well as solid rolling on the surface roughness and hardness is analyzed.