Abstract
The laser metal deposition (LMD) process is used to increase the productivity rate in the field of laser additive manufacturing. Large structural Ti-6Al-4V components can be manufactured resource efficiently with this approach. In contrast, conventional manufacturing processes machine up to 95% from the bulk material to produce parts for the aerospace industry, as described by Peters et al., 2003. Compared to the powder bed based additive manufacturing the LMD process generates a local material deposition by feeding the powder directly to the substrate. On top of the surface, the laser beam will liquefy the additional material. Consequently a single track is deposited, which can be extended to a surface or 3D-structures. To qualify the LMD process for an economic industrial use, it is necessary to understand the physical phenomena during the building process. Especially for high wall structures, the thermal boundaries vary with the building height and therefore the process lacks in reproducibility and quality . In this paper, a new approach of adapted process parameters to the thermal conditions during the building process is presented. The laser power and processing speed vary for every layer until a stable building rate is achieved. The aim is to narrow the geometric tolerances of the additive manufactured structures. In addition, the influence of the building strategy on the resulting microstructure is determined.
