The aim of this project is to reduce the high residual stresses and the shrinking of the material caused by the high cooling rate during the building process, which leads to crack formation. In this project, a heated building platform helped to reduce the temperature gradient, which leads to certain microstructural changes that made these materials processable with selective laser melting.
In most industrial applications, the lightweight design and the development of individual, functional customized products have been and still are of major interest for material development. Therefore, materials such as aluminum-, titanium-, nickel-based alloys, as well as steels came into focus due to their specific, aligned density and mechanical characteristics. In view of these aspects, high strength aluminum alloys, e.g., EN AW 7075, have not been considered yet for additive manufacturing due to their inferior processability. Aluminum is only given as an example to emphasize the need for research and to discern the effects of a heated building platform concerning the resulting mechanical and microstructural properties. With regards to the future microstructural and mechanical tests, a tool steel (H13, X40CrMoV5-1) was chosen since this material is a commonly applied steel in industrial applications. Moreover, this steel is difficult to process via SLM without further processing modifications. The second analyzed material was the aluminum alloy AA7075. Due to the occurring hot cracks, a heated platform up to 400°C represents a promising solution to avoid these defects.