Materials and process development for Additive Manufacturing of high-quality metallic components is currently done at institute MATERIALS by using two complementary technologies:
In generative laser cladding, often called laser metal deposition (LMD ), the powder alloy is fed directly into the laser beam and melt together with the already existing metal structures.
In selective laser melting (SLM ), also called 3D metal printing or laser beam melting (LBM), the volume of the final component is generated layer by layer out of a powder bed via local melting of the existing powder particles.
Both technologies complement one another in their different strengths:
LMD is an additive manufacturing technology for producing metallic components. Starting point is an alloy powder which is fed directly into the laser process. Thus, mixing different materials in any desired ratio is possible, which is an essential advantage of this technology. Therefore, the material properties can be designed gradually, and the fabrication of composites (e.g. sandwich structures) is feasible. Another advantage of LMD is that the substrate geometry can be quite arbitrary.
The production of complex tools via LMD mostly needs intermediate machining, as well as the surface of the final components needs final processing depending on the quality demands. These additional processing steps can be performed at MATERIALS in Niklasdorf in a combined laser and milling station, which has the advantage of improved accuracy and reduced turn-around time.
This popular term describes the technology of selective laser melting (SLM) out of the powder bed. With this technology the component to be generated is built up layer by layer: slices of less than 50 µm thickness are fused together to a solid microstructure by a laser beam to form the final component. Precision and accuracy in vertical direction are defined by the layer thickness, whereas in lateral direction these parameters can be also controlled by the selected laser parameters and exposure strategies in dimensions far below 50 µm. Essential for this technology is (in contrary to the so-called laser sintering) that the original powder is completely molten: The manufactured parts show nearly no porosity any more, while the macroscopic material properties are satisfactory and even comparable to those achieved by conventional manufacturing.
While in conventional manufacturing the costs per part decrease with increasing batch size, an advantage of SLM is that also single parts can be produced at reasonable costs.
The most important advantage of SLM is the manufacturability of components with highly complex geometries: e.g. branched cooling channels immediately beneath the surface can be realized. Components can be optimized in shape as material can be omitted in volume sections where no forces are applied to, which may lead to a drastic reduction in weight. Parts that need to be composed out of several components when manufactured conventionally can be manufactured as one single component using SLM. Industries with a continuously rising fraction of additively manufactured components are the aerospace industry on one hand, where the reduction of weight is essential, and the medical technologies on the other hand, where, e.g. individual dental implants can be manufactured in a quick and cost-efficient way.