Abstract
The first hype of Additive Manufacturing (AM) is running out gradually and many companies realize that AM is not the allrounder and wonder drug as it was claimed years ago. Technologies like Selective Laser Melting (SLM) and Electron Beam Melting (EBM) offer theoretically extremely attractive possibilities in terms of tailoring local microstructures and geometrical freedom. However, in today’s practice the complex processes during solidification makes it hard to guarantee reproducible properties and geometries. Furthermore, investment is high, safety issues related to the use of loose powders have to be considered and the building process is comparably slow.
Alternative to SLM and EBM there is a number of additive technologies based on using a binder-powder mixture. This mixture can be formed to near-net-shape geometries by a variety of different techniques like filament printing, injection moulding, extrusion or even screen printing. Binder jetting is regarded as an additive technique for high volume production. Basically, each technique is optimized for a typical kind of geometrical features and number of parts to be produced. However, the combination of these techniques is quite easily done and attractive, because in all cases the processing after shaping is the same, namely debinding and sintering. Thus, independent of shaping microstructure and properties are the same or at least very similar. Compared to SLM and EBM some advantages arise, e.g. no need to handle loose powders (besides of binder jetting), homogeneous microstructure and stress-free parts and generally lower investments. On the other hand, size limitations related to the debinding process and shrinkage during sintering as well as change in mechanical properties have to be discussed.
This talk gives an overview on available techniques and achievable properties, focused on the processing of titanium alloys.
