Metal-MEX

Untersuchung des Entbinderns und Sinterns beim Materialextrusionsverfahren (MEX) und Erarbeitung von Korrelationen zwischen den gewählten Prozessparametern und den mechanischen Eigenschaften der Bauteile

Aim of the development

Up to now, powder bed fusion (PBF) has been the focus of additive manufacturing of metallic components. Due to the low build rates and especially the cost-intensive equipment technology, alternatives to PBF are demanded. The group of material extrusion (MEX) processes has lower investment costs and higher build rates. In order to make this process category usable for other material groups - plastics have been the focus so far - a transition from pure polymer materials to metal- or ceramic-filled plastic filaments is currently taking place. This is possible by filling a binder system with particles or mixing powder with the binder and then "printing" it. In a subsequent step, after the actual molding, the strength is then produced by removing the binder and sintering the particles together. The aim of the project was to determine the factors influencing debinding and sintering on the resulting material properties by means of material extrusion of additively manufactured metallic components. Based on the scientifically validated findings, boundary conditions and procedures to be observed are derived.

Advantages and solutions

The solution approach consisted of two main elements. Firstly, the transfer of previously available findings on debinding and sintering along the MIM process chain (powder injection molding) to the field of additive manufacturing. On the other hand, experiments and investigations were carried out in order to be able to work out the differences to MIM. As a result, it was possible to develop parameter sets and recommendations for action that ensure high geometric reproducibility and good results with regard to the mechanical properties in the area of the solid material. Based on the materials considered, it was also possible to identify the limits of the existing plant technology, which offer starting points for further development work. Overall, the project can be regarded as a success, since the extensive investigations enabled a broad knowledge base to be built up on the basis of which the metal extrusion process can be further developed.

Target market

The research project has provided a fundamental understanding of the technology chain of additive manufacturing in the metal extrusion process and evaluated the technologically relevant boundary conditions. This created the basis for further application-specific development of the process in collaboration with interested SMEs, thus adding another process to the range of additive manufacturing technologies. Particularly advantageous - especially for small companies - are the significantly lower investment costs for the shaping equipment compared to other additive processes. The project has demonstrated that molding can be implemented with a conventional FDM printer. Accordingly, the potential for implementation in the industrial environment is high. Users also benefit from the fact that the research project deliberately worked with freely available system technology and materials. The results are therefore not linked to a fixed overall process or plant system, such as those marketed by Markforged. The industrially described implementation of substeps of the technology chains is thus guaranteed.