MAMMA

The proposal MAMMA aims to bridge the gap in additive manufacturing between different material types by combining the easy processing of polymers with the high performances of metals and ceramics. To achieve this goals novel formulations obtained combining different materials will be developed together with novel surface treatments of the printed parts. The rationale to develop the novel formulations will be to obtain highly filled polymeric systems (i.e. >30wt%) which might contain metals, ceramics or a combination of both. The highly filled systems will be processed by FDM-like systems but without transforming them into filaments prior to printing. This last option, made available using novel printing machines able to work with pellets or plastic rods, will allow to skip all the current limitations which hinders the use of highly filled systems in state of the art FDM printers. The objects printed therefrom will be further processed by debinding/sintering procedures to remove the polymeric phase when full metallic or ceramic objects will be needed. Hot Isostatic Pressing (HIP) will also be used to densify the printed parts to exploit the full potential in terms of mechanical properties. HIP will be applied on PEEK parts and metal/ceramic parts to improve the final mechanical properties .The proposal MAMMA aims also to introduce novel approaches for the functionalization of the printed parts with surface processing methods which can be thought as post-processing methods for the printed parts thus, these novel methods will be highly integrated within the 3d printing processing cycle. For some applications, plastic or metallic printed parts will be further processed by wet-based methods to obtain polymeric objects with functional non-organic structures decorating the polymer surfaces.
To achieve these goals, the material-structure-processing correlations will be further investigated. The metal parts obtained by this novel approach will be compared to similar parts processed by traditional metal additive manufacturing. This comparison will shed more light on the economic and technical benefits or limitations of the proposed approach over well consolidated metal additive approaches. The rheological behavior of the highly filled systems developed here will be investigated focusing on the melt behavior during processing. This approach is rather novel for additive manufacturing but, it will help to strengthen and rationalize the understanding of materials processing behavior. The debinding/sintering/HIP cycles will be modelled and analyzed by using advanced characterization techniques to find optimal processing conditions which can yield parts with controlled porosity, good inter layer adhesion and minimal shrinkage. Finally, the mechanical properties of the printed objects will be modelled considering the internal structure developed by processing to obtain mechanical data useful for design purposes.
As result of the project three different demonstrators (ie. a metal knee, a plastic reinforced (PEEK + Carbon Fibers) gear and a metal screw.) will be produced using the materials and the techniques developed. These demonstrators will be compared to parts obtained with traditional approaches to validate the technologies studied in the project.