A comparatively new approach for the manufacturing of metal parts is the use of fused deposition modeling (FDM). Here, a metal powder filled filament is processed to manufacture components (green part). The subsequent process chain is identical to that of metal injection molding (MIM). Thus, the polymer binder is initially removed from the component (brown part). The metal particles are finally sintered in a furnace to form a pure metal component (white part/final part). The aim of this study is the investigation of the FDM process for the fabrication of metal components with regard to process parameters. This includes the consideration of material-specific parameters influencing the extrusion process. Especially, the material temperature and material behavior within the FDM nozzle are analyzed. On this basis, the mechanical properties of specimens manufactured with different nozzle sizes and strand geometries are examined. The resulting properties are used to evaluate the suitability of the specific strand-nozzle combination for processing the metal-polymer composite. In particular, the density of the components and the process reliability are important evaluation criteria. Finally, the comparison of white parts with parts manufactured in selective laser melting (SLM) shows the possibilities offered by processing metal-polymer composites in FDM.

Fused deposition modeling (FDM) is a widely used manufacturing process and the materials market is growing due to the increased requirements on materials. In particular, processing of high‐temperature materials such as PEEK is challenging. The aim of these studies is to investigate and improve the processability of a carbon fiber reinforced polyether ether ketone (PEEK) material in the FDM process. The first step is to define the relevant process parameters, which remain constant over the entire investigation. In particular, the material‐specific temperatures must be defined. Based on previous investigations regarding the weld seam strength and the warpage of the selected PEEK materials, a method to determine and adjust essential process parameters should be developed. One approach is the consideration of the volumetric polymer discharge at a stationary filament feed rate. The optimized adjustment of the feed rate ensures increased component densities and an improved process reliability. In this context, the component areas with non‐stationary extruder movement, such as in corner areas, have got a huge influence on the component quality. The acceleration and deceleration processes do not result in a desired uniform strand geometry due to the pressure changes within the nozzle. The acceleration can result in thinner strands while the deceleration can lead to a thickening of the polymer discharge. The aim is to adjust the pressure inside the nozzle depending on the acceleration profile to enable a homogenous strand geometry. The method should therefore allow the improvement of the processability of PEEK materials.

Individualized and complex additively manufactured metal components are increasingly used in an industrial environment. One possibility to manufacture such metal components is the fused filament fabrication (FFF) process. Here, a metal powder-filled polymer filament is processed (green part). For the realization of purely metallic components, the FFF-manufactured components are subjected to a post-process, which corresponds to the metal injection molding (MIM) process chain. In a first step, the polymer binder contained in the components is removed (brown part). Afterwards, the metal particles are sintered (white part). For the production of high-quality components, the porosity of the components must be considered. Essentially, the porosity of the components results from the characteristic FFF structure caused by the deposition of single strands. This has a direct influence on the porosity of the white parts and accordingly on the resulting part properties. Within this study, a filament consisting of copper particles and a polymer binder matrix of polylactide acid (PLA) is used. This filament offers the possibility to produce complex, thermally conductive, and electrically conductive components. During the examinations, the influence of the FFF-specific process parameters on the manufactured green parts is investigated. For this purpose, the stationary and non-stationary extrusion areas will be considered. The aim is to achieve a homogeneous strand geometry and, thus, the highest possible part density. This should lead to the reliable processing of copper-filled polymer filaments in FFF and provide a good basis for the production of pure copper components.

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