Generating serial components via additive manufacturing (AM) a deep understanding of process-related characteristics is necessary. The extrusion-based AM called fused layer manufacturing (FLM), also known as fused deposition modeling (FDM™) or fused filament fabrication (FFF) is an AM process for producing serial components. Improving mechanical properties of AM parts is done by adding fibers in the raw material to reinforce the polymer. The study aims to create a more detailed comprehension of FLM and process-related characteristics with their influence on the composite.
Thereby, a short carbon fiber-reinforced polyamide (CarbonX™, 3DXTECH, USA) with 12.5 wt.-% fiber weight content, 7 μm fiber diameter and 150 to 400 µm fiber length distribution was investigated. To separate process-related characteristics of FLM, reference specimen were fabricated via injection molding (IM) with single-batch material. For mechanical characterization, quasi-static tensile tests were carried out in accordance to DIN 527-2. Quality assessment including fiber orientation and void content was performed via computed tomography (CT) and polished specimen.
The quasi-static tensile tests clarify effects on mechanical properties depending on process-related characteristics of FLM. CT assessments show high fiber orientation of FLM specimen in the printing direction. Comparing the resulting surface quality of FLM and IM emphasizes a significant difference. Due to process-related characteristics, the tensile strength of FLM specimen increase up to 28 % compared to quasi-homogenous IM specimen.