Investigation of the weld seam quality of particle filled polymers in the fused filament fabrication process

Abstract The fused filament fabrication (FFF) is an additive manufacturing process in which thermoplastic strands are deposited. Due to thermal fusion of the strands, the FFF can be characterized as a plastic welding process. The resulting weld seams are weak points in the component structure and, thus, determine the mechanical properties. Thereby, the weld seam quality is significantly influenced by the process temperatures. To estimate the mechanical properties, knowledge of the resulting weld seam quality is required. In the context of material development, the weld seam quality can also be used as a criterion for the basic evaluation of the processability. In the present study, the influence of particulate fillers on the weld seam quality of a thermoplastic polymer matrix is investigated. With regard to the material, the influences of the filler type and the filler volume fraction are considered. In terms of the process, the influence of the process temperatures on the weld seam quality is evaluated. The aim is the description of the resulting weld strength and the comparison to the base material strength by means of the welding factor. For this purpose, an existing method is applied and adapted with regard to process reliability and comparability. Highlights Test plan is determined on the basis of a thermal analysis Method adaptation enables faster and reliable specimen manufacturing Higher process temperatures lead to higher weld seam strengths Filled polymers show a significantly reduced weld seam strength Relationship between filler content and weld seam strength is shown