Impact of processing conditions and sizing on the thermomechanical and morphological properties of polypropylene/carbon fiber composites fabricated by material extrusion additive manufacturing

Abstract

For the 3D printed composites, fiber alignment is affected by the direction of melt‐flow during extrusion of filaments and subsequently through the printing nozzle. The resulting fibers orientation and the fiber‐matrix compatibility have a direct correlation with mechanical properties. This study investigates the impact of processing conditions on the state of the carbon fiber types and their orientation on the mechanical properties of 3D‐printed composites. Short and long carbon fibers were used as starting reinforcing materials, and the state of fibers at the beginning and on the printed parts were evaluated. Strong anisotropy in terms of mechanical properties (flexural and impact properties) was observed for the samples printed with different printing orientations. Interestingly, the number of voids in the printed composites was found to be correlated with the fiber types. The present work provides a step towards the optimization of tailored composite properties by additive manufacturing.

Additively Manufactured Composite Lug with Continuous Carbon Fibre Steering Based on Finite Element Analysis

“…The CCF layers break within a narrow window around the location of the maximum stress, indicating some strength variation over the length of the CCF and potentially undulation-induced load variation between layers highlighted in Figure 6 a (red box), and the reasoning is that already discussed in Figure 5 . In Figure 6 b, the CT scan of both primary and secondary fractures shows uneven failure, which is an attribute of MEX specimens similarly reported by authors Savandaiah et al [ 3 ] and Spoerk et al [ 5 ]. Voids between each layer are inherent to MEX due to layered processing and result in poor load transfer between layers, causing jagged teeth fractured appearance [ 4 , 17 ].…”

“…The behaviour of materials extrusion (MEX) additive manufacturing of short-fibre-reinforced thermoplastic composites had been well studied as processing effects on thermomechanical and morphological properties [ 1 , 2 ]. Several researchers have investigated the influence of fibre length distribution [ 3 , 4 ], process-induced anisotropy [ 5 ] and thermal material [ 6 ] properties on the functional performance [ 7 ] of the parts produced via MEX composite additive manufacturing. The key aspect for the adoption of composite MEX is the light-weight potential of parts and assemblies by functional optimisation of the end-user application [ 8 ].…”

Rapid consolidation of 3D printed composite parts using compression moulding for improved thermo mechanical properties

“…Length distribution analyses were performed with proprietary image processing software, Image-Pro plus and FASEP 3E, supplied by XYZ High Precision, Germany. The sample preparation and measurements are based on the procedure detailed in the previously published work (Unterweger et al, 2020;Savandaiah et al, 2021aSavandaiah et al, , 2021b.…”

Comparison of CAD and Voxel-Based Modelling Methodologies for the Mechanical Simulation of Extrusion-Based 3D Printed Scaffolds

“…Moreover, during the deposition process, voids may appear, leading to a higher porosity and consequently, affecting the mechanical properties. This effect depends on the materials used, especially in composite materials [ 43 ]. Therefore, both the dimensional deviation and the voids arising lead to differences between the simulated and the experimental mechanical results.…”