Development of an Additive Manufacturing System for the Deposition of Thermoplastics Impregnated with Carbon Fibers

Abstract

This work presents an innovative system that allows the oriented deposition of continuous fibers or long fibers, pre-impregnated or not, in a thermoplastic matrix. This system is used in an integrated way with the filamentary fusion additive manufacturing technology and allows a localized and oriented reinforcement of polymer components for advanced engineering applications at a low cost. To demonstrate the capabilities of the developed system, composite components of thermoplastic matrix (polyamide) reinforced with pre-impregnated long carbon fiber (carbon + polyamide), 1 K and 3 K, were processed and their tensile and flexural strength evaluated. It was demonstrated that the tensile strength value depends on the density of carbon fibers present in the composite, and that with the passage of 2 to 4 layers of fibers, an increase in breaking strength was obtained of about 366% and 325% for the 3 K and 1 K yarns, respectively. The increase of the fiber yarn diameter leads to higher values of tensile strength of the composite. The obtained standard deviation reveals that the deposition process gives rise to components with anisotropic mechanical properties and the need to optimize the processing parameters, especially those that lead to an increase in adhesion between deposited layers.

Continuous fibre composite 3D printing with pultruded carbon/PA6 commingled fibres: Processing and mechanical properties

“…As well as in-house manufactured feedstock prepreg materials, researchers have utilized conventional thermoplastic prepreg sheets and cut them into small width tapes for 3DP [48,67]. Besides in-nozzle impregnation and the use of prepregs, commingled fibres, which are commonly used in textile composites, have also been utilized for continuous fibre printing [66,17,18,55]. In these studies, commingled fibre tows of reinforcing fibres and thermoplastic fibres are pultruded from a heated metal die and consolidated into a rod-shaped filament to be used as the feedstock materials in the FFF printing process.…”

A review of fused filament fabrication of continuous natural fiber reinforced thermoplastic composites: Techniques and materials

“…This is preferable as the melting of polymer outside of the heated zones could cause clogging in the extruder mechanism. 67 This extrusion head structure could be constructed by opening a hole on any ordinary FFF print head. The filament feed channel is along the Z-axis and perpendicular to the print bed.…”

“…(A) continuous fiber added in the cold zone. The graphs from left to right are main view, cut view showing filament and fiber yarn, and real deposition head 67 ; (B) Left: schematic representation of the fused filament fabrication (FFF) process, right: the working process of the extruder head 68 ; (C) Left: structure of extruder head, right: printed sample 64 . (D) Left: Schematic of the FFF process of continuous flax/PA6 composite, right: Photograph of the modified printer's zone 41 …”

“…In existing literature, it is believed that the channel for continuous fiber should be located in the cold zone of the extrusion head between the heat sink and the hot zone, as shown in Figure 6A. This is preferable as the melting of polymer outside of the heated zones could cause clogging in the extruder mechanism 67 . This extrusion head structure could be constructed by opening a hole on any ordinary FFF print head.…”

Designing the organoplastics based on aromatic polyamide, study of their operational properties and applicability

“…Authors of study [8] emphasize that the reinforcement of polyamides with long carbon fibers makes it possible to obtain reliable structural plastics for tribotechnical purposes. However, they arrange the carbon fibers along a single direction, which leads to the anisotropy of the materials' properties; in addition, one cannot achieve good adhesion between the components.…”