3D Printing of Low-Filled Basalt PA12 and PP Filaments for Automotive Components

Abstract

Fused Deposition Modeling (FDM) enables many advantages compared to traditional manufacturing techniques, but the lower mechanical performance due to the higher porosity still hinders its industrial spread in key sectors like the automotive industry. PP and PA12 filaments filled with low amounts of basalt fibers were produced in the present work to improve the poor mechanical properties inherited from the additive manufacturing technique. For both matrices, the introduction of 5 wt.% of basalt fibers allows us to achieve stiffness values comparable to injection molding ones without modifying the final weight of the manufactured components. The increased filament density compared with the neat polymers, upon the introduction of basalt fibers, is counterbalanced by the intrinsic porosity of the manufacturing technique. In particular, the final components are characterized by a 0.88 g/cm3 density for PP and 1.01 g/cm3 for PA12 basalt-filled composites, which are comparable to the 0.91 g/cm3 and 1.01 g/cm3, respectively, of the related neat matrix used in injection molding. Some efforts are still needed to fill the gap of 15–28% for PP and of 26.5% for PA12 in tensile strength compared to injection-molded counterparts, but the improvement of the fiber/matrix interface by fiber surface modification or coupling agent employment could be a feasible solution.

Mechanical Performance of Recycled 3D Printed Sustainable Polymer-Based Composites: A Literature Review

“…Natural fibers are already known for having a positive effect on the development of printable feedstock, and basalt fibers reinforced composite suitable for 3D printing have already been synthesized with the optimal weight fraction being 5% wt. [101,102], while cocoa beans shells used as filler helped reduce warping issues of rPP filament by 67% [103]. Tamarind fruit shells (TFS) and corn husk fibers (CHF) have been inserted into PP blends, but minimal reduction of warping was observed, and the maximum weight fraction reached was relatively low (3% for TFS, 7.5% for CHF).…”

“…Basalt fibers in a direction horizontal to the tensile test helped increase strength and close the difference gap to 15-28% in comparison to IM PP specimens. The direction of the inserted fibers after extrusion had an immediate effect on performance, with horizontal direction giving greater strength but angular direction increasing ductility and flexibility [101,102]. Natural fibers are an excellent alternative and a sustainable way to utilize agricultural waste.…”

“…Polymers that require high levels of energy for the degradation process are stated as difficult to recycle, as PC or PS are primary examples of the aforementioned plastics and are mainly utilized in polymer blends with adequate properties, since the exploitation of them in additive manufacturing as sole materials was challenging due to the high temperature demands occurred from the difficulty of melting and degrading. It was found that the rABS/PC blend showed no decomposition or quality drop in weather exposure, making it a sustainable solution for outdoor applications [102], while recycled ABS/PS/PLA allowed for property optimization and had great load-bearing stability [108,123]. Metal powder-reinforcement rABS had around 100% more UTS than the plain matrix polymer [109].…”