Electrical Resistivity of 3D-Printed Polymer Elements

Abstract

During this study, the resistivity of electrically conductive structures 3D-printed via fused filament fabrication (FFF) was investigated. Electrical resistivity characterisation was performed on various structural levels of the whole 3D-printed body, starting from the single traxel (3D-printed single track element), continuing with monolayer and multilayer formation, finalising with hybrid structures of a basic nonconductive polymer and an electrically conductive one. Two commercial conductive materials were studied: Proto-Pasta and Koltron G1. It was determined that the geometry and resistivity of a single traxel influenced the resistivity of all subsequent structural elements of the printed body and affected its electrical anisotropy. In addition, the results showed that thermal postprocessing (annealing) affected the resistivity of a standalone extruded fibre (extruded filament through a printer nozzle in freefall) and traxel. The effect of Joule heating and piezoresistive properties of hybrid structures with imprinted conductive elements made from Koltron G1 were investigated. Results revealed good thermal stability within 70 °C and considerable piezoresistive response with a gauge factor of 15–25 at both low 0.1% and medium 1.5% elongations, indicating the potential of such structures for use as a heat element and strain gauge sensor in applications involving stiff materials and low elongations.

Influence of Manufacturing Process on the Conductivity of Material Extrusion Components: A Comparison between Filament- and Granule-Based Processes

“…Stankevich et al observed a decrease in resistivity as nozzle diameter increased for a CB-PLA composite [ 11 ]. The observed behavior may have been due to the smaller nozzle’s increased susceptibility to clogging, or a restricted flow cross-section, resulting in uneven polymer melt application and higher variability.…”

“…The influence of nozzle diameter has rarely been investigated, as shown in the table (literature review). Previous studies in this field have been conducted by Stankevich et al (using PLA/CB and PVDF/G), Dembek et al (using PLA/CNT), and Nassar et al (using PCL/copper) [ 11 , 20 , 34 ]. The DoE in this study matched that of Nowka et al in [ 4 ].…”

“…The studies differ fundamentally in terms of the process variants that are used. The majority of publications use the more common process of filament MEX [ 10 , 11 ] (the list is a selection). Granule MEX is much less commonly used to produce electrically conducting specimens [ 12 , 13 ].…”

“…The resistivity of the filament MEX process has been extensively studied with respect to the influence of most process parameters [ 10 , 11 ]. Studies have often used commercially available filaments [ 4 , 10 , 11 , 18 , 20 ]. In contrast, the granule MEX process has only been used to process custom-made conductive polymer composites.…”

DC Electric Metamaterial Behavior in Fused Filament Fabrication Prints With Tuned Interfaces

“…As material ProtoPasta conductive PLA with a diameter of 1.75 mm is used [50]. This material has a reported resistivity of 0.06 Ω m to 0.34 Ω m, depending on the print settings and geometry [44], [51]- [53]. The samples are squares of 30 x 30 x 0.2 mm, printed on top of oxidized silicon wafers, where a spray is used to improve adhesion (3DLAC).…”