Nanomaterials-based 3d Printer Filament Electrical CharacterizationScott Merry, [email protected], Inc., Seattle, WA 98103
Introduction
In the Fused Deposition Modeling™ (FDM) method of 3d printing, polylactic acid (PLA) plastic filament is melted and squeezed out of the printer’s nozzle as it lays down one layer at a time of a 3d model designed using specialized software (Figure 1).
Researchers are synthesizing nanomaterials-based PLA filaments with novel behaviors. Two properties of interest are electrical resistance and capacitance. These are characterized using:
Volume Resistivity (ρ, units Ω-cm): • Low values indicate more conductive material
ρ = RA / l R is resistance measured over length of filament lA is cross-sectional area of filament
Relative permittivity (εr, unitless): • High values indicate better dielectric material
εr = Cd / 8.85 x 10-12 A C is capacitance measured across depth d of
printed flat plate of materialA is area of the rectangle8.85 x 10-12 is the permittivity of air
Conclusion
Volume Resistivity F-Electric™ can be used for 3d printing of entire electronic circuits, using this material where wire or conductive traces would normally be used, with unmodified PLA as the structure on which to build.
Dielectric BehaviorWith some improvement, the dielectric filament may be a candidate for use as electromagnetic interference shielding, a capacitive touch button, or in combination with conductive filament as a 3d-printed capacitor.
Future WorkWhile F-Electric™ is already in use worldwide, researchers are fine-tuning the chemical synthesis of the dielectric prototype to further increase relative permittivity.
Acknowledgements
Michael Toutonghi, CEO, Functionalize, Inc.
Peter Kazarinoff, Alissa Agnello, Kristine Schroeder, North Seattle College/SHINE
Chris Sanders, North Seattle College/Electronics
ReferencesBoylestad, R. (2007). Introductory circuit analysis (11th ed.). Upper Saddle River, N.J.: Pearson/Prentice Hall.
ud Din Khan et al, “Permittivity and Electromagnetic Interference Shielding Investigations of Activated Charcoal Loaded Acrylic Coating Compositions,” Journal of Polymers, vol. 2014, Article ID 193058, 7 pages, 2014. doi:10.1155/2014/193058
Method
Each filament measured the industry standard of 1.75 mm diameter.
Plain, Makerbot™-branded PLA filament was chosen as a control in comparison to Functionalize™ F-Electric™ for volume resistivity, and to a prototype material for relative permittivity.
Resistance was measured over a 1 m length of filament taken directly from the reel.
For relative permittivity, plate capacitors (Figure 2) were constructed of 3d printed 0.4 mm thick rectangles of plastic sandwiched between aluminum foil. Capacitance was measured with a portable meter.
Discussion
Volume Resistivity in the F-Electric™ material was significantly lower.
Relative Permittivity in the prototype material wassomewhat higher.
Figure 2. Plate capacitor
a. 3d printing design software b. 3d printer. Photo courtesy Lisa Eisner
e. 3d printed materials. Photo courtesy Functionalize, Inc.
c. 3d printer in action, and d. closeup of filament being extruded from nozzle. principledtechnologies.com/insights/techeverywhere
Figure 1. 3d printing
