EXPLORING THE MANUFACTURABILITY AND RESISTIVITY OF CONDUCTIVE FILAMENT USED IN MATERIAL EXTRUSION ADDITIVE MANUFACTURING

Open Access
Author:
Gao, Harry
Area of Honors:
Mechanical Engineering
Degree:
Bachelor of Science
Document Type:
Thesis
Thesis Supervisors:
  • Dr. Nick Meisel, Thesis Supervisor
  • Dr. Jacqueline O'Connor, Honors Advisor
Keywords:
  • Conductive
  • Filament
  • Additive
  • Manufacturing
  • 3D
  • Printing
  • Multifunctional
  • Direct
  • Write
  • PLA
  • Graphene
  • Material
  • Extrusion
  • Deposition
  • Resistivity
  • Design
Abstract:
Additive manufacturing (AM) has the unique advantage of being able to build multifunctional parts with embedded electronic systems all at once, without the need for post-print assembly. However, many existing forms of multifunctional AM require expensive materials or equipment and are not easily accessible to hobby-level users. Currently, most hobby-level desktop 3D printers are only used with non-conductive polymer filament such as polylactic acid (PLA) or acrylonitrile butadiene styrene (ABS). Recently however, conductive filaments have become increasingly available for material extrusion desktop printers. Ideally, the use of these filaments would allow circuitry to be directly printed simultaneously with the rest of the base structure, enabling complex, inexpensive, multifunctional structures. However, the resistivity of conductive filament is significantly impacted by the geometry of the print and the printing parameters used in the build process. In this study, two types of commercially-available conductive filament (Protopasta Conductive PLA and BlackMagic Graphene) were tested under a variety of print parameters and geometries. The effects of print temperature, layer height, extrusion speed, and orientation on resistivity were quantified. In addition, the effects of simultaneous dual extrusion were also analyzed. It was found that print temperature, layer height, and orientation all significantly affect the resistivity in various ways. The knowledge from this research will allow users to design better multifunctional parts that have reduced resistivity and better utilize the unique advantages of AM due to an improved understanding of the underlying process-structure-behavior relationships.