04/12/2021
By Sokny Long

The Francis College of Engineering, Department of Plastics Engineering, invites you to attend a master's thesis defense by Brian Koker on “Design and Characterization of Dual-Material Fused Filament Fabrication Filaments for Enhanced Diffusion."

Master’s Candidate: Brian Koker
Defense Date: Thursday, April 22, 2021
Time: 2 to 3:30 p.m. EST
Location: This will be a virtual defense via Zoom. Those interested in attending should contact brian_koker@student.uml.edu and committee advisor Jay_Park@uml.edu at least 24 hours prior to the defense to request access to the meeting.

Committee Chair (Advisor): Jay Park , Assistant Professor, Plastics Engineering, UMass Lowell

Committee Members:

  • David Kazmer, Professor, Plastics Engineering, UMass Lowell
  • Amy Peterson, Associate Professor, , Plastics Engineering, UMass Lowell
  • Eric D. Wetzel, Team Lead, US Army Laboratory Weapons and Materials Research Directorate (CCDC-ARL)

ABSTRACT:
Previous research in the field of bicomponent thermoplastic 3D printing material showed promise in developing structures with tough, near-isotropic properties; a feat that is unheard of in tradition fused filament fabrication (FFF) systems. The combination of a core with a significantly higher glass transition temperature (Tg) than the sheath allows for parts that can be annealed to increase molecular diffusion between layers while maintaining dimensional stability. The use of a thermal draw tower in previous research allowed for rapid prototyping of material and geometric combinations but lacks viability as a larger scale manufacturing process due to the bottleneck of creating dual material preforms and additional processing requirement. Using a convention coextrusion technique, with an additive manufacturing driven iteration process, showed promise as a scale-up technique, and was able to produce larger quantities of consistent filament needed for more comprehensive analysis and production. Compared to current state of the art ABS filaments, this filament showed around a 5 time increase in z- direction impact toughness, and around a 3 time increase in z-direction tensile strength after annealing.

The enhanced thermal stability of this material allowed for higher print temperatures which also demonstrated significantly improved strength. This research continues to demonstrate the ground-breaking improvements to FFF that are possible through dual material filaments as well as the manufacturing feasibility of such a product.

All interested students and faculty members are invited to attend remotely.