Title: Fused Deposition Manufacturing of Polymer Composites via Dynamic Co-extrusion

Researcher: Robert Lahaie

Sponsors: Stratasys, Greene Tweed, CCDC Soldier Center, Hutchinson Aerospace and Industry

Collaborators: Ph.D Candidate Robert Lahaie, Dr. David Kazmer, Dr. Christopher Hansen

Abstract: The dynamic co-extrusion of the multiple material streams has been enabled with the integration of a customized 3D printer hot end. The research is investigating hot end designs with miniaturized spiral-flow and bifurcating-flow dies (see Figure 1). The material streams are fed at pressure with the inner material flowing within the core of the outer spiral/bifurcating flow paths. The two flows are combined in situ to produce extrudate having a shell-core, multi-layer, and mixed flows into the downstream nozzle die. The hot end design has been implemented onto a desktop FFF 3D printer to perform validation work of the hot end. Validation work has included, but not limited to, izod impact specimens, dimensional stability during annealing tests, and tensile bars (see Figure 2). Additionally, the research has investigated material transient response times by means of printing serpentine patterns to analyze the amount of extrudate required to make a complete color change (see Figure 3). Ongoing research is investigating additional material combinations and test cases to broaden the possible applications for Fused Deposition Manufacturing of Multiple Materials (FD3M).