About this Abstract |
Meeting |
2024 ASC Technical Conference, US-Japan Joint Symposium, D30 Meeting
|
Symposium
|
2024 ASC Technical Conference, US-Japan Joint Symposium, D30 Meeting
|
Presentation Title |
Micro-computed tomography to characterize in situ control of fiber volume fractions in fused filament fabrication |
Author(s) |
Joshua Green, Mark Flores, Ian Rybak, Ivana Hernandez, Mauricio Lopez, Mathew Schey |
On-Site Speaker (Planned) |
Joshua Green |
Abstract Scope |
Recent advancements in fused filament fabrication provide a new opportunity to explore functional gradients beyond topology optimization by enabling functional gradation of composite concentration. Accurate control of fiber volume fraction was demonstrated in steady state extrusion, during stepwise transitions, and within a functional gradient.
Commercial filaments composed of carbon fiber reinforced polylactic acid (PLA+CF) and non-reinforced polylactic acid (PLA) were processed through an active-mixing hotend and extruder assembly mounted on an FFF printer to provide local composition control of carbon fiber concentration in a PLA matrix. Supported by custom software, mix ratios were set by altering the feed rates for each extruder, and a mixing rod was configured to rotate in proportion to the total filament extruded providing constituent dispersion and distribution. Specimens were evaluated using thermogravimetric analysis and micro computed tomography. Deep learning models were applied for image segmentation and analysis of voids and fibers. Both filaments were analyzed to determine input characteristics as a reference for analyzing mixtures.
Steady state mixtures of 0:100, 25:75, 50:50, 75:25, and 100:0 PLA+CF:PLA were evaluated to determine the accuracy of prescribing filament extrusion ratios to facilitate control of carbon fiber density and to identify microstructural effects of active-mixing composites in FFF. Transitions between the maximum and minimum carbon fiber content were characterized throughout the progressive change in composition including regions of purge, transition, and steady-state extrusion. A functionally graded structure was developed by varying mix ratios in each raster and evaluated to determine accuracy of local composition control. |
Proceedings Inclusion? |
Definite: Post-meeting proceedings |