Overview: For Dr. Kun Fu’s laboratory, this study aimed to assess print parameters of a novel carbon nanotube (CNT) additive manufacturing process. I explored how key 3D printer parameters affect the structural integrity of carbon nanotube structures.
Background:
Dr. Fu's lab developed a novel method to fabricate pure CNT structures using a traditional FDM 3D printer—printing the desired structure with a CNT composite filament (a mixture of CNTs embedded in a polymer matrix) (Fig. 1), coating the print in a microwave-absorbing susceptor fluid, then heating it in a 1100W microwave to vaporize the polymer matrix and leave behind a pure CNT structure (Fig. 2). Before 3D printing, a “slicer” software converts a CAD model into machine instructions, controlling parameters such as infill density, infill pattern, number of base layers, and print bed temperature (Fig. 3), all of which affect the final product’s structural integrity .
Objective:
Determine the best 3D printing slicer settings (infill density, pattern, base layer count, and print bed temperature) for producing mechanically robust CNT structures.
Methodology:
I conducted a series of eight trials in which I varied four key slicer parameters independently while keeping all other settings constant (Fig. 4):
I executed a series of experiments using the same rectangular prism CAD model sent through the lab's process, leaving a pure CNT structure. These specimens were printed under controlled variations: infill densities of 25% and 50%, infill patterns (rectilinear vs. honeycomb), base layer counts of 2 versus 4, and bed temperatures set at 50 °C and 70 °C, while maintaining a constant extruder nozzle temperature of 200 °C. These were coated in susceptor fluid and microwaved, leaving pure CNT structures behind.
I then assessed the structural integrity of each structure by subjecting it to 10 seconds of physical agitation and visually comparing the degree of flaking, warping, and retention of the original geometry. I focused on modifying the slicer settings, executing the printing trials, and performing the comparative analysis of the resulting CNT structures.
Key Results:
Interior Fill Percentage: Prints with 50% infill retained a more defined rectangular shape and exhibited significantly less flaking than those with 25% infill, which broke along the corners.
Interior Fill Pattern: The honeycomb infill pattern produced a more cohesive and stable structure compared to the rectilinear grid, which showed increased susceptibility to shear forces and flaking along its edges.
Number of Adjacent Base Layers: Samples printed with 4 base layers demonstrated a more intact and sharply defined base, with reduced crumbling at the edges compared to those with only 2 layers.
3D Printer Bed Temperature: A higher bed temperature of 70 °C resulted in flatter edges and less warping, due to a smaller temperature differential between the bed and the extruder, compared to a 50 °C setting.
Conclusion:
The study confirmed that adjusting the slicer parameters can significantly enhance the structural integrity of CNT composite structures. The optimal settings identified were a 50% interior fill, a honeycomb infill pattern, 4 adjacent base layers, and a 3D printer bed temperature of 70 °C. These parameters yielded CNT prints that more closely retained the intended geometry with minimal flaking and warping under physical stress. The findings guide future 3D printing procedures for robust CNT applications in advanced nanomaterial fabrication.