Steven from 3D Printer Academy released a video to his YouTube channel in early 2024 to discuss how wall line counts and infill contribute to the strength of 3D prints. The full video is here:
Bonus: the precursor to this video is here.
Strength tests were performed on 3D printed beams with grid infill and showed some interesting results. All of the following images are screenshots from the video above.
With increasing wall line count…
- Strength increases linearly
- Strength to weight ratio increases but with diminishing returns
With increasing infill percentage…
- Strength increases
- Strength to weight ratio decreases
The optimal strength/weight ratio is around 20% infill and 3 walls.
Regarding the relative strength/weight ratio of infill types, lightning infill had the highest value, and the author believes that due to the nature of lightning infill, the object is very light, so most of the strength may be coming from the walls. I agree and would also add that because lightning infill is not uniformly distributed throughout the object, the findings related to this infill type should be interpreted in that context. The infill types with the next highest strength/weight ratios were gyroid and 3D honeycomb.
Note that if you use Cura as your slicer, it does not currently come with 3D honeycomb or honeycomb infill. You can get honeycomb infill for Cura, but if you want 3D honeycomb infill, you will need to use another slicer.
Personally I like cubic and gyroid because they are “airtight” in all 3 axes and presumably could withstand forces equally in all directions. Does this information influence how you will slice your next 3D model?
