All of those extrusions with a monotonic pattern around the outside and a quite random inner shape I need to not be there. This is not the actual top shell layer but I’m assuming support for the top shell layer. The way the slicer implemented the “scaffolding” is quite unbalanced which is important when this model is going to spin at high RPMs. I circled in red what I thought would disable this but nothing changed. I also tried screwing around with other values around that general section with no results.
That “scaffolding” as you call it, is added to allow whatever is printed above it be structurally constructed.
If you change the preview “view” to filament you will see different colours within the model to indicate whatever their purpose is.
If you wish to get rid of them, the model would need to be uniformly shaped the entire height of the shape, then they is nothing to support.
If you are going to spin something at a high rate of RPMs, the shape must be a simple cylinder or you will introduce the same properties employed to swap a simple motor into a vibrating motor.
This model is a complex shape but is balanced (everything is revolved/uniformly circular patterned around the center) and the “bridge” (as the slicer calls it) should be able to be disabled without having to change the model geometry. Unchecking the “display” for the “bridge” though shows me even more imbalanced features in the infill though.
Edit: I would also assume that even without the “bridge” in the model the infill alone should be able to support the shell above it. I might have to just print this with solid infill as these “features” don’t seem to be available for me to turn off. This however would introduce more centrifugal forces from the added weight.
Have you tried other infill patterns?
Yeah, they seem to not affect the placement of the “bridges.”
If all else fails, you can cut the thing in half and add 4 bolts.
If center-of-mass evenness is a thing you’re wanting you may have better luck with a more predictable massfill infill like rectilinear
Is the rotational balance really so critical that those elements are problematic? Then I fear that 3D printing just isn’t the right method to produce them in my opinion. E.g. the seam probably causes much more imbalance than those bridges.
Regarding the patches: I guess that you have a rounded or chamfered top edge, so that support starts at the edges first? BambuStudio extends the lines to the next line below, so that it doesn’t start midair.
If you want to avoid those patches, I would make the edge sharp.
Or use 100% infill as you suggested.
Maybe concentric infill or concentric top is also helpful?
It is a rounded top, and other shell patterns don’t really make a difference. Now in reality, the imbalance is probably not a huge difference from these elements, but it would be nice to try to eliminate any vibrations if possible. I will most likely just print this with that 15% infill and hope the vibrations aren’t too bad. Last night I printed it with 100% infill (~10g difference from predicted weight of 15% infill) and the gyroscopic forces proved to be a pretty big problem.
If you use low infill it is even more important to select one that distributed evenly. Intersecting walls generates “infill attachment lines” for many common complex infill types and those are not going to be friendly to your goal. Check your preview.
Orcaslicer nightly has a feature to command infill to do things like rotation, flat sheets, holes. etc that might be useful to you too.