Support for inside a dome
I have a dome, 148mm in diameter, and 3mm thick. There's more to it than that, I've uploaded a 3mf file of it from PrusaSlicer. The short version is I'm having trouble with supporting the inside.
I imported this into PrusaSlicer and saw that the underside of the top of the dome would need support, so I added a post in the middle and an inverted cone coming down from the top to support the top. The interior of the dome does not have to be empty, but I don't want to fill it with filament when that's not needed. I'm looking for suggestions or ideas on how to support the inside of the top of the dome without a lot of extra supports or using large amounts of filament. I also don't want to have to upgrade to a test version of PrusaSlicer to use organic supports. Since there's a chance I'll be using the STL sometimes and won't have access to PrusaSlicer, I'd like to just design the supports into the STL so it can be just loaded by any slicer and printed as-is, without more support needed.
What are some good ways to support the underside of the top without using massive amounts of filament and supports?
RE:
I have printed a hollow globe, one of those lithophane moon lamps, diameter about 200 mm. It worked without supports on an MK3S. But if you want supports, you can always try the new organic supports in the middle, they do not need much material. Perhaps paint them on in the middle or use a modifier part to limit them to the middle if the default setting "supports from the build plate" would fill the whole void with supports.
RE: Support for inside a dome
I have printed a hollow globe, one of those lithophane moon lamps, diameter about 200 mm.
Interesting! Isn't that section at the top almost a flat overhang at that point?
RE: Support for inside a dome
I can't find an attached 3mf file. What you describes seems like a reasonable approach, so I wonder why it didn't work.
Formerly known on this forum as @fuchsr -- until all hell broke loose with the forum software...
RE: Support for inside a dome
Interesting! Isn't that section at the top almost a flat overhang at that point?
Yes. The overhang/print stability warning in PrusaSlicer is a bit pessimistic sometimes! 🙂
I just looked up the project for that moon lamp. I printed it in white PETG. Here a view of the top on the inside through the opening for the lamp socket. There is a smudge on the outside, this was printed about 2.5 years ago.
RE:
I can't find an attached 3mf file. What you describes seems like a reasonable approach, so I wonder why it didn't work.
I've attached the file to this comment, so let's see if it works. It looks like it's uploaded, but I don't see an actual "Uploaded successfully" message or anything like that. I have a warning the max size is 10MB, but the file is only 466k.
Edited: Okay, attached it, got nothing when it posted. Here's the image showing it's attached - obviously it's not uploading.
Ah - it only adds .zip files. Got it!
RE: Support for inside a dome
Yes, we've been asking for 3mf uploads forever but for reasons unknown we still have to zip them before the forum software allows them.
Still looks like a reasonable strategy to me. I'd probably make the stem a bit thicker. When scrolling through the layers in the slicer preview I noticed that around the 68 mm mark it looks a bit funky. When I look at the cross section in Fusion the top cone of the support structure is flat and thus not giving any support to the top curvature of the dome. I'd model it to adhere to the shape of the dome, with perhaps a 0.25mm gap in between.
Formerly known on this forum as @fuchsr -- until all hell broke loose with the forum software...