Extrusion Interruptions in "perfect" cylinder
Hello,
I'm running PrusaSlicer 2.0.0 on Windows 10. I just created a cylinder in Fusion360 (10.8mm OD, 7.77mm ID), exported the STL on High, and then sliced it with the 0.15mm Quality MK3 profile (plus a brim of 4mm). Here's a view inside PrusaSlicer:
The printed part shows these periodic interruptions as well. I've not seen this before on other cylinders, I've done.
Is this a bug, or have I got a bad setting?
RE: Extrusion Interruptions in "perfect" cylinder
Can you post a larger picture? I can't see any "interruptions". There is a bit of a moire effect on the picture (making "smiles" on the face of the cylinder) but that would not show up on the printed part, and the moire effect is completely dependent on the zoom factor and resolution you are using to view the on-screen model.
RE: Extrusion Interruptions in "perfect" cylinder
They look like seam joins to me. There’s a setting under print settings for seam position which is normally set to hidden, that puts them on corners normally but for a cylinder it doesn’t have a corner so they go to something like nearest. If you set it to rear do the gaps then all align ? If so then it is the seam.
You can minimise them with tuning for things like extrusion rates etc but you can’t get rid of them completely.
That said I believe there is a bug in slicer when it comes to cylinders and seams but I’ve only experienced it with single wall thickness cylinders. I’ve got an issue open over on the Github page for it. I think it’s related to retraction, or rather that it’s not extruded fully after a retraction so you try try experimenting with extra filament after retraction on the advanced settings under printer.
If you do figure it out let me know 😊
RE: Extrusion Interruptions in "perfect" cylinder
Many factors affect seams: retraction & de-retraction; linear advance & k-factor; axis jerk & acceleration; filament melt compressibility & nozzle design; to name a few.
Forcing seams to the rear if the part has a favored surface can hide the artifacts; avoid using random and nearest.
And, vase mode eliminates seams entirely.
RE: Extrusion Interruptions in "perfect" cylinder
Here's the Larger image of PrusaSlicer as requested, and a photo of the actual part it produced. I should have been clear before--I'm pretty sure that they are seams, it just seems (ok, random bad pun there, but I'll take it!) odd that the PICTURE of the sliced part would show such a wide gap and the REAL part shows them too, as well as a spiral pattern. Note I'm NOT in VASE mode. Normally I've seen seams that show as a bump more than an actual hole. And the spiral pattern has me wondering too. Yes, this is Polyalchemy Elixir, and yes, it does act rather differently than other filaments, but I've printed other curved things without issue in this filament--just nothing quite so small.
