.25 inch thick bands around walls of 3D printed box at random positions across otherwise identical prints
I have a few things going wrong with this print which may or may not be related (Ghosting, Hull Line, etc.), but the most confounding one for me is the .25 inch tall bands that I have arrows pointing to.
Things of note:
Both Boxes are from the same print file, print settings and PLA spool.
Despite these properties being identical, the boxes have the bands in different locations.
The bands are concave on the outside of the box and convex on the inside of the box. Like some invisible force is pulling the material towards the XY center.
Unlike the hull line where the walls meet the base or the ghosting surrounding the notch holes, these mid-height bands do not seem to line up with any other feature on the model, their positioning appears to be random.
My belt tension is tuned and everything x,y,z related is freshly calibrated.
I'm new to 3D printing so I don't really know where to begin on troubleshooting this.
RE: .25 inch thick bands around walls of 3D printed box at random positions across otherwise identical prints
Post your 3mf if possible buddy.
RE: .25 inch thick bands around walls of 3D printed box at random positions across otherwise identical prints
Post your 3mf if possible buddy.
Agreed, that would be helpful. Please be aware that the forum does (annoyingly) not accept .3mf files as attachments, but drops them silently. You will need to Zip the file to make it available here.
RE: .25 inch thick bands around walls of 3D printed box at random positions across otherwise identical prints
Double-check that the filament moves freely in the PTFE tube (which is just common-sense advice, haven't seen it in context of this exact issue).
If you happen to have a different spool of PLA, I'd try another one. Excessive diameter tolerances could alternate between over- and underextrusion. Not very likely IMHO but an easy experiment.
RE: .25 inch thick bands around walls of 3D printed box at random positions across otherwise identical prints
Very low probability in this case but zoom way in in the slicer and make sure there's no trace of it there. I was having a problem with a part and finally realized that the printer was printing exactly what I sent it!
RE: .25 inch thick bands around walls of 3D printed box at random positions across otherwise identical prints
I do not have the original 3mf file as I had significantly changed the settings after printing those in an effort to debug the hull line issue. However, I think I have an idea about what is going on here. I think I'm experiencing something similar to what this user did: https://www.reddit.com/r/ender3/comments/10ejeba/psa_that_zbanding_you_cant_explain_it_could_be/
I think what I described as "some invisible force is pulling the material towards the XY center" is actually the box slightly expanding for a while due to heat and then contracting back to where it was before after cooling down a bit. I've been printing with Overture PLA and it seems to have a lot of thermal contraction compared to other brands. It had a hard time adhering to the plate due to warping and when I fixed the adherance problem, it just starting warping the steel plate along with it. I did some test prints of just the first quarter inch or so of the box with both Overture PLA and Elegoo PLA+ and the Elegoo had dramatically less warping. I tuned it a bit to minimize it further.
I'm going to try to reprint this with the Elegoo PLA+ and the tuning to minimize warping and see if the weird banding disappears.
RE: .25 inch thick bands around walls of 3D printed box at random positions across otherwise identical prints
I just noticed that Prusa Connect keeps a record of the telemetry of the print jobs. The graphs for the prints show a chamber temp increase and extruder fan speed increases around times that roughly line up with when the bands likely appeared, which seems to support the idea that this is a thermal contraction issue.
RE: .25 inch thick bands around walls of 3D printed box at random positions across otherwise identical prints
Or I guess thermal "expansion" is more accurate in this case.
RE: .25 inch thick bands around walls of 3D printed box at random positions across otherwise identical prints
As for the source of the heat increases at random times, I think it's because I inadvertantly placed the printer directly below a heater vent. When my apartment's heater turns on it is blowing hot air directly into the Core One's intake vents