HELP - First prints have major layer melting!!!
Just got my new Mini+ set up yesterday and was excited to start printing. The first print was the Prusa logo on the USB drive which printed perfectly. Then I tried the Rocktopus that my son has been asking for. This ran fine for 1-2 hours then I went to bed and left it to finish. At some point the layers started melting but then it corrected and built fine for a while and had another few bad layers near the end. I then tried printing the benchy directly from the USB drive and at some point had the same issue with melting. I suspect this is due to insufficient cooling on low volume layers but would love to hear the advice of more experienced Mini+ users.
Here are the settings that were used for each print:
Filament: Hatchbox PLA True Black
Prusa Logo
Settings: Printed directly from USB with no changes
Results: Excellent 1st layer adhesion, nearly perfect print
Rocktopus
Settings: Sliced in PrusaSlicer with default 0.20mm QUALITY settings and Hatchbox PLA filament profile
Results: Excellent 1st layer adhesion, layer melting at some point near the beginning then near the end
Benchy
Settings: Printed directly from USB with no changes
Results: Excellent 1st layer adhesion; some melting near the middle of the hull, major melting at the top of the hull where I stopped the print
Best Answer by mrstoned:
Without any other test and info, i would venture a guess a mechanical binding along the Z (height) axis.
I would check if the trapezoid nut is perhaps too tightly screwed in place.
Can happen on pre-asembled as kit. Check: Step 26; https://help.prusa3d.com/guide/3-x-axis-extruder-assembly_199519#200484
RE: HELP - First prints have major layer melting!!!
UPDATE:
Ran another benchy and watched for the issue at the same point. It started happening again so I adjusted the speed down on the fly which didn't help. Then I adjusted the flow factor down which corrected the issue for a few layers but then it started gapping so I had to turn the flow back up. The same thing happened at the top of the smoke stack. So it looks like over extrusion but something about those particular layers is causing over extrusion just on those layers. Is there an overlap or infill setting that could be causing this on certain layers?
RE: HELP - First prints have major layer melting!!!
Without any other test and info, i would venture a guess a mechanical binding along the Z (height) axis.
I would check if the trapezoid nut is perhaps too tightly screwed in place.
Can happen on pre-asembled as kit. Check: Step 26; https://help.prusa3d.com/guide/3-x-axis-extruder-assembly_199519#200484
Prusa Mini+ kit. BondTech extruder. FW 5.1.2
Prusa MK3S+ kit. Stock. FW 3.11.0
Prusa MK3S+, used. Stock. FW 3.13.3
RE: HELP - First prints have major layer melting!!!
You are correct. I actually just figured this out when I looked at all the printing attempts and found issues with all of them at the exact same z heights. I just finished a nearly perfect benchy!
