Strange Print Issue (photos included)
I’ve been having this issue recently.
the parts are not physically strong and pull apart very easily, especially near the areas where there are gaps of the perimeter wall. Gaps seem to only happen on the backside of the print. I have successfully printed this file before without issue.
Question for you:
what type of issue does this look like?
History/ Context:
this printer has 30days of print time on it & has had 1 or 2 rebuilds through out that time.
I stopped using my printer for awhile after I damaged a nozzle trying clean off some plastic residue.
eventually I got a new printing nozzle.
but now recently I’ve been having this printer issue.
worth mentioning after my most recent print there was some plastic between the nozzle and the heat block.
so I removed and reinstalled, this time much tighter. Same issue though.
my theories:
- filament has gone bad (testing different filament now)
- enclosure causing PETG to get too hot. Although not an issue in the past I don’t think (testing with door open now)
- Filament has filled up in between the nozzle and heater block and preventing nozzle to be fully secured
- 3D file has been corrupted and printing with a bad file (have printed this file successfully)
- Hot end has been damaged during reinstall of nozzles. It was a pain to do.
- partially clogged hot end/ nozzle
any thoughts welcome!
thanks!
Best Answer by Lynn:
When i first saw you pics, I immedialy thought wet filament, but to be honest it could have other causes. How did it look with a different filament?
RE: Strange Print Issue (photos included)
More photos
if helpful
RE: Strange Print Issue (photos included)
When i first saw you pics, I immedialy thought wet filament, but to be honest it could have other causes. How did it look with a different filament?
RE:
When you replaced the nozzle did you follow this process: https://help.prusa3d.com/article/changing-or-replacing-the-nozzle-mk2-5s-mk3s-mk3s-mk3-5_2069 did you use a genuine Prusa nozzle or some cheap nozzles? Are you seeing any more leakage above the heat block?
In the Final Inspection section do you have a gap between the nozzle and the heat block like in the image? Your extrusion looks uneven which could be why you're getting delamination. Heat creep could be an issue, I see that the layers are pretty even down low and gets worse the higher up it goes. If your PTFE tubing in the heat break is leaving a gap, the gap fills with plastic and can partially solidify causing a gap. I've had this with my Mini and had similar symptoms that just continued to get worse.
Cheers
-Bob
Prusa I3 Mk2 kit upgraded to Mk2.5s, Ender3 with many mods, Prusa Mini kit with Bondtech heat break, Prusa I3 Mk3s+ kit
RE: Strange Print Issue (photos included)
Hi Lynn, thanks for the response.
I'm thinking (and hoping) you are right.
My print is still going right now, but so far seeming better.
Variables I've changed for this 1st Round of Testing:
1. Got rid of variable layer height on my print file. Previously had variable layer height which seemed unnecessary.
2. Changed to a PETG filament that has been stored properly with silica beads.
3. Leaving enclosure door cracked open to reduce ambient temperature. (Max ambient temp only hitting 75 degrees. previously it was hitting 80 or higher I believe)
I will post final results when it is finished printing, it hasn't hit the area that was worst in the print.
RE: Strange Print Issue (photos included)
Hi Bob,
Thanks for the response.
See notes I had above too for context.
I believe I did follow those instructions correctly. I do indeed have a gap between the heater block & the nozzle. Good thought though.
agreed that the part doesn't look too bad towards the bottom, which could be explained by heat creep.
If I still have issues with the print after this round...
- I should x2 check the specs on the nozzle, but I think it should be ok. It wasn't particularly cheap, so hopefully it was the real deal. Good idea.
- I should also look into the PTFE tubing, not quite sure I understand but I can hunt down that info.
RE: Strange Print Issue (photos included)
The way your nozzle is constructed is that you have a short piece of PTFE tubing in the heat break in the area of the heat sink. PTFE is a naturally slippery material which give the filament a smooth path through the heat break until it nears the melt zone in the heat block. If the PTFE tubing isn't pressed securely to the heat break a gap can form between the bottom of the PTFE and the heat break which can fill with plastic, since this is in an area where you're near the melt temperature of the filament but not quite the filament gets into a semi-liquid state which makes it more plastic than liquid and increases the back pressure to the extruder motor, when it's severe you can hear the bondtech gears slip on the filament and you get a clicking sound.
I've yet to have the PTFE tubing cause a problem on an I3, but it's been a real problem on the Mini. Prusa does warn if you don't get the full nozzle assembly properly placed in the print head it can create issues. However, if you print a lot with ABS, or Nylon or other high temp filaments the PTFE tubing can shrink, this is what happens on the Mini.
Prusa I3 Mk2 kit upgraded to Mk2.5s, Ender3 with many mods, Prusa Mini kit with Bondtech heat break, Prusa I3 Mk3s+ kit
RE: Strange Print Issue (photos included)
I understand better now. thanks!
definitely will look into this if I continue to have issues.
Print is looking pretty clean so far though so I think we got it solved.
RE: Strange Print Issue (photos included)
RE: Strange Print Issue (photos included)
Here is the final result using 1st Round of Testing Variables.
Success!
My guess is that it was the filament. However I will later on try closing the door just out of curiosity to see if it bombs a print.
also another variable that changed that I just realized is that the infill changed to gyroid, I doubt this had an affect though.
Thanks Folks, appreciate the help & ideas!