Knocking hotend off track
We make multi day prints , of large models and experience that the hotend is knocked over by the nozzle. That obviously causes failure.
This does not occur when printing smaller models, such as benchy.
The picture shows the state of things just prior to a "hit", you can see that blob just waiting ....
These blobs comes from buildup on the nozzle that is deposited. This does not look like a constant buildup, but something that occurs with some time in between.
In general the extrusion looks good on extrusion tests.
Filament : PETG
Hotend: Rapido UHF, 0.6 mm nozzle
Temp: 235
Slicer: Orcaslicer
Flow ratio : 0.9 , and checked with flow calibration to be a little on the low side.
Pressure advance 0.06
7 Replies
Is that transparent or white petg?
White PETG
Ok. If it was transparent, I'd say up the temp. Polymaker needed 10c over the black
Your first sentence doesn't make sense.
"...the hotend is knocked over by the nozzle"
The nozzle is on the end of the hotend it's screwed into the hotend. It can't knock it over...
Did you mean the part is getting knocked over by the hotend hitting it?
You obviously have some warping/extrusion/retraction issues.
But it also looks like your part is printed on a raft instead of a brim, and the raft is only one layer and monotonic.
That's going to reduce bed adhesion quite a lot...
Bad description, and bad model. It was a simple thin pole used to generate a tree support.
So the issue condenced.
The extruder will accumulate blobs, that deposit on the model , causing the head to hit it at get out of alignment, or knock a tall model over.
My current test model is a 19x12 multiboard, where the blobs are the bother.
I have
Reduced flowrate from calibrated optimal by 20%
Adjusted temp up/down
Calibrated Pressure advance (0.06) and tested 0.04 to see if it makes a difference (No it didnt)
Current tests
Retratraction values 0.2 - 0.4 -0.6, now running 1.0mm (35mm speed)
Retratraction values 0.2 - 0.4 -0.6, now running 1.0mm (35mm speed)
Nozzle might be damaged?
If the tip is not flat or the hole is not round it could pick up filament or drag some along with it.
You may well be on to something. Pardon the rubbish quality, but the nozzle has "issues"..
Now testing with alternate nozzle
