When loading filament into a newly installed 0.2mm hotend, the nozzle with termisor shifts down by 1.5mm, so it starts scraping the cleaning zone and the print bed. Fluidd writes that the active nozzle size is 0.4mm, and all settings (flow, pressure advance, speed, etc.) are like for a 0.4mm nozzle. All parameters in the config also point to a 0.4mm size.
However, during installation, I manually set the size to 0.2mm for all 4 nozzles in the printer itself. Also, for some reason, this problem occurs specifically with only one first nozzle, meaning on the leftmost toolhead. The other three hotends calibrated completely fine and did not change.
Can you please tell me what the reason could be? I have already tried two nozzles, and both of them were damaged in the exact same way.
Looks like presure provided for 0.4 nozzel pushed 0.2 nozzel and termistor. After the nozzel gets dislocated, fillament starts coming out of it like it normally should.
Can you post the GCode? I’d be interested to see if it’s treating head 1 as a 0.2mm or a 0.4mm nozzle. If it’s treating it like a 0.4mm nozzle, that would cause quite a bit of pressure inside the head.
The failure occurred specifically during the first loading of the filament into the head and hotend using the factory macro. Here’s what Fluidd says about the extruder, even after I change the nozzle size in the printer’s menu.
I still have three nozzles left that were fine after loading filament on the other heads; I want to remove one of them and test it to see how it behaves.
Yes, but the construction should be able to withstand fault conditions. The pressure would be just as great in any diameter nozzle if it got blocked. In engineering, you do not (if possible) allow the hardware to fail if somebody else makes a mistake in the software, or if a user inputs the wrong data, and a blocked nozzle is a “normal” fault condition, to be expected and therefore anticipated in manufacture.
Clearly the software/firmware bugs need to be addressed, but the failed hot-end is a case for replacement under warranty. I suggest it has a manufacturing defect, with the heat break slightly under-diameter or the heat sink over-diameter, so that the interference-fit isn’t tight enough.
I thought you said you’ve already tried this with two nozzles. I wonder whether this is a batch problem.
Yes the pressure will be too high for correct extrusion with the wrong settings. But if the hotend is in a healthy state, no extruder should be able to apply enough pressure to unseat a shrink-fit hotend.
In other words: the issue is with the hotend to begin with and the settings are irrelevant in this case. However it would still be good practice to indeed have the settings in a correct state.
The hotend has a production error and I advise to get it replaced under warranty.
Yes, I tried another 0.2 nozzle from the next print head and everything was fine. I guess I was just very unlucky to run into a defect twice. Thank you all for your help!
