My printer stops extruding randomly, what am I missing?
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@re_tour Nice little cube - reminds me a bit of the first iMac… sorry, last century
Sure I’m glad you found the culprit. In my eyes, the most valuable achievement after this tour de force is that you now have profound knowledge of how each and every component of the filament path works - you’ve really touched every single aspect. Congratulations, truly
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@infiniteloop I cheered too soon...
Now that I started printing a part that I made, I started having problems.
It seems like I've got some heat creep going on, however, I can't reproduce the issue manually. I already set like 0,5mm retraction, I have the same result.
I tried pushing the ptfe tube as far as I can down the hotend but it won't go any further...
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It seems like I've got some heat creep going on, however, I can't reproduce the issue manually.
A heat creep develops over time, sometimes, it needs an hour to show up. So you’re right: it’s hard to reproduce in tests.
Maybe it’s a good idea to take a break and to summarise your current configuration: I understand that you have a working extruder, a dragonfly hotend and fresh PTFE tubing? Now, what kind of filament did you use, at which speed, which temperature?
Assuming all of this is fine, we are left with a topic @oliof brought up: is the cooling of the hotend sufficient? Can you publish some images so that we get an idea of the air duct and the air flow before and behind the hotend?
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@infiniteloop Yet again, I must say that I did something really stupid, which I just came to realize....
So...the thing is, that to make my life easier during wiring, I put the part cooling fans and the hotend fans on the same step down module...which means that unless I manually turn the part cooling fans on, the hotend fan won't be on until like the second-third layer or so...which I guess is plenty enough time for a clogging to happen, but correct me if I'm wrong.
But anyway, yes. Extruder stepper motor is working, motor gear fixed in place, marked with a sharpie to know if its slipping. Ptfe tube check, hotend is good, coupling is good. I've tried different PLA-s, Gembird, 3D Jake eco PLA and filamentum. Hotend was set to 220°C with the filamentum one and 210 with the gembird and 3DJake.
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the hotend fan won't be on until like the second-third layer or so...which I guess is plenty enough time for a clogging to happen …
The hotend fan should be triggered at 45°C - you'll have to add the time until the hotend reaches printing temperature to the time for the two layers. Let's see what happens after you've rewired the fan …
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@infiniteloop I've wired the hotend fan to the board fan, which also turns on at 45°C.
Seems like the biggest failure in this rebuild was me.
Never mind, at least now I'm (almost) completely aware of how and why my 3D printer functions and hopefully I can troubleshoot almost anything that happens which is extrusion related. Thanks again! -
I've wired the hotend fan to the board fan, which also turns on at 45°C.
That's unwise: The board fan refers to the temperature of the MCU, whereas the tool fan should be coupled to the thermistor on the hotend. The MCU not even tells the truth about the (potentially) hottest components on the board - usually the stepper drivers. However, it can be used as an indicator when active cooling of the board would be desireable.
When the hotend is activated, it's readings go rapidly in excess of 45°C - the MCU stays cool, in other words, the two temperature values are absolutely unrelated. The tool fan must step-in as soon as the hotend becomes hot, else, the cold part of the hotend is heated up, too - which is something you would like to avoid.
If you think it's too much wiring effort to reconfigure your hotend fan, simply set it to "always on".
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@infiniteloop some people turn the board fan on based on the hotend temp taking it as a proxy for "machine will get load". So thats not necesarily wrong.
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some people turn the board fan on based on the hotend temp taking it as a proxy for "machine will get load".
Interesting approach. I could not find hints to this in the config of the OP, but at least for the tool fan, this would be good news
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@infiniteloop I'm back after some rest and I can gladly say that this saga ends here.
I realized that wiring it straight up to the board fan wasn't a great idea, so I configured two separate fans: one of them is the part cooling fan and one of them is the hotend+board fan. The latter turns on when the hotend reaches 30°C, which means both the hotend and the board gets cooling whenever there's job to be done. The part cooling fan works as intended, I just separated it from the hotend fan.
I dare to post these results after 4 test prints, all of which were successful with no issues whatsoever.
I thank all of you, especially @infiniteloop and @oliof. Because of you guys I now have an insight which I didn't before and now can troubleshoot much more stuff on my printer as before. There's always something new under the sun I guess.
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