#Temperature dropping when mid-print, sometimes causing a thermal runaway

1 messages · Page 1 of 1 (latest)

slow sundial
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I don't understand why is this happening or what could cause it.

My printer generally works well, however, sometimes it just doesn't, with no apparent change in the settings or hardware. I haven't pinpointed what triggers this yet.

In some occasions, when printing, the temperature starts dropping very slowly. It drops by just a couple degrees over several minutes, however, sometimes it's just enough to trigger a thermal runaway, which halts the print.

The first attached image is from today. 20 minutes into the print, the temperature starts dropping from 205 to 203 over the course of 5 minutes. I was watching the printer live while this happened. It then had some kind of hiccup (it stopped in place for a couple seconds) and then it just resumed the print normally, and temperature started rising again, from 203 to 205 in another 5 minutes.

After this, the temperature remained stable for the entirety of the print, with a maximum variance of just 0.3ºC up or down.

Sometimes, the drop in temperature is too large (and by too large I mean 3-4ºC) and the printer triggers a thermal runaway, which halts the print. It's frustrating, because this happens 20-30 minutes into the print, and I cannot determine if the print is going to fail or not until it does.

It only happens when printing. If I set the hotend temperature to 205ºC and I let it for hours, nothing happens. It just remains stable. This made me believe it's either related to the PSU or the motherboard (my tests were with only hotend, maybe hotend+bed+motors makes the components not able to keep up).

I believe the cables are not an issue, because in a 6 hours print, the temperature only drops off for 10 minutes, starting 20-30 minutes into the print. If it was the cables, they would definitely fail multiple times during a 6 hours print. I believe the same applies to the thermistor, however I don't really know anything for sure.

My printer is an Ender 3 v2, with a fullmetal hotend and extruder, and BLTouch.

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dreamy kernelBOT
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AI Help

It sounds like you are experiencing temperature fluctuations during printing. Here are a few troubleshooting steps you can take to address this issue:

  1. Check the Connections: Make sure all the connections related to the hotend, thermistor, and heater cartridge are secure. Loose connections can lead to temperature fluctuations.

  2. PID Tuning: Perform a PID tuning on your printer. This process adjusts the parameters that control the heating element to maintain a stable temperature. Instructions for PID tuning can usually be found in your printer's firmware or online resources.

  3. Insulate the Hotend: Insulating the hotend can help maintain a stable temperature by preventing heat loss. There are various insulating materials available for this purpose.

  4. Check the Power Supply: If the issue persists, it's worth checking the power supply. A faulty power supply can lead to inconsistent power delivery, resulting in temperature fluctuations.

  5. Update Firmware: E...

WARNING: This response is AI generated and may contain errors.
slow sundial
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PIDs are tuned. The hotend isn't insulated, but given how it only fluctuates for 10 minutes out of a 6hr print, I believe that's not the issue.

white flower
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My thinking behind the z axis: If it always takes the same time and a non moving printer doesn't reproduce the issue, its maybe (somehow) related to the height of the hotend. Do you print with the same materials etc?

slow sundial
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yes, same materials, slightly different settings (200 vs 205ºC) happens in both cases

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I am using a Raspberry Pi 4 as my octoprint host, I've been using it for a couple years I believe, no issues with it so far

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once this print ends I'll try the z axis thing

white flower
# slow sundial I am using a Raspberry Pi 4 as my octoprint host, I've been using it for a coupl...

https://community.octoprint.org/t/put-tape-on-the-5v-pin-why-and-how/13574 just as a precaution

OctoPrint Community Forum
Put tape on the 5V pin - Why and how

First of all this whole tutorial isn't a mandatory mod - you just need it if you run into issues (weird things are happening and you've already ruled out the more common suspects) or if the always running fan and illuminated display (even when the printer is turned off) disturbes you. I'm starting with the why part: If you connect a 3D printer...

slow sundial
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I haven't done that, maybe I should

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noted, I'll do that and check the z axis once the printer lets me