Thermal Runaway issue- Hotend temp starts to fall around level 4 at steady decline. Could it be the g-code?
I was printing a circular lid for a container the other day when my printer suddenly stopped with a loud beeping sound. The error message on the screen read "M112 called. Emergency Stop." I checked Octoprint and the error message was "Thermal Runaway. I then decided that I would try printing from the SD card instead of Octopi to see if the printer would stop and display a "Thermal Runaway" error. It stopped at the same level (level 4 I think) at almost the same point in the print and displayed "Thermal Runaway" error. When the printer reaches this level it starts printing fast, the front fan starts spinning at high speed and the hotend temperature readings begin a steady decline until the printer has an emergency stop.
Here are a few things I have done so far to make sure my thermistor cables and other hardware are not at fault (followed this article's instructions https://help.prusa3d.com/article/thermal-runaway-i3-series_2131):
- Visually checked the thermistor if it is still securely and correctly installed in the heater block.
- Moved the whole extruder left and right, at the full length of the X-axis, and wiggled the cable wrap behind it to see whether there are any fluctuations in the temperature readings. There were non.
- Checked the thermistor cable connector on the EinsyRAMBO . Re-seated the connector to be extra sure.
- Checked the fan shroud for any kind of damage.
Since then I decide to try printing something else to see if maybe the g-code was faulty instead of the printer. After printing the Benchy g-code file that came with the printer on the SD card it printed of just fine with no issues that I could see. Another thing that might be causing my issue it that I recently updated my printer's firmware to 3.12.2. I would also like to mention that I generated the g-code from my own 3D model in Prusa Slicer.
Does anyone know what could be causing this? Could it be g-code or firmware related or is it something else?
RE: Thermal Runaway issue- Hotend temp starts to fall around level 4 at steady decline. Could it be the g-code?
Ok so I generated new g-code from the same stl file, set the print quality 0.2mm quality instead of 0.2mm speed (which was the print quality setting of the g-code file that failed with the thermal runaway issue) and it printed fine with very little hotend temperature fluctuations (no less than -5 degrees Celsius). So it seems like the speed setting might have something to do with it.
Also I tried printing the old g-code file again that failed previously and it printed without failing however it was a much warmer day than the day it failed. The day it failed the temperature was 12 degrees Celsius (hotend temperature went down to 199 degrees Celsius and then emergency stopped) and the day it didn't fail it was 25 degrees Celsius (the lowest the hotend temperature went down to was 201 degrees Celsius). If anyone has any insight or suggestions please let me know.
External cooling or heating going outside limits or occurring suddenly can cause this sort of thing; drafts, air conditioner outlets, space heaters ... so protecting the computer from air movements and maintaning a comfortable room temperature will often be enough.
Cheerio,
RE: Thermal Runaway issue- Hotend temp starts to fall around level 4 at steady decline. Could it be the g-code?
Yeah, so I don't know what indoor temp was (the forecast said outside was 12-13 degrees Celsius), but I know for certain that the printer is nowhere near any windows or doors that could allow for a breeze, we didn't have fans or aircons on because it was cold and we also didn't turn the heaters on because it wasn't that cold. Do you think printing a g-code file set to print quality 0.2mm speed on cold day is what caused the hotend not to be able to keep up with the front fan cooling?
Probably not. One workaround that used to be OK with the old firmware was to blow the printer with a hairdryer for a couple of minutes or (not advised) to stand a large mug of hot tea on the build sheet before printing. How this fits in with the new thermal protection I don't know. Once running the printer generates plenty of heat for ordinary conditions.
Cheerio,
RE: Thermal Runaway issue- Hotend temp starts to fall around level 4 at steady decline. Could it be the g-code?
Made a youtube video detailing my issue:
A little more dramatic than most issue videos we see here...
Two other things to check: The heater connection and wiring; even the 5 degree drop you saw on the slower print is a lot. If the heater is running only intermittently that could cause problems. And the extruder fans; clean the blades with a stiff paintbrush and, with a needle pick out any strands of fine stringing, cat hair or he like that are wrapped around the hub.
Cheerio,
RE: Thermal Runaway issue- Hotend temp starts to fall around level 4 at steady decline. Could it be the g-code?
i have the same issue with my MK4. My solution: Reduce the part cooling fan to 50%. That works on big parts and PLA. On small parts the cooling is more important. Then a lower Print speed is also recommend
RE: Thermal Runaway issue- Hotend temp starts to fall around level 4 at steady decline. Could it be the g-code?
A bit of an old thread but a question: do you use the silicone sock for the heater block and have you set the printer hardware settings related to the sock to match?
RE:
i order some heaters from Aliexpress they work very good so far. I also order silicon sock. That helps a lot to keep the temperatur constant.
My original heater from Prusa, 3 Pcs have all to highg resistans. So the heater has not the power they need for fast printing
RE: Thermal Runaway issue- Hotend temp starts to fall around level 4 at steady decline. Could it be the g-code?
Hi all, I'm facing the same issue so I'd like to ask what was the solution.
I'm running MK3,9 with fw 5.1.3 indroors in my flat so ambient temperature is about 23°C. Printer is partialy enclosed so I'm sure this problem is not caused by amb temp.
Everything was ok up to now. I'm printing mostly big models so I use 0,8mm nozzle and PETG and PLA. I've alrerady printed few objects from PLA and PETG with his 0,8mm nozzle without any issues.
What happens now is, that at second layer the temperature starts to be unstable, fall down and print ends with Thermal Runaway error
I've measured heater resistance and thermistor resitance and it seems to be ok for me (thermistor is about 88-94 kohm at 23°C) and heater is about 15 ohm. It seems to be ok for me, so I've downgraded fw to 5.1.2 and tried to create new gcode using other material setting in Prusaslicer
With problematic prints I've used PrusamentPLA and PrusaPLA material setting in PrusaSlicer. I have used other PLA setting now and it seems that problem is solved, so from my point of view the problem is probably somewhere in slicer/material/gcode.
I'll appreciate any hint advice or your experience with this issue
data of one failed prints - it seems to be really really weird, hotend temperature is really unstable
