THERMAL RUNAWAY

Hey guys,

I am new to this forum but I have been 3D printing for a while now. I made my printer from a kit online that uses an arduino board and marlin softwear I believe. In the past I used PLA to print and have never had an issue, but the other day I tried printing ABS. Because I was printing ABS I increased my bed temperature. I set the temperature to 80 degrees Celsius and let the print start. After the second layer of the print, my LCD screen said "Thermal Runaway" and terminated my print. I then lowered my bed temp down to 75 and the problem happened again but later on in my print. Finally I turned the bed temp back down to 60 (same temp I use for PLA) and the error did not show up again.

Does anyone know what might be causing this? I read up on it and have a general Idea what "Thermal Runaway" is but I dont fully understand it enough to fix it. I would love to know the fix so I cant crank my bed up to 110 for ABS prints without it shutting off!

Thanks guys,

Matt

make sure your thermistor cables dont run too close to high voltage power cables. This can cause EM cross talk, even if for only a couple milliseconds, your printer wont risk melting itself, and immediately goes into thermal runaway.

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If you need some help, or don't understand what I just said, feel free to send me a PM anytime

Printer: Prusa i3, 2 E3D v6 Hotends, Arduino + RAMPS 1.4 with a Bypassed 5V Regulator, 400w Insignia ATX PSU, Custom Designed Bowden Extruders

@DaGameFace thank you for your response. Ill make sure to check that this is not the issue.

If the temperature takes to long to change depending on the pid control the firmware will see that as an error. Afaik it is possible to increase the timeout value.

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[www.bonkers.de]
[merlin-hotend.de]
[www.hackerspace-ffm.de]

to be clear, there is no real danger of melting from EM crosstalk, the printer only sees the garbled signal caused by it and this can read as a very high or very low temp. That is what triggers the runaway. I was not clear in my first post

I found the section in the code where the timeout value was set. I had mine at 10 seconds. I increased it to 60 seconds and tried to run the print again and it still threw the error.

I've had this problem and it was caused by shitty polyfuses on RAMPS board.

Those two in the red box get really hot and trip. Needs a cooling fan or replace with blade fuse.