Thermal runaway during normal operation
I was breaking my head what went wrong printing a small component with PETG. It seemed the printer was unable to keep the bed temperature. The indicated temperature decreased resulting in a thermal runaway error. Measuring the actual bed temperature gave a value much higher than the set temperature! What goes wrong here is that, whilst printing a small component in the middle of the sheet, the blower cool the area where the thermistor is located. The thermistor is fooled and the bed will heat up further. The indicated temperature drops fast however and the printer runs into an error. I was able to avoid this placing the component in a corner of the build sheet instead of the middle. I am not happy with this behavior. Is there a solution? Locating the thermistor on another spot? Or even better, mounting more thermistors and take the average temperature to control the heatbed? Who recognizes this?
Thanks,
Dick CW
RE: Thermal runaway during normal operation
this has been an issue for a long time, however it is relatively rare. the thermistor should be towards the left side of the middle of the heatbed, so most of the time, the extruder is moving over a relatively large area including the thermistor area, and the cooling effect over the thermistor is relatively small,
however if you have a single small part to the left side of centre, then all bets are off... because the extruder spends more time over the thermistor area...
regards Joan
I try to make safe suggestions,You should understand the context and ensure you are happy that they are safe before attempting to apply my suggestions, what you do, is YOUR responsibility. Location Halifax UK
RE: Thermal runaway during normal operation
Or print multiple copies of the component so the extruder doesn't need to stay in place. Or even just a small cube somewhere else.
Formerly known on this forum as @fuchsr -- until all hell broke loose with the forum software...