Thermal Runaway
Hi there,
I've had this fault occur on the same part printed in both PETG and PLA. I purposely changed the material to PLA on the second attempt to see what effect a reduced printing temperature would have (if any) on it. However, the print stopped at more or less the same position as when printed on the first attempt with PETG. The prints are approx 220mmL x 115mmW x 25mmH and both failed when around 20mm high?
From what I understand 'thermal runaway' is when the hot end temp increases more than 15 deg C from the nominal and will halt the print as a safety precaution? I've had the MK3S printer about a year and had absolutely no problems whatsoever and have printed larger parts than this.
Anybody had anything similar happen to them or any knowledge of what this may be?
Really appreciate your thoughts guys.
Cheers
Chris
RE: Thermal Runaway
I could be a broken thermistor wire as it happens at the same height.
Have a look at my models on Printables.com 😉
RE: Thermal Runaway
I did think of that!. I've tried looking for anything obvious but no real joy. Ran all the diagnostics etc, everything seems ok? Is it a new complete hot end or can you buy the thermistors separately?
Cheers
RE: Thermal Runaway
I did think of that! I've tried looking for anything obvious but no real joy. Ran all the diagnostics etc, everything seems ok? Is it a new complete hot end or can you buy the thermistors separately?
Cheers
RE: Thermal Runaway
@chris-p37
Thermal Runaway can also happen if the fan speed is too high. Simply reduce and test again. You can also use a silicone sock to save the heat in the area of the nozzle and the heating block.
Statt zu klagen, dass wir nicht alles haben, was wir wollen, sollten wir lieber dankbar sein, dass wir nicht alles bekommen, was wir verdienen.
RE: Thermal Runaway
An open circuit thermistor normally causes a Mintemp error
I would suggest this is likely to be a loose heater connector, an loose fuse or a broken heater wire... overactive cooling fan, incorrectly installed hot end assembly, as the printer has been in use for a year, I would look at the heater wires...
the extruder moves relentlessly from side to side, during printing, and this may cause work hardening and fractures inside the insulation.
this can lead to the heater being disconnected at some points within the working region.
try pre heating the extruder, move the extruder
when the temperature has stabilised, raise your extruder to say 20mm, then see if the temperature changes. if not move the extruder to the end of it's travel one way, see if the temperature drops aver a short while, if no problems try moving to the other side of travel, pause and check for the temperature to dip. if nothing happens, try 30mm
Good luck, 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
OK, i'll have a look thanks.
RE: Thermal Runaway
Thanks Joan,
The print is using nearly all of the X Axis so the cable bundle is getting maximum movement. I have just pre-heated the printer and moved the axis around even with the failed part under neath as reference... Going to be a process of elimination I think.
RE: Thermal Runaway
Good luck Chris
Just noticed, this is a Mk2.5 12 volt system...
My Mk1 had thermal runaway issues, and the power supply voltage was below 12volts.
I used the adjuster on the edge of the power supply connector strip, under the protective covers, to raise the voltage,
If I recall correctly, I raised the voltage to 12.8 volts. and the problem went away...
that printer now has the Mk2.5 heatbed, and does not give thermal runaway on either the extruder or the heatbed... (The mk2.5 uses the same extruder heater as the Mk1 and Mk2.)
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
I've just ordered a new heater and thermistor if all else fails....
RE: Thermal Runaway
Hi Chris,
Did you order the 12 volt heater and not the 24volt heater?
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
Joan,
Hi Joan,
I ordered the 24V 40W hotend heater cartridge.
So, what i've found is that the hot end temp is perfectly stable in any position over the bed until the filament fan comes on, upon which the temp drops right off and the 'Thermal Runaway' error is displayed. I even tried pausing the print when the fan comes on to see if the hot end temp increases away from the printed surface which it struggled to do.
RE: Thermal Runaway
The 24V 40W heater was specified for the Mk3s printer?
RE: Thermal Runaway
@chris-p37
The 24 v heating cartridge only provides about 10 watts of power when connected to the mk2, i.e. not enough to reach the required temperatures.
I would change the order to a 12V variant. It's always good to have a sparepart.
Change the fanspeed in the Slicer software!
Statt zu klagen, dass wir nicht alles haben, was wir wollen, sollten wir lieber dankbar sein, dass wir nicht alles bekommen, was wir verdienen.
RE: Thermal Runaway
Why does it specify the 24V for the MK3s?
RE: Thermal Runaway
My Mk3s printer has a 24v power supply, i thought that was one of the upgrades from the MK2's that all of the MK3's have...?
Also, where in the slicer software do you adjust the fan speed?
Many thanks.
RE: Thermal Runaway
@chris-p37
The MK3 and MK3S uses a 24 V power supply (nozzle temps up to 305degree and bed temps 122degree). The Mk2 series only 12V. That is why the heating cartridges differ. The same applies to the heating bed.
Statt zu klagen, dass wir nicht alles haben, was wir wollen, sollten wir lieber dankbar sein, dass wir nicht alles bekommen, was wir verdienen.
RE: Thermal Runaway
Are you saying you should run a 12V heater with the 24V system then??
RE: Thermal Runaway
@chris-p37
You are posting in the wrong section (MK2 series). If you have a MK3 or MK3S Upgrade you need 24V parts.
The fan speed you can controll here: (reduce until the error disappears)
Statt zu klagen, dass wir nicht alles haben, was wir wollen, sollten wir lieber dankbar sein, dass wir nicht alles bekommen, was wir verdienen.
RE: Thermal Runaway
Thanks for this.