Loss of heating to hot end mid print
Hello I'm in dire need of help with my MK3
Have had a relative trouble free first months of printing, but I had a severe clog a few weeks ago which required me to dismantle the hot end assembly to remover the clog. Now when I started printing again I noticed that after a few minutes of printing the thermal runaway is triggered.
I have watched it happen several times now. I preheat, start a print and everything is fine, then few 10 minutes into printing the hot end starts losing temperature quickly and the thermal runaway triggers around 140 deg C (printing PLA at 210 with heated bed at 60).
I have tried turning of the fans to see if they are cooling the nozzle to fast, rerunning the PID calibration, checking my wiring, changing slicer, chancing filament, downloading the new drivers and many more things. However, nothing is solving the issue.
I have noticed that if I try to preheat directly after the failure it is kind of stuck in this mode and wont heat up again. I will have to leave it for half an hour or so to be able to pre-heat it again. Kinda feels like some faulty component on the board that is overheating and shutting of the power to the hot end. Anyways top test this?
Does anyone know what this is? Any help is much appreciated!
Best Answer by sergey.k4:
Basically, it looks like a RAMBO is faulty. I contacted the support and they are sending me the new board.
Re: Loss of heating to hot end mid print
I would start with a wiring check- the thermistor wires are very small and easy to kink or break... also the heater cartridge wires are prone to partially breaking right at the joint of the cartridge itself.
Other things to check:
check the routing on extruder carriage, something may be pinched.
grub screw for thermistor is snug but not tight
heater cartridge screw is snug but not tight
check connectors for looseness
check wiring routing through the top of electronics box (may have worn through shielding)
Anything can be made better
https://www.myminifactory.com/users/Joe%20Prints
Re: Loss of heating to hot end mid print
the heater might have a broken wire in the cable bundle between the back of the X carriage and the einsy housing
due to cable fatigue, from the back and forward motion!
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: Loss of heating to hot end mid print
the heater might have a broken wire in the cable bundle between the back of the X carriage and the einsy housing
due to cable fatigue, from the back and forward motion!
regards Joan
Thank you for the suggestion. However, I don't think so as the problem disappears after letting the printer cool down for a while. If any wires are broken it would most likely not work at all.
Re: Loss of heating to hot end mid print
I would start with a wiring check- the thermistor wires are very small and easy to kink or break... also the heater cartridge wires are prone to partially breaking right at the joint of the cartridge itself.
Other things to check:
check the routing on extruder carriage, something may be pinched.
grub screw for thermistor is snug but not tight
heater cartridge screw is snug but not tight
check connectors for looseness
check wiring routing through the top of electronics box (may have worn through shielding)
I really don't think it is an wire issue, because if I leave the printer of for 30 min after a failure it as restored it self. Seems more of a heating up issue that an actual connection to power issue?
Re: Loss of heating to hot end mid print
no problem.
it was only a suggestion based on the device heating whilst stationery and cooling whilst in motion..
often a broken wire works to the left of the heatbed and not to the right!
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: Loss of heating to hot end mid print
no problem.
it was only a suggestion based on the device heating whilst stationery and cooling whilst in motion..
often a broken wire works to the left of the heatbed and not to the right!
Yes well it is printing for several minutes before losing heat so movements seems OK
Re: Loss of heating to hot end mid print
I wonder if it something where the thermistor grub screw is too tight..... and after building up enough heat- through thermal expansion it starts to act finicky.... then it cools(shrinks) and returns to normal ?
When this happens, is the thermistor reading faulty, or the heater not heating properly?
Anything can be made better
https://www.myminifactory.com/users/Joe%20Prints
Re: Loss of heating to hot end mid print
I wonder if it something where the thermistor grub screw is too tight..... and after building up enough heat- through thermal expansion it starts to act finicky.... then it cools(shrinks) and returns to normal ?
When this happens, is the thermistor reading faulty, or the heater not heating properly?
No the thermistor value seems fine, it is reading the correct temp when the printing is working and when it is losing heat it is reading plasuble values as it decreases in heat. Very strange...
Re: Loss of heating to hot end mid print
is the Bed LED lit, while the temperature is going down?
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: Loss of heating to hot end mid print
is the Bed LED lit, while the temperature is going down?
regards Joan
Not sure specifically about the LED but bed temperature stays stable.
Re: Loss of heating to hot end mid print
My bed LED Flickers whilst temperature is being maintained
if yours is off, when the temperature is dropping, you have a starting point that the issue is before the heatbed.
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: Loss of heating to hot end mid print
Okay so an update. I checked for the flickering LED on the hot bed connection and it is flickering. Nothing wrong with the heated bed as someone suggested.
I tried to pre heat PLA on the printer without starting a print to monitor what happened. After around 20 min the decrease in temperature started happening. I had a second thermocouple at hand to measure on the heater block and it was decreasing just as the built in thermistor was displaying. With other words: the thermistor is fine...
However, I can still not figure out why the heater is suddenly starting to decrease?? Must be a faulty board or something?
Re: Loss of heating to hot end mid print
I though the no activity after XX minutes but still heated shut-off was a safety feature in Marlin.
Re: Loss of heating to hot end mid print
I though the no activity after XX minutes but still heated shut-off was a safety feature in Marlin.
I believe that is 30 min
Anything can be made better
https://www.myminifactory.com/users/Joe%20Prints
Re: Loss of heating to hot end mid print
I though the no activity after XX minutes but still heated shut-off was a safety feature in Marlin.
First off all, when this feature is triggered would it not turn of the "set temperature"? Mine just starts dropping and finally triggering thermal runaway?
Secondly, this also happens when I'm printing, is there a possibility that my printer thinks it is idle even tough it is mid print??
Re: Loss of heating to hot end mid print
I would assume that since this had not started until after disassembling due to a clog, that the wires to the heater cartridge are faulty in some way- either partially broken, pinched, or loose somewhere
Anything can be made better
https://www.myminifactory.com/users/Joe%20Prints
Re: Loss of heating to hot end mid print
I would assume that since this had not started until after disassembling due to a clog, that the wires to the heater cartridge are faulty in some way- either partially broken, pinched, or loose somewhere
Disassembled my hotend completely now and I cant find any kinks or breaks in the wire... I don't think it is the issue. Any ideas, anyone?
Re: Loss of heating to hot end mid print
Hi Warrawarra,
are you able to check the power voltage when the printer is live,
if the voltage begins to sag, you may get the sort of issue you are describing,
there is a voltage monitor on the LCD Screen, at the very bottom of the support menu
it might not be accessible quickly enough
mine shows 23.6 volts pretty consistently even when heating for abs
if the voltage begins to drop, you could experience difficulty maintaining temperature.
it's possible that the switching FET may be failing, in which case the main power voltage could be good, but the heater output could be poor
my mk1 couldn't maintain temperature with full fan on, so I increased the power supply output to 13 volts and all was well. it's since been upgraded twice but still has the same PSU
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: Loss of heating to hot end mid print
Hi Warrawarra,
are you able to check the power voltage when the printer is live,
if the voltage begins to sag, you may get the sort of issue you are describing,
there is a voltage monitor on the LCD Screen, at the very bottom of the support menu
it might not be accessible quickly enough
mine shows 23.6 volts pretty consistently even when heating for abs
if the voltage begins to drop, you could experience difficulty maintaining temperature.
it's possible that the switching FET may be failing, in which case the main power voltage could be good, but the heater output could be poor
my mk1 couldn't maintain temperature with full fan on, so I increased the power supply output to 13 volts and all was well. it's since been upgraded twice but still has the same PSU
regards Joan
Hey Joan,
Thank you! I'm looking now. Before pre heat: stable 24.0 V. During pre heat (PLA) 23.9 V, maintaining temp: between 23.9 and 24.0 V
Will monitor to see what happens when temp starts dropping.