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Thermal Runaway after Firmware Uldate

Posted by Vgala9 
Thermal Runaway after Firmware Uldate
March 18, 2017 09:59AM
I continue getting thermal runaways throughout the printing. I successfully printed a 30 minute print last night after the first thermal runaway, but then had two failed prints earlier this morning after about 10 minutes into the project.

I expect this is a thermistor issue, but it's new and reads properly. It's a new hot end assembly as well. I have a spare thermistor but I don't really want to unseat the current one unless I have to.

Any thoughts would be appreciated. I can't find any good hits in the forum for this issue.
Re: Thermal Runaway after Firmware Uldate
March 19, 2017 01:39AM
Thermal runaway shutdown is normally triggered when the temperature of the bed or extruder exceeds the MAXTEMP value. Have a look in your firmware settings and make sure that the values are suitable for the temperatures you are using during printing.

If you are using a solid state relay for controlling either the bed or extruder then make sure that it is a DC/DC type not AC/DC. The AC/DC ones do not turn off without current reversal (not possible in a DC only system).
Re: Thermal Runaway after Firmware Uldate
March 20, 2017 08:31PM
 * If you get false positives for "Thermal Runaway" increase THERMAL_PROTECTION_HYSTERESIS and/or THERMAL_PROTECTION_PERIOD
 */
#if ENABLED(THERMAL_PROTECTION_HOTENDS)
  #define THERMAL_PROTECTION_PERIOD 60        // Seconds
  #define THERMAL_PROTECTION_HYSTERESIS 6     // Degrees Celsius

I had bumped both the period and the hysteresis, but I keep getting thermal runaway shutdowns. Do you have any suggestion for the values? Should I just disable the thermal protection?
Re: Thermal Runaway after Firmware Uldate
March 21, 2017 10:44AM
I would put the period back to the original settings and increase the hysteresis to 8. However, before you increase the hysteresis, make absolutely sure that your part cooling fan is blowing below the tip of the nozzle, and not onto the nozzle or extruder heater block. If it blows onto the block it can affect the temperature and may cause similar problems. If you have an extruder cooling fan, then make sure that the heat-sink fins are horizontal and not vertical for the same reason.
Re: Thermal Runaway after Firmware Uldate
March 21, 2017 02:01PM
Quote
Supermec
I would put the period back to the original settings and increase the hysteresis to 8. However, before you increase the hysteresis, make absolutely sure that your part cooling fan is blowing below the tip of the nozzle, and not onto the nozzle or extruder heater block. If it blows onto the block it can affect the temperature and may cause similar problems. If you have an extruder cooling fan, then make sure that the heat-sink fins are horizontal and not vertical for the same reason.

Thanks for your reply. See attached photo.

My extruder fan doesn't blow on the nozzle directly, but the nozzle may experience some "drafts" from the air flow contacting the bed and dissipating outward. The cooling fins have no other way to orient than horizontally due to the bolts. The cooling is aided from the fan blowing onto the fins.

The firmware from HICTOP did not have thermal runaway protection, which is why I was considering removing it. I'll try to bump
The values again, but it seems I get to the second layer of my print and we stop due to the thermal runway.
Attachments:
open | download - IMG_1556.JPG (232.5 KB)
Re: Thermal Runaway after Firmware Uldate
March 21, 2017 03:37PM
I've now bumped it to 120 for the period and 10 for hysteresis. Your suggested mods found failure at identical location as previous.
Re: Thermal Runaway after Firmware Uldate
March 21, 2017 05:11PM
Quote
Vgala9
I've now bumped it to 120 for the period and 10 for hysteresis. Your suggested mods found failure at identical location as previous.

And here's the resulting failure attached. I actually caught it on video too.

I'm out of ideas besides replacing thermistor (which was purchased as part of a new hot end).

Any ideas would be appreciated. I was just going to comment it out but it's like a trip to the beach. Sand is everywhere.
Attachments:
open | download - IMG_1558.JPG (483.1 KB)
open | download - IMG_1562.JPG (29.1 KB)
Re: Thermal Runaway after Firmware Uldate
March 22, 2017 02:03AM
What filament were you printing, ABS or PLA, and what were the target temperatures for bed and extruder? I assume with the bed showing an actual tempeature of 86C that it was ABS. Some hot bed / PSU combinations are under powered and struggle to get the bed above around 86C unless in an enclosure. If your target bed temperature was above 86 this could be what has triggered the failure.
Re: Thermal Runaway after Firmware Uldate
March 22, 2017 05:52AM
Quote
Supermec
What filament were you printing, ABS or PLA, and what were the target temperatures for bed and extruder? I assume with the bed showing an actual tempeature of 86C that it was ABS. Some hot bed / PSU combinations are under powered and struggle to get the bed above around 86C unless in an enclosure. If your target bed temperature was above 86 this could be what has triggered the failure.

I am printing ABS at 220C extruder temp and 88C bed temp. I have always printed at 88C until I've recently updated the firmware (previous firmware, as I mentioned, did not have the thermal protection built in). I did notice that the heated bed dropped below the 88C setpoint on layer 2, so perhaps I need to either lower the setpoint to 80C for the bed or increase the hysteresis value for the bed.

The way the code is written, specifically the comments, a thermal failure of the heated bed would result in a "heating failed" message on the screen. If you believe that "thermal runaway" will be displayed in the case of either hot end or bed failure, then this may be the smoking gun. I will try to lower the bed temp setpoint later tonight.

As an aside, I am using Cura. I am not sure if you have experience with Cura or use a different slicer, but I know that some other programs allow you to disable the heated bed after the first few layers. Does Cura have such a setting? I could not locate it last night.
Re: Thermal Runaway after Firmware Uldate
March 23, 2017 01:25PM
Having had a look at the Marlin website I think that thermal runaway can affect the bed as well as the extruder. The comment is "if the measured temperature drifts too far from the target temperature for too long the machine will shut down with a Thermal Runaway error". Have a look in the advanced config.h file.
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