Heater fault

RivianAdventurer

Hi,
I received this sequence of faults today:

Error: Heater 1 fault: exceeded allowed temperature excursion: target 210.0°C actual 194.4°C
Warning: Tool 0 was not driven because its heater temperatures were not high enough or it has a heater fault

It happened twice on the same file at a time where there was a high and consistent volumetric flow. I restarted the print after the first time.

The second time it got to a similar stage in the file the error triggered again. This time I cleared the error and continued printing and observed the extruder heater. To my surprise it couldn't hold temp, it kept steadily decreasing throughout this part of the print. This time the temp didn't go low enough to trigger and once the volumetric flow reduced the heater got back up to temp and the rest of the print was fine.

For reference I am using a dragon HF with a 40W heater @12v with a 0.6mm copper nozzle. The volumetric flow for this print was from 1.060 mm^3/s to 20.650 mm^3/s. The section where it stopped was running about 19-20 mm^3/s.

I have since re-calibrated my heater and hopefully it doesn't happen again. Is there something else I could be doing to give me more stable temperatures in the future?

Phaedrux

@rivianadventurer said in Heater fault:

Is there something else I could be doing to give me more stable temperatures in the future?

You're exceeding the capabilities of the heater to keep up. How did you verify that your hotend is capable of a volumetric flow of 20mm^3/s? The error during the print would indicate it can't keep up.

I suggest you go through this extruder calibration guide, particularly the part measuring the max flow rate and see what you get.

https://duet3d.dozuki.com/Guide/Ender+3+Pro+and+Duet+Maestro+Guide+Part+4:+Calibration/40#s165

Ways to increase your flow capability would be to: Insulate the block, switch to 24v power and heater, increase the set temp so there is more thermal inertia to push through the high flow rate peaks. Or just reduce the print speed to bring the flow down to a more manageable rate.

You can also see here about handling heater faults.
https://docs.duet3d.com/en/User_manual/Troubleshooting/Heater_faults

deckingman

@rivianadventurer In addition to what @Phaedrux has said, did you happen to have a part cooling fan running when the temperature dropped? If so, a silicone sock might help or some re-arrangement of the part cooling air stream to prevent cold air being blown over the nozzle block.