@infiniteloop No, I didn’t touch the heatbreak as this is a Revo nozzle there is no PTFE tube inside just the nozzle tightened all the way in into the Roto extruder. The PTFE tube coming from the top barely gets inside the assembly without reaching the hobbed gears.

@elmoret it is a nozzle from the early beta testing of the revo system when those were shipped without sock, so, for your point, it is genuine. There is no air path blocked aside from the front where the toolboard is supposed to be installed and the back for the mounting system, did you mean that?

@elmoret this particular nozzle didn't have a sock. The heatsink fan can be seen in the third picture from top to bottom

@Phaedrux For sure

@infiniteloop I managed to try a fresh 0.4 nozzle and replaced the original extruder cooling fan with an slightly bigger one, still not working.

Also, I saw on the TMC2240 datasheet that Spreadcycle can compensate to some degree for the back EMF coming from the stepper, switched to that mode but didn't work as well

More ideas are appreciated before I take the leap and go for an smart orbiter.

@infiniteloop I hadn't thought of that, I will try a fresh nozzle and upgrade the fan, thanks for the suggestion

@elmoret This problem started while printing ABS but I have since reverted to testing with PLA with the same results, the motor keeps stalling after 15-20 minutes of printing when coming from a cold start and sooner on later prints.

@Notepad I have also tested with the absolute max current E3D recomends, 0.6A peak with the same result, I think anything beyond that might risk damaging the coils.

I will open a case with E3D to be sure the motor is not damaged at this point.

For anyone following.

I just measured the coils resistance in "hope" for them to be out of spec but they are not. Both measured 7.6 ohms at room temperature.

I haven't been able to print ABS nor PLA. I will keep trying tweaking the configuration but I feel that I have tried everything.

@dc42 the Duet3 control board is not installed inside the closed chamber as the roto toolboard is. How can this calibration affect the outcome of the printing tests?

Is there anything off in the M69 P121.0 report?

@dc42 these are the current settings:

M569 P121.0
Driver 121.0 runs forwards, active low enable, mode spreadCycle, ccr 0x00053, toff 3, tblank 0, hstart/hend/hdec 5/0/0, pos 8

@dc42 I sent the command as soon as I realized it was failing, 2minutes difference top, at that point I hadn't enabled anything related to stall detection.

Quick update of my tests:

• Disconnected the Roto motor from the Roto toolboard and rewired it to use a Duet3 stepper driver - Still failing
• Printed the exact same test print but now with PLA hoping that the ABS ambient temperature was the trigger of the motor failure but it also failed
• Inspected the whole motor assembly but found no issues apart from maybe insufficient grease on the gears (waiting for the grease to test)

At this point I'm almost sure the motor or some configuration is the problem but I can't find the root cause of it