Extruder Heating Fault only during printing ABS



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    Recently re-converted my Tevo Little Monster's MKS board to an M3D Duet Maestro. I went down this path a few months back only to return the board due to the random short to ground issues. The Maestro is back in and I have done maybe 12 hours of PLA printing without issue. I print this at 200°C

    I have been trying all day to print ABS at 235° and have immediately been getting extruder heating faults once I start printing. The temperture is highly erratic jumping +/-30°C within a few seconds.

    Once I switch back to printing PLA at 210° the machine runs fine and temperatures are stable.

    Some notes:

    1. I mostly print ABS and the machine has hundreds of hours doing so with the stock board. I did not change the slicer settings. The part cooling fan is not turned on at all.

    2. I can manually heat the extruder to 235° and extrude out a glob of filament at various speeds temperature is stable within 2°

    3. My loading and changing filaments at 235° is fine. temperatures are stable within 2°

    4. The issue seems to happen if the machine is running a print job. Then the temperature reading is more erratic.

    Checked the connections and they seem fine but given the above this seems to be a firmware issue?

    Where to start?



  • Possibly relevant info

    in config.g

    ; Heaters
    M307 H0 B0 S1.00 ; Disable bang-bang mode for the bed heater and set PWM limit
    M305 P0 T100000 B4138 C0 R2200 ; Set thermistor + ADC parameters for heater 0
    M143 H0 S120 ; Set temperature limit for heater 0 to 120C
    M305 P1 T100000 B4138 C0 R2200 ; Set thermistor + ADC parameters for heater 1
    M143 H1 S285 ; Set temperature limit for heater 1 to 285C



  • Things that come to mind.

    Have you done a PID tune? Was the cooling fan active during the tuning, but now absent printing ABS?

    Are you sure you have the right values for configuring the thermistor?

    Do you have any values being overridden by config-override.g?

    Are you sure the thermistor is firmly secured?



  • Thank you. The PID tune seems to have done the trick. Temps are stable now. I am surprised that it made a big difference.


  • administrators

    @infamous_panda said in Extruder Heating Fault only during printing ABS:

    The temperture is highly erratic jumping +/-30°C within a few seconds.

    That usually indicates a wiring problem.



  • @dc42 Yes that was my first assumption. As far as I can tell, the connections are good. I ran PLA 190°C and ABS 235°C back to back. The PLA ran fine for hours, where the ABS would fail within seconds of starting the print. If it were wiring I assume that it would be erratic for both situations. Also it would be erratic when changing filaments (240°C). The issue only occured during printing.


 

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