Thermal Runaway :(

Discussion in 'Calibration, Help, and Troubleshooting' started by Liam Woinson, Apr 25, 2016.

  1. Liam Woinson

    Liam Woinson Member

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    About 1/2 of the way through the print I had a thermal runaway :( anyone know why it happens?? And what is the cure? Just need an answer quick to get the print done. Thanks
     
  2. PsyVision

    PsyVision Moderator
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    Sounds like your fans went too high so the temp dropped too low ?
     
  3. Alex9779

    Alex9779 Moderator
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    What style of head do you use? New Hybrid or V1.0?
    Maybe there is a bridge to be print at that stage of the print? Maybe the fans kick in too high?
    Old style head with fans does not really support more than 80% of fans and you have to position them as low as possible...
     
  4. PsyVision

    PsyVision Moderator
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    It's old style and he was at 100% (G+ photos) - lower the % and you should be good to go.
     
  5. Liam Woinson

    Liam Woinson Member

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    I'm using PLA. What is the highest I should run the fans at?? They have been set to only go up to 70% dunno why they have gone to 100% how would I lower the fans when bridging?? It's come out really nice what it's printed
     
  6. Falc.be

    Falc.be Well-Known Member

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    its an option in S3D under the tab cooling. I have turned it off
     
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  7. Liam Woinson

    Liam Woinson Member

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    will re try when I'm home and see what happens
     
  8. R Design

    R Design Well-Known Member

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    All things being equal, I found PLA to be relatively friendly to thermal runaway.

    When you increase the nozzle temperature from 210 to 250 to print something else, the heater has to work a lot harder just to keep up the temperature. So it's in a worse position when the fan comes on.

    And then if you do 250C and and a Volcano pumping lots of cold filament through: my experience is that one can FORGET using much of the fan at all.

    Kapton tape has arrived but have not started wrapping the heater blocks yet.

    Also 3mm bullet connectors have arrived so could swap in the e3d 40W heater (the BB is 30W by standard)...
     
  9. Liam Woinson

    Liam Woinson Member

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    I'm going to probably change out the heaters then. Didn't realise they are only 30W might set it to eventually run the fans at like 40%
     
  10. R Design

    R Design Well-Known Member

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    There are people who disagree with me.

    All I know is that when I attached an oscilloscope is that to maintain the nozzle at 250C with no fan and no extrusion, the PWM has the 30W on for 75% of the time. (And the resistance of my heater suggests it's on spec, the voltage of my power supply is above 24v.)

    I really have the impression it's doing it's best!
     
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  11. Old_Tafr

    Old_Tafr Well-Known Member

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    Must get my scope out and actually use it........... have you tried looking at the motor signals too?
     
  12. R Design

    R Design Well-Known Member

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    The motors weren't giving me any trouble.

    ;)
     
  13. Old_Tafr

    Old_Tafr Well-Known Member

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    But it would still be interesting to know if it is possible to see the signal and what (if anything) it can tell us. Sometimes you have to do things just for the hell of it. :eek:
     

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