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Solved Extruder heating up, then cooling back down when it starts to print.

Discussion in 'Troubleshooting' started by Demoux, Jan 29, 2016.

  1. Demoux

    Demoux New Member

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    Before I start, this printer is a school printer owned by my computers teacher. I unboxed it, set it up and got it running, and have been troubleshooting it over the past few months. Most hiccups I have been able to sort through in the short amount of time I have to tinker with it. But after the last one, a clogged hot end, it started back up fine, and when I went to print, MatterControl showed the extruder and bed heating up, once it gets to 235 (I print in ABS.) it immediately starts going down in temperature before it prints. I made sure the thermometer and heating element were put back into the hot end when I screwed everything back together. It is definitely heating up, but I am unsure as to why it cools down before it prints, and only then. Any help would be greatly appreciated.
     
  2. mark tomlinson

    mark tomlinson ༼ つ ◕_ ◕ ༽つ
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  3. afat08

    afat08 Member

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    Are you running a heated bed? If so, what temp?
     
  4. Demoux

    Demoux New Member

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    I can check the console log tomorrow. As I said, it is a school printer. I will post a log if possible.

    I am running a heated bed. It runs at 80 Degrees Celsius and does not lose heat like the hot end does when It goes to print.
     
  5. mark tomlinson

    mark tomlinson ༼ つ ◕_ ◕ ༽つ
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    The temperature drop sounds like an error being raised by the firmware. The logs should show that.
     
  6. afat08

    afat08 Member

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    Drop the bed temp down to 70 and try that
     
  7. Demoux

    Demoux New Member

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    Done. The bed preheats fine. it stops heating if I start to preheat the extruder, however.
     
  8. Demoux

    Demoux New Member

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    Here's a log. I turned the printer on, connected, and preheated.
    A noteable error that I am getting on the console is
    <-Error:Extruder switched off. Temperature fell too much during print!
    <-Error:printer stopped due to errors. Fix the error and use M999 to restart. (Temperature is reset. Set it after restarting)
     

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    • Log.txt
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  9. WheresWaldo

    WheresWaldo Volunteer ( ͠° ͟ʖ ͡°)
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    What is the start up gcode?
     
  10. Demoux

    Demoux New Member

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    Code:
    G28 ; home all axes
    G29
    G1 Z5 F5000 ; lift nozzle
    M109 S[temperature] ; set the extruder temp and wait
    G28 Z0 ; Home Z again in case there was filament on nozzle
    G29
    M565 Z0
     
  11. Quest

    Quest Member

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    You need a temperature on the M109 other wise it sets the temp to 0.
    M109 S220 ; set the extruder temp and wait .This should be set to the temp that you want to print with.
     
  12. WheresWaldo

    WheresWaldo Volunteer ( ͠° ͟ʖ ͡°)
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    Actually @Quest some slicers will replace that variable with an actual number when you slice your object. Cura and Slic3r both work this way, not sure if MatterUnControlled does.

    @Demoux Is that all of it, where is the command to heat the bed, should be either M140 or M190?
     
  13. mark tomlinson

    mark tomlinson ༼ つ ◕_ ◕ ༽つ
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  14. Demoux

    Demoux New Member

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    Well the problem isn't so much with the bed. When I start the print the bed heats fine. The bed isn't the problem, its the extruder. It heats fine and it detects the temperature fine. When I first go to preheat it, it will heat up perfectly for a little while, and then the console shows
    <-Error:Extruder switched off. Temperature fell too much during print!
    <-Error:printer stopped due to errors. Fix the error and use M999 to restart. (Temperature is reset. Set it after restarting)
    Sometimes I also get something along the lines of "Error:MINTEMP" and then something else. It's not too frequent though.

    All of this is without even telling it to print. When I tell it to print it does the same thing, heats up and then cools back down because of the error. My slicer isn't really as important. It's currently set to slic3r but I switch to MatterSlice every once and awhile if that is important.
     
  15. Quest

    Quest Member

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    I've been using repetier host and it did not fill that in.
    It's been a while sense I've used Cura or Slic3r as a stand alone.
     
  16. mark tomlinson

    mark tomlinson ༼ つ ◕_ ◕ ༽つ
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    Loose wiring to the extruder thermistor, or a bad connection or a bad thermistor.
    Watch your temperature graph in the print software and see what temperature is doing. It is at some point falling... a lot.
     
  17. Demoux

    Demoux New Member

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    The thermistor is reading fine. When I tell it to preheat, the temperature slowly climbs like it usually does. When it gets that error after heating up a bit, it shows it slowly fall while it cools. I have taken it out and put it up to my hand, and the temperature changed to my hands temp. I also know the extruder is heating. By hitting preheat and sending the m999 code, and preheating again, I can get it (Albeit slowly,) to 235, and it will melt the ABS when touched to the hot end. Everything seems perfectly fine. Something is just telling it something is broken, and I dont know if this is a hardware, software, or firmware issue.
     
  18. WheresWaldo

    WheresWaldo Volunteer ( ͠° ͟ʖ ͡°)
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    @Demoux I had a similar problem but it was hard to diagnose, until I noticed a strange clicking noise coming from the Robo. What I noticed is it would cool and error out every time the gcode started heating the extruder. The bed heater uses a lot of power and as soon as it kicked on the power supply would click and then the heating failed message. I ended up replacing the power supply and all is well. Your issue is not firmware nor software, it is electrical and needs to be solved as such.

    Sorry I can't be more specific, as you know it is sometimes hard to get all the details of an issue correct when you can't actually see the issue for yourself and are going by a written description.
     
  19. mark tomlinson

    mark tomlinson ༼ つ ◕_ ◕ ༽つ
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    The firmware is shutting it down because it sees the temperature jumping (down).
    That is bad hardware in that either the connection to the thermistor is bad or the thermistor is loose on the hotend or bad wiring/connection to the RAMPS baord.

    It is hardware.
     
  20. Demoux

    Demoux New Member

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    It was the thermistor. I noticed the black cover was kind of hard to pull back over the red wire, so I pulled it back a bit and somehow the red cord came detached from the metal that goes into the thermistor head. Any way I can fix this? or would just trying to get a new one be my best bet?
     

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