V6 Temp Fluctuations - Print wont start

Discussion in 'E3D-v6 and Lite6' started by MotoGP1199, Sep 21, 2018.

  1. MotoGP1199

    MotoGP1199 Member

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    Ok, So I just put on a new E3d V6 24V Bowden(genuine) and I'm having issues where the temperature of the extruder fluctuates 5-10 degrees and will not stabilize to let a print start. It will get close to target, looks likes its going to stabilize and then jump up or down a few degrees enough to not let the print start. I have had it start once after 5 min, and then other times it wouldn't start a print until after 40-50min wait time. Settings are correct for Marlin (thermistor setting 5, and auto-tuned many many times). My print cooling fan is off since it had not started printing yet so I know its not causing issues.

    What I have done so far to troubleshoot.......

    - Checked heater cartridge, labeled 24v, and 17 OHMs resistance
    - Checked voltage going to heating element (23.9VDC when heating up, cant read once PID kicks in)
    - Changed out ALL wires going to thermistor and heating cartridge
    - Tried auto tuning with/without sock, multiple temps, mounted and not mounted to printer.
    - Replaced thermistor
    -Installed old/stock hotend complete (holds 1 Degree differential with no issues, very stable.) Used same wires.
    - Installed old/stock hotend heater cartridge on E3d, did not work.
    - Fan has the label pointing in toward cooling fins(blowing at fins). Hope this is correct???
    -Run different firmware, however current firmware works perfect with my stock hot end.
    -Check OHMS from MKS board 24+ into thermistor connector and it reads the same as my bed connector. Bed holds temp perfect 1* diff.
    -Manually adjust PID settings for about 8 hours with no luck.

    Printer is a Tevo Tornado with Gen L Version 1.0 Board., Marlin 1.1.9

    ANY help would be appreciated.

    EDIT to add.
    - Heater wires are RED, assuming it is 40w
    - Thermistor is cartridge style with BLUE wires.
    - Perform M502 and M500 after every autotune, and Verify settings with M301
     
    #1 MotoGP1199, Sep 21, 2018
    Last edited: Sep 21, 2018
  2. Old_Tafr

    Old_Tafr Well-Known Member

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    Thoughts....

    • Controller itself is kaput?
    • Wires to thermistor have an outer screen? that is as well as the two wires for the signal, in which case the screen should be continuous and grounded at one end only.
    • The blue shroud that clips on the heat sink can be fitted the wrong way up, it isn't symmetrical. And the position (up or down) can be wrong.
    • PID tuning needs to be done in a draft free environment as this can cause the parameters to be completely wrong.
    • Assumed 40 watts? watts = V squared / R = 24 * 24 / 17 = 33 so 30 watts ish. Sounds daft but maybe it don't have enough power? Maybe combined with PID not correct means it powers on and off incorrectly and can't keep up or switches at the wrong time?
    If all else fails and sounds like it has then a test away from the print head sounds appropriate.
     
    #2 Old_Tafr, Sep 21, 2018
    Last edited: Sep 22, 2018
  3. MotoGP1199

    MotoGP1199 Member

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    Thanks for the response. I really appreciate it.

    1. I don't think the controller is bad as it still works great if I hook it up to my stock hotend.
    2. I do not have it grounded and the extensions from the thermistor from e3d do not have a shield.
    3. Per E3d's instructions, the blue shroud can be fitted either direction. After reading this I did try it both ways and it acts the same.
    4. PID has been done with no fans on in room, no windows open. Same environment that I tune my stock hotend with.
    5. Maybe its a 30watt heater. It does have the RED wires. I think changing out the heater is my next step :)
    6. I have tested it with it mounted to the print head and not mounted to the print head with the same results.

    As a side note, I have changed some settings in firmware to allow it to start printing temporary to try and figure this out. One thing I noticed is that my temps are way different. To print PLA+ I had to adjust my hotend temp from 215 up to 230. Also when my fans kick on (pointed at nozzle only, My temp immediately drops 5*(could be wrong PID settings??). Same fan/print head I was using with my stock hot end and do not have this issue, both setups point only at the nozzle. The fan/cooling setup I have just has a different mounting bracket for the E3d Hotend. Not sure if I should change the heater for a new one or try a different thermistor (NON-104GT-2) style.
     
  4. Old_Tafr

    Old_Tafr Well-Known Member

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    The difference then is....

    Stock hotend works .......... with the the same ..thermistor ...and ....heater cartridge..... controller..... wiring .....etc?

    Accepting that the PID tuning will be different.
     

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