Issue with nozzle temperature not settling (PID values?)

Discussion in 'Calibration, Help, and Troubleshooting' started by Ray, May 13, 2016.

  1. Ray

    Ray Well-Known Member

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    Hi All,

    I have been using my BB Dual 1.0 for a while now, mainly using PLA at a temp of between 190 and 200.

    I have just started printing in ColorFabb XT and so am using a temp of between 240 and 245, however I hit a problem today where the LCD screen just says Heating.....

    I was using the start up scripts that had the following line:

    ;heat extruder 0
    T0 ; select extruder 0
    M109 S[extruder0_temperature] ; set extruder 0 temperature and wait

    It looks as though the nozzle temperature is never stabilizing, the bed I have set to 65 and it hardly moved from that, however the nozzle is set to 245 yet bounces between 242 and 250.

    I am using Alex RC6 build and wondered if I should be using different PID values (i.e. tuning them) or if something could possibly have come loose (thermistor etc.) to cause this problem.

    My current fix is to comment out the above code from the startup script and manually wait for the temperature and then print.
     
  2. R Design

    R Design Well-Known Member

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    Identify which LED on the Rumba corresponds to the heater and you can see what it's doing during the "heating" period.

    Is it on continuously? (Heater working hard.) Is it flickering a lot? (PID turning heater on and off.)

    The how to (it's easy and fun!) on PID tuning is http://reprap.org/wiki/PID_Tuning

    My experience with printing XT is that indeed the extra 40-50degrees C generally challenge the system, the heater having to work a lot harder just to maintain temperature.

    I remember a case in this forum of flickering temperature as yours but don't remember how it was resolved.
     
  3. Henry feldman

    Henry feldman Well-Known Member

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    BTW for PID tuning there is an octoprint plug in which makes it super easy... Once you do it your temperature curves are dead flat. Of course cooling fans are a problem until the silicone covers ship...
     
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  4. Miasmictruth

    Miasmictruth Well-Known Member

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    This may or may not apply to you guys. But by wrapping the heating block with kapton tape ibhavr had no issues with hearing even with 100% fan.

    Until E3D releases the silicone covers it's a way to shield the block
     
  5. Ray

    Ray Well-Known Member

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    Thank you all for your advice, I did suspect it was the PID values, as @Henry feldman pointed out, I used the OctoPrint plugin and now my temperatures are nice and steady and it starts to print as I would expect.
     
  6. Dr Jeep

    Dr Jeep Well-Known Member

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    Where is that plugin Henry, I can't find it (if I search for PID or tuning in the plugin repository)
     
  7. Henry feldman

    Henry feldman Well-Known Member

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  8. Ray

    Ray Well-Known Member

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    #8 Ray, Jun 4, 2016
    Last edited: Jun 4, 2016

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