Default/Suggested thermistor resistance (Firmware)

Discussion in 'Calibration, Help, and Troubleshooting' started by Tinino, Nov 23, 2017.

  1. Tinino

    Tinino Member

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    Hey guys, I've got an E3Dv6 Chimera, and I've been having a lot of issues regarding extrusion, for whatever reason it seems to only want to easily extrude PLA at temperatures of 220c, I am able to get it to extrude around 200c however it results in significant under extrusion at higher layers when the fan kicks in. I have yet to do a PID autotune because I've attributed a majority of this to the fact that my resistance in the firmware is wrong, it leads me to believe the temperature readouts I'm getting are well off (or I could be wrong). I wanted to clarify if there's a recommended value for this. I've read through the E3D wiki and I found the values to enter, but those don't seem to be proper. I've never used the chimera before, so, in your own experience is it normal for them to under extrude at 200c with PLA? I wouldn't think so but maybe I'm wrong. Anyway, any help with this would be appreciated.
     
  2. Tinino

    Tinino Member

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    Hi guys. I hope bumping is okay. I'm still not sure of what the correct thermistor resistance would be for the chimera. I don't think it's a standard 100k thermistor, is it? Thank you for your time.
     
  3. jfb

    jfb Well-Known Member

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    I believe this is likely to be correct
    In Marlin firmware, these are the #5 thermistor. See the RepRap Wiki for more info, or refer to the datasheet.

    Specifications:
    • R25: 100.0kΩ±3%
    • B Value: 4267K±2%
    • Operating Temperature: -50~300°C
    Source: http://aus3d.com.au/e3d-thermistor-cartridge

    NB: I do not have a Chimera :) Perhaps E3D can confirm?
     
  4. elmoret

    elmoret Administrator

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    The Chimera assembly instructions talk about the correct settings for the thermistor, and that is thermistor 5, in Marlin firmware at least. It is a 100k thermistor, but there are many types of thermistors.

    220C for PLA is pretty normal for E3D hotends. Note that different hotends put the thermistor in different places, which impacts the printing temperature. If 220C works for your setup, no worries!
     
  5. Tinino

    Tinino Member

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    Thank you very much, I checked the wiki but I don't think the values I found were correct. I've saved this info, going to browse it sometime tomorrow or Friday and I'll reply if it works alright for me. And honestly, my sincerest thanks for replying with this info, I was having a hell of a time finding the right stuff, so hopefully this will work out alright for me. Thanks again.

    @elmoret

    That's really interesting, I've got 5 printers, I've used a couple Bowden clones but maybe it's just because the actual e3d heatblocks are milled from better materials, I'm not doubting you necessarily but I just find it surprising that 220 for PLA would be the norm on it. Any elaboration on why this is the case? Obviously the lower the temp the better the accuracy at least in most cases, balancing between quality and layer adhesion is important so that's why I'm so nit-picky about my temperatures. Thank you!
     
  6. elmoret

    elmoret Administrator

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    When it comes to 3D printing, the right temperature depends on a number of factors. Presence of a part cooling fan, type of thermistor (cartridge, stud, or just stuck in a hole), location of thermistor, etc all influence things.

    Find what works good on a particular printer and off you go. Same way that with some ovens you make a cake at 350F, and some ovens you might need 375F.
     

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