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Improve the hotend performance

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    If you have experienced any grinding or extrusion issues, you can reduce this problems just by applying a simple trick: add some thermal grease to the hotend. Follow these steps:

    1. Remove the hotend from the Sigma. Check this video out (until minute 1:18):

    2. Once the hotend is out (and cooled down!), use pliers to untighten the aluminium block. Be careful not to damage the wiring:

    You will have two subassemblies: On one side, the heatsink. On the other side, the nozzle + aluminium block + heatbreak + wiring:

    3. Then, add some Thermal Grease on the upper thread of the heatbreak. The higher thermal conductivity of the grease, the better performance of the hotend. We are using this reference:



    4. Assemble both subassemblies again, making sure the thermal grease is spread evenly on the heatsink thread:


    Use pliers to tighten firmly both parts:


    5. Finally, mount the hotend back to the Sigma. Follow the video instructions, from minute 1:19:


    Nice work but i think this is the only place the Sigma is lacking. It seems the hotends have many issues including this one. The worse thing i’ve found so far is the wear on the nozzle when using carbon fiber, after about 30 hours printing it’s worn out. Also replacing the whole hotend just for nozzle wear? It seems really silly. I know you are trying to make it easy to replace but it also puts a higher cost on it.
    I’m in the process of testing the E3D v6 hotend with great results so far.


    I’d just like to add that I have put some thermal paste on the heat break and have seen a huge improvement in performance. PLA that would previously block within minutes is working flawlessly. And ColorFabb PLA/PHA is also now working great! I can pretty much print with any material out there now.
    I’m just blown away how a small change like this can make such a massive improvement in performance.
    In my opinion this is a must do mod. Thankfully it is cheap, quick and easy to do. Hope BCN3D do this to all the new machines being built.


    can you please explain more about what you’ve done? as i’m suffering from printing colorfabb pla materials !


    I can’t see the photos, can you please check?


    Tomorrow we’ll check.
    This image by Christian Gassner is also very useful:


    By the way, if you are using e3D is also very important to use thermal paste.


    Hi can anyone tell me if there is a trick to unscrewing the hotted casing, had no problem with 2 hotends but the third one does not want to move.


    We ran a segment on how to remove the heatbreak from both sides using the M6 blot mentioned before:


    Hi Rubin,
    I just did what has been listed here. I changed nothing else and Colorfabb is working Fabb!


    Why is this not done at the factory?

    roger uceda

    We are currently applying heatsink paste in production.
    Printers with a serial number bigger XXX.160616.YYY have this improvement already done at the factory. Also all the spare parts hotend have it done.


    What about maximum operating temperature of the thermal paste? The one you recommend has 200 deg. limit, higher temperature pastes usually have lower thermal conductivity. I was wondering whether this paste will degrade over some time working at 200+ temperatures?

    roger uceda

    Yes, it’s true!
    This is the reason why we only recommend to use it in the upper part of the hotend, where you only have 60-100 degrees.


    Would HY610 be more suitable?

    roger uceda

    It seems to be better in terms of heat resistance:

    roger uceda

    I found some more compounds on Amazon:
    thermal conductivity – 8.5 W/mK,
    temp. range – not indicated
    thermal conductivity – 11 W/mK,
    temp. range – up to 150
    These look promising, knowing that heat sink temperature is only up to 100

    roger uceda

    11W/mK ! it sounds very high 😉


    Hello all
    the best for thermal grease it is this one:
    u can find it everywhere (amazon included) for cheap price
    max t°C= 350°C
    and 12,5W /mK
    to clean or unmount after a while it is very very easy
    people who knows how to mount computer, knows this one, and how much it is important the W/mK
    I use only this and recommend at 200% 😉
    PS: of course only at the final threads not on the “point”
    I put only on the 2/3 of the lenght


    I have really problems with printing colorfabb PLA. Even have bondtechs and an R17 machine. Do I have to do this procedure?


    I don’t think you do. Thermal grease is being applied since some time on 2016 hot ends and I would suggest it should be applied on R17 hot ends.
    What kind of part are you having problems with? We only had problems with parts with a lot of retractions…otherwise it prints ok

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