Jump to content
UltiMaker Community of 3D Printing Experts

Trouble setting extruder tension - plastic dust gets into tube


Recommended Posts

Posted · Trouble setting extruder tension - plastic dust gets into tube

No matter how I adjust the tension spring/bolt in my Ultimaker extruder, the filament is getting ground up, and plastic dust is getting drawn up into the bowden tube, resulting in an eventual jam.

I've backed off the bolt so that the distance between the blue plastic block and the washer at the other side of the spring is 12.39mm and it's still happening.

When initially feeding the filament (before it gets to the hot end, so no resistance) I can see very small dimples in the filament caused by the knurled bolt.

What should I try next?


  • Link to post
    Share on other sites

    Posted · Trouble setting extruder tension - plastic dust gets into tube

    The extruder mechanism should be able to push the filament just fine, without grinding it, so long as a) there isn't any physical impediment to its path, and b) you're printing at a sufficiently slow volume per second, so that necessary force isn't too high. Once it gets too high, then the filament stops moving, and the teeth grind it, rather than pushing it.

    So... firstly check for any restrictions. Is the Bowden tube squeezed or damaged at either end, or has the teflon coupler at the hot end gotten melted or damaged so that it presses on the filament?

    Then... consider what speed you're printing at. For best results, make sure that speed x layer height x bead width is less than 8mm³/s on an UM1.

    Also, don't use the Ulticontroller to advance or load filament - it can push it waay too fast. Just turn the big gear by hand.

    Finally, check your retraction speed settings... you probably don't want to be retracting much above 35mm/s - especially if you have the firmware from Cura 13.12, or another custom-built firmware that fixes the retraction speed bug. Retracting too fast, or doing lots of retractions close together can grind the filament - especially on a UM1.


  • Link to post
    Share on other sites

    Posted · Trouble setting extruder tension - plastic dust gets into tube

    I doubt it's retraction as I believe the speed is capped at 25mm/sec typically - but I haven't looked at Daid's latest build.

    I bet you are simply printing too cold or too fast. What is your temp, layer height, and print speed?

    For example 190, .2, 100mm/sec will grind up your filament. But 220, .1, 100mm/sec should be fine.

    My spring compression amount by the way is 11.5mm and Illuminarti's is 11.0mm. That's with the filament loaded and the clamp closed.


  • Link to post
    Share on other sites

    Create an account or sign in to comment

    You need to be a member in order to leave a comment

    Create an account

    Sign up for a new account in our community. It's easy!

    Register a new account

    Sign in

    Already have an account? Sign in here.

    Sign In Now
    • Our picks

      • UltiMaker Cura 5.3 stable released
        In this stable release, Cura 5.3 achieves yet another huge leap forward in 3D printing thanks to material interlocking! As well as introducing an expanded recommended print settings menu and lots of print quality improvements. Not to mention, a whole bunch of new printer profiles for non-UltiMaker printers!
          • Thanks
          • Like
        • 25 replies
      • Here it is. The new UltiMaker S7
        The UltiMaker S7 is built on the success of the UltiMaker S5 and its design decisions were heavily based on feedback from customers.
        So what’s new?
        The obvious change is the S7’s height. It now includes an integrated Air Manager. This filters the exhaust air of every print and also improves build temperature stability. To further enclose the build chamber the S7 only has one magnetically latched door.
        The build stack has also been completely redesigned. A PEI-coated flexible steel build plate makes a big difference to productivity. Not only do you not need tools to pop a printed part off. But we also don’t recommend using or adhesion structures for UltiMaker materials (except PC, because...it’s PC). Along with that, 4 pins and 25 magnets make it easy to replace the flex plate perfectly – even with one hand.
        The re-engineered print head has an inductive sensor which reduces noise when probing the build plate. This effectively makes it much harder to not achieve a perfect first layer, improving overall print success. We also reversed the front fan direction (fewer plastic hairs, less maintenance), made the print core door magnets stronger, and add a sensor that helps avoid flooding.

        The UltiMaker S7 also includes quality of life improvements:
        Reliable bed tilt compensation (no more thumbscrews) 2.4 and 5 GHz Wi-Fi A 1080p camera (mounted higher for a better view) Compatibility with 280+ Marketplace materials Compatibility with S5 project files (no reslicing needed) And a whole lot more  
        Curious to see the S7 in action?
        We’re hosting a free tech demo on February 7.
        It will be live and you can ask any questions to our CTO, Miguel Calvo.
        Register here for the Webinar
          • Like
        • 18 replies
      • UltiMaker Cura Alpha 🎄 Tree Support Spotlight 🎄
        Are you a fan of tree support, but dislike the removal process and the amount of filament it uses? Then we would like to invite you to try this special release of UltiMaker Cura. Brought to you by our special community contributor @thomasrahm
        We generated a special version of Cura 5.2 called 5.3.0 Alpha + Xmas. The only changes we introduced compared to UltiMaker Cura 5.2.1 are those which are needed for the new supports. So keep in mind, this is not a sneak peek for Cura 5.3 (there are some really cool new features coming up) but a spotlight release highlighting this new version of tree supports.  
          • Like
        • 22 replies
    • Create New...