Jump to content
UltiMaker Community of 3D Printing Experts

Backflow ABS

Go to solution Solved by gr5,

Recommended Posts

Posted · Backflow ABS

Dear Ultimaker community,


I've had a problem related to backflow after printing with ABS in an S5; the part didn't stick to the bed, and before I could realise ABS had already gone up through the gap between the nozzle and the silicone covers. Fortunately, it seems that is has only reached the nozzle. I'd like to know, is there any guide on how to clean that plastic? How should I proceed without damaging any part?


Thank you



  • Link to post
    Share on other sites

    Posted · Backflow ABS

    we had one of these and used acetone to soften the abs and removed it with pliers.

    Nozzle still works like a charm, but use a small brush of paper towels to apply the acetone

    • Like 1
    Link to post
    Share on other sites

    • Solution
    Posted · Backflow ABS

    Just heat the nozzle to about 120C in the menu on the printer.  Open the door and clean with a tissue or paper towel.


    More importantly - this is called a "head flood" and you got the most mild version ever but it can be a disaster.  It's never happened to me but it happens a lot - especially to people who have printed fewer than 100 prints.


    The fix is to get your parts to stick better to the bed.  Ultimaker has much advice on this.  I have a whole video on this on youtube.  The main tricks:  squish, temperature, brim, rounded corners, glue.  I talk about each of these for many minutes as they are complicated and it's good to understand.


    squish, temp, brim are set by the ABS profile by default.  Don't skip brim if your parts aren't sticking (I don't use brim except very rarely for the most difficult of prints).  So if you haven't messed with profiles you probably just need to worry about the last issue, glue.  I recommend Magigoo.  They have a product specifically for ABS.  Get that.  It will save you major headache (no head flood).


    If you have 20 minutes, this video will teach you a lot:


    • Like 1
    Link to post
    Share on other sites

    Posted · Backflow ABS

    Thank you both for your help! I tried first heating it up and it went off in one piece, so it wasn't necessary to use acetone; I imagine it can be helpful in more severe cases.


    Anyway, I realised that the Print Core 1, where it all happened, doesn't fit with the silicone cover so good as in the Print Core 2, as number 2 is a little bit lower than the first. That said, I imagine it's easier to have head flooding in the first one rather than in the second. So, do you know if there is any other option to protect better the first printcore? Like a tighter silicone nozzle cover?


    Thank you again,


    PS: kudos for your video gr5! Nice to see and very helpful!

  • 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
        • 22 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...