Jump to content
UltiMaker Community of 3D Printing Experts

Gaps in the top layer


Recommended Posts

Posted · Gaps in the top layer

Again and again I have gaps in different objects in the top layer, but only when printing on my UM2Go


The result looks like this:



In Cura layer view, everything looks fine:



So I investigated several hours to solve the issue. What I have tried and done:

  • Different object heights -> doesn't matter it is always the same
  • Reduced speeds -> still the same
  • Set extra skin wall count to 0 -> same result
  • Set skin overlap percentage to 15% -> same result
  • Set line width from 0.4 to 0.35 -> same result


Then I tried to print the same object on my UM2+ Extended -> looks good, no gaps!

Then I sliced the object with Simplify 3D -> looks good no gaps!


The interesting part is, that the wall count defaults to 2 on the Um2Go. When I print with only 2 walls then there are no gaps! But printing with 3 or 4 or 5 walls, there are gaps, every time.


Then I tried to create the Go in Cura with the UM2 profile, but same result as with the Go profile, gaps.


Next try, added the printer with the UM2+ profile and yes, no gaps. The difference between the UM2 and the UM2+ profile is the line width. UM2 defaults to 0.4 and UM2+ to 0.35. But printing with the UM2 profile and manually set 0.35 line width is also not working for me.


Now I also know why I only see it from time to time. I often print with defaults, so 2 walls and there are no gaps. But for some prints I need more walls and then I see the gaps.


Really strange issue....


If someone with a Um2Go is willing to try it, here is the project file: UM2GO_Guide.3mf

  • Link to post
    Share on other sites

    Posted · Gaps in the top layer

    So I think I solved the problem and found the root cause. After additional test prints and just changing a single setting with every print, I found that it is caused by the mixed speeds which is used by default. Just lowering the generic speed was not helpful, but equalizing all speeds to the same value did the job.


    I was also wrong, that a 2 walls print and a print with the UM2+ Cura profile is good. They are much better, but under the magnifying glass I saw also very tiny gaps in these objects.


    Anyway, it shows once again how important it is to adjust the speeds and not to rely on Cura's default calculation. With the UM3 and S5 I always do this, because otherwise I don't get dimensional accuracy. With the UM2 printers I have never needed this before.

    • Like 1
    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
        • 24 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...