Jump to content
Ultimaker Community of 3D Printing Experts

Can't get rid of this line / gap in circular prints

Recommended Posts

Posted · Can't get rid of this line / gap in circular prints

I'm stumped on why I'm getting these gaps or lines in my prints, mostly when the print involving circular drawing. Here are two pics

The first print is a recreation of "Fat Man"; the first atomic bomb

Line or Gap in Print

As the extruder head rotates around the print, the filament seems to "jump" in the same section.

Here's another print of a funnel. It was a failed print, but you'll notice the same gap/line located in roughly the same cooridinates. In both cases the line appears and seems to occur in all circular prints.

IMG 2162


After printing the atomic bomb, I noticed my X-Y motors were a bit loose. I tightened these up, then printed with retraction on. Here is the reprint of the atom bomb


IMG 2163

The line is still there. There are also some inconsistent layers, but I beleive this is due to a much needed axis alignment. It's the line/gap that is driving me nuts.

In a previous post, I'm also having issues with my Z axis - but not sure if this is related.


Any help is greatly appreciated.


  • Link to post
    Share on other sites
    Posted · Can't get rid of this line / gap in circular prints

    Hi Owen - thanks ... I've noticed this seam also on some (very rare) square prints. Does it also have an effect on cornering? For example a cube's corners seem a bit bent and not sharp?


  • Link to post
    Share on other sites
    Posted · Can't get rid of this line / gap in circular prints

    It's a z seam. It's either where the head turns around to do the inner wall (if you have one) or more likely it's where the head pauses while the z axis moves up to the next layer.

    What's probably happening is there's still some pressure in the head and a little plastic oozes while the print head isn't moving.

    Maybe you can reduce pressure by printing more slowly or at higher temperature. Or alternatively maybe lower temperature will reduce leakage? I would try it on a small cylinder. Experiment with speed and temperature. Take notes. And pictures. Let us know what happens. The nice thing about a tall cylinder is you can change settings while you print. Both cura and the UC let you change print speed and temperature while printing so you can print a few mm, mark the cylinder with a sharpie and then try a new settings. Keeping notes as you go.

  • Link to post
    Share on other sites
    Posted · Can't get rid of this line / gap in circular prints

    gr5 - One other question - one of these prints were done using the quickprint settings in Cura. So, if the quickprint settings are preconfigured, shouldn't the z seam be less noticeable or non existent?


  • Link to post
    Share on other sites
    Posted · Can't get rid of this line / gap in circular prints

    Most people don't care about the z seam. I don't know what the "quickprint" settings are and I don't really care but I will just take a guess and say it prints at a higher mm/sec which I would expect to emphasize the z seam as extruder is going from "fast" to "stopped" and you will get a little leakage.

    There are several obvious limitations of the UM. One being you can't print in mid air. A less obvious one is that when the feeder slows down or stops, the plastic keeps oozing for a little while and the opposite: when you speed back up it takes a little time for the plastic to be back up to speed. This causes all kinds of minor imperfections and there are tricks to reduce these. One is to print with less volume of plastic (slower). One is to print hotter. One is to reduce speed changes: speed up your z axis - read about it in the forums - so it doesn't stay in one spot as long or slow down head movement so a brief stop is less contrast from full speed.

    Another z seam trick is to place it at a different spot on each layer. Kisslicer does this. You might want to try it once you've mastered every setting in Cura. Another trick is the joris setting but this only works for cups and can completely mess up slicing for something that isn't a cup.


  • 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

      • Talking additive | The 3D printing podcast
        Why should we be the only ones asking questions? Join us and ask Jabil all your questions on September 22nd 5pm CET
          • Like
        • 3 replies
      • Ultimaker masterclass: Optimizing your Ultimaker Cura workflow
        Save your seat for either broadcast on September 23.
        What will you learn?
        · Best practices for iterative print preparation and every lesson you should learn from each print
        · The right way to use per-object settings and when they are most useful
        · Easy-to-use resources for anyone who wants to develop their own printer definitions, plugins, or print profiles
        · How to optimize print profile settings and whether to “keep” or “discard” changes
        · When is the right time to export your drawing from CAD? (Based on Ultimaker Cura’s surprising power as 3D control software)
        · And a whole lot more tips and tricks!
        How can I join?
        This free masterclass will take place twice:
        1. 11am CEST (5pm SGT, 5am EDT)
        2. 5pm CEST (11am EDT, 8am PDT, 11pm SGT)
          • Like
        • 0 replies
      • Do you use 3D printing at work? Let us know
        It doesn't matter if you are using 1 Ultimaker or 10, there is inspiration in everything. We're looking for ...
        • 1 reply
    • Create New...