Jump to content

Recommended Posts

Hi there

In order to test the x-y-accuracy of my new Ultimaker (no modifications so far) I printed a cube with 1cm length at 0.1mm z-resolution (using Cura) in PLA. The results I got were x=9.4mm, y=9.9mm and z=10.2mm. I'm fine with the y-scale, also with the z-scale as I printed a 0.3mm first layer. However, the x-scale seems to be out of range.

I then checked the distances for certain head movements. When driving 150mm in x-direction I got 151.5mm; the same for the y-direction. I adjusted the x- and y-step values and saved them in the EPROM. Checking the driving showed it was ok then. But the cube-print stayed the same, I still got 9.4mm instead of 10mm.

When checking the Ultimaker forum I found a post about shrinking, arguing the shrink in x-direction might be significantly higher due to the fan blowing in that direction. I tested this theory by setting the fan to 25% PWM; it didn't change anything.

I would like to ask the experts among you I they had any idea what might be wrong.

I'm aware I could change the x-scale in Cura for compensation but I'm not looking for a work-around but for a serious solution.

I'm looking forward to your inputs...

Stefan

 

  • Link to post
    Share on other sites

    The plastic is shrinking. I doubt the fan makes much difference X versus Y as it blows more on top of the print than a particular side. Plus the shrinking should be exactly equal in X and Y shouldn't it?

    Look at your 6 X pulleys. Move the head back and forth. Are the pulleys round? Or do they wobble? Some people have found pulleys with the hole not centered. Other's had the hole so large that when they tightened the set screw the pulley moved to the side. Maybe if you do something that is the same length as the circumference of a pulley (approx 60mm?) it will be more accurate? Just some thoughts.

    Usually people who really care about a dimension design something in CAD, print it, then adjust by the error and print again. It seems crazy but that's also how most people do it with word documents (print everything twice). And it works as the printer may be off a bit due to shrinkage but it's pretty consistent if you print with the same settings and with the same PLA and with the same air temp etc.

     

  • Link to post
    Share on other sites

    Posted · Wrong scale

    Thanks a lot for your help. I checked they pulleys; they show a very slight wobble which seems to origin from the natural play they have on the axis. But when checking I found the x-motor not fixed very vell to the back plane and the front x-belt being not as tight as the back belt and as it should be. After having fixed these two issues, I get quite accurate prints (9.8mm when 10mm in the model, 100.0mm when 100mm in the model, 30.5mm when 30.6mm in the model, etc...) even when printing with 150mm/s!

     

  • Link to post
    Share on other sites

    PLA will always shrink a tiny bit !!

    I just modelled very accuartly a replacement part for some tubberwear and it came out about... 03mm too small

    you can either just print with a tiny bit more meat where you need it or just accept the nature of PLA.

    Best wishes.

    Ian :-)

     

  • 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

      • Help Us Improve Cura – Join the Ultimaker Research Program
        🚀 Help Shape the Future of Cura and Digital Factory – Join Our Power User Research Program!
        We’re looking for active users of Cura and Digital Factory — across professional and educational use cases — to help us improve the next generation of our tools.
        Our Power User Research Program kicks off with a quick 15-minute interview to learn about your setup and workflows. If selected, you’ll be invited into a small group of users who get early access to features and help us shape the future of 3D printing software.

        🧪 What to Expect:
        A short 15-minute kickoff interview to help us get to know you If selected, bi-monthly research sessions (15–30 minutes) where we’ll test features, review workflows, or gather feedback Occasional invites to try out early prototypes or vote on upcoming improvements
        🎁 What You’ll Get:
         
        Selected participants receive a free 1-year Studio or Classroom license Early access to new features and tools A direct voice in what we build next
        👉 Interested? Please fill out this quick form
        Your feedback helps us make Cura Cloud more powerful, more intuitive, and more aligned with how you actually print and manage your workflow.
        Thanks for being part of the community,

        — The Ultimaker Software Team
        • 0 replies
      • Cura 5.10 stable released!
        The full stable release of Cura 5.10 has arrived, and it brings support for the new Ultimaker S8, as well as new materials and profiles for previously supported UltiMaker printers. Additionally, you can now control your models in Cura using a 3D SpaceMouse and more!
          • Like
        • 18 replies
    ×
    ×
    • Create New...