Jump to content
Ultimaker Community of 3D Printing Experts

UM3+UM3E Holes printing under-size

Recommended Posts

I have done a lot of research into this and it seems to be caused by many factors and there isn't really an answer how to fix this.

What I have done to minimize this is print a test piece of varying diameters (10mm-100mm for me). Then i measure the actual and compare it to the virtual size. This gives me a good idea of what size a hole will come out as and I adjust the model before printing.

Share this post

Link to post
Share on other sites

All technologies including FDM and injection molding have weirdnesses like this (e.g. in injection molding if you want 90 degrees corners your cad part better not have 90 degree corners).

I add typically .4mm DIAMETER (not radius) to all vertical holes.

The cause of all this is that the filament sticks to itself while cooling and shrinking in a fraction of a second as it comes out of the nozzle and it's like sticky mucus (like snot). It's pulling like a liquid rubber band and pulling inward on these vertical holes.

Horizontal holes don't need to be adjusted in diameter (but you might want to put pointy tops to the holes).

Share this post

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 | a new interface
      We're not only trying to always make Ultimaker Cura better with the usual new features and improvements we build, but we're also trying to make it more pleasant to operate. The interface was the focus for the upcoming release, from which we would already like to present you the first glance. 
        • Like
      • 114 replies
    • "Back To The Future" using Generative Design & Investment Casting
      Designing for light-weight parts is becoming more important, and I’m a firm believer in the need to produce lighter weight, less over-engineered parts for the future. This is for sustainability reasons because we need to be using less raw materials and, in things like transportation, it impacts the energy usage of the product during it’s service life.
        • Like
      • 12 replies

Important Information

Welcome to the Ultimaker Community of 3D printing experts. Visit the following links to read more about our Terms of Use or our Privacy Policy. Thank you!