Jump to content
UltiMaker Community of 3D Printing Experts

PLA shrink factor


Recommended Posts

Posted (edited) · PLA shrink factor


I’m printing a huge model for a client in PLA. It will imbed metal parts and components that must fit accurately with some tolerancing. 

My first sample test part I printed at 0.1 mm resolution and that wasn’t accurate enough to fit the small metal parts. But it worked well at 0.06mm. 

However to print the full complete product at 0.06 mm will take 6 days!! That’s too long, and there’s risk for an error in the print. 

Only alternative is to print at a lower resolution and expand these features. But by how much? It must fit metal discs that are about 0.08” And a metal bearing spinner at about 0.27” tall by 0.86” diameter. If i am to print this at a lower resolution, I’ll need to widen these dimensions a bit with more tolerance. But how much?

Edited by t-squareddesign
  • Link to post
    Share on other sites

    Posted · PLA shrink factor

    In my experience, there are a lot of things that influence accuracy: temperature, speed, flowrate, material, even color (some colors melt better than others, not sure why, maybe due to fillers?), etc. Further there are things like layer-lines (curved edges), blobs, ringing, thickening of corners due to nozzle slowing down,... All these have an effect.


    The only way to know, is test. Make your typical features in real size in a small test model, and try that. For me, I usually take 0.1 to 0.5mm extra, depending on how tight a fit I want, and whether it are inner openings or outer sides.


    Be aware that PLA will deform even under moderate warmth. You can not leave it in your car, even not in mild sunny weather in spring or autumn (internal stress relaxation). And it will deform quite fast under continuous load (creep deformation). Don't ask how I know.  :-)  This might not be suitable for every technical application.


    If the application allows it, I usually go for plenty of tolerance. Otherwise I calculate some post-processing in from the beginning: some filing, sanding, cutting,...


  • 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

      • New here? Get ahead with a free onboarding course
        Often getting started is the most difficult part of any process. A good start sets you up for success and saves you time and energy that could be spent elsewhere. That is why we have a onboarding course ready for
        Ultimaker S5 Pro Bundle, Ultimaker S5, Ultimaker S3 Ultimaker 2+ Connect.   
        They're ready for you on the Ultimaker Academy platform. All you need to do to gain access is to register your product to gain free access. 
        Ready? Register your product here in just 60 seconds.
          • Like
        • 14 replies
    • Create New...