Printout size is different to drawing

mark_dutton343

I have a simple drawing of a cup holder adapter. It comprises 2 parts. The male part that goes into a cup holder and a female part that takes a larger cup.
https://cad.onshape.com/documents/974752804deb743dc674fd9a/v/0a7d1a8c6540790b3bb1e4e1/e/c97b14553bca5079f2da2a67

The issue I have is that I have dimensioned the outside diameter of the smaller part at 74mm, yet it prints at 78mm. I thought that it might be a problem with my printer, but the inside diameter of the larger part, which is 89mm, prints precisely to 89mm and the two parts fit perfectly together when assembled.

I am at a loss as to what is going on and I thought I would ask here in case there is something I am missing regarding dimensions.

tim_hess427

Not sure what the issue is, but a few things you could check:

1. make sure you're downloading/exporting from the correct version and not an older version accidently
2. open up the stl in a different program after downloading (you may be able to use windows 10's 3D viewer application or MeshMixer from autodesk). Verify correct dimensions.
   
3. Try to measure the dimensions in your printing software.
   
4. Make sure you didn't accidentally scale your model in the printing software.
   
5. Make sure there aren't some weird printer settings turned on that would add additional walls to the outside of your part.

What printer and print software are you using?