Issues with printed Parts


first of all I wanted to put my topic in the “Parts issues”-category, but its locked. So heres my problem:

I have calibrated all my axis and my extruder and my prints are pretty nice. If I print a specific length on the X-, Y- or Z-axis the prints are the exact same length as they should.
However, if i would like to print an object with a hole (it doesn’t matter if its round or square), it is smaller than it should.
E.g I wanted to print a cube with a hole in the middle with a diameter of 8mm. In the printed object the hole is only 6.8mm in diameter.

What am I doing wrong?



It’s a slicer issue : circles are drawn as polygon meshes :

So all curves are actually segmented polylines and a polygon always has smaller area than its enclosing circle.
Other causes :

  • when making a turn you get more material in the interior side than the exterior side (filament is squeezed and the next point comes into play).
  • filaments tends to cut corners when path turns.
  • if you’re extruding too much filament or if it’s too hot it will spread on a wider area (correct values for PLA : 190° and 75% flow).

How can I “cure” the slicer problem? Or do I have to live with that problem? I hope not.

Thx for your help

Only cure is to design the holes a bit bigger (10% should do the trick) or to drill them afterwards.

The only parameters you can modify to improve things a bit are the temperature and flow.