Dimensions in printed model does not match all dimensions in stl

[toilet-ovule-add 0]

Hi,

I just printed my first model with an Ultimaker 3 with PLA and a layer height of 0.1mm, no supports. The printer is calibrated (x/z and z). The model is simple wheel for a robot which has to be attached to a stepper motor.

When measuring the outer dimensions of the wheel, the dimensions of the design and model match.

But the hole in the middle is 3.01mm x 5mm in the design, in the printed model this is 2.4mm x 4.4mm.

Is this expected and should i calculate a scaling factor due to shrinking of materials ? Or is there another issue i should fix ?

[vtlli 2]

As far as I understand nozzle’s center trace perimeter of the layer and has thickness 0.4mm. For that reason for precise prints I always do reductions 0.4-0.5mm and never was warring about hundredths of mm.

It’s matter of experimenting.