Incorrect inner diameter of parts?

so how precise parts should i get if it prints everything like 0,23…0,40mm too small? doesnt even matter if i choose the ultrafine 0,0x profile or not, the part will still be smaller

It sounds like you need to re-scale the file in your slicer.

what or where is that

If your using the real Cura, you click on the item on the plate…the one your slicing…the the left side will highlight. It will be the 2nd button.

Scale

Internal hole sizes printing smaller is something that is common across all printers & slicers. You need to adjust for it when designing your model. Cura has a setting called “Hole Horizontal Expansion” that will adjust internal hole sizes without affecting the rest of the model dimensions. Give it a try.

HoleHorizExpansion

ok the hole expansion might fix it, but why is it printing it incorrectly in the first place?

There could be any number of reasons like incorrectly calibrated extruder e-steps causing over extrusion, but most likely it is caused by the hole perimeter being printed pulling the semi molten previous layer inwards as it goes around the circle.

i still dont get the whole point of this thing… if i add the expansion number to the gcode, then it actually prints the size that i need, but why cant it do it itself with the original model that has been spoonfed into the gcode for it to print ?

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