Ring printing issues

When i want to print a ring with a known inner and outer diameter, the diameters are always smaller then what i want. what can i do about this?

Yeah, make it larger in your design.

Every FDM/FFM 3D printer on this planet will have this issue.
This is something inherent of this technology.

Not 100% but i think you may need to print in multiples of the printed bead width. Probably am wrong as am not an experienced user but seems likely.

waht do you mean?

I mean multiples of the printed line width: e.g. if your printed line width is 0.5 mm say, then your ring width must be dimensioned in multiples of 0.5mm: 0.5 mm or 1mm or 1.5 mm, 2mm and so on.

Note that by ‘ring width’, i mean the wall thickness of your printed ring

About the inaccuracy of the printed circles you can read this page.