3D printer for robot parts?

[CatalinaWOW]

Saying any device is dimensionally accurate or not is meaningless without standards.  No 3D printer is going to be able to hold 0.1 mm accuracy.  Best accuracy for such printers will be on the order of nozzle size, which is most commonly 0.4 mm.  With care you can do better for critical dimensions, but unless all dimensions of your part are integral multiples of the line width tweaking in one area will cause a loss in another.

Nozzle size is about how fine features in can print, not accuracy.

Two general things control accuracy.  Positioning of the print head which involves motor step size, belt stretch and similar issues and size and repeatability of the  "toothpaste" squeezed from the nozzle.  If the latter is perfectly repeatable the slicing process can compensate and it has no impact on accuracy.  It is never perfectly repeatable though which is why I suggested "on the order of".  Smaller nozzles have smaller impact.