The precision should be no trouble, but you should understand your printers tolerance capabilities.
If you print a 30mm hole and a 30mm box to go in it, it might not fit, usually you would oversize the hole or undersize the box. By how much depends on your printers characteristics. Easy to test by printing said box then measuring how close to 30mm it was.
If you print a 30mm hole and a 30mm box to go in it, it might not fit, usually you would oversize the hole or undersize the box. By how much depends on your printers characteristics. Easy to test by printing said box then measuring how close to 30mm it was.