I am not familiar with the Fadal 8030, but basically there are two types of encoder mounting, one is the through-hole type where the encoder disk is mounted to the actual motor shaft directly, these are usually the most awkward to remove due do the disk seizing onto the shaft over time. The second type is the separate mount type that has a flexible coupling between encoder and motor shaft. Either way it is usually necessary to remove the encoder before the motor end plate. There is often an access hole to get to any set screw.
Hopefully someone who has done it on a Fadal may answer.
Al.
CNC, Mechatronics Integration and Custom Machine Design
“Logic will get you from A to B. Imagination will take you everywhere.”
Albert E.