electric motor or electric pump made with CNC 3D printer or mill for a CNC machine

I was wondering if it would be worthwhile to try to make an electric pump or electric motor for a CNC machine (printer or mill) using a CNC machine.

I know motors are mainly metal, but as long as the heat does not build up, the casing should be able to be plastic or whatever material, right?

Some copper wire and a magnet should be the only resources else than the building material and the motor could be of a unique design since it would be made by a CNC for a CNC.