An exemplary grinding machine includes a grinding unit and a receiving unit. The grinding unit includes a rotor, a first spindle, and a first driver unit connected in series. The first spindle has a first end coupled to the rotor. The first driver unit is coupled to an opposite second end of the first spindle and configured for driving the rotor to rotate relative to a first axis. The receiving unit includes a container configured for receiving the rotor therein. The container has an inner spherical grinding surface defining a central second axis. The first axis is parallel to and spaced from the second axis.
