Position controller for controlling a rotation center of a tilting head

A position controller for controlling a rotation center of a rotating spindle to which a tool is secured in a machining center, comprising:

• an offset attachment having a body combined to the rotating spindle and a spherical contact secured to the body;
• an offset detector built in the machining center such that the offset detector selectively move out into a process area of the machining center and automatically detects a tool offset from a contact point with the spherical contact as a position error of a tip point of the tool;
• an offset data processor connected to the offset detector and individually storing at least a pair of first and second tool offsets by respective rotation positions of the rotating spindle;
• and
• an operator connected to the storing unit and generating a transform offset of the first tool offset by a rotational transform and a center error vector from the transform offset and the second tool offset.