The invention, relating to an internal, active, compensatory and method and device
for the rotational main-shaft of a cutting tool with axial bias-and-swing, mainly
applies an active technique to a gas-floating main-shaft to thereby control its
bias-and-swing. A sensor at the exterior of the main-shaft directly measures the
axial bias-and-swing of the cutting tool. Taking the measured data as feedback
signals, the cutting point of the cutting tool is maintained at an axial positioning
accuracy that is predetermined. Further, the invention is arranged with an electromagnetic
controlling module to the mandrel's tail end at the interior of the main-shaft
for taking non-contacting magnetic force to finely tune the axial position of the
mandrel, such that an active compensatory function of the axial position of the
cutting point of a cutting tool in action is achieved.
