Patent ID: 7853351

Claim:
A CNC machine tool having a CNC Controller, a workpiece support, a cutting tool tip in a tool head including a motor and a spindle for holding a tool with the spindle being: i) pivotable in any direction about a pivot point so as to define an acute included angle α with a Z-axis coordinate passing through the pivot point; ii) rotatable through any desired angle of rotation β about that pivot point; and iii) displaceable in any of three orthogonal X, Y and Z axes in an orthogonal 3D X,Y,Z coordinate system, the improvement comprising the CNC Controller for generating instructions controlling the motor and movement of the tool head relative to a workpiece mounted in the workpiece support, said CNC Controller including: a) first means for establishing a predetermined programmed path of movement of the tool head, spindle and tool relative to the workpiece; b) second means for generating instructions transmitted to said tool head and motor to cause said tool to move along said programmed path with movement along said path in predetermined ones of at least two of said X, Y and Z axes; c) third means for recording and storing the magnitudes of all X, Y and Z displacements of said tool including the magnitude of all angular displacements of said tool as a result of pivotal movement of said spindle and rotational movement of said tool about the Z-axis coordinate passing through said pivot point, the rate of change of each said displacements, the location of the tool in said orthogonal X, Y, Z coordinate system, and changes in the dimensions of said tool; d) fourth means for generating instructions for tilting said spindle through an acute angle α with the Z-axis coordinate passing through said pivot point and at any desired rotational angle β about said axis so as to inherently induce unwanted displacement of the cutting tool tip of said tool in at least two of said X, Y and Z coordinates, and for transmitting said tilting instructions to said tool head and motor; and, e) fifth means responsive to the unwanted displacements in at least two of said X, Y and Z coordinates induced by said fourth means for generating compensatory displacements of said tool in the ones of said X, Y and Z coordinates where unwanted displacements are occurring with said compensatory displacements being generated: i) simultaneously in real time with said unwanted displacements; ii) equal in magnitude with respect to said unwanted displacements; iii) opposite in direction with respect to said unwanted displacements; and iv) at the same rate of change as the rate of change of said unwanted displacements, and transmitting compensatory displacement instructions to said tool head and motor to perform said compensatory displacements; whereby, the cutting tool tip of said tool remains precisely on said programmed path of tool movement at all times irrespective of the unwanted displacements inherently resulting from the tilting instructions generated by said fourth means.