Patent ID: 8000833

Claim:
A method for cutting a given portion of a surface of a core insert, comprising: defining a Cartesian coordinate system on the surface of the core insert; storing coordinates of each point on the given portion of the surface; defining a polar coordinate system on the surface with the pole thereof coinciding with the origin of the Cartesian coordinate system and the polar axis coinciding with one of the coordinate axis of the Cartesian coordinate system; aligning a cutting portion of a turning tool with the origin of the Cartesian coordinate system; rotating the core insert about a rotational axis passing through the origin of the cutting portion of the turning tool; moving the core insert at a predetermined feed pitch in a fixed direction perpendicular to the rotational axis away from the cutting portion of the turning tool; calculating the coordinates of the cutting portion of the turning tool in the Cartesian coordinate system based on the coordinates thereof in the polar coordinate system wherein the cumulative feed pitches serve as the radial coordinate of the cutting portion in the polar coordinate system, and the rotational angle of the core insert serves as the angular coordinate thereof; cutting the given portion of the surface using the cutting portion if the calculated coordinates of the cutting portion of the turning tool in the Cartesian coordinate system match with the stored coordinates of any point on the given portion of the surface.