Abstract: A starting hole for milling in a surface of a workpiece by a CNC milling machine with a milling cutter mounted to a rotating spindle is created by milling a first hole at a first diameter to a first depth into the workpiece along the axis of the starting hole; and then successively milling a second hole at a second diameter to a second depth into the workpiece along the axis of the starting hole, wherein the second diameter is smaller than the first diameter. One or more additional holes may be successively milled to additional depths at successively smaller diameters.

Abstract: A method of generating control code for a CNC machine is described. The method includes the steps of: (1) generating in a computer a first plurality of coordinate values, xi, yi, zi, said first plurality of coordinate values representing a plurality of first connected line segments which surround a vertical axis, said first connected line segments gradually descending to a first predetermined depth, (2) generating in a computer a second plurality of coordinate values xj, yj, zj, said second coordinate values representing a plurality of second connected line segments which surround the vertical axis, said plurality of second connected line segments having a starting point at approximately the first predetermined depth, and gradually descending to a second predetermined depth greater than the first depth, and (3) converting the first and the second coordinate values to a code for controlling the CNC machine.

Abstract: A method for generating a tool path for milling a region of a workpiece is disclosed. The region has a first side meeting at its respective ends a first end of each of a second side and a third side. The method includes the steps of: (1) determining, using a computer, a radius of curvature and a center of each of a succession of circularly shaped tool passes, each successive tool pass advancing into the region from the first side of the region, wherein the radius of curvature and the center of each advancing tool pass is determined such that an engagement of the cutter following the tool path does not exceed a predetermined value of cutter engagement, and (2) generating instructions for controlling the milling cutter to mill the region in accordance with the generated tool path.

Abstract: A method is disclosed for generating a tool path for milling a region of a workpiece having first, second and third sides. The method includes: generating a first arc having a corresponding in-process material boundary intersecting the first side and which is tangent to the second side and to the third side; generating a succession of one or more second arcs, having a corresponding in-process material boundary which intersects the first side, is parallel to the first arc, and progresses by a corresponding first predetermined value from the first arc toward the first side until the in-process material boundary corresponding to one of the second arcs has a maximum distance from the first side less than the first predetermined value; and thereafter generating a succession of transition passes connecting each one of the second arcs end to end with the first arc to form the tool path.