Tool path generation method, tool path generation device, and machine tool control device

A device for generating a plurality of adjoining tool paths which is a movement path of a rotary tool with respect to a workpiece for machining the workpiece by moving the rotary tool and the workpiece relative to each other, the device comprising a computer aided manufacturing (CAM) device and a processor, wherein the processor is configured to:

• generate a tool movement curved surface along a surface of the workpiece to be machined,
• select a machining pattern which defines a scanning policy for determining a path of a scanning machining path, an equal-height contour machining path or a radial machining path along which the tool moves repeatedly and adjacently,
• generate dividing lines along the tool movement curved surface,
• project the machining pattern selected by the machining pattern selection unit onto the tool movement curved surface,
• calculate positions of intersections between curves which are trajectories of the tool when the tool moves along the tool movement curved surface and the dividing lines so that the intersection points on adjacent trajectories are adjacent each other along the dividing line,
• determine tangent vectors of the curves at the intersection points,
• determine a Nerves curve, a Bezier curve or a B-spline curve passing and connecting the intersection points using the tangent vector, and
• generate a tool path represented by movement commands which interpolates the intersection points using the Nerves curve, the Bezier curve or the B-spline curve;
• wherein the CAM device sends the tool path to a controller of a machine tool, and
• wherein the machine tool cuts the workpiece according to the tool path.