This invention provides a novel tool path planning method for five-axis flank milling by imposing the constraints of curve interpolation on the tool path. The tool motion is described in the form of spline curves during its optimization-driven calculation process, instead of discrete cutter locations in CNC linear interpolation. The coefficients of the curve equations are generated by minimizing accumulated geometrical errors on the machined surface using optimization algorithms. The continuity imposed by the spline motion reduces uneven modifications of cutter locations during the optimization process. The resultant tool path yields superior.

Provided is cam curve generating device that generates a cam curve that is smoothly connected to an out-section cam curve and reduces fluctuations in speed of a driven shaft and acceleration of the driven shaft. Cam curve generating device includes section divider that divides an application section into a plurality of sub-sections, and cam curve generator that generates a cam curve in the application section. The division condition includes a length and the type of each of the plurality of sub-sections. The boundary condition includes a position, speed, and acceleration of the driven shaft at each of a start and an end of the application section. Cam curve generator generates a cam curve that allows a position of the driven shaft, speed of the driven shaft, and acceleration of the driven shaft to be continuous at each of boundaries of the plurality of sub-sections.