Five-axis NURBS Toolpath Fitting Method Based on Shear Leap Characteristic Points

A five-axis NURBS tool path fitting method based on shear leap characteristic points is proposed to address the problem of generating dense discrete tool data points during five-axis tool path planning of the existing computer-aided manufacturing system. The shear leap degree of each knife position point is calculated using three adjacent points, and the dominant point of shear leap degree is selected as the initial type value point for sample fitting, and the precision-preserving type value point is added in the area where the local fitting deviation exceeds the limit, until the obtained curve meets the accuracy requirement. The simulation results show that the fitting accuracy can be well preserved even if a large number of original discrete tool position data points are removed using the method of this paper, which is of high value for the application in the field of spline CNC programming.