You can specify NURBS interpolation for tool motion in Creo NC for 3-axis and 5-axis machining using the OUTPUT_3DNURBS parameter. If you set this parameter to YES, the CL file contains NURBS motion as shown in the following example:

The first statement indicates the beginning of the NURBS motion for 3-axis machining. The subsequent MOVNRB statements define the NURBS motion, where:

o—Order of the curve

k—Number of knots

w—Number of weights always set to zero

n—Number of control points

s—Length of the curve.

k1,...kk—Actual knot values as scalars. One statement can have a maximum of 24 values.

cp1,...cpn—Actual control points as x-, y-, and z-coordinates. One statement can have a maximum of 24 control points.

The MOVNRB statement preceding the GOTO statement indicates the start of the actual point-to-point output for the NURBS motion. The last MOVNRB statement indicates the end of the NURBS motion.

In this case, the initial feed rate is defined before the NURBS motion. However, it can change during the NURBS motion.

NURBS interpolation is supported in Surface Milling (3-axis and 5-axis), Finishing, Trajectory Milling, Swarf Milling, Profile Milling, Volume Milling, Roughing, Reroughing, Local Milling, Face Milling, Pocket Milling, and Corner Finishing.