Some CNCs can interpolate axes along mathematical curves. A single program block can describe a complete curve that might once have required several blocks of short lines.

The potential benefit is higher feed rate. This is true even when the CNC has plenty of processing power. Curve interpolation lets the control system change direction along the curve more gradually, maintaining a higher average feed rate than it can when “cornering” from one straight line segment to the next.

NURBS interpolation is one type of curve interpolation. To take advantage of the capability, one requirement is a CAM system capable of outputting NURBS tool paths.

Video courtesy Makino.