**5.7 Circular and linear tool path interpolation**

Due to the inconveniences of the traditional linear interpolation method for machining complex forms, an alternative is to use circular interpolation associated with linear interpolation to describe a tool path. That combination can maintain the continuity of the curve C1 and showed many advantages about the isolated utilization of segments of straight line (SOUZA, 2004). This approach, however, can only be applied to planar motion by interpolating two axes of the CNC machine, since the great majority of CAD / CAM / CNC are unable to carry out circular interpolation in three dimensions. Thus, it has aimed utilize polynomials Spline to describe complex tool paths.

Fig. 17. Determination of CL by CC
