Tool-Path Generation in terms of NURBS for High Speed Machining

In spite of increasingly utilizing high speed machining (HSM), the conventional tool path generation methods which are based on linear/circular blocks by applying standard strategies like parallel, z constant and Iso are usually employed in practice. Even though these tool-paths are employed by non-linear interpolators they have inherent limitations for HSM applications. This paper presents a new method for tool path generation in terms of NURBS. In order to increase the continuity of machining in HSM, a helical topology tool path in terms of NURBS is developed. This method reduces the number of CNC blocks up to five times. This algorithm creates a 2D-horizontal guide plane by offsetting the contour edges of the design surface. After that the inside offset of the contour is generated at a computed distance and then the contour and all its offsets are projected on the CL-surface. Finally, the tool-paths are approximated with NURBS approximation algorithm. The algorithm is designed to minimize the number of control points. An example of proposed approach consisting the comparison of the conventional method and verification is given.