An Efficient NURBS Path Generator for a Open Source CNC

In this paper a NURBS path generator (on the plane XY) is proposed to be developed for those CNC machine tools and robot which are Open Source or Opening Architecture. The goal is to use simple and efficient techniques to manufacture geometries which are very complex, whose main feature is the presence of free-form surfaces and contours. To reach this goal, the NURBS path generator has been optimized in order to enable the user to select among three different options to generate the tool path, using a specific parameter. The three options are respectively called “NURBS interpolation with constant increments of u parameter” (NICU), “NURBS interpolation with constant displacement increments by linear motion”(NICL), “NURBS interpolation with constant displacement increments by circular motion” (NICC). The NURBS path generator has been implemented for an Open Source Numerical Control (LinuxCNC) in order to evaluate its efficiency, by simulations and experimental tests, in terms of computational complexity, comparison between the trajectory covered and the path programmed, capability to follow speed and path trends.