Application of NURBS Curve Interpolation Algorithm in Steam Turbine Blade NC Machining

Abstract

In order to improve the machining efficiency and precision of steam turbine blade, the accurate mathematics model of complex blade is built with non-uniform rational B-spline. An ameliorative adaptive feed speed interpolation algorithm for an non-uniform rational B-spline curve is proposed aim at blade curvature radius great change. The faster feed speed is adopt to increase the machining efficiency when the blade curvature radius is big. The feed speed is adaptive to control the chord error within the specified range when the blade curvature radius is small. Normal acceleration is guaranteed within the permission scope. The blade is machined on CNC machine with NURBS interpolation to obtain high speed. Test results show that the machining efficiency of blade is not only further improved, but also the contour accuracy is guaranteed.