Integral Impeller Geometric Modeling And Five-axis Nc Machining

Impellers are a type of representative parts with relatively normal sculpture and marked shape. The design of the working surface relates to several subjects such as aerodynamics, hydrodynamics and so on. So machining means, machining precision and machining quality of the surface all have large effect on the capability parameters. Anyhow impellers' design and manufacture are inseparable.The capabilities of impellers based on traditional method that the blade and the hub, which have different roughcasts from each other, are welded into one integral after separately finished, which is a waste of time and energy, are difficult to be guaranteed. The development of multi-axis especially 5-axis NC technologies makes it impossible and increasingly prevalent to machine integral impellers in recent years.Taking tool-path scheduling, tool position calculation and so on as the core, uniting with the denotative content of NC machining such as geometric modeling technologies, etc, 5-axis NC machining of integral impellers is relatively generally studied.The inverse calculating method of the curves on ruled blade surface by using B-spline interpolation is discussed and fatherly geometric modeling of the integral impeller with ruled blade surface by UG is accomplished. The results indicate that one cubic B-spline interpolating curve using cumulative chord length parametrization of a group of dimensional points and thickness values at each point and the thickness values are C2 . The method also can be used in interpolation and approximation.The side machining rough tool-path and finish tool-path in 5-axis NC machine tool after the local character of the 3-D integral impeller's blade surface by using differential geometry knowledge is analyzed are created. The results indicate that the blade surface can be constructed based on the shroud camber line, the hub camber line and the corresponding blade thickness when the side machining tool path of a 3-D integral impeller is planned. Then the tool axis track surface will be created and the blade surface will be shaped as the tool moves along the surface.Gouge detecting by NC simulation system is needed to judge the integral satisfaction capability of the machined surface. The tool, part geometry, machining conditions, tool-path and the material removal process are simulated by computer simulating technology to gain a rational optimized milling plan finally. The results indicate that it's an effective method for complicate surface design and NC tool position verification to combine theory analysis and simulation technology.The CLSF is converted into NC program that can be performed by the given NC machine tool. The real workpiece is machined in 5-axis machine tool in order to test the validity of theoretic analysis.