Study On Modeling Technology Of Surface And Simulation Based On Reverse Engineering

With the development of the times and the unceasing progress of science and technology,the demands of users on the product performance and appearance were getting more and more in-depth,a large number of complex free curves and surfaces came into being.Shorter product development time and production cycle has become an important factor for enterprises to improve their competitiveness.In the context of the above,Non-Uniform Rational B-Spline(NURBS)has become one of the most effective methods to construct complex free curves and surfaces in the manufacturing,such as in the aerospace,automobile,mold,and so on.Based on Reverse Engineering,this paper depply studies the methods of constructing complex free curves and surfaces by NURBS,and the complex free surfaces are analyzed and simulated.The main contents are as follows:(1)The basic theory of NURBS curve and surface is introduced,and the coordinate points of impeller blade profile are obtained through the coordinate measuring machine(CMM).Then making a detailed introduction on the cubic NURBS curve and surface.Programming the cubic NURBS curve in MATLAB by selecting parameter direction,defining the node vector and the boundary conditions,inversing control vertices.Then constructing the impeller blades profile of Exhaust gas turbocharger through the matrix method of the cubic NURBS surface;(2)Construction of the quartic NURBS curve and surface is introduced in detail,and the formula of the quartic NURBS curve in inversing control vertices is given,and the quartic NURBS curve are constructed by inversing control vertices.Then using the matrix method of the quartic NURBS surface to construct the impeller blades profile of Exhaust gas turbocharger by skinning in the MATLAB;(3)Constructing the solid model of the cubic NURBS surface and the quartic NURBS surface in CATIA,and then constructing overall shape of the impeller of Exhaust gas turbocharger.On this basis,contrasting and analyzing the error and fairness between the cubic NURBS surface and the quartic NURBS surface.(4)Making CNC machining process simulation of impeller in CATIA.It's easy to produce interference,collision and other issues through the CNC machining process simulation because of the complex free curves and surfaces,therefore,this paper uses five-axis linkage CNC technology.Analyzing the tool path after the simulation,and then getting the tool path equation and the tool path graph of roughing,semi-processing and finishing.