Research On The Virtual Simulation On Sprial Bevel & Hypoid Gears Machining Based On STL Format

As basic component, sprial bevel and hypoid gear is widely used in mechanical products. Its complicated tooth surfaces make the 3D modeling difficult. And trial cut is needed to adjust design and processing parameters for desirable tooth surfaces machining. But the process of trial cut which sinks money and wastes time is hard to meet the needs of present market for the development of the products. In this paper, the virtual simulation on sprial bevel & hypoid gears machining, based on STL format file, has been carried out by using computer simulation technology.The simplified method of the cutter and the workpiece entities is proposed depending on the practical manufacture. By using 3D modeling software, the 3D solid models of the cutter and workpiece are constructed, and they are stored as files in STL format for further virtual machining simulation.The arcticle analyzes the characteristics of STL file, and implements the read and display of STL file. In addition, a method for realizing the whole process of the virtual sprial bevel & hypoid gears machining simulation is put forward: the 3D solid models of the cutter and workpiece in STL format are discreted as the point clouds which represent their surfaces, then stored in linked lists with special data structure. Through Boolean operations between the point clouds of the cutter and the workpiece, the surface of the workpiece is reconstructed according to the updated point clouds, and the process of machining simulation is completed. The intersection algorithm between rays and triangular mesh is studied and a method of 3D surface reconstruction based on 3D point clouds with special data structure is proposed. Finally, the storage file in STL format is studied and realized.In this paper, the principle of the kinematic transformation from traditional machine to CNC gear generator is introduced, and then the method for finding the coefficients of expression is put forward. The process is realized by using MATLAB,VC and MATCOM which could implement mixed programming with Visual C++ and MATLAB. The method solves the complex mathematical models int the process. Based on this, the translation and rotation process of cutter and workpiece is discussed, and the expression of rotation matrix is worked out, which reflects that one vector rotates by any other space vector. Then the posture change of cutter and workpiece in process is realized, and finally, the virtual simulation on sprial bevel & hypoid gears machining is realized.