The Geometrical Simulation System Of A 5-Axis NC Milling Machining

With the development of modern industry, the geometrical shape of a part is becoming more and more complex. Machining simulation has become an indispensable and important processing to verify NC programs and CL data before actually machining. It is also an important field in CAD/CAM, CIMS and virtual manufacturing. Specially, many investigators have attached importance to 5-axis NC machining simulation. In this thesis, three key technologies have been solved partly such as simulation efficiency, high quality three-dimensiona graphics display and simulation errors.For efficiency of simulation, the explicit solution has been obtained based on the theory of envelope with the geometrical model of general cutter. Calculational efficiency of a sweep volume of cutter has been geatly enhanced by our method comparing with the conventional implicit method. The approachs of finding intersecting points rapidly between triangles and lines which paralleling Z-axis and rapid location are proposed to improve forming dexel model of sweep volume of the cutter. One-dimensional bool subtraction of dexel models can be used to improve the efficiency of the processing for removing material.As far displaying graphics, the point-view can be changed during machining simulation by displaying the perspective projections of triangles with OpenGL. Those techniques such as prefect WM_PAINT mechanism for animation and real-time capturing keyboard message are adopted to enhance the quality of graphics and the performance of man-machine interaction.As far as simulation errors are concerned, analyzing approximation and sampling error of work-piece and cutter introduce models and controlling methods of errors. An optimized dexel model is presented as well. Machining error and collision detection are modeled between cutter holder and work-piece in simulation.Moreover, CL data driving the simulation model conversion model from CL data to inputting data for machining simulation in the machine coordinate frame is represented to drive models of simulation by CL data.Experiments are conducted to demonstrate the developed methods. The results show that these techniques are very efficient for real-time machining simulation, high quality three-dimensional graphics and performance for man-machine interaction.