Research Of Key Technology And Software Development In NC Machining Simulation

We have been doing research on NC machining process simulation and program verification thoroughly for a long time. Under the support of the fund of 95 plan of National Scientific and Technologic Committee and the fund of Scientific and Technologic Committee of Jiansu province, we developed NC machining simulation system named RealCut 1.0. This article contains some main topic listed below:1. We use the technology of object-oriented analysis (OOA) and object-oriented design (OOD) to analysis and design the system construction and user interface. Now this system has been ready for commercialization.2. For the needing of engineering application, we proposed and implemented some key algorithms of lathe machining simulation, such as rapid creating and displaying realistic picture, rapid converting input NC file into a kind of middle file format defined by us and a material remove algorithm.3. A simulation geometrical model and real-time and dynamic realistic picture creating and displaying algorithm was proposed and implemented. The quality of our realistic picture is nearly as good as the ray-trace. This algorithm simplified the calculational methods of point of intersection and improved system speed. Because this algorithm makes the small triangular face normal to be a byproduct of calculating point of intersection, it does not need other time to calculate it. So it is possible to display high quality realistic pictures smoothly on microcomputer.4. Presented and implemented a rapid local hidden face remove algorithm used of milling machining simulation. This algorithm has high implementing speed and good reliability, because it makes use of OpenGL's high ability of process display buffer, deep buffer and stencil buffer efficiently. Unlike the isometric projection algorithm this algorithm can display workpiece from any direction.5. For making system more efficient, we use a series of technologies to speed up calculation and displaying realistic picture of simulation, such as OpenGL display list to speed up display cutter, image copy to speed up displaying cutter movement and local refresh to speed up displaying material remove process.6. Present a method of subdividing rough workpiece and a kind of data structure to save information of each points. Based on this, we proposed a NC program verification algorithm named Z&N. This algorithm can work well for high precise parts without needing finer subdivision. This algorithm has higher efficient than the method which uses tool path envelope intersection with normal vector of surface of geometry model and has higher verification precise than the method that uses tool path envelope intersection with z direction vectors.All NC machining simulation research results told before have been used successfully to develop software named RealCut 1.0. A lot of application instances reveals that the software can display high quality realistic picture and simulation result is same as realmachining. All errors in real machining such as gouges and misses can be seen during simulation. So it is very useful to find problems of NC machining program and has already played an important role in improving software of NC machining program and ensuring machining quality.