Modeling And Machining Simulation For Free-form Surface Parts Based On Group Technology

Free-form surface parts are related to national defense and civilian application fields such as aviation, shipping, energy source and mechanism. Free-form surface parts is a research hotspot in the machinery manufacturing industry because they are complex in structure, and are difficult to model and to machine. CAD/CAM technology plays a significant role in solving these problems. Blade surface consists of free-form surface,3D modeling and NC programming of the blade is crucial for the machining. By the application of CAD/CAM,3D model of the blade can be constructed. After making a reasonable machining process, the NC programming will be completed automatically. It points out the developing direction of blade manufacture technique.Structure characteristics and NC machining technique of the steam turbine blade are analyzed based on Group Technology. And then, on the UG NX platform, the blade CAD/CAM system is developed by UG/Open tool and VC++6.0. After the difficult points of modeling and machining are studied, modeling and NC programming for blades can be completed rapidly, and the traditional method of design and manufacture are improved, and conditions are provided to realize standardization, serialization, network for enterprise,so that the quality of blades is enhanced, the design cycle is shortened, the manufacture cost is reduced.After the structure characteristics and functions of steam turbine blade are analyzed, the blades are classified based on thought of group technology. And then blade CAD module is developed and module design thoughts are established. Through the study of sectional profile connection and blade surface modeling method, the automatic modeling of blade surface is implemented by programming. Modeling procedure for blade root and blade tip is implemented by feature parameter design technology.The key technology of blade manufacture is studied, and then blade CAM module is developed, which can automatically complete the NC programming. In the end, the blade CAD/CAM system is verified with an example, and its result indicates that the system is convenient, precise and efficient.