Development Of Intelligent CAD System And Research Of Light-Weight Technology For Large Assembly

Large assemblies are used more widely in industry such as aircrafts, ships, compact molds and product lines and so on. With the development of CAD/CAM technology, all the design process of the product, virtual manufacture and digital mock-up can be accomplished in the computer. Large assembly becomes a necessary element in modern design process because of these. The design method of large assembly become an important factor to the development of the market and design efficiency.Large assembly includes large number of parts, compact structure relationships and large data capacity. At present, large assemblies are designed by hands in the company with the problems as follows. First, the designer need spend a lot of time on repeat modeling because of low degree of parametric model, which extend the design cycle. Second, the designer need to generate the 3D models, drawings and BOM by hands, which lead to low efficiency and mistakes in the design process. Third, the operation of large assembly in the computer is inconvenient because of its'large data capacity. The collaborative design on network and movement simulation can't be done smoothly. In additional, the company needs to hide the key design technologies when sharing models during the cooperation. With a deep analysis on the features and design method of large assembly, a standard model library is generated by the parametric design and modular design technology. The method of auto update of assembly and intelligent assembly technology and auto generation of drawing and BOM are achieved on the base of recursive algorithm. An intelligent CAD system is developed by the integration of these technologies.Meanwhile, with the research on the light-weight technology, the light-weight process of large assembly is divided into four parts such as suppression or replacement of the small compact parts, suture of the surface features in the model, suture of the assembly gap and model hollowing. And the light-weight technology is integrated into the intelligent CAD system and the simplified model is used to assembly, which simplify the structure of the assembly. The data capacity of large assembly is decreased greatly which assist the model simulation.At present, the method is achieved successfully on the base of inventor by secondary development technology. The CAD system is used in the production successfully, and the design efficiency is improved greatly. The light-weight method is also used into the simulation and collaborative design and gotten good result in the design process.