Quality Control Of NC Tube Bending Process Based On The 3D FEM Simulation

The numerical control (NC) tube bending process used as a method of thin walled tube bending has been widely applied in fields of aeronautics and astronautics. However, the process planning based on the traditional "trial-and-error" method limits the predominance of this advanced process. In this dissertation, NC tube bending process has been researched by using 3D FEM numerical simulation in conjunction with theoretical analysis. Based on the database technology, the NC tube bending simulation system (NCTBS) is developed in order to make this process systematize and standardize and to control forming quality effectively. A brief introduction to the project and its results obtained are as follows:A mechanical model corresponding to reality has been established through analyzing the stress of NC tube bending process. The stress field, strain field and energy formula have been established as the base of 3D FEM simulation of NC tube bending process.A 3D FEM simulation program of NC tube bending is developed based on the ANSYS software platform, and some key techniques have been studied. Used this program as a core, NCTBS system which combines with CAD/CAE/CAPP/CAM subsystems on the database is developed. Its reliability has been tested though examining.The influence laws of mould structure, including wiper die and the style, size and installed position of mandrel, have been studied. Combined with the theoretical analysis of perfect pure bending, the tendency of relative bending radius R/D and relative wall thickness t/D to one of the major quality target -the maximum wall thickness reduction ratio is also studied.Used as a computer aid NC tube bending process planning (CAPP) software in practice production of factory, NCTBS system could control forming qualityeffectively. The design based on database technology enables the factory to accumulate the foundation process database scientifically and effectively; promotes the quick-forming and quick-transforming production capacity of mass production. The achievement of this study is important to the development of technology and practice of NC tube bending process.