Research On The Technology Of Feature-based Concurrent Design For Part Structure

According to the requirements of advanced part design and manufacturing process, and some representative parts as examples, a feature-based concurrent design methodology is put forward and a system for part structure is built up. All these works are supported by "985"project fund of ministry of education, Research on the exploitation of automatic system for 3D virtual mechanism. The main outcomes in this paper are stated as follows: A feature-based concurrent design condition for part structure is given on the basis of the concurrent engineering theory. Moreover, some key technologies are also analyzed systematically at the same time. Then, the framework and procedure of the whole system are built up respectively. At last, the status and functions of above system on the 3D virtual mechanism creative design are discussed extensively. The features of design, manufacturing, technique and evaluation are reinterpreted and a new kind of feature, that is neutral feature, is defined for the first time. Through the delamination mapping among these features, the nonfigurative requirement can be transformed into 3D structure shapes and constraints. After that, generalized Boolean operation is used to build the detail part model with the constraints. A mixed mapping methodology is put forward between the design feature and manufacturing feature: the direct mapping is used for the transformation between the shape feature of design field and manufacturing field; the indirect mapping between the design region and manufacturing region that is bridged by the neutral feature is used for the nongeometry information mapping. So the whole design information can be provided for the CAD/CAPP/CAM. AOS tree, a nonlinear methodology for process planning, is used in the box part design for the first time. It can depict the data of process planning perfectly. After searching the detail AOS tree, the working step, procedure and manufacturing resource can be calculated at the same time. Thus the solid foundation for the manufacturing evaluation of part is laid. Analytic Hierarchy Process (AHP) method is used in the multi-objective optimization for part structure for the first time. First, because all the factors will affect the evaluation result simultaneously, different sub-objective functions are built up for different measure factors. Then, AHP method is used to confirm weighting coefficients of the evaluation factors. Furthermore, weighting factors and sub-objective functions that are normalized linearly are taken into evaluation function. According to above function, the evaluation result can be received, and the optimized scheme of part structure can also be gained. A feature-based concurrent design software is developed for axial and box parts. This software is relied on the Windows 2000 and VC++6.0, and the 3D modeling function of the software is build on redeveloping of the SolidWorks-2000.