Research on Template-Based Parameterized Structure Design for Drawing Dies
The structure design of drawing dies is a very compLicated and knowledge-intensive process. This paper describes a template-based parametric design system for drawing dies which adopt template as the die design knowledge base and instantiate it to complete the design of the main components of drawing die. Some key technologies such as the template technology, the parameterization technology and the top-down assembly design technique have been studied. The template for drawing dies is defined by using the "top skeleton" assembly structure, and the associative geometry-driven design and parameter-driven design of dies structure is reaLized by adopting WAVE technique and parameterized design method. The design process of template-based drawing dies structure is estabLished and the rapid design of structure is implemented by applying UG secondary development. At last, effectiveness of our method is verified by some examples.
A Hybrid Intelligent Systems Approach for Die Design in Sheet Metal Forming
Die design is heavily experience based and the die design process is an iterative procedure of trial and error in order to obtain a final die design for the successful manufacture of stampings. Most automotive industries use internal guidelines and past experience for die design. Even though powerful computer-aided design systems are being used in automotive industry, the lack of adequate analysis tools at the initial die geometry design stage hinders the die manufacturing process, and also necessitates lead times of the order of 5–30 weeks [1]. At the concept design stage, and during the initial die development process, the variations in geometry and process conditions are so large that it is prohibitively expensive to use 3D finite element analysis. The complexity of die design heuristic knowledge hinders the development and application of knowledge-based systems.Hybrid intelligent systems are computer programs in which at least one of the constituent models simulates intelligent behaviour [2]. These models could be knowledge-based systems, artificial neural networks, fuzzy logic systems, etc. In this approach both artificial neural networks, knowledge-based systems and finite-element analysis (FEA) for modelling the design process are used. A simulation-based design approach [3] for the die design process is followed. Artificial neural networks (ANNs) are preliminary design tools which indicate the formability of the component geometry, for the selected process and material conditions. The ANN module is trained from FEA results for a generic set of component geometries, process conditions, and material properties. The final die design validation is carried out by FEA. The intelligent frame-work incorporates rules for material selection, process parameter selection and their modification.Component geometry is a critical parameter which affects the manufacturability of the given part. Hence, an intelligent geometry handling module, which automatically modifies and optimises the geometry of the designed die, is implemented in the present system. Knowledge-based blackboard architecture is used for the integration of various analysis models such as CAD, FEA, and ANN, as an intelligent framework for die design [4]. The hybrid intelligent system provides an integrated decision support environment for simulation and analysis of the forming process, both during the initial die design phase and during the die tryout phase. The hybrid intelligent systems approach supports the capability for automatic evaluation of prospective die design for manufacturability, and performs automatic modification of design inputs. Applications of the hybrid intelligent system for die design are described together with a comparison with shop floor data.
Rotational Analysis of the CrO Bands
The (0, 1), (0, 0) and (1, 0) bands of the CrO, which appear in the red and yellow region, are analysed rotationally, and we have been able to show that these bands owe to the transition 5 Π- 5 Π. We have shown the theoretical formulae for the quintet state, which can be applied in the case of nearly (a), and obtained the molecular constants as follows,