Knowledge Based Research On The Modeling Technology Of Products And Application To Hot-Runner Design

The paper which supported by 863 High-tech Research and Development Program of China (Project No. 2006AA04Z114), National Nature Science Fund (50775201) and Zhejiang Nature Science Fund (Y107428) researched knowledge-based modeling design of mechanical products from theory to application. Having overviewed domestic and overseas modern knowledge-based design of mechanical and hot-runner systems, several new thoughts, principles and methods has been posed for design information representation of products, concepts design of products, structure design of hot runners, simulation of temperature field and optimization of structure, by means of knowledge representation, knowledge reasoning, knowledge driven and knowledge fusion. The research is both theoretically and academically valuable for solving problems about knowledge-based design of mechanical system and design of multi-cavity plastic injection mould hot runner system. Main research contents:Chapter1 introduced domestic and overseas knowledge-based design methods of products were comprehensively presented by different understanding of knowledge meaning, character analysis of various knowledge representations; Moreover, analyzed domestic and overseas application of hot runner systems, structure design methods of plastic injection mould hot runner and relevant CAD/CAM/CAE technologies, and application of knowledge to lead out the main contents and research method of the paper.Chapter2 researched knowledge modeling methods of products design information, and posed a concept that as the knowledge subset describing a certain object, knowledge unit reflects characters of contents and structure, problem presentation, reasoning principles and methods of relevant knowledge within certain degree. Besides, it analyzed the functions and properties of knowledge unit, and posed meanings of products design knowledge unit in different levels. Having classified products design into function design, concept design and structure design, information models were established for each of them. Knowledge representation correlation between levels of information models were posed as well.Chapter3 presented thoughts based on knowledge reasoning and design task planning through the representation of design rules. Hot runner concept design procedure has been designed focusing on the characteristics of hot runner systems. That was decomposing the concept design scheme by decomposition of functions of hot runner systems, and then establishing a space model of concept design for hot runner systems.Chapter4 introduced a concept of knowledge unit of runners from the angle of the combination of logic and graphics. Based on unitized decomposition and normalization for various layouts of real runner products, the unitized structure that contains primary information of runner layout has been obtained, which is used as the basic unit for layout design. The concept of runner unit and its topological and vector representation were posed. The network model and vector model of runner layout that based on runner unit were established, and the variation and reconfiguration technologies of the model were researched.The multi-cavity hot runner structure design consists of three functional models, namely, gate model design, runner plate model design and nozzle model design. The process of defining by knowledge unit reasoning, matching and operating data information by the rules of knowledge base and conclusion acquiring were analyzed. The variable structure design of products was realized by the driving mechanism of knowledge unit, the derivation and combination of structure unit, and the guidance of design knowledge. The design of the three modules of hot runner was discussed in details.Chapter5 realized automatic reading of pre-analytical parameters of finite element knowledge fusion, and inheritance of temperature field analysis results. With the results, by means of hybrid method of SDBDF, and performing optimized design for hot runner structure, the integrated design of plastic hot runner system has been realized.Chapter6 analyzed real products by design principles and methods, and decomposition of each functional module. The knowledge-based multi-cavity hot runner system design was realized, and has been applied in real manufacturing. Chapter7 made conclusions and prospects.