真空环境下差压注型工艺决策方法研究

发布时间：2018-02-01 05:05

本文关键词： 真空注型 STL分层体素化质量控制　出处：《河南科技大学》2017年硕士论文　论文类型：学位论文

【摘要】：随着市场一体化加剧,企业为在激烈的市场竞争中生存发展并占据有利地位,必须满足客户对产品多样化与个性化需求,具有较强开发能力的增材制造(Additive Manufacturing,AM)技术已经成为当今研究的热门课题。3D打印技术和快速模具(Rapid Tooling,RT)技术是AM主要技术支撑,RT中应用最为广泛的真空注型(Vacuum Casting,VC)技术,对产品创新、缩短开发周期、发展绿色生产具有积极的推动作用。但是,目前对VC产品的质量控制主要依靠人为经验,自动化程度低,一定程度上制约VC技术的快速发展。因此,研究VC产品质量智能控制方法,改变传统依靠人为经验的模式,对提高VC领域产品生产效率和新产品开发能力具有重要的现实意义。本文以VC成形工艺为研究对象,以VC工艺过程为主线,以提高VC产品质量为目的,基于计算机图形学、可视化技术、智能控制理论等,研究VC成形工艺机理,总结目前VC产品在成形时出现的质量缺陷和形成缺陷的原因,分析影响产品质量的关键工艺参数;研究模具型腔几何特征获取方法,建立一种基于产品STL模型的模具型腔几何信息获取方法;在此基础上,研究产品质量的智能控制方法,建立基于案例推理(Case Based Reasoning,CBR)与基于规则推理(Rule Based Reasoning,RBR)相结合的产品质量智能控制模型;最后,根据研究所得理论、方法及控制技术,建立VC产品质量智能控制系统,并试验验证上述理论方法的正确性和有效性,为实现VC产品工艺智能决策和质量智能控制提供一种可行的方法。论文的主要研究内容包括以下几个方面:1.针对目前VC成形工艺主要依赖工作人员经验,试模周期长,VC产品质量的稳定性较差等问题,分析VC产品常见质量缺陷和VC成形工艺机理,阐述影响产品质量的关键因素及亟待解决的问题。2.研究模具几何特征获取方法,提出一种逆向几何求交算法,通过对产品STL模型进行快速分层和离散化处理,构建描述模具型腔的体素化模型,并以此模型为基础,获取产品体积、表面积和平均壁厚等模具型腔几何信息,为快速获取VC产品几何特征信息提供一种可行的方法。3.针对目前VC产品质量依赖于设计人员经验控制,造成产品质量稳定性差、成本高的问题。以历史案例为支撑,总结工作人员的知识经验,采用CBR与RBR相结合的推理方法,建立描述VC成形工艺和质量控制的混合智能决策模型,实现VC产品缺陷智能修正,为产品的质量智能控制提供一种有效方法。4.基于产品质量智能控制模型,在Microsoft Visual Studio 2010环境下,开发CBR与RBR相结合的产品质量智能控制系统,并对某电器盒盖进行成形试验,验证上述理论方法的正确性和有效性。
[Abstract]:With the aggravation of market integration, in order to survive and develop in the fierce market competition and occupy a favorable position, enterprises must meet the needs of customers for product diversification and individuation. Additive Manufacturing with strong development ability. AMtechnology has become a hot research topic. 3D printing technology and rapid tooling RTT technology are the main technical support of AM. The vacuum casting technology, which is widely used in RT, plays an active role in product innovation, shortening development cycle and developing green production. At present, the quality control of VC products mainly depends on artificial experience, low degree of automation, to some extent restricts the rapid development of VC technology. Therefore, the research of VC product quality intelligent control method. It is of great practical significance to change the traditional mode of relying on artificial experience to improve the production efficiency and the ability of new product development in VC field. This paper takes VC forming process as the research object. Taking VC process as the main line and improving the quality of VC product, based on computer graphics, visualization technology and intelligent control theory, the mechanism of VC forming process is studied. This paper summarizes the quality defects and the causes of forming defects in VC products, and analyzes the key process parameters that affect the quality of VC products. The method of obtaining geometric characteristics of die cavity is studied, and a method of obtaining geometric information of die cavity based on product STL model is established. On this basis, the intelligent control method of product quality is studied, and case Based Reasoning based on case-based reasoning is established. The intelligent control model of product quality based on CBR and rule-based reasoning rule Based reasoning (RBR); Finally, according to the theory, method and control technology, establish VC product quality intelligent control system, and test the correctness and effectiveness of the above theory and method. This paper provides a feasible method for realizing the intelligent decision and quality control of VC products. The main research contents of this paper are as follows:. 1. The VC forming process mainly depends on the experience of the staff. This paper analyzes the common quality defects of VC products and the forming process mechanism of VC products. The key factors affecting product quality and the problems to be solved urgently are described. 2. The method of obtaining geometric features of die is studied, and an algorithm of inverse geometric intersection is proposed. Through the rapid delamination and discretization of the product STL model, a voxel model describing the mold cavity is constructed, and the volume of the product is obtained on the basis of the model. Surface area, average wall thickness and other die cavity geometry information provide a feasible method for the rapid acquisition of VC product geometry information. 3. The quality of VC products depends on the designer experience control. The problem of poor product quality stability and high cost. Taking the historical case as the support, summarizing the staff's knowledge and experience, adopting the reasoning method of the combination of CBR and RBR. A hybrid intelligent decision model describing VC forming process and quality control is established to realize the intelligent correction of VC product defects. Provide an effective method for product quality intelligent control. 4. Based on product quality intelligent control model, under the environment of Microsoft Visual Studio 2010. A product quality intelligent control system combined with CBR and RBR is developed, and the forming test of an electrical box lid is carried out to verify the correctness and validity of the above theory and method.
【学位授予单位】：河南科技大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：TQ320.52;TP391.73

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