盒形件微拉深成形有限元分析与模具设计

发布时间：2018-01-28 22:21

本文关键词： 微拉深盒形件本构模型有限元分析微模具设计　出处：《大连海事大学》2017年硕士论文　论文类型：学位论文

【摘要】：随着微机械及微机电系统的发展,微零件需求量逐渐增加,微拉深成形技术以其高效率、低成本及可实现大批量生产等优点关注度逐渐升高,但微拉深成形属于微观尺度下塑性变形,其成形理论及生产经验不成熟,制约了微拉深成形技术的应用。微拉深工艺可成形各类腔体,多种因素影响其复杂的成形工艺,现有研究成果多局限于回转体,而盒形件微拉深成形相关研究较少。本文以盒形件为研究对象,采用数值模拟的方法对其微拉深成形进行分析,确定成形规律的影响因素,并以此为依据,设计出成形盒形件的微拉深模具。针对微成形中特有的尺度效应现象,在对现有体现尺度效应的本构理论进行整理分析的基础上,对表面层模型进行修正,推导出适用于面心或体心立方晶格材料的本构关系。在此基础上,对微拉深成形试验进行有限元数值模拟,通过模拟结果与试验结果对比分析,验证该修正表面层模型的合理性。将修正表面层模型应用到盒形件微拉深成形有限元分析中,以工件、模具及成形工艺等参数为变量因素进行对比分析。分析结果表明:盒形件在微拉深成形中圆角与直边成形会相互影响,与传统拉深成形过程类似;板料材料晶粒尺度会影响微拉深力及工件成形厚度的变化,存在尺度效应;模具间隙、凸模圆角及模具零件加工质量均会影响微拉深力的变化趋势;冲压速度对微拉深力的影响较小。研究盒形件微拉深的成形规律对其机理研究、工艺设计及模具设计具有一定的指导意义。基于有限元分析结果,结合盒形件微拉深加工尺寸小、形状特殊等特点,对模具凸、凹模尺寸等参数进行优化计算,设计出一套微拉深模具。为避免手工送料与卸料对毛坯和工件的影响,设计出自动送料机构与弹性自动卸料机构。通过运动仿真证明模具结构合理、运动无干涉,可为同类型微模具设计提供参考。
[Abstract]:With the development of micro machinery and micro electromechanical system, the demand for micro parts is increasing gradually, and the attention of micro drawing technology is increasing because of its high efficiency, low cost and the ability to realize mass production. However, micro-drawing forming belongs to micro-scale plastic deformation, and its forming theory and production experience are not mature, which restricts the application of micro-drawing technology. Micro-drawing process can form all kinds of cavities. Many factors affect the complex forming process, and most of the existing research results are confined to the rotary body, but the research on the box micro-drawing forming is less. This paper takes the box as the research object. The method of numerical simulation is used to analyze the micro-drawing forming, and the influencing factors of forming law are determined, which is based on it. According to the special scale effect phenomenon in microforming, the surface layer model is modified on the basis of the analysis of the existing constitutive theory which embodies the scale effect. On the basis of this, the finite element numerical simulation of micro-drawing forming test is carried out, and the simulation results are compared with the experimental results. To verify the rationality of the modified surface layer model, the modified surface layer model is applied to the finite-element analysis of micro-drawing forming of box-shaped parts. The parameters such as die and forming process are compared and analyzed. The results show that the circular corner and straight edge forming of box parts in micro-drawing will interact with each other, which is similar to the traditional drawing process. The grain size of sheet metal will affect the variation of micro-drawing force and forming thickness of workpiece, and there is a scale effect. The change trend of micro-drawing force will be affected by die clearance, punch fillet and machining quality of die parts. The influence of stamping speed on the micro-drawing force is small. The research on the forming law of box micro-drawing has a certain guiding significance for its mechanism research, process design and die design. Based on the results of finite element analysis. Combined with the characteristics of small dimension and special shape of the box parts, the parameters such as die convex and die size are optimized and calculated. In order to avoid the influence of manual feeding and unloading on blank and workpiece, the automatic feeding mechanism and elastic automatic unloading mechanism are designed. The motion has no interference and can provide reference for the design of the same type of micromould.
【学位授予单位】：大连海事大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：TG38

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