微挤压成形工艺数值模拟及实验研究

发布时间：2018-04-30 07:30

本文选题：微成形 + 微成形模具　；参考：《山东建筑大学》2015年硕士论文

【摘要】：近年来,微成形技术逐渐成为机械制造领域研究的重点,微成形技术得到广泛的应用与其成形性好、成形精确、低耗高效等优点是分不开的。微塑性成形技术以塑性变形方式来制造微型零件,适合微型零件的批量制造,实现高质量低成本,微成形技术自出现以来,就一直受到世界各国及各科研机构的重视,在航天、军用、医疗、微电子等领域具有十分重要的应用前景。由于加工对象尺寸微小,存在尺度效应,传统塑性加工成形机理和材料变形规律不能直接应用于微成形。无论是对微成形模具的设计还是对成形过程中问题的探索,微塑性成形技术都是一个新的研究领域,对于微成形技术的研究具有十分重要的科学意义。本文采用计算机数值模拟与实验研究相结合的方法,研究分析微塑性成形正挤压工艺中的基本规律和内在机理。首先,针对微成形技术的发展过程,以及工艺、尺寸效应、微模具、数值模拟技术方面的进展和现状进行综合分析。整理微成形技术的相关理论基础。包括刚塑性有限元理论、晶体塑性有限元理论以及应变梯度理论,并依此作为本文的理论依据。其次,对微成形工艺模具设计进行了初步探讨,参考传统挤压模具的设计方法,设计并制造出了操作简便、易于组装及拆卸的微挤压模具。再次,利用制造好的模具,选取典型的微型正挤压工艺进行实验研究,分析不同坯料高度、尺寸条件下,微细特征挤压高度成形规律以及它们对成形性的影响。在实验的基础之上,分别对采用纯铝材料的微挤压成形件和采用ECAP超细晶纯铝材料的微挤压成形件进行微观组织观察和分析。第四,对微塑性正挤压成形过程进行数值模拟。以刚塑性有限元理论为基础,运用有限元软件deform对微型正挤压工艺过程进行了数值模拟,分析成形规律并把模拟结果和实验结果相对比,验证模拟方法的可靠性。在此之上,建立四种具有不同过渡段设计的微模具模型,以消耗能量、流动性、效率、积压缺陷为目标,进行了多次模拟分析,揭示各过渡段变化对微细挤压工艺的影响,并确定最佳合理方案。
[Abstract]:In recent years, microforming technology has gradually become the focus of research in the field of mechanical manufacturing. Its wide application is inseparable from its advantages of good formability, precision, low consumption and high efficiency. Micro plastic forming technology makes micro parts by plastic deformation, which is suitable for batch manufacturing of micro parts, and achieves high quality and low cost. Since its emergence, micro forming technology has been attached great importance to by countries and scientific research institutions all over the world. Military, medical, microelectronics and other fields have a very important application prospects. Because of the small size and scale effect, the traditional plastic forming mechanism and material deformation law can not be directly applied to micro forming. Microplastic forming technology is a new research field, which is of great scientific significance to the research of micro-forming technology, not only for the design of micro-forming die but also for the exploration of the problems in the forming process. In this paper, the basic law and internal mechanism of micro-plastic forming forward extrusion process are studied and analyzed by combining computer numerical simulation with experimental research. Firstly, the development process of microforming technology, as well as the process, size effect, micromold, numerical simulation technology progress and current situation are comprehensively analyzed. The theoretical basis of finishing microforming technology. It includes rigid-plastic finite element theory, crystal plastic finite element theory and strain gradient theory. Secondly, the design of microforming process die is discussed preliminarily. Referring to the design method of traditional extrusion die, the micro-extrusion die is designed and manufactured, which is easy to operate and easy to assemble and disassemble. Thirdly, the typical micro-forward extrusion technology is selected to study the forming law of micro-characteristic extrusion height and its influence on formability under different blank height and size. On the basis of the experiments, the microstructure of micro-extruded parts with pure aluminum and micro-extruded parts with ECAP ultrafine grain pure aluminum were observed and analyzed respectively. Fourthly, numerical simulation of micro-plastic forward extrusion process is carried out. Based on the rigid-plastic finite element theory, the micro-forward extrusion process was simulated by finite element software deform. The forming law was analyzed and compared with the experimental results to verify the reliability of the simulation method. On the basis of this, four kinds of micromould models with different transition stages are established. Aiming at energy consumption, fluidity, efficiency and backlog defects, several simulation analyses are carried out to reveal the influence of each transition stage on the micro-extrusion process. And determine the best and reasonable scheme.
【学位授予单位】：山东建筑大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：TG376

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