【作者】 张凯；

【导师】 袁国定；

【作者基本信息】 江苏大学 ， 机械制造及其自动化， 2008， 硕士

【摘要】 随着微器件需求的日益增多,LIGA(德文Lithograpie GalvanoformungAbformtmg)、光刻、蚀刻等传统微细加工技术,已无法满足大批量三维复杂微器件的生产要求。而塑性加工具有生产效率高、成本低和产品精度高等特点,所以结合塑性加工方法的微挤压、微冲压等微塑性成形技术得到了广泛的发展。目前,微挤压研究多数集中在冷挤压上,但是微冷挤压变形抗力大,充模不均匀。传统温挤压不仅可以减少变形抗力,而且可以增加材料的流动性,因此微温挤压技术有更好的发展前景。但传统的加热装置复杂且不易控制,将会影响微型产品的质量和成本。激光辅助加热可控性好,效率高,可以实现有选择性的加热,因此激光加热技术与微成形技术的结合为微塑性成形技术的发展提供了新的途径。本文阐述了激光加热技术和微型温挤压技术的基本理论,讨论了激光加热有限元模型,运用数值模拟技术对激光加热温度场进行研究,在此基础上对微型温挤压成形过程进行了模拟。本文的主要研究内容如下:1.阐述了微型温挤压的特点,讨论了微型温挤压和传统温挤压的差异;研究了仿真建模中的关键问题,包括网格的划分、热力耦合模型的建立和摩擦模型的处理等。2.论述了传热学的基本理论;实验研究了激光加热铝合金温度场的分布;借助有限元软件ABAQUS建立激光加热的有限元模型,对激光功率、光斑大小和加热时间等参数对微器件温度场分布的影响进行了研究。3.提出了激光双面加热的方法,基于激光加热的有限元模型,对激光功率、光斑大小和加热时间进行组合得到均匀分布的温度场;设计了激光双面加热系统,并介绍了激光器、激光光路和检测控制装置。4.建立了微型温挤压成形的有限元模型,基于激光双面加热得到的均匀分布温度场,运用正交试验的方法,对凹模入模锥角、工作带长度和圆角半径三个结构参数进行优化,得到了微型温挤压的最优结构参数。更多还原

【Abstract】 With the growing demand for micro components, the microfabrication techniques such as LIGA, lithography, etching and other traditional ones could not satisfy the requirement of manufacturing complex three-dimensional products in mass. The plastic processing has the advantages including the low cost, high efficiency and precision. So the combination with micro-forming technology and conventional plastic processing, such as micro-extrusion and micro-stamping, has been widely developed. Most of the existing research on micro-extrusion is focused on micro-cold extrusion, which has difficulty in the high deformation resistance and uneven molding filling. Therefore, the micro-scale warm extrusion is proposed to decrease deformation resistance and increase the material fluidity. To solve the complexity and difficult control in the traditional heating system that influence the quality and cost of micro components, the laser-assisted heating method has been presented because of its high control ability, efficiency and ease of selective heating. The new method combining laser-heating with microforming can find its extensive applications in other microforming fields.In this paper, the basic theories including laser-heating and micro-scale warm extrusion are systematically studied. The laser-heating FE (Finite Element) modeling and temperature distribution are investigated. On the basis of the results, the forming simulation of micro-warm extrusion is made. The main work and results are as follows.1. The characteristics of micro-scale warm extrusion and the difference between micro and macro extrusion are discussed. The key problems in the simulation, such as meshing, thermal-mechanical coupling model and friction model, are investigated.2. Heat transfer theory is described. The temperature distribution of aluminum alloy using laser-heating method is studied through serial experiments. The FE modeling of laser-heating is set up based on ABAQUS. The influences of laser parameters including laser power, heating time and spot diameter, on temperature distribution are analyzed3. Double-sided laser-heating method is carried out and the uniform temperature distribution can be obtained by the optimization of laser parameter. The heating system of micro-scale warm extrusion which includes laser, optical path and detection device is designed and introduced.4. Forming process with double-sided laser heating method is simulated under different die structure parameters such as cone angle of femal die, die land length and cavity die radius. Finally, the die structure parameters are analyzed and optimized using orthogonal experiment method.更多还原