激光间接冲击金属箔板剪切微铆接工艺研究

发布时间：2018-06-25 01:33

本文选题：激光冲击成形 + 金属箔板　；参考：《江苏大学》2017年硕士论文

【摘要】：随着生物医疗器械和微机电系统的迅猛发展,产品的精密化和微型化成为了工业制造发展的一个重要趋势,而在精密微器械的制造过程中离不开异种轻质材料的耦合使用,因此微制造业迫切需要可以连接异种箔板材料的高效微连接技术。本文结合激光冲击成形技术和无铆钉铆接技术提出了一种激光间接冲击金属箔板剪切微铆接新工艺,旨在实现微尺度下同种或异种金属箔板的连接,以扩大基于材料塑性变形的连接技术的应用范围。本工艺采用脉冲激光代替传统微冲头,利用软膜作为冲击压力的传递媒介,结合微细电火花加工的微凹模完成微尺度下金属箔板的铆接过程。本文从基础理论、可行性分析、工艺参数三个方面对激光间接冲击金属箔板剪切微铆接工艺进行了研究:首先,研究了激光与物质之间相互作用产生等离子体的机理,确立了冲击波峰值压力的数学模型;讨论了软膜和工件之间的阻抗匹配;探讨了高应变率下材料的塑性变形屈服条件;研究了传统剪切铆接技术中连接点的形成过程和连接机理。其次,进行了激光间接冲击金属箔板剪切微铆接工艺的可行性实验研究。实验结果表明:单次脉冲下无法形成较大内锁,需要使用多次脉冲激光并结合适中的激光能量才能解决该问题;材料组合总厚度与模具深度之间存在匹配关系,随着总厚度的增加,能够使其形成较大内锁的模具深度也相应增大;本工艺更适合连接上板厚于下板的材料组合;在可形成内锁的激光能量区间内,随着激光能量的增大,两层金属箔板之间的内锁尺寸逐渐增大,而上层箔板的最小厚度逐渐减小;相同的板厚条件下,Al/SS材料组合的拉伸强度最高,约为Al/Cu与Cu/Cu材料组合的三倍;另外,Cu/Cu、Al/Cu、Al/SS三种材料组合经过拉伸剪切实验后的失效形式各不相同,分别为:下板部分剪切、完全脱扣以及上板部分剪切。最后,采用脉冲激光能量更大的激光器验证了该工艺在连接较厚箔板时的适用性,改进了激光间接冲击金属箔板剪切微铆接工艺的实验系统,研究了新系统中工艺参数对金属箔板连接效果的影响,通过拉伸剪切实验探讨了内锁尺寸和上板颈部厚度对拉伸强度及其失效模型的影响,通过纳米压痕实验测试了连接点处上下层金属箔板纳米硬度的变化。实验结果表明:吸收层厚度对箔板的材料流动和内锁的形成有很大影响,实验中可根据所使用激光能量的大小来选取最优的吸收层厚度;相比其余厚度的软膜,厚度为100μm的软膜更适合激光间接冲击金属箔板剪切微铆接工艺;在单层板厚小于200μm的范围内,本工艺的最优模具深度可由近似80%的上板厚度与下板厚度相加得到;连接点的拉伸强度及其失效模型都取决于内锁尺寸和上板颈部厚度,连接点只有同时具备较大的内锁尺寸和较大的上板颈部厚度才能具有较高的连接强度;经过激光冲击后连接点处的材料纳米硬度都有所提高,且材料塑性变形程度越大的区域其相应的纳米硬度越高。本文研究为微尺度下金属箔板的连接提供了新途径并为进一步应用奠定了理论基础。
[Abstract]:With the rapid development of biological medical instruments and microelectromechanical systems, the precision and miniaturized production of products is an important trend for the development of industrial manufacturing. In the manufacturing process of precision micro devices, the coupling of different light materials can not be used. Therefore, the micro manufacturing industry is urgently required to connect the high efficiency micro connection of the dissimilar foil material. In this paper, a new technology of laser indirect impact metal foil plate shearing micro riveting is proposed by laser shock forming technology and riveting without riveting. The purpose is to realize the connection of the same or dissimilar metal foil in the micro scale, so as to expand the application range of the connection technology based on the plastic deformation of the material. The micro punch, using the soft film as the transmission medium of the impact pressure, combined with micro EDM micro die to complete the riveting process of the metal foil on the micro scale. This paper has studied the laser indirect impact metal foil plate shearing micro riveting process from three aspects: basic theory, feasibility analysis and process parameters. First, the laser is studied. The mechanism of plasma interaction with matter is produced, the mathematical model of the peak pressure of shock wave is established, the impedance matching between the soft film and the workpiece is discussed, the yield condition of the plastic deformation under the high strain rate is discussed, the forming process and the connection mechanism of the connection point in the traditional shear riveting technology are studied. Secondly, it has been carried out. The experimental study on the micro riveting process of laser indirect impact metal foil plate is studied. The experimental results show that a large internal lock can not be formed under a single pulse. It is necessary to use multiple pulse lasers and moderate laser energy to solve the problem. The total thickness of the material has a matching relationship with the depth of the die, and the total thickness increases with the total thickness. With the increase of laser energy, the internal lock size between two layers of foil plates increases gradually with the increase of laser energy, and the minimum thickness of the upper foil plate decreases gradually; the same is the same. Under the condition of plate thickness, the tensile strength of Al/SS composite is the highest, about three times the combination of Al/Cu and Cu/Cu. In addition, the failure forms of the three kinds of material combinations of Cu/Cu, Al/Cu and Al/SS are different after the tensile shear test, respectively: the partial shear of the lower plate, the complete release and the partial shear of the upper plate. Finally, the pulse laser energy is greater. The laser verified the applicability of the technology in connecting the thick foil plate, improved the experimental system of the laser indirect impact metal foil plate shearing micro riveting, and studied the effect of the process parameters on the bonding effect of the metal foil plate. The tensile shear test was used to explore the tensile strength and the tensile strength of the inner lock and the thickness of the upper plate. The results show that the thickness of the absorption layer has a great influence on the material flow and the formation of the internal lock. In the experiment, the optimum thickness of the absorption layer can be selected according to the size of the laser energy used in the experiment, and the thickness of the absorption layer can be selected in the experiment. The soft film with the thickness of 100 mu m is more suitable for the laser indirect impact metal foil plate shear micro riveting process. The optimum die depth of this process can be obtained by adding approximately 80% of the thickness of the upper plate and the thickness of the lower plate in the range of less than 200 mu, and the tensile strength and failure model of the connection point depend on the size and the upper of the internal lock. The thickness of the plate neck, the connection point only with the larger internal lock size and the larger plate neck thickness can have higher connection strength. After the laser shock, the nanoscale hardness of the material at the connection point is improved, and the higher the plastic deformation degree of the material, the higher the hardness of the nanoscale. This paper is a micro scale. The connection of metal foil provides a new way and lays a theoretical foundation for further application.
【学位授予单位】：江苏大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：TG665;TG938

【参考文献】