共查询到20条相似文献,搜索用时 125 毫秒
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微管道流体的流动特性 总被引:9,自引:1,他引:9
讨论微流体特性及其测量方法,并进行了微直圆管道内微流体运动特性的初步试验研究。开发一种适于微流体测量的施加和保持压力的方法。以去离子水和直径为10-50μm直圆管为对象进行一系列试验,并与用Navier-Stokes方程式描述的微圆管道流体流动规律进行了比较。 相似文献
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无掩膜流动刻蚀技术研究 总被引:1,自引:0,他引:1
为了实现玻璃材料高深宽比微结构的加工,提出了一种基于微尺度下流体分层流动现象的微流道内无掩膜流动刻蚀方法。通过对玻璃基体材料进行大量的工艺实验,明确了流动参数对于刻蚀成型微结构深宽比、侧壁形状、刻蚀速率的影响。证明了可以通过改变刻蚀剂与隔离剂的流动参数实现对成型微结构形貌的控制。实验结果表明约束流动刻蚀工艺可以在玻璃基体材料上加工出形态复杂、大深宽比的微结构,微结构的形貌取决于微流道中流体的流速。本实验的结果对于微尺度下分层流动的特性研究有一定的参考价值,并可为解决各向同性材料的微结构加工难题提供有效的解决方案。 相似文献
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驱动电压波形修圆对微流体脉冲惯性力和驱动效果的影响 总被引:1,自引:1,他引:0
介绍了微流体脉冲驱动-控制技术,分析了微流体脉冲驱动-控制过程,指出在这一过程中影响微流体流动的主要因素是微流道固壁加速度和流体内部的黏性力。采用"椭圆修圆法"对方波驱动电压进行修圆,针对修圆点的位置决定微流体的驱动方向,获得了不同修圆位置和修圆系数的驱动电压修圆波形。通过实验探索了波形修圆对微流道固壁运动加速度、微流体脉冲惯性力和流体驱动效果的影响规律并进行了机理分析。所得流体体积流量可在0~15.4pl/min连续变化,远小于现有的微流体驱动技术。本文的研究成果可为微流体脉冲驱动-控制技术在微流体系统中的进一步应用提供参考。 相似文献
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传统的流体传感器由于存在着灵敏度低、体积大、成本高等缺点,而且微流体与宏观流体流动特性不同,所以其在微流体的流体特性测量中存在很大的局限性。随着MEMS技术的发展,硅微机械流体传感器的出现克服了传统流体传感器的缺点。硅微机械流体传感器已成为MEMS的研究热点之一。按其用途进行了分类,着重介绍了流体压力传感器、流量传感器和表层摩擦力传感器。分别从各种传感器的基本原理、性能、应用范围、优缺点及其所能达到的技术指标方面进行了描述。基于MEMS的硅微机械流体传感器具有广阔的前景。 相似文献
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数字化无阀微泵的泵送性能实验研究 总被引:1,自引:0,他引:1
研制出一种新型的基于微流体数字化技术的数字化无阀微泵,并对无阀微泵的泵送性能进行实验研究。该微泵泵送出的液体量微小、可控,可达纳升级。针对不同粘度液体,改进驱控参数,实现了连续流、离散流的泵送。实验验证了设计原理的正确性。 相似文献
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中国微纳制造研究进展 总被引:10,自引:2,他引:8
介绍了中国微纳制造领域的总体概况。从微构件力学性能、微纳摩擦磨损及粘附行为研究、典型微流体器件输运特性研究、拓扑优化技术在微纳结构设计中的应用研究、微传热学的研究和微测试方法和装置的研究具体介绍了微纳制造基础理论方面取得的进展。从设计方法、硅基微机电系统(Micro electro mechanical system,MEMS)制造工艺、非硅MEMS制造工艺等方面介绍了微系统设计与加工工艺研究进展。从物理量微传感器、微执行器件与系统、微纳生化传感与分析和微能源等方面介绍了微纳器件与微纳系统的研究进展,最后对中国微纳制造发展进行了总结和展望。 相似文献
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纳米技术及其在微型机械中的应用 总被引:1,自引:0,他引:1
纳米技术及微型机械被认为是21世纪的核心技术。文中介绍了纳米技术及微型机械的基本概念及纳米加工技术、纳米材料技术、纳米摩擦学等纳米技术在微型机械中的应用。 相似文献
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微细孔超声加工关键技术 总被引:3,自引:0,他引:3
为提高微细孔超声加工的微细程度和精度,研究微细孔超声加工的关键技术,包括高精度的机床本体、超声加工单元、微细工具的制备技术、微细工具几何参数的选择等。对微细工具的动态压杆稳定性进行分析,结果表明微细工具的压杆稳定性不仅与静压力有关,还与超声振幅有关。导出判别动态压杆稳定性的Mathieu方程,并经简化给出工具临界压力和临界长度的计算判据,解决因工具长度、静压力(压应力)大小和超声振幅选择不当而导致的加工中出现工具轴弯曲、折断、破坏孔的形状精度的问题。对工件振动方式的微细孔超声加工进行的试验表明,微细工具的磨损率随着进给速度和超声振幅的增大而增加。在所研制的微细超声加工系统上可加工出直径13 μm的微细孔。 相似文献
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Baichuan Sha Stefan Dimov Christian Griffiths Michael S. Packianather 《The International Journal of Advanced Manufacturing Technology》2007,33(1-2):147-156
Micro-injection moulding is one of the key technologies for micro-manufacture because of its mass-production capability and
relatively low component cost. The aspect ratios achievable in replicating micro features are one of the most important process
characteristics and constitute a major manufacturing constraint in applying injection moulding in a range of micro-engineering
applications. This research studies the effects of five process and one size factors on the achievable aspect ratios, and
the role they play in producing micro components in different polymer materials. In particular, the following factors are
considered: barrel temperature, mould temperature, injection speed, holding pressure, the existence of air evacuation and
the sizes of micro features. The study revealed that the barrel temperature and the injection speed are the key factors affecting
the aspect ratios of micro features replicated in PP and ABS. In case of POM, in addition to these two factors, the mould
temperature is also an important factor for improving the replication capabilities of the micro-injection moulding process.
For all three materials, an increase of feature sizes improves the melt flow. However, the melt fill of micro features does
not increase linearly with the increase of their sizes. 相似文献
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Vijay Kumar Jain Subodh Kalia Ajay M. Sidpara 《The International Journal of Advanced Manufacturing Technology》2012,59(9-12):987-996
Electrochemical micromachining (ECMM) is an advanced machining process for machining of electrically conducting materials. In the present work, a micro nozzle and a fluidic mixer having complex structures are made using masking technique by ECMM process. Mask is made of 50-μm transparent sheet and the micro nozzle and micro mixer are fabricated on an 800-μm thick copper sheet. The resulting rough inner walls and bottom surface of micro nozzle are finished using magnetorheological fluid-based finishing process. Surface finish of the nozzle is significantly improved after finishing. A comparison of width, depth, and surface roughness of the micro nozzle is also carried out before and after finishing. The mixing behavior of two fluids is visualized by microscope in micro mixer. The rough inner walls of the mixer’s channels act as obstructions and result in zigzag path of flowing fluid. Hence, mixing occurs at microscopic level because of rapid molecular diffusion. 相似文献
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The friction force developed in the demolding phase of the micro injection molding process is mainly determined by mold surface finish, which affects the tribological phenomena occurring at the polymer–tool interface. In this work, the effects on the ejection force of two cavity surfaces machined with different technologies (viz. micro milling and micro electro discharge machining), but with similar value of Ra, were investigated. The relations between different surface topography parameters and the ejection force were then analyzed, in order to identify the parameters that most appropriately describe the friction at the polymer–tool interface. The experimental results showed the strong interactions between the mold surface texture and the micro injection molding process parameters that promote the replication, such as mold temperature and holding pressure. The different machining technologies generated two mold textures that have a similar value of Ra, but their influence on friction can be properly described only using several other surface topography parameters. 相似文献
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Built-up edge (BUE) is generally known to cause surface finish problems in the micro milling process. The loose particles from the BUE may be deposited on the machined surface, causing surface roughness to increase. On the other hand, a stable BUE formation may protect the tool from rapid tool wear, which hinders the productivity of the micro milling process. Despite its common presence in practice, the influence of BUE on the process outputs of micro milling has not been studied in detail. This paper investigates the relationship between BUE formation and process outputs in micro milling of titanium alloy Ti6Al4V using an experimental approach. Micro end mills used in this study are fabricated to have a single straight edge using wire electrical discharge machining. An initial experimental effort was conducted to study the relationship between micro cutting tool geometry, surface roughness, and micro milling process forces and hence conditions to form stable BUE on the tool tip have been identified. The influence of micro milling process conditions on BUE size, and their combined effect on forces, surface roughness, and burr formation is investigated. Long-term micro milling experiment was performed to observe the protective effect of BUE on tool life. The results show that tailored micro cutting tools having stable BUE can be designed to machine titanium alloys with long tool life with acceptable surface quality. 相似文献