扫描射流掩膜电解加工微坑阵列试验研究

表面织构在摩擦学、热能交换以及生物医学等许多领域发挥重要作用,其中微坑阵列是常用的表面织构.为了能在金属表面制造出微坑织构,对掩膜电解加工微坑阵列的文献进行了研究与分析,在分析了射流掩膜电解加工技术的基础上,提出使用一种扫描射流掩膜电解加工的方法,利用光刻胶做掩膜,成功地在不锈钢上加工出海量微坑阵列.设计实验,探究了电...     

动态被动阀微泵的设计优化和制造

研究的动态被动阀微泵是一种基于微机械技术的振膜型无阀微泵。相对于有阀微泵而言，有更高的工作频率和可靠性，结构简单，加工制造的成本比较低，更容易满足实际应用中的各种要求。讨论了动态被动阀的工作机理，结合流体力学的基本理论与动态被动阀微泵的特点，采用有限单元方法以及相关工具软件ANSYS/FLOTRAN，对整个动态被动阀微泵模型进行了计算、求解和模拟，并根据计算结果及加工工艺特点对其结构进行优化。用基于集成电路制造技术的微细加工工艺分别对动态被动阀微泵的各组成部分进行加工，并组装成完整的动态被动阀微泵。     

基于AutoCAD的掩膜用微齿轮渐开线齿廓拟合

应用微电子行业的深硅刻蚀技术ICP制备微齿轮过程中,设计微齿轮掩膜板时,为了将AutoCAD等软件设计的微齿轮渐开线轮廓正确导入LinkCAD等光刻掩膜文件格式转换软件中,需将渐开线齿廓非样条化.针对分度圆直径1mm的微齿轮渐开线齿廓按等基圆中心角的方式分别进行8、12、20分段,并分别用直线和圆弧段拟合.实验证明,微齿轮渐开线应用8分段并用圆弧拟合能获得相对光顺和精度最高的拟合曲线,能满足微齿轮齿廓要求.采用的方法为其他类似曲线段的拟合提供了有价值的参考.     

基于数字微镜器件的无掩膜光刻技术进展

基于空间光调制器的无掩膜光刻是光刻技术重要发展方向之一.近年来,随着数字微镜器件芯片集成度与性能的提高,数字微镜器件无掩膜光刻成为一种主要的数字光刻技术.由于可灰度调制的光反射式"数字掩膜"替代了传统光刻中使用的预制物理光掩膜版,该技术极大地简化了光刻制版流程,提高了光刻的灵活性,广泛应用于平面微纳器件、超材料、微流控...     

准分子激光刻蚀技术在微机械中的应用研究

准分子激光刻蚀技术在微机械领域有着十分广泛的应用前景,用该技术制作的聚合物微结构深宽比大、精度高,并且工艺简单。我们分析了准分子激光刻蚀原理,探索了这种技术的工艺方法和技术条件,特别对掩膜的结构和制作工艺进行了较为深入的研究。本文采用简易的实验装置,用自行研制的三种结构掩膜进行了准分子激光刻蚀实验,得到了50μm 深的聚合物材料微机械构件。     

钛合金疏水表面微坑阵列的掩膜电解加工仿真与分析

为改善钛合金疏水性能,获得较高的接触角,使用掩膜电解技术对钛合金进行了凹坑阵列表面微织构的加工。首先,建立微坑阵列掩膜电解加工的数学模型并进行多物理场耦合仿真;其次,分析掩膜电解加工参数对微坑阵列的作用,并借助润湿理论模型获得微坑阵列的固-液接触面积比;最后,以该面积比为因变量,以电解质质量分数、电解电压和掩膜尺寸为自变量,进行正交试验仿真和极差分析,获得最佳工艺参数组合。与仿真预测值相比,微坑阵列单元体直径、间距、深度、固-液接触面积比和表面接触角的测量值误差均小于8%,从而表明该方法在未经低表面能材料修饰的情况下,成功制备了接触角约为140°的微坑阵列。     

相变传热微通道技术的研究进展

快速增加的系统发热已经成为当代先进微电子芯片系统研发和应用中的一项重大技术挑战.近年来,微通道相变传热试验和理论分析都证实了其具有高热流密度的传热特性,预示这一技术未来在电子通信、航空航天等产业领域的先进微系统散热/冷却应用上的巨大前景.对相变传热微通道研究领域的三个主要方面(微通道内微热流体动力学过程及传热机理、微通道结构与传热特性的影响关系、微通道结构(器件)的制造技术等)的最新研究进展进行了回顾与综述,探讨相关的理论基础和研究方法,并对这一研究领域的发展趋势做了分析和展望.     

基于DMD无掩膜光刻快速制作亲疏水图案化表面

亲疏水图案化表面在表面张力限制的微流控技术中能够发挥显著作用。常见的方法在制作表面的微图案时都需要实物掩模版,这类方法不具备灵活调节制造亲疏水表面微图案的形状与尺寸的能力,并且因制作掩膜而导致制作成本和时间成本都很高。因此,提出了基于DMD无掩膜光刻技术快速制作亲疏水图案化表面的方法并可用于自组装微液滴阵列。该方法利用DMD无掩膜曝光系统进行加工,一步成型地完成了亲疏水图案化表面的疏水处理和微图案化处理。这种方法无需实物掩模,能够灵活调控加工表面疏水图案的形状与尺寸,工艺简单快捷,降低了制作成本。     

微纳制造技术文献计量分析

对微纳制造技术领域2000-2010年时间段的SCI和EI文献计量分析,结果显示,近年来该领域的研究呈现出增长趋势,美国在微纳制造领域的研究处于绝对领先的地位.SCI文献分析表明,纳米尺度的制造技术、微米尺度的制造技术、微机电系统、微流体、微加工等是近年来研究的热点领域;EI分析则显示,光刻技术、微加工、微机电器件、纳米结构材料、扫描电子显微镜等是研究的热点.     

微流控芯片模具化学蚀刻制造工艺研究

为制造微流控芯片模具实现微流控芯片的大批量生产,采用三酸型蚀刻液对图案掩膜的P20模具钢进行蚀刻加工。观测蚀刻的微流道形状和尺寸,分析蚀刻深度、流道宽度、蚀刻因子和面粗糙度等随加工时间的变化规律。结果表明加工时间越长,微流道侧壁垂直性越好,蚀刻因子越大,但面粗糙度越差。因为反应产物附着于工件表面,特别是侧壁上,使侧向蚀刻速度低于深度方向蚀刻速度,而蚀刻反应产生热量,使工件反应表面温度升高,蚀刻速度加快,影响表面质量。蚀刻反应中,合理控制掩膜尺寸、加工时间、搅拌速度和反应温度等,才能得到满足要求的微流控芯片模具。     

用于高精度小尺寸零件制作的光固化快速成型技术的现状与发展

用于高精度小尺寸零件制作的光固化快速成型技术源于快速原型技术 ,利用光诱导树脂固化 ,实现逐层堆积的原理制作零件原型。本文回顾了近年来该领域中开发出的主要工艺方法、原理及系统构成 ;本文还提出了以变形反射镜器件为核心构建新型动态视图发生器 ,采用整层曝光固化工艺实现原型快速制作的新方法。和其它方法使用的动态视图发生器相比 ,本文提出的新型动态视图发生器具有更高的分辨率和更高的对比度 (可达 10 0 0∶1)。     

基于快速成形的MEMS微制造技术

评述了当前主要的MEMS微制造技术方法及特点，综述了基于快速成形的MEMS微制造系统的基本原理和基本结构，目前所能达到的精度与应用典型实例，微型制造技术的优越性与局限性，对最新发展的每一层面一次曝光的高速快速成形MEMS微制造系统原理与研究示例进行了介绍。     

Design of microstereolithography system based on dynamic image projection for fabrication of three-dimensional microstructures

As demands for complex microstructures with high aspect ratios have increased, the existing methods, MEMS and LIGA, have had difficulties coping with the number of masks and fabricable heights. A microstereolithography technology can meet these demands because it has no need of masks and is capable of fabricating high aspect ratio microstructures. In this technology, 3D part is fabricated by stacking layers, 2D sections, which are sliced from STL file, and the Dynamic Image Projection process enables the resin surface to be cured by a dynamic image generated with DMD™ (Digital Micromirror Device) and one irradiation. In this paper, we address optical design process for implementing this microstereolithography system that takes the light path based on DMD operation and image-formation on the resin surface using an optical design program into consideration. To verify the performance of this implemented microstereolithography system, complex 3D microstructures with high aspect ratios were fabricated.     

Cross-section segmentation for improving the shape accuracy of microstructure array in projection microstereolithography

Microstereolithography is a microfabrication technology done in a layer-by-layer fashion. It is useful to fabricate a microstructure with both a high aspect ratio and a complex shape. Projection microstereolithography is suitable for microstructure array fabrication due to the fast process time using patterned light irradiation. However, nonuniform light intensity on the resin surface deteriorates the fabrication precision. This research proposes the cross-section segmentation for uniform exposure energy on the resin surface. Each subsection consisting of a cross-section is separately converted into an image file. The estimated exposure time of each subsection is stored in a text file and used during the fabrication. Finally, several microstructure arrays are fabricated to verify this method.     

Dynamic characteristics of an eccentric crack in a functionally graded piezoelectric ceramic strip

The dynamic response of an eccentric Griffith crack in functionally graded piezoelectric ceramic strip under anti-plane shear impact loading is analysed using integral transform method. Laplace transform and Fourier transform are used to reduce the problem to two pairs of dual integral equations, which are then expressed to Fredholm integral equations of the second kind. We assume that the properties of the functionally graded piezoelectric material vary continuously along the thickness. The impermeable crack boundary condition is adopted. Numerical values on the dynamic stress intensity factors are presented for the functionally graded piezoelectric material to show the dependence of the gradient of material properties and electric loadings.     

Improvement of the representative volume element method for 3-D scaffold simulation

Predicting the mechanical properties of the 3-D scaffold using finite element method (FEM) simulation is important to the practical application of tissue engineering. However, the porous structure of the scaffold complicates computer simulations, and calculating scaffold models at the pore level is time-consuming. In some cases, the demands of the procedure are too high for a computer to run the standard code. To address this problem, the representative volume element (RVE) theory was introduced, but studies on RVE modeling applied to the 3-D scaffold model have not been focused. In this paper, we propose an improved FEM-based RVE modeling strategy to better predict the mechanical properties of the scaffold prior to fabrication. To improve the precision of RVE modeling, we evaluated various RVE models of newly designed 3-D scaffolds using FEM simulation. The scaffolds were then constructed using microstereolithography technology, and their mechanical properties were measured for comparison.     

含裂纹的齿轮耦合转子系统非线性动力学特性分析

在考虑滑动轴承的非线性轴承油膜力以及齿轮齿侧间隙影响的情况下,综合了转轴裂纹以及齿轮质量偏心等常见故障,建立了齿轮耦合转子系统的振动模型并推导了系统的无量纲运动方程.利用数值积分对方程进行了求解,并分析了齿侧间隙以及转轴横向裂纹对齿轮耦合转子系统非线性动力学特性的影响.     

Dynamic propagation of a weak-discontinuous interface crack between two dissimilar functionally graded layers under anti-plane shear

The dynamic propagation of an interface crack between two functionally graded material (FGM) layers under anti-plane shear is analyzed using the integral transform method. The properties of the FGM layers vary continuously along their thicknesses. The properties of the two FGM layers vary and the two layers are connected weak-discontinuously. A constant velocity Yoffe-type moving crack is considered. The Fourier transform is used to reduce the problem to a dual integral equation, which is then expressed to a Fredholm integral equation of the second kind. Numerical values on the dynamic energy release rate (DERR) are presented for the FGM to show the effect of the gradient of material properties, crack moving velocity, and thickness of FGM layers. The following are helpful to increase resistance to interface crack propagation in FGMs: a) increasing the gradient of material properties, b) an increase of shear modulus and density from the interface to the upper and lower free surface, and c) increasing the thickness of the FGM layer. The DERR increases or decreases with increase of the crack moving velocity.     

Transient response of a permeable crack normal to a piezoelectric-elastic interface: Anti-plane problem

In this paper, the anti-plane transient response of a central crack normal to the interface between a piezoelectric ceramics and two same elastic materials is considered. The assumed crack surfaces are permeable. By virtue of integral transform methods, the electroelastic mixed boundary problems are formulated as two set of dual integral equations, which, in turn, are reduced to a Fredholm integral equation of the second kind in the Laplace transform domain. Time domain solutions are obtained by inverting Laplace domain solutions using a numerical scheme. Numerical values on the quasi-static stress intensity factor and the dynamic energy release rate are presented to show the dependences upon the geometry, material combination, electromechanical coupling coefficient and electric field.     

基于惯量伪速度的机械多体系统高效率动力学建模

对于多个体组成的复杂大型多体系统,传统动力学建模方法推导过程费时费力,通过形位参数建立的二阶微分方程组冗长、繁多并且计算量大难以求解。伪速度从运动的本质出发,引入速度级独立变量代替广义坐标,拓宽了独立变量的选取范围,得到了形式简洁的可积分的一阶微分方程组。笔者通过旋量递推与惯量伪速度结合,研究了高效率的建模方法,对两类伪速度进行区分,并阐述了惯量伪速度的物理含义,并得到了伪速度建模的优点。得到的对角化一阶动力学方程形式简洁,直接面向计算机编程实现,易于设计解耦控制或非交互控制,并把建模过程应用于Puma560机器人中。