随着对减小零件尺寸和增加其复杂性和准确性的日益增加的需求，传统机床已经不能有效的加工微型元件了。一个典型的例子是牙科种植体（生物医学设备）和和用于机械手表机芯的齿轮轴。由于这些零件的复杂几何形状和严格的公差要求，市面上只有很少一部分机床有能力加工它们。我们设计的多轴数控“车削-铣削-滚齿加工中心对加工精密复杂工程零件是非常有效的。此机器为8轴机床，除了执行加工的8轴外，还有一个自动上料机构和一个自动收集机构,可以实现自动上料，加工，收集等整条生产线的运作。运用电子齿轮技术以保证精密滚齿功能；运用先进控制技术（深层交叉耦合技术）以保证多轴的同步控制，实现加工的高效，高精度，并且容易使用。另外，为了保障机床精度，我们研发了多轴数控机床几何误差的软件补偿技术。根据实验测试，此加工中心的车削精度为0.003毫米，铣削精度为0.005毫米，滚齿误差小于0.0075毫米。 / 众多的生物医学零件是轴不对称零件。虽然这些零件可以用传统的数控加工方法进行加工，但是效率极低且成本高。而基于我们加工中心的新型铣削方法可以有效、高精度的加工这些零件。这种方法是运用极坐标的插值原理，比利用笛卡尔直角坐标系加工的原理更加优越，特别是当需要一个线性轴和旋转轴插值生成曲线时。为了方便使用这个极坐标插值模块，我们开发了一系列特殊的极坐标加工G代码。整个开发的程序模块最终融入我们多轴数控“车削-铣削-滚齿“加工中心。 / 另外一个重要的发现是运用滚齿方法加工轴对称和轴不对称零件。从滚齿方法被发明出来的这100年中，其一直是最有效的加工齿轮的方式。它的高效是由于多个刀齿同时切削工件。现在，滚齿是一种标准的加工方式并且每天运用这种方法加工几百万个零件。但是，没有人用这种方法加工轴不对称零件。经过仔细研究滚齿原来，可以得出以下观点：一）齿轮的齿形是与滚刀的齿形一样的；二）齿轮轮廓是由工件和滚刀的相对位置确定的。把滚刀设计和控制工件和滚刀的相对位置结合起来，我们发现运用滚齿的方法是可以加工各种轴对称和非对称部分，例如：星形零件和多边形零件。特别是，该方法可以有效的加工不断变化的轴不对称零件。最后，我们比较其的加工效率和传统的铣削加工，结果验证运用这种方法的加工时间远小于采用铣削方法。 / 我们设计的加工中心和新型加工方法在生物医学工程有很多的应有。牙科种植体就是一个典型的例子。具权威机构统计，约有10%的人会在一生中选用种植牙技术对牙齿进行修复。但是不幸的是，没有人研究个性化种植体。目前，市面上的种植体并不能精确的适合病人牙根情况，完成特殊口腔环境的牙齿修复。所以，对个性化种植体的研究是迫切并具有市场效益的。关于个性化种植体研制的一个难点是其的制造。个性化种植体之所以难加工是由于它的复杂形状及所用材料（钛）。但是，我们设计的多轴数控“车削-铣削-滚齿“加工中心和基于此机床的新型加工方法可以有效、高精度的加工此种植体。 / With the ever increasing demand for reduced size and increased complexity and accuracy, traditional machine tools have become ineffective for machining miniature components. A typical example is the dental implant and the other is the pinion used mechanical watch movement. With complex geometry and tight tolerance, few machine tools are capable of making these parts. We designed and built a CNC Turn-Mill-Hob Machining Center that is capable of machining various complex miniature parts. The machining center has 8 axes, an automatic bar feeder, an automatic part collection tray, and a custom-made CNC controller. In particularly, the CNC controller gives not only higher accuracy but also ease of use. In addition, to improve the accuracy, a software based volumetric error compensation system is implemented. Based on the experiment testing, the machining error is ± 4 μm for turning, ± 7 μm for milling, and the maximum profile error is less than ± 7.5 μm for gear hobbing. / Many biomedical parts are axial asymmetric parts. While these parts can be machined using conventional CNC machining methods, the efficiency is low and the cost is high. We proposed a new CNC machining method based on polar coordinate interpolation, which is better than the Cartesian coordinate interpolation when rotational axes are involved. To facilitate the use the polar coordinate interpolation module, a special G code is developed. This module is integrated into our CNC Turn-Mill-Hob Machining Center. / Another important development is the use of hobbing method for machining axial symmetric / asymmetric parts. Invented some 100 years ago, hobbing is the most efficient method for machining gears. Its efficiency lies on multiple teeth simultaneous cutting. Presently, gear hobbing is a standard manufacturing process making millions of gears every day. Though, no one has used it for machining axial asymmetrical parts. After carefully examining the gear hobbing, it is found that the profile of the gear tooth is determined by a combination of the profile of the hob tooth and the relative position and motion between the hob and the workpiece. Therefore, by tuning the hob tooth profile and controlling the relative position and motion between the hob and the workpiece, it is possible to machine various axial symmetrical and asymmetrical parts, such as a start, a hexagon and etc. This method is efficient to machine continuously changed axial asymmetrical parts. This is validated by means of experiments. The experiments also indicate that the new method is much more efficient than the conventional milling method. / Our machining center and new machining methods have many practical applications. Dental implant is a typical example. It is estimated that 10% of the people will need dental implants in their life time. Presently, there are a number of brands in the market, though these implants may not fit for patients who have special oral conditions. In this case, custom-made implants are necessary. The key problem of the custom-made dental implant is manufacturing. Our multi-axes CNC Turn-Mill-Hob Machining Center and the new machining method can effectively machine the custom-made dental implants. Moreover, the efficient is good. / Detailed summary in vernacular field only. / Detailed summary in vernacular field only. / Detailed summary in vernacular field only. / Detailed summary in vernacular field only. / Chen, Xianshuai. / Thesis (Ph.D.)--Chinese University of Hong Kong, 2012. / Includes bibliographical references (leaves 116-127). / Electronic reproduction. Hong Kong : Chinese University of Hong Kong, [2012] System requirements: Adobe Acrobat Reader. Available via World Wide Web. / Abstract also in Chinese. / Abstract --- p.I / 摘要 --- p.III / Acknowledgement --- p.V / Table of Contents --- p.VI / List of Tables --- p.VIII / List of Figures --- p.IX / Acronym --- p.XIII / Chapter Chapter 1: --- Introduction --- p.1 / Chapter 1.1 --- Background --- p.1 / Chapter 1.2 --- Overall Literature Review --- p.3 / Chapter 1.3 --- Objectives --- p.17 / Chapter Chapter 2: --- The Multi-Axes CNC Turn-Mill-Hob Machining Center --- p.18 / Chapter 2.1 --- A Brief Review --- p.18 / Chapter 2.2 --- The Design and Prototype --- p.20 / Chapter 2.3 --- The CNC Controller --- p.26 / Chapter 2.4 --- The Calibration --- p.32 / Chapter 2.5 --- Cutting Tests --- p.35 / Chapter 2.6 --- Summary --- p.43 / Chapter Chapter 3: --- Hobbing Gears and Axial Asymmetric Parts --- p.45 / Chapter 3.1 --- A Brief Review --- p.45 / Chapter 3.2 --- The Theory --- p.47 / Chapter 3.3 --- Computer Simulation --- p.54 / Chapter 3.4 --- Cutting Tests --- p.68 / Chapter 3.5 --- Summary --- p.78 / Chapter Chapter 4: --- Millining Axial Asymmetric Parts --- p.80 / Chapter 4.1 --- A Brief Review --- p.80 / Chapter 4.2 --- The Theory --- p.81 / Chapter 4.3 --- Cutting Tests --- p.89 / Chapter 4.4 --- Summary --- p.94 / Chapter Chapter 5: --- Machining Dental Implants --- p.95 / Chapter 5.1 --- A Brief Review --- p.95 / Chapter 5.2 --- The Database of Custom-made Dental Implant --- p.98 / Chapter 5.3 --- The Design and FEA --- p.103 / Chapter 5.4 --- Cutting Tests --- p.108 / Chapter 5.5 --- Summary --- p.110 / Chapter Chapter 6: --- Concluding Remarks and Future Work --- p.111 / Chapter 6.1 --- Concluding Remarks --- p.111 / Chapter 6.2 --- Future Work --- p.113 / Bibliography --- p.116 / Publication Record --- p.127

Bioanalytics involves quantitative measurements of complex biological samples that contain metabolites, DNA, RNA, and proteins. Efficient sample preparation for downstream analysis and sensitive detection of analytes can be achieved via bioanalytical microdevices. Fully realizing the potential of these devices requires tool characterization and bioprocess optimization, in addition to understanding device physics. Therefore, this thesis introduces multiphysical modeling and experimentation of microdevices, with applications to diabetes care and single-cell analysis. To understand the physics of viscometric glucose microsensors, this thesis presents a model of the sensor, which couples the fluid flow with vibrating diaphragms. The model is used to predict the sensor response to glucose via theory of squeeze-film damping and vibrations of pre-stressed plate. A first-principle-based model resulting from the theory can be evaluated from the device's geometric and material properties, and quantitatively determines the device response to vibrational excitations at varying glucose concentrations. Next, this thesis introduces a theoretical model for viscometric glucose microsensors that employ harmonic microcantilever oscillation in the sensing liquid. The presented model associates the unsteady Stokes equation with the motion of a bounded viscous liquid to understand the hydrodynamic impact on the cantilever. With a proper consideration of the viscosity and bounded geometry of liquid media, the model relaxes the thin-film assumption required for the diaphragm-based model, enabling an accurate representation of fluid-structure interactions based on fundamental structural vibration and fluid flow equations. Next, this thesis presents an experimental exploration of a hydrogel-based affinity microsensor for glucose monitoring via dielectric measurements. The microsensor incorporates a synthetic hydrogel that is attached to the device surface via in situ polymerization, which eliminates mechanical moving parts required in the viscometric glucose sensors. Changes in the dielectric properties of the hydrogel when binding reversibly with glucose molecules have been measured using a MEMS capacitive transducer to determine the glucose concentration. Experimental results demonstrate that in a glucose concentration range of 0–500 mg/dL and with a resolution of 0.35 mg/dL or better, the microsensor exhibits a repeatable and reversible response, and can potentially be useful for continuous glucose monitoring in diabetes care. Additionally, this thesis presents a microfluidic preprocessing method that integrates single-cell picking, lysing, reverse transcription and digital polymerase chain reaction to enable the isolation, tracking and gene expression analysis at single-cell level for individual cells. The approach utilizes a photocleavable bead-based microfluidic device to synthesize and deliver stable complementary DNA for downstream gene expression analysis, thereby allowing chip-based integration of multiple reactions and facilitating the minimization of sample loss or contamination. Finally, this thesis ends with concluding remarks and directions of future work towards continuous glucose monitoring and high-throughput single-cell genetic analysis.

Thesis (Ph.D.)--Ohio University, June, 2006. / Title from PDF t.p. Includes bibliographical references (p. [69]-[78])

La creciente demanda de energía portátil requerida por sistemas miniaturizados está impulsando el desarrollo de nuevas tecnologías y materiales para lograr una eficiente generación de energía a una microescala. Los microgeneradores termoeléctricos ofrecen una oportunidad para recolectar el calor residual de dispositivos electrónicos y convertirlo en energía, eliminando a la vez dicho calor. La baja eficiencia de conversión termoeléctrica de los materiales semiconductores utilizados actualmente en microelectrónica ha limitado su aplicación para fines de aprovechamiento energético. Sin embargo, recientemente se ha constatado una mejora de varios órdenes de magnitud en las propiedades termoeléctricas del silicio cuando se presenta en forma de nanohilos, abriéndose de esta manera la oportunidad para la integración de generadores termoeléctricos en microtecnología de silicio. En esta tesis se han integrado monolíticamente matrices densas y ordenadas de nanohilos de silicio (Si NWs) en un dispositivo micromecanizado también en silicio. La técnica VLS-CVD ha sido utilizada para el crecimiento lateral controlado de los nanohilos. La microestructura ha sido apropiadamente diseñada para adaptar el crecimiento tridimensional de las matrices de nanohilos de silicio en una arquitectura plana y para asegurar el acceso eléctrico a los nanohilos. Adicionalmente, el dispositivo permite el establecimiento de un gradiente de temperatura interno plano cuando se pone en contacto con una fuente de calor, lo que da lugar a un microgenerador termoeléctrico completo en el que los nanohilos de silicio actúan como el material termoeléctrico nanoestructurado. Esta tesis tiene por objeto presentar los primeros desarrollos de integración de materiales termoeléctricos, técnicas de caracterización y tecnologías de fabricación realizados en el IMB-CNM (CSIC), sentando las bases para el desarrollo de futuras generaciones de microgeneradores termoeléctricos. Esta tesis se compone de cuatro capítulos. En el primer capítulo se presenta una breve introducción al mundo de la termoelectricidad, revisando el estado del arte de materiales y dispositivos termoeléctricos. El segundo capítulo está enfocado en las técnicas experimentales y tecnológicas empleadas a lo largo del estudio. El capítulo tres describe el proceso seguido para el diseño, simulación y fabricación de un microgenerador termoeléctrico plano basado en una sola matriz de nanohilos de silicio. Finalmente, el capítulo cuatro estudia el aumento en el rendimiento de los microgeneradoes termoeléctricos mediante matrices de nanohilos de silicio conectadas transversalmente, adaptando y explotando aún más el crecimiento lateral 3D de nanohilos de silicio VLS. / The increasing demand for portable power required by miniaturized systems is driving the development of new technologies and materials to achieve efficient energy generation at the microscale. Apart from removing heat from electronic devices, thermoelectric microgenerators offer an attractive opportunity to harvest waste heat converting it into power. The low thermoelectric conversion efficiency of current bulk microelectronics semiconductor materials has limited their implementation for energy harvesting purposes. However, recent studies have proven, at single nanowire level, that nanostructuring of silicon into nanowires greatly enhances the thermoelectric properties of this material, opening up the opportunity for the integration of thermoelectric generators into silicon microtechnology. In this thesis, dense and well-ordered arrays of silicon nanowires (Si NWs) have been monolithically integrated into a silicon micromachined device. The VLS-CVD technique has been used for the controlled lateral growth of nanowires. The microstructure has been appropriately designed to adapt the tridimensional growth of the Si NWs arrays to a planar architecture, and to assure electrical accessibility to the nanowires. Additionally, the device allows an internal in-plane temperature gradient to be established when placed in contact with a heat source, giving rise to a complete thermoelectric microgenerator in which the Si NWs act as the nanostructured thermoelectric material. This thesis is intended to bring new background in thermoelectric materials integration, characterization techniques and fabrication technologies to the IMB-CNM (CSIC), paving the way for the development of future generations of thermoelectric microgenerators. The work presented in this thesis is divided into four chapters. The first chapter introduces thermoelectricity and its underlying physics, reviewing the state-of-the-art of thermoelectric materials and devices. The second chapter focuses on the experimental and technological tools employed along this study. The third chapter describes the process followed for the design, simulation and fabrication of the building block of the proposed planar thermoelectric microgenerators based on a single Si NWs array. Finally, chapter four studies the enhanced performance of thermoelectric microgenerator structures by means of transversally linked Si NWs arrays, further adapting and exploiting the 3D lateral growth of VLS Si NWs.

Thesis (M. S.)--Mechanical Engineering, Georgia Institute of Technology, 2005. / Lackey, Jack, Committee Member ; Kurfess, Thomas, Committee Member ; Melkote, Shreyes, Committee Chair. Includes bibliographical references.

Thesis (M.S. in chemical engineering)--Washington State University, August 2005. / Includes bibliographical references.

Thesis (M. S.)--Mechanical Engineering, Georgia Institute of Technology, 2006. / Zhou, Min, Committee Member ; Melkote,Shreyes, Committee Member ; Liang, Steven, Committee Chair.

Au cours des dernières décennies, l'étude des puces microfluidiques capables d'exécuter des processus chimiques et biologiques sur quelques centimètres carrés a été un domaine de recherche actif. De telles plateformes offrent un environnement fermé et contrôlable qui permet une mesure reproductible et évite toute contamination externe. Cependant, ces environnements sont fermés, ce qui empêche l'utilisation de sondes de mesure ou d'effecteurs fixés à l'extérieur de la puce microfluidique. Pour répondre à ce besoin, nous proposons d'utiliser des microrobots rotatifs hélicoïdaux évoluant dans un fluide. Les microrobots proposés sont conçus grâce à la lithographie 3D par laser. Ils présentent une forme hélicoïdale de 5.5 µm de diamètre et environ 50 µm de longueur. Une couche mince ferromagnétique déposée sur ces microrobots permet de les propulser et de les contrôler grâce à un champ magnétique tournant homogène.Le premier défi est l'intégration stable de microrobots à l'intérieur d'un environnement microfluidique. Dans cette thèse, nous avons donc d'abord prouvé que ces microrobots peuvent utiliser leur propre mobilité pour s'intégrer individuellement à l'intérieur d'une puce microfluidique en utilisant un microcanal relié à un réservoir ouvert. Pour cela, nous avons développé un mouvement 3D où le microrobot évolue dans le fluide et deux mouvements 2D où il évolue sur une surface. En passant facilement d'un mouvement à l'autre, les microrobots peuvent utiliser les différents avantages de chaque mouvement pour obtenir une mobilité suffisante à cette intégration. Nous avons nommé ce modèle de microrobot "Roll-to-Swimm"(RTS).Ensuite, pour utiliser un microrobot comme capteur de force sur puce microfluidique, il est nécessaire de caractériser la force générée par l'hélice de chaque RTS. Une méthode de caractérisation est proposée, dans laquelle les différents paramètres d'environnement tels que le flux parasite, le gradient de température et l'impact des surfaces, sont contrôlées avec précision grâce à l'environnement microfluidique. Nous en concluons que le modèle de microrobot "RTS" peut appliquer une force de 10 à 45 piconewton avec une erreur maximale de 38 %. La composante principale de cette erreur (73 %) est due à l'évolution de l'aimantation du RTS. Par conséquent, les efforts visant à réduire cette erreur doivent d'abord se concentrer sur la propriété de magnétisation du RTS. Cette erreur peut également être temporairement réduite en caractérisant la RTS juste avant son utilisation dans une expérience.Enfin, nous présentons trois preuves de concept pour démontrer que notre méthode de caractérisation rapproche les microrobots hélicoïdaux des applications potentielles. Tout d'abord, nous mesurons la diminution de la force du RTS lorsqu'il pousse une microbille. Cette mesure est essentielle pour connaitre la force appliquée par le RTS sur un objet ou pour mesurer l'état de surface en utilisant des billes comme interface. Une microbille de 10 µm de diamètre à la pointe du RTS réduit la propulsion de 6 %. Deuxièmement, nous utilisons la caractérisation du RTS pour mesurer la vitesse locale de l'écoulement dans un canal. Puis nous proposons d'utiliser cette mesure de vitesse pour le contrôle du microrobot grâce à un contrôle automatique du RTS qui adapte le type de mouvement en fonction de la vitesse de l'écoulement. Ce contrôle a été testé expérimentalement avec différentes conditions d'écoulement. Troisièmement, nous utilisons la caractérisation du RTS pour effectuer des simulations numériques afin de trouver une stratégie de contrôle dans des microcanaux de taille inférieure à 20 fois le diamètre du RTS. Le modèle de cette simulation a été validé en comparant ces résultats avec des données expérimentales. Finalement, nous proposons un système de contrôle permettant de maintenir le RTS centré à l'intérieur de microcanaux courbes évoluant en 3D, en utilisant seulement une acquisition d'image en 2D. / Microfluidic chips that could perform chemical and biological processes on a few centimeter square footprint have been an active area of research in the past decades. Among other advantages, this platform offers a closed and controllable environment that allows reproducible measurements and avoids external contamination. However, such closed environments prevent the use of tethered probes to measure or apply a specific force on an element inside the microfluidic chip. Therefore we propose to use a helical rotating microrobot inside a microfluidic chip to answer this need. The proposed microrobots are designed with 3D laser lithography, and have a helical shape of 5.5 µm in diameter and around 50 µm length. A thin ferromagnetic layer is deposited on these microrobots which allows us to propel and control them with a homogenous external rotating magnetic field.The first challenge is the stable integration of these microrobots inside microfluidic environments. Therefore, in this thesis we first proved that these microrobots can use their own mobility to integrate themselves selectively (one by one) inside a microfluidic chip through a microchannel connected to an open reservoir. For this, we have developed a 3D motion where the microrobot evolves in the fluid and two different 2D motions where it evolves on a surface. By switching easily from one motion to another, the microrobots can use the different advantages of each motion to get sufficient mobility required for this integration. We named our microrobot design Roll-To-Swimm (RTS) in reference to this characteristic.Then in order to use a microrobot as on-chip force sensor, a precise characterization of the force generated by the helical shape is necessary for each RTS. A characterization method is proposed, where the different environment parameters (parasite flow, temperature gradient and impact of near surfaces on the flow) are controlled precisely thanks to the microfluidic environment. The characterization shows that the force range of the RTS is between 10 and 45 piconewton with a maximum error of 38 %. We also conclude that the main component of this error (73 %) is due to the evolution of the RTS magnetization. Therefore the efforts to reduce this error should first focus on the magnetization property of the RTS. This error can also be temporarily reduced by characterizing the RTS just before its use in another experiment.Finally, we present three different proofs of concept to demonstrate that our characterization method brings helical microrobots closer to potential on-chip force sensing applications. Firstly, we show that it is possible to measure the diminution of the RTS force when it is pushing a micro spherical bead. This is essential toward applying force on an object with this RTS or to use beads as an interface between the RTS and the surface to measure friction forces. A microbead with 10 µm in diameter at the tip of the RTS reduces it propulsion of 6 %.Secondly, we use the RTS characterization to measure local flow speed. We demonstrate this feature by measuring flow profiles in fluid channels. We show the potential use for of microrobot control by proposing an automatic control of the RTS that adapts the motion to the measured flow. This control has been tested experimentally with different flow conditions. Thirdly, we use the characterization of the RTS to perform numerical simulations in order to find a control strategy in small microchannels. Indeed we demonstrate that for microchannels below 20 times the RTS diameter, the channel walls have an impact on the RTS motions. The model of this simulation has been validated by comparing this result with experimental data. Finally we propose a control scheme for maintaining the RTS centered in a curved microchannel by only using a 2D image feedback.

This work addresses the advanced probabilistic modeling of the stochastic nature of microgrinding in the machining of high-aspect ratio, ceramic micro-features. The heightened sensitivity of such high-fidelity workpieces to excessive grit cutting force drives a need for improved stochastic modeling. Statistical propagation is used to generate a comprehensive analytic probabilistic model for static wheel topography. Numerical simulation and measurement of microgrinding wheels show the model accurately predicts the stochastic nature of the topography when exact wheel specifications are known. Investigation into the statistical scale affects associated microgrinding wheels shows that the decreasing number of abrasives in the wheel increases the relative statistical variability in the wheel topography although variability in the wheel concentration number dominates the source of variance. An in situ microgrinding wheel measurement technique is developed to aid in the calibration of the process model to improve on the inaccuracy caused by wheel specification error. A probabilistic model is generated for straight traverse and infeed microgrinding dynamic wheel topography. Infeed microgrinding was shown to provide a method of measuring individual grit cutting forces with constant undeformed chip thickness within the grind zone. Measurements of the dynamic wheel topography in infeed microgrinding verified the accuracy of the probabilistic model.

Thesis (Ph. D.)--University of Missouri--Rolla, 2007. / Vita. The entire thesis text is included in file. Title from title screen of thesis/dissertation PDF file (viewed December 6, 2007) Includes bibliographical references.