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Dissertations / Theses on the topic 'Electro machining'
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1
Ivanov, Atanas. "Electro discharge machining for micro manufacturing." Thesis, Cardiff University, 2008. http://orca.cf.ac.uk/54758/.
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Due to the high precision and good surface quality that it can give, Electrical Discharge Machining (EDM) is potentially an important process for the fabrication of micro tools, micro components and parts with micro features. However, a number of issues remain to be solved before micro EDM can become a reliable process with repeatable results and its full capabilities as a micro manufacturing technology can be realised. This work presents some developments in advancing the state-of-the-art in the micro EDM process. EDM drilling and EDM milling are regarded as separate processes as they require different approaches in investigating and implementing the results of the study. At the beginning, special attention is paid to factors and procedures influencing the accuracy achievable, including positioning approaches during EDM and electrode grinding. In particular, the main parameters affecting the size and position of a machined feature are discussed and new techniques for minimising errors are proposed. The technological capabilities of different methods of setting up and dressing the electrode on the machine are analysed. Factors contributing to electrode wear, the main systematic cause for inaccuracy of the dimensions achieved, during the micro EDM process are studied. A method for calculating the volumetric wear ratio based only on geometrical information obtained from the process is proposed. This study investigates the suitability of micro EDM electrode wear compensation methods. Electrode shape deformation and random variations in the volumetric wear are also investigated as the two main factors affecting the applicability of the wear compensation methods as well as indicating the accuracy achievable with micro EDM. When producing features and parts on the micro scale, the phenomena that take place between the electrodes in EDM is not fully understood. A barrier to a complete exploitation of the potential natural tolerance of this process and to the further development of the process towards the production of components on the nano-scale is therefore in place. An analytical micro EDM model of electrode wear based on electrode shape deformation and wear ratio is suggested, verification of which requires experimental work with pure metals. Electrode-tool wear is studied during the micro EDM process of pure metals and the effect of electrode wear on the process accuracy and process variability. Objectives in this case are to advance the experimental knowledge of the electrical discharges during micro EDM operations which often conflicts with existent theoretical models of the EDM process. In particular, the remit of this investigation is to identify the effects that electrode materials have on selected electrical characteristics of the discharge process. An exploratory data analysis (EDA) approach is adopted in order to draw conclusions from the performed experimental activity. The material removal mechanism in the micro EDM process was confirmed to be mainly attributed to the melting and vaporisation phenomenon. Metal removal takes place as a result of the extremely high temperature generated by the discharge sparks. It was also found in this study that the volumetric wear ratio depends not only on the sparking conditions but also on the electrode materials. In addition, the research also proved that the electrode material severely influences the energy distribution between the electrodes during the sparks.
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Alla, Chaitanya Chakravarty Reddy. "MEMS-enabled micro-electro-discharge machining (M³EDM)." Thesis, University of British Columbia, 2008. http://hdl.handle.net/2429/4170.
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A MEMS-based micro-electro-discharge machining technique that is enabled by the
actuation of micromachined planar electrodes defined on the surfaces of the workpiece is
developed that eliminates the need of numerical control machines. First, the planar
electrodes actuated by hydrodynamic force is developed. The electrode structures are
defined by patterning l8-µm-thick copper foil laminated on the stainless steel workpiece
through an intermediate photoresist layer and released by sacrificial etching of the resist layer.
The planer electrodes are constructed to be single layer structures without particular features
underneath. All the patterning and sacrificial etching steps are performed using dry-film
photoresists towards achieving high scalability of the machining technique to large-area
applications. A DC voltage of 80-140 V is applied between the electrode and the workpiece
through a resistance-capacitance circuit that controls the pulse energy and timing of spark
discharges. The parasitic capacitance of the electrode structure is used to form a resistance
capacitance circuit for the generation of pulsed spark discharge between the electrode and the
workpiece. The suspended electrodes are actuated towards the workpiece using the
downflow of dielectric machining fluid, initiating and sustaining the machining process.
Micromachining of stainless steel is experimentally demonstrated with the machining voltage
of 90V and continuous flow of the fluid at the velocity of 3.4-3.9 m/s, providing removal
depth of 20 µm. The experimental results of the electrode actuation match well with the
theoretical estimations. Second, the planar electrodes are electrostatically actuated towards
workpiece for machining. In addition to the single-layer, this effort uses double-layer
structures defined on the bottom surface of the electrode to create custom designed patterns
on the workpiece material. The suspended electrode is electrostatically actuated towards the
wafer based on the pull-in, resulting in a breakdown, or spark discharge. This instantly
lowers the gap voltage, releasing the electrode, and the gap value recovers as the capacitor is
charged up through the resistor. Sequential pulses are produced through the self-regulated
discharging-charging cycle. Micromachining of the stainless-steel wafer is demonstrated
using the electrodes with single-layer and double-layer structures. The experimental results
of the dynamic built-capacitance and mechanical behavior of the electrode devices are also
analyzed.
3
Yahya, Azli. "Digital control of an electro discharge machining (EDM) system." Thesis, Loughborough University, 2005. https://dspace.lboro.ac.uk/2134/13655.
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This thesis presents a model of the complete Electro Discharge Machining (EDM) system and the design and implementation of a digital controller for the servomotor control and the gap voltage and current pulse power generator. A Matlab/Simulink simulation is used to investigate the EDM system model behaviour and based on the simulation results, a compensated EDM control system is designed. Simulation studies were also earned out to predict the material removal rate of a steel workpiece in mm3/min . The control software of the EDM control process and servo system control was performed mainly in software with minimal hardware implementation. The control hardware consists of an eZdsp, userinterface device and analogue signal processing and interfacing circuit. The eZdsp communicates with the user-interface device by sending the information/instruction to the LCD screen while the user-interface device uses push button switches to communicate with the eZdsp. It is shown that one DSP microcontroller can be used to provide the control functions for the EDM system. The experimental studies of the Electro Discharge Machining process using a copper electrode, a graphite electrode and steel workpiece materials are presented in tabular and graphical forms. The analysis of the experimental results show that the material removal rate is influenced by the process parameters such as the gap current Igap• gap voltage V arc. pulse on-time Ion, and sparking frequency F, as well as the material properties of the electrode and the workpiece. Comparison studies between simulation and experimental results show reasonable agreement. Further improvement was made to the EDM process model based on the comparison studies. As a result, the predicted material removal rate using the improved EDM process model shows better agreement with experimental results.
4
Morgan, Christopher James. "MICRO ELECTRO-DISCHARGE MACHINING: TECHNIQUES AND PROCEDURES FOR MICRO FABRICATION." Lexington, Ky. : [University of Kentucky Libraries], 2004. http://lib.uky.edu/ETD/ukymeen2004t00197/MicroEDM.pdf.
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Thesis (m.s.)--University of Kentucky, 2004.<br>Title from document title page (viewed Jan. 5, 2005). Document formatted into pages; contains viii, 77p. : ill. Includes abstract and vita. Includes bibliographical references (p. 74-76).
5
Schöpf, Martin. "Electro Chemical Discharge Machining (ECDM) : Neue Möglichkeiten zum Abrichten metallgebundener Diamantschleifscheiben /." Zürich, 2001. http://e-collection.ethbib.ethz.ch/show?type=diss&nr=14120.
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Moses, Mychal-Drew. "A Study on the Micro Electro-Discharge Machining of Aerospace Materials." TopSCHOLAR®, 2015. http://digitalcommons.wku.edu/theses/1448.
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Electrical Discharge Machining (EDM) is a non-traditional machining process that uses hundreds of thousands of minute electrical sparks per second to machine any electrically conductive material, no matter the hardness or how delicate it is. EDM allows a much greater range of design possibilities, unconstrained from the traditional machining processes, in which material is removed mechanically by either rotating the cutting tool or the work piece. Shapes that were impossible to machine by any other method, such as deep, precision, square holes and slots with sharp inside corners, are readily produced. It provides accurate geometries in high- aspect ratio holes and slots, blind undercuts, small holes adjacent to deep sidewalls, and complex cuts in thin, fragile parts. Micro-EDM is a growing form of manufacturing and will continue to expand within various production fields. Micro-EDM is especially attractive for the applications where the cutting time is minimal, but precision and accuracy are maximized. Micro- EDM is a non-traditional cutting process, which consistently produces ultra-precise holes with fine surface finishes and better roundness, while holding extremely close diameter tolerances. The process could be an excellent problem-solving tool for configurations that are difficult or impossible to produce using conventional machining processes. This study presents a comparative experimental investigation on the micro-EDM machinability of difficult-to-cut Ti-6Al-4V and soft brass materials. As both materials are electrically conductive, they were machinable using the micro-EDM process irrespective of their hardness. The machining performance of the two materials was evaluated based on the quality of the micro-features produced by the micro-EDM process. Both blind and through micro-holes and micro-slots were machined on brass and Ti-6Al-4V materials. The quality of micro-features was assessed based on the shape accuracy, surface finish and profile accuracy of the features. Finally, the arrays of micro-features were machined on both materials to compare the mass production capability of micro-EDM process on those materials.
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Dahmardeh, Masoud. "Micro-electro-discharge machining of carbon-nanotube forests and its application." Thesis, University of British Columbia, 2014. http://hdl.handle.net/2429/46266.
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Carbon nanotubes (CNTs) are relatively new materials with exceptional properties which have attracted significant interest in the past two decades. The ability to grow arrays of vertically aligned carbon nanotubes, so called CNT forest, opened up opportunities to develop different types of novel devices enabled by the material. A key in facilitating micro-electro-mechanical systems (MEMS) applications of the material is the ability to pattern the material in a batch mode with high precision and high reproducibility. Patterning CNT forests prior to, during or after the growth is reported. The mentioned techniques are, however, primarily for the formation of two-dimensional types of patterns (with uniform heights). Laser micromachining is reported to shape CNT forests for different applications while exhibiting its inherent limitations including tapered sidewalls, lack of high-precision depth control, and thermal damages. Hence, there is a need to develop machining techniques to fabricate CNT forests in any shape for MEMS and other applications.
This thesis is based on the idea that a powerful micromachining technique is a path that should be taken to reach a successful integration of smart materials such as nanotubes and MEMS (and other) devices to achieve more complex and improved devices. This work develops an effective micromachining technique based on dry micro-electro-discharge machining (??EDM) to produce free-form, three-dimensional (3D) patterns out of CNT forests with high precision (~2-??m machining tolerance), high-aspect-ratios (of about 20), high reproducibility, and at very small machining voltages (~10 V) which corresponds to several orders of magnitude smaller discharge energy (0.5 nJ compared to 15 ??J). The machining mechanism has been found to be different from the one in typical ??EDM. Furthermore, techniques to achieve high removal precision with tighter tolerance are investigated. Also, elemental and molecular analysis of the machined structures is carried out to observe the level of cross-contamination of the process. To demonstrate an application of the processed nanotubes, high-power MEMS switches that integrate micropatterned CNT forests as electrical contact have been developed. Micropatterned CNT forests as field emitters and atomic force microscopy (AFM) probe tips are also demonstrated.
8
Mediliyegedara, T. K. K. R. "Intelligent process monitoring and control approaches for electro chemical discharge machining." Thesis, Glasgow Caledonian University, 2006. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.426445.
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Anwar, Mohammed Muntakim. "A study on micro-patterning of polypyrrole using micro-electro-discharge machining." Thesis, University of British Columbia, 2012. http://hdl.handle.net/2429/43339.
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Huang, X. "The electro-discharge machining of ink jet nozzle and their precision measurement." Thesis, Cranfield University, 1997. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.393258.
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Wang, Ningyuan. "Investigation for improvement and application of MEMS-based micro-electro-discharge machining (M3EDM)." Thesis, University of British Columbia, 2011. http://hdl.handle.net/2429/30885.
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MEMS-based micro-electro-discharge machining (M3EDM) is a batch microfabrication technique utilizing planar electrode actuators to machine conductive materials. The low contrast pattern transfer issue in electroplating mold fabrication is firstly analyzed and improved by eliminating the contact gap and adding a rehydration step. The new method gives a better structure profile with near vertical sidewalls. The causes and mechanisms of spin coating non-uniformity and bonding voids are discussed, as well. The deformation on the foil electrode area where discharges occur is explained by abnormal heat shock, tool wear, material softening and discharge-brought reactive force. A feedback control circuit with pulse discrimination is developed to detect the harmful short pulse and prevent thermal shock. Nickel is proposed and tested as the new material for actuators owing to its higher mechanical and thermal resistance. The optimized nickel based electrodes together with the affiliation circuit are applied to cantilever MEMS contact switch fabrication. The photoresist melting in the photoresist sandwich structure is observed. A new reverse fabrication process is proposed and processed in order to minimize the photoresist melting. The method partially addresses the issue. The further directions for improvements and the potential application of the reverse process to reusable M3EDM devices are discussed.
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Arthur, Alan. "A study of the performance of electro-discharge machining electrodes made by StereoLithography." Thesis, University of Nottingham, 1997. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.362903.
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Čumpl, David. "Trendy vývoje elektroerozivních hloubících strojů." Master's thesis, Vysoké učení technické v Brně. Fakulta strojního inženýrství, 2008. http://www.nusl.cz/ntk/nusl-228108.
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In this work, a principle of Electro Discharge Sinking Technology is described as well as comparison of individual machine producers. Further, description of an electrode production technology is included together with a recommendation of a machine to a middle mechanical engineering company. Last part is dedicate technical and economical analysis on concrete types of machines and adumbration another trends of development.
14
Kakavand, Pegah. "A Comparative Study on Micro Electro-Discharge Machining of Titanium Alloy (TI-6AL-4V) and Shape Memory Alloy (NI-TI)." TopSCHOLAR®, 2015. http://digitalcommons.wku.edu/theses/1466.
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The purpose of this research was to investigate the surface modifications that take place during the machining of NiTi SMA and Ti-6Al-4V with micro-EDM. This was done by creating an array of blind holes and micro-patterns on both work-pieces. To analyze the machined surface and investigate the results, scanning electron microscope (SEM), energy dispersive X- ray spectroscopy (EDS) and X-ray diffraction (XRD) techniques were employed. In addition, the effects of various operating parameters on the machining performance was studied to identify the optimum parameters for micro-EDM of NiTi SMA and Ti-6Al-4V. Recently, aerospace and biomedical industries have placed a high demand on nonconventional machining processes, which can be used to machine high strength and hardto- cut materials such as Titanium alloys, Shape Memory Alloys (SMA) and Super Alloys. Electrical Discharge Machining (EDM) is one of the non-traditional technologies that remove materials from the workpiece through a series of electrical sparks that occur between the workpiece and cutting tool with the presence of dielectric liquid. Obtaining smooth and defect-free surfaces on both workpieces was one of the challenges due to the re-solidified debris on the machined surface. The experimental results showed that there was significant amount of re-casting and formation of resolidification of debris on the Ti surface after machining. On the other hand, the surface generated in NiTi SMA were comparatively smoother with lesser amount of resolidified debris on the surface. By analyzing the results from XRD and EDS, some elements of electrode and dielectric materials such as Tungsten, Carbon and Oxygen were observed on NiTi and Ti surface after machining. In the study of effect of operating parameters, it was found that the voltage, capacitance and tool rotational speed had significant effect on machining time. The machining time was reduced by increasing the voltage, capacitance and tool rotational speed. The machining time was found to be comparatively higher for machining NiTi SMA than Ti alloy. Comparing all the parameters, the voltage of 60 V, capacitance of 1000 PF, and tool rotational speed of 3500 RPM were selected as optimum parameters for this study. Although signs of tool electrode wear and debris particles on the machined surface were observed for both workpieces during the micro-EDM process, Ti alloy and NiTi SMA could be machined successfully using the micro-EDM process.
15
Shafik, Hassan Abd Alla Mahmoud. "Computer aided analysis and design of a new servo control feed drive for electro discharge machining using piezoelectric ultrasonic motor." Thesis, De Montfort University, 2003. http://hdl.handle.net/2086/4301.
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Kim, Hyung-jun. "The analysis of mitigation of the influence of electro-discharge machining on the thermal fatigue properties of H-13 die steel." Case Western Reserve University School of Graduate Studies / OhioLINK, 1991. http://rave.ohiolink.edu/etdc/view?acc_num=case1055884230.
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Mahbub, Md Rashef. "INVESTIGATING THE EFFECT OF MECHANICAL PROPERTIES AND SUB-SURFACE MICROSTRUCTURE OF TITANIUM ALLOY ON CELL ATTACHMENT MACHINED BY ELECTRO-DISCHARGE MACHINING." Miami University / OhioLINK, 2019. http://rave.ohiolink.edu/etdc/view?acc_num=miami1564671363905827.
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Blom, Ricky J. "Production and Evaluation of Rapid Tooling for Electric Discharge Machining using Electroforming and Spray Metal Deposition Techniques." Queensland University of Technology, 2005. http://eprints.qut.edu.au/16014/.
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To survive in today's manufacturing environments companies must push the standards of accuracy and speed to the highest levels possible. Electro Discharge Machining (EDM) has been used for over 50 years and recent developments have seen the use of EDM become much more viable. The goal of this research is to produce and evaluate electrodes produced by different manufacturing methods. The use of electroforming and spray-metal deposition has only recently become viable methods of producing usable rapid tooling components. The speed and accuracy as well as the cost of manufacture play a vital role in the tool and mould manufacturing process. Electroforming and spray-metal deposition offer an alternate option to traditional machining of electrodes. Electroforming is one method of producing electrodes for EDM. The fact that electroforming can be used to produce multiple electrodes simultaneously gives it the advantage of saving on costs when multiple electrodes are needed. Spray-metal deposition offers another alternative that is much cheaper and relatively faster to manufacture. The used of these non-traditional manufacturing methods in this research are compared to the performance of traditional solid electrodes in terms of machining time, material removal rate, tool wear rates and surface roughness at several standard machining settings. The results of this research are presented in this thesis along with conclusions and comments on the performance of the different methods of electrode manufacture. The major findings of the research include the solid electrodes performed better than the electroformed electrodes in Material Removal Rate (MRR), Tool Wear Rate (TWR), and Surface Roughness (Ra) at all machine settings. However it was found that the production cost of the solid electrodes was six times that of the electroformed electrodes. The production of spray metal electrodes was unsuccessful. The electrode shell walls were not an even thickness and the backing material broke through the shell making them unusable. It is concluded that with further refinements and research, electroforming and spray metal processes will become an extremely competitive method in electrode manufacture and other rapid tooling processes.
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Dahmani, Rabah. "Optimisation d’un procédé d’usinage par microélectroérosion." Thesis, Lyon 1, 2015. http://www.theses.fr/2015LYO10058/document.
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L’objet de cette thèse est d’étudier un procédé de fraisage par microélectroérosion (μEE), qui est un procédé sans contact permettant d’usiner tous les matériaux durs conducteurs d’électricité à l’aide d’un micro-outil cylindrique ultrafin. Le principe consiste à créer des micro-décharges électriques entre le micro-outil et une pièce conductrice immergés dans un diélectrique liquide. En faisant parcourir à l’outil un parcours 3D, il est possible de creuser une forme complexe dans la pièce avec des détails à fort rapport d’aspect. Dans ce travail, nous avons tout d’abord amélioré un procédé d’élaboration de microoutils cylindriques ultrafins par gravure électrochimique de barreaux de tungstène. Des outils de diamètre 32,6 ± 0,3 μm sur une longueur de 3 mm ont été obtenus de manière automatique et reproductible. L’écart type a été divisé par 2 par rapport à l’état de l’art antérieur. Des outils de diamètre inférieur ont été obtenus avec une intervention de l’opérateur, et ce jusqu’à 3 μm de diamètre. Puis ces micro-outils ont été mis en oeuvre pour usiner des pièces avec le procédé de fraisage par microélectroérosion. Pour ce faire, une machine de 2ème génération a été entièrement développée sur la base de travaux antérieurs. Il a été possible d’usiner de l’acier inoxydable dans de l’eau déionisée avec des micro-outils de 3 μm de diamètre sans détérioration de l’outil. Par ailleurs, Le procédé de μEE a été caractérisé en termes de résolution d’usinage, taux d’enlèvement de matière et usure de l’outil. Un générateur de décharges original a permis d’usiner avec des micro-décharges de 1 à 10 nJ / étincelle avec une diminution très sensible de l’usure de l’outil par rapport à l’état de l’art. Un procédé original de caractérisation en ligne des décharges et de cartographie dans l’espace a aussi été développé<br>This work aims at studying Micro Electrical Discharge Milling (μEDM milling), which is a non-contact process allowing machining all hard and electrically conductive materials with a cylindrical ultrathin tool. The principle is based on the creation of electrical micro discharges between the tool and an electrically conductive part immersed in a liquid dielectric. By means of a 3D path, the tool machines a complex shape in the part with high aspect ratio details. In this work, we have firstly improved a process for making cylindrical ultrathin micro-tools by electrochemical etching of tungsten rods. Tools with a diameter of 32.6 ± 0.3 μm and a length of 3 mm have been obtained with an automated and reproducible process. Standard deviation has been divided by 2 by comparison with the previous state of the art. Tools with diameter as low as 3 μm have been fabricated with the help of the machine operator Then these micro-tools have been used for machining parts with the μEDM milling process. To do so, a second generation machine has been entirely developed on the basis of previous work. It has been possible to machine stainless steel in deionized water with 3 μm micro-tools without damaging the tools. In other respects, the μEDM milling process has been characterized in terms of machining resolution, material removal rate and tool wear. An innovative generator of discharges allow machining with 1 to 10 nJ / spark with a reduced tool wear by comparison to the state of the art. An innovative process for the on line characterization of discharges with spatial distribution capability has been developed
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Girardin, Guillaume. "Développement d’un procédé d’usinage par micro-électroérosion." Thesis, Lyon 1, 2012. http://www.theses.fr/2012LYO10315/document.
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L’électroérosion (EE) est une technique d’usinage sans contact de matériaux conducteursd’électricité ; elle particulièrement bien adaptée à l’usinage de matériaux durs. Le principe consiste àcréer des décharges électriques érodantes entre un outil et une pièce à usiner, toutes deuximmergées dans un diélectrique. Dans cette thèse, nous avons étudié la miniaturisation de ceprocédé, la microélectroérosion (μEE), qui se présente comme un procédé complémentaire destechniques de micro-usinage mécanique, laser, ou encore des techniques issues de lamicrotechnologie du silicium (RIE, DRIE, LIGA). Toutefois, la résolution de la μEE est limitée.Dans ce travail, nous avons tout d’abord développé un procédé original d’élaboration de microoutilscylindriques en tungstène par gravure électrochimique. Celui-ci permet d’obtenir de manièrereproductible des micro-outils de diamètre 15 μm et de rapport hauteur sur diamètre supérieur à 50.Des micro-outils plus fins ont aussi été obtenus (jusqu’à 700 nm) mais avec des problèmes dereproductibilité. Par ailleurs, un prototype de machine de fraisage par μEE a été développé avec uneélectronique entièrement caractérisée. Des micro-canaux de 40 μm de largeur ont été obtenus dansl’acier d’inoxydable et 25 μm dans le titane ; une rugosité Ra de 86 nm a été atteinte dans des cavitésde 600 x 600 x 30 μm. Les limitations du dispositif expérimental ont aussi été mises en évidence.Dans la dernière partie de ce travail, nous avons procédé à l’étude des microdécharges et du microplasmas’établissant entre micro-outil et pièce à l’aide de caractérisations électriques. La résistanceet l’inductance des décharges ont été déterminées expérimentalement puis intégrées dans unmodèle permettant de prévoir la durée des impulsions de courant et leur intensité. Des pistes pourl’amélioration de la résolution d’usinage sont proposées en conclusion de ce travail<br>Electro Discharge Machining (EDM) is a non-contact technique allowing machining of electricallyconductive materials; it is well adapted for the machining of hard materials. The principle is based onthe creation of eroding electrical discharges between a tool and a piece, both immersed in adielectric. In this thesis, we have the studied miniaturization of the process, called micro electrodischarge machining (μ-EDM), which is considered as a complementary technique of mechanical orlaser micro-machining techniques and silicon micro technology processes (RIE, DRIE, LIGA)..However, the resolution of μEDM is limited.In this work, we have firstly developed an original method for making tungsten micro-tools withcylindrical profile by electrochemical etching. This method allows the reproducible fabrication ofmicro-tool with 15-μm diameter. Thinner micro-tools were also obtained (down to 700 nm) withreproducibility problems. Furthermore, a prototype machine for milling μ-EDM was developed with afully characterized electronics. Micro channels were obtained respectively in stainless steel with awidth of 40μm and in titanium with a width of 25μm; a surface roughness Ra of 86 nm was achievedin 600 x 600 x 30 μm cavities. Besides, the limitations of the apparatus were highlighted. In the lastpart of this work, we have studied the micro-discharge and the micro-plasma between the micro-tooland the part with electrical characterization. The resistivity and the inductance of the sparks weremeasured and integrated in a numerical model in order to explain the duration of the microdischarges and their intensity. Solutions for improving the machining resolution are also discussed atthe end of this work
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Kalenda, Jan. "Elektroerozívní obrábění při výrobě tvarových dutin." Master's thesis, Vysoké učení technické v Brně. Fakulta strojního inženýrství, 2009. http://www.nusl.cz/ntk/nusl-228789.
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In this diploma thesis is theoretically written about the production of shaped cavities using electroerosive sinking. The possibilities of usage and the production of electrodes for own usage likewise development of technology, tools and machines for electroerosive machining. The quality of machined surface and surface layer using own process of electroerosive sinking of shaped cavities are as well mentioned in this project.
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Kuchařík, Milan. "Drátové elektroerozivní obrábění při výrobě přesných střižných nástrojů." Master's thesis, Vysoké učení technické v Brně. Fakulta strojního inženýrství, 2008. http://www.nusl.cz/ntk/nusl-228030.
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Work is focused on theoretic analisis of manufacturing precise shears tools by unconventional technology closely focused on wire electro discharge machining consideration operation costs of this metod.It is discribing development of this method, machines and tools for electrical discharge machining. It is mention facts influencing quality of cut surface during manufacturing of cutting tools, strategy of cutting workpiece, stage and quality of surface layer after WEDM as long with economic viewpoint and benefits of WEDM technology.
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Jakeš, Jan. "Trendy použití elektroerozivních technologií." Master's thesis, Vysoké učení technické v Brně. Fakulta strojního inženýrství, 2008. http://www.nusl.cz/ntk/nusl-228107.
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In this work, description of a basic principle of electro discharge machining and its technological possibilities was made. Possibilities of individual EDM machine producers and their comparison were described. Furthermore, the use of electro discharge machining in Zdas a.s. was shown. Trends in a development of the electro discharge technology are included, too.
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El-Hofy, H. A. G. "Fundamental studies of electrochemical arc wire machining." Thesis, University of Aberdeen, 1985. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.377368.
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Wong, Ming-ho Horatio, and 黃明浩. "Computer integration of the electrical discharge machining process." Thesis, The University of Hong Kong (Pokfulam, Hong Kong), 2004. http://hub.hku.hk/bib/B30071653.
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Newton, Thomas Russell. "Investigation of the effect of process parameters on the formation of recast layer in wire-EDM of Inconel 718." Thesis, Atlanta, Ga. : Georgia Institute of Technology, 2008. http://hdl.handle.net/1853/22580.
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Ekmekci, Bulent. "Theoretical And Experimental Investigation Of Residual Stresses In Electric Discharge Machining." Phd thesis, METU, 2004. http://etd.lib.metu.edu.tr/upload/1138189/index.pdf.
Full textAbstract:
Electric Discharge Machining (EDM) is a process for eroding and removing material by transient action of electric sparks on electrically conductive materials immersed in a dielectric liquid and separated by a small gap. A spark-eroded surface is a surface with matt appearance and random distribution of overlapping craters. It is mechanically hard and stressed close to ultimate tensile strength of the material and sometimes covered with a network of micro cracks. The violent nature of the process leads a unique structure on the machined surface and generates residual stresses due mainly to the non-homogeneity of heat flow and metallurgical transformations.
An extensive experimental study is presented to explore the surface and sub-surface characteristics together with the residual stresses induced by the process. Layer removal method is used to measure the residual stress profile in function of depth beneath. A finite element based model is proposed to determine residual stresses and compared with the experimental results.
The residual stress pattern is found to be unchanged with respect to machining parameters. Thus, a unit amplitude shape function representing change in curvature with respect to removal depth is proposed. The proposed form is found as a special form of Gauss Distribution, which is the sum of two Gaussian peaks, with the same amplitude and pulse width but opposite center location that is represented by three constant coefficients. In each case, agreement with the proposed form is established with experimental results. Results have shown that these coefficients have a power functional dependency with respect to released energy.
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Ibrahim, Rashidi. "Vibration assisted machining : modelling, simulation, optimization, control and applications." Thesis, Brunel University, 2010. http://bura.brunel.ac.uk/handle/2438/4732.
Full textAbstract:
Increasing demand for precision components made of hard and brittle materials such as glasses, steel alloys and advanced ceramics, is such that conventional grinding and polishing techniques can no longer meet the requirements of today's precision manufacturing engineering. Particularly, in order to undertake micro-milling of optical glasses or other hard-machining materials, vibration assisted machining techniques have been adopted. However, it is essential and much needed to undertake such processes based on a scientific approach, i.e. the process to be quantitatively controlled and optimized rather than carried out with a trial-and-error manner. In this research, theoretical modelling and instrumental implementation issues for vibration assisted micro-milling are presented and explored in depth. The modelling is focused on establishing the scientific relationship between the process variables such as vibration frequency, vibration amplitude, feedrate and spindle speed while taking into account machine dynamics effect and the outcomes such as surface roughness generated, tool wear and material removal rate in the process. The machine dynamics has been investigated including a static analysis, machine tool-loop stiffness, modal analysis, frequency response function, etc, carried out for both the machine structure and the piezo-actuator device. The instrumentation implementation mainly includes the design of the desktop vibration assisted machining system and its control system. The machining system consists of a piezo-driven XY stage, air bearing spindle, jig, workpiece holder, PI slideway, manual slideway and solid metal table to improve the system stability. The control system is developed using LabVIEW 7.1 programming. The control algorithms are developed based on theoretical models developed by the author. The process optimisation of vibration assisted micro-milling has been studied by using design and analysis of experiment (DOE) approach. Regression analysis, analysis of variance (ANOVA), Taguchi method and Response Surface Methodology (RSM) have been chosen to perform this study. The effects of cutting parameters are evaluated and the optimal cutting conditions are determined. The interaction of cutting parameters is established to illustrate the intrinsic relationship between cutting parameters and surface roughness, tool wear and material removal rate. The predicted results are confirmed by validation experimental cutting trials. This research project has led to the following contribution to knowledge: (1) Development of a prototype desktop vibration assisted micro-milling machine. (2) Development of theoretical models that can predict the surface finish, tool wear and material removal rate quantitatively. (3) Establishing in depth knowledge on the use of vibration assisted machining principles. (4) Optimisation of cutting process parameters and conditions through simulations and machining trials for through investigation of vibration assisted machining.
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Wong, Basil T. "THERMAL HEAT TRANSPORT AT THE NANO-SCALE LEVEL AND ITS APPLICATION TO NANO-MACHINING." UKnowledge, 2006. http://uknowledge.uky.edu/gradschool_diss/387.
Full textAbstract:
Nano-manufacturing is receiving significant attention in industry due to the ever-growing interest in nanotechnology in research institutions. It is hypothesized that single-step or direct-write nano-scale machining might be achieved by coupling nano-probe field emission with radiation transfer. A laser may be used to heat a workpiece within a microscopic region that encloses an even smaller nanoscopic region subjected to a focused electron beam. The electron-beam supplies marginal heat sufficient to remove a minute volume of material by evaporation or sublimation. Experimentally investigating this hypothesis requires an estimate of the power needed in the electron-beam. To this end, a detailed numerical study is conducted to study the possibility of using the nano-probe field emission for nano-machining. The modeling effort in this case is divided into two parts. The first part deals with the electron-beam propagation inside a target workpiece. The second part considers the temperature increase due to the energy transfer between the electron-beam and the workpiece itself. A Monte Carlo/Ray Tracing technique is used in modeling the electron-beam propagation. This approach is identical to that of a typical Monte Carlo simulation in radiative transfer, except that proper electron scattering properties are employed. The temperature distribution inside a gold film is predicted using the heat conduction equations. Details of the various numerical models employed in the simulation and a series of representative results will be presented in this dissertation.
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Kaya, Rabi, and Anders Ödling. "Development of an EDM-tool for theNuclear Industry." Thesis, KTH, Maskinkonstruktion (Inst.), 2014. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-156718.
Full textAbstract:
Electric Discharge Machining (EDM) is a machining method suitable for repair and maintenance operations in nuclear power plants. Crack removal and material sampling are two common operations where EDM is used in the nuclear power industry. Each crack removal or material sampling operation is unique, a new EDM-tool is therefore designed for every operation. This, together with the fact that the electrode used in the EDM-tool usually wears out before the crack is removed or the sample has been collected, is the foundation of this thesis. The objective was to develop one or several concepts of a modular EDM-tool with the ability to change electrode at repair location. This to shorten the development time for EDM-tools and the time for electrode change during an EDM operation. The concepts would be developed to the extent that a prototype could be manufactured and tested. The result is in accordance to the objective with one fully developed concept ready for manufacturing. It has not yet been manufactured, and therefore not been tested. There are still some sections of the tool that needs to be verified, for example the electric supply to the electrode. The concept consists of; a slim EDM-tool with the ability to lock the rotating electrode shaft, compact dielectric fluid- and electric-supply, hydraulic actuator with belt drive and an electrode magazine with place for 3 electrodes. Keywords: Nuclear, EDM, Electric Discharge Machining, Product development, Crack removal<br>Electric Discharge Machining (EDM) är en avverkningsmetod lämplig för reparations- och underhållsarbete i kärnkraftverk. Sprickbortagning och materialprovtagning är två vanliga operationer som utförs med hjälp av EDM inom kärnkraftsindustrin. Varje sprickbortagningsoch materialprovtagnings operation är unik, därför utvecklas ett nytt EDM-verktyg inför varje operation. Detta tillsammans med det faktum att elektroden som används i EDM-verktyget ofta slits ned innan sprickan har avverkats eller provet har tagits ligger till grund för detta examensarbete. Målet var att utveckla ett eller flera koncept av modulära EDM-verktyg med möjligheten att byta elektrod på plats där aktuell reparation utförs. Detta för att korta ned utvecklingstiden för nya EDM-verktyg och minska tiden för reparations och underhållsarbeten. Koncepten skulle utvecklas så långt att en prototyp kunde tillverkas och testas. Resultatet är i linje med målet, ett välutvecklat koncept som är redo för tillverkning och testning. Det har än så länge inte blivit tillverkat och således inte testats. Konceptet består av ett smalt EDM-verktyg med möjlighet att låsa elektrodrotationen, kompakt dielektrikum- och ström-tillförsel, hydraulisk aktuator med kuggremsdrift och ett elektrodmagasin med plats för 3 elektroder. Nyckelord: Kärnkraft, EDM, Electric Discharge Machining, Produktutveckling, Sprickborttagning
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Kadermani, Mohamed Munir. "Electrical-static discharge in single point diamond turning machining of contact lens polymers." Thesis, Nelson Mandela Metropolitan University, 2015. http://hdl.handle.net/10948/4055.
Full textAbstract:
Single Point Diamond Turning (SPDT) is a technology widely applied for the fabrication of contact lenses. One of the limiting factors in polymer machining is wear of the diamond tool due to electrostatic discharge resulting in poor surface quality of the machined products. The research work presented in this dissertation highlights the electrostatic properties of contact lenses during machining operations and the effects these properties have on the surface quality of the work piece materials. Two contact lens samples were experimented on, Definitive 74 (Silicone Hydrogel) and Tyro 97 (Rigid Gas Permeable). The electrostatic surface potentials (ESPs) were measured during turning operations using an electrostatic voltmeter and the surface roughness measurements were taken using a surface profilometer. Response Surface Methodology (RSM) techniques were employed to create predictive models for both surface roughness and ESPs with respect to the cutting speed, feed rate and depth of cut. Predictive surface roughness models were successfully generated for both materials and the cutting speed and feed rate were identified as the parameters with most effect on surface roughness. In addition, an electrostatic model was successfully generated for the Definitive 74 contact lens material which cited the cutting speed and feed rate as the most effective parameters on the material’s electrostatic behaviour. However, no relationship was evident between the machining parameters and electrostatic behaviour of Tyro 97.
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Roberts, Bryndan. "Integration of an electrical discharge machining module onto a reconfigurable machine tool." Thesis, Nelson Mandela Metropolitan University, 2014. http://hdl.handle.net/10948/6182.
Full textAbstract:
Electrical Discharge Machining (EDM) is a non-contact manufacturing process in which material is removed from a metal workpiece by high frequency electrical pulses produced between an electrode and the workpiece. EDM machines are usually stand-alone devices, and are quite expensive. The objective of this research was to integrate an EDM machine and an existing reconfigurable CNC machine tool, using a modular approach, to enable conventional milling and EDM to be conducted in a co-ordinated fashion on the same machine tool.
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Golub, Marcia A. "Nano electric discharge machining of gold thin films with a modified scanning tunneling microscope." College Park, Md. : University of Maryland, 2005. http://hdl.handle.net/1903/2545.
Full textAbstract:
Thesis (M.S.) -- University of Maryland, College Park, 2005.<br>Thesis research directed by: Dept. of Electrical and Computer Engineering. Title from t.p. of PDF. Includes bibliographical references. Published by UMI Dissertation Services, Ann Arbor, Mich. Also available in paper.
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Miller, Scott Franklin. "Wire electro-discharge machining of advanced engineering materials." 2003. http://www.lib.ncsu.edu/theses/available/etd-04082003-123221/unrestricted/etd.pdf.
Full text
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Chen, Yu-Hua, and 陳玉華. "Surface Crack Susceptibility of Electro-discharge Machining Process." Thesis, 2003. http://ndltd.ncl.edu.tw/handle/50780014794467635956.
Full textAbstract:
碩士<br>國立成功大學<br>機械工程學系碩博士班<br>91<br>The research is to evaluate the crack susceptibility of EDMed surface by changing the parameters of EDM and material properties. In the beginning of this research, the surface crack susceptibility of JIS SKS93, a high carbon tool steel, was analyzed with EDM parameters：peak current, pulse duration, and duty factor, and then marked a crack critical line (CCL) curve. Furthermore, the type of EDMed surface crack of JIS SNCM439, SCM440, SKS2, SK2, and SKH9, the steel in common use, was generalized and discussed as its relation.
According to the former results, the EDMed surface cracks could be categorized as Pore Crack, Contour Crack, Network Crack, Radiate Form Crack and Arcing Crack. Among them, the former three cracks are assumed as basic types. Radiate Form Crack and Network Crack are thought to occur under long pulse duration processing, and Arcing Crack usually appears due to unstable discharge machining.
The results revealed that a higher peak current could not only improve the material removal rate, but also reduce the surface crack susceptibility. Although the peak current may restrain the density of surface crack, it promoted the cracks to become wider and made the cracks extend into the Heat-Affected Zone as it exceeded 8A. When pulse duration time is below 70μs, the total area of crack reduces with the raise of peak current. Moreover, the larger Duty Factor is, the higher the density of surface crack. The crack widths of various Duty Factors are alike due to the similarity of thickness and the analogy of microstructure of white layer in all conditions. The results also indicate that not only increasing the peak current and shortening the pulse duration time, but also a lower carbon equivalent and a higher thermal conductivity of steel could reduce and improve the surface crack susceptibility. As a conclusion, the steel sequence from low crack susceptibility to high one is low alloy steel, carbon tool steel, high speed steel, cold work steel.
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Wu, Jian-Jihi, and 吳建緻. "The Machining Characteristics of a TiNiAl Ternary Shape Memory Alloy Using Electro-Discharge Machining." Thesis, 2011. http://ndltd.ncl.edu.tw/handle/23516397055480594675.
Full textAbstract:
碩士<br>國立高雄應用科技大學<br>機械與精密工程研究所<br>99<br>This study investigates the influence of the machining characteristics on TiNi-based shape memory alloys (SMAs) using multiple-electrodes in die-sinking EDM. The material’s intrinsic properties and several machining parameters, e.g. the electrode material, electrode polarity, discharge current IP and pulse duration tP, can significantly affect the EDM characteristics. Experimental results reveal that the material removal rates (MRRs) of TiNi-based SMAs in the EDM process exhibit a reverse relationship to the product of the alloy’s melting temperature ( l ) and thermal conductivity (J), i.e., the MRRs will have the sequence Ti50Ni50 >Ti49.4Ni50.2Al0.4 > Ti35.5Ni49.5Zr15. Having a least l*J value, Ti50Ni50 alloy has the largest Ra value and craters diameter, Ti49.4Ni50.2Al0.4 alloy the next largest and Ti35.5Ni49.5Zr15 alloys the smallest after electro-discharge machining. The recast layer consists of the oxides Ti2O3, ZrO2, NiO, TiO and the deposition particles of the consumed Ti electrode and dissolved de-ionized water. The TiO oxides in the recast layer can be identified by XPS and TEM. The hardening effect near the outer surface for EDMed Ti49.4Ni50.2Al0.4 alloy originates from the recast layer. The thickness of the recast layer and the value of contact angle vary with the electro-discharge energy.
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Lin, Yan-Sheng, and 林晏生. "A Study of Insulated Layer on Tungsten Carbide Electrode for Electro-Chemical Machining." Thesis, 2011. http://ndltd.ncl.edu.tw/handle/50730360509218305759.
Full textAbstract:
碩士<br>逢甲大學<br>機械工程學所<br>99<br>In electro-chemical machining, dispersive current distribution on electrode results in poor precision; one effective way to improve this problem is to insulate part of the electrode which makes the electric field concentrate. When cylindrical electrode is used for drilling purposes, pure electrode leads to great deviation in the hole dimension. In contrast, the insulated electrode on the side-wall could concentrate the electric field at
the tip, which improves the processing accuracy.
In this thesis, the sol-gel processing is used to fabricate ceramic insulated layers on cylindrical micro electrode, and dip coating method to fabricate additional epoxy layers. Using ceramic and epoxy as double layer materials, has the advantages of low processing temperature, low cost and easy for batch manufacturing process. In order to evaluate the insulation performance of coated layers, first, use the electro chemical bath to detect the threshold voltage of the layers for electrolysis. Further experiments are conducted by the electro chemical drilling test, and the average pore size, inlet and outlet of the hole deviation and half-cone angle are measured. The results show that ceramic-epoxy double coatings combine the advantages of heat resistance for ceramic and the acid resistance with good insulating properties for epoxy. With the ceramic-epoxy double coatings, the precision of the electro-chemical drilling hole is improved. With the 100μm diameter electrode, the average size reduce from 390.75μm(WC electrode) to 174μm(ceramic-epoxy double coating), inlet and outlet of the hole deviation from 125.5μm to 23.75μm, half-cone angle from the original 3.59° to 0.68°, repeatability
of 60%, deviation value less than 10μm.
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Wu, Wei-Chieh, and 吳瑋榤. "Micro Machining Using Micro-EDM Combined with Electro-codeposition." Thesis, 2006. http://ndltd.ncl.edu.tw/handle/76253981674426257186.
Full textAbstract:
碩士<br>國立中央大學<br>機械工程研究所<br>94<br>Abstract
This study presents a novel process of using micro-electro-discharge-machining (micro-EDM) combined with electro-codeposition to fabricate the micro-grinding-tool to machining a micro-hole on high nickel alloy. During the machining process, a micro-grinding-tool is fabricated by wire electro-discharge grinding (WEDG) and electro-codeposition directly by using micro-EDM for machining the micro-hole and by micro-grinding to finish the hole wall.
The experimental result shows the suitable parameters obtained to fabricating micro-grinding-tool for electro-codeposition are considered to be the following: electric current of 10 mA, hole diameter of positive ring is 5 mm, SiC particle size of 4μm, SiC particle concentration of 10 g/L, rotational speed of 15 rpm and CTAB of 150 ppm. By this method, The micro-grinding-tool will provided with smoothness surface on coating layer, uniform particle distribution and suitable adhesion particle quantity. Finally, the tool feed adopts as 30 μm/min in micro-grinding process, the surface roughness reduces from 1.47 μm Rmax (0.2 μm Ra) to 0.462 μm Rmax (0.026 μm Ra) after micro-grinding.
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呂金昇. "Study of electro-magnetic interference for vertical machining center." Thesis, 2008. http://ndltd.ncl.edu.tw/handle/41877961680351813091.
Full textAbstract:
碩士<br>國立彰化師範大學<br>電機工程學系<br>96<br>As European Union (EU) has many safety regulations on machine tools, machine tool makers in Taiwan should enhance the knowledge of Conformite Europende (CE) declaration required by EU. In CE regulations, the effects of electromagnetic noise to machines may cause damage to operators, or flaws in the products. Therefore, it is the key to help Taiwan machinery makers to follow EU and CE safety requirements. Also, the machine has to fulfill the requirement for electromagnetic interference.
This thesis is focused on electro-magnetic interference to Vertical machining center and develops efficient solutions to market competition and upgrade business level. Finally, the objective of Taiwan machinery industry are the European and Japan advanced markets, in other word, higher profit will go through out European countries and Japan.
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TSUI, Hai-Ping, and 崔海平. "A study on stainless steel machining by using Electro-chemical machining with precise electrophoretic deposition polishing." Thesis, 2008. http://ndltd.ncl.edu.tw/handle/76206647850532888197.
Full textAbstract:
博士<br>國立中央大學<br>機械工程研究所<br>96<br>Surface roughness of the machined parts can be improved by polishing process. Nevertheless, manufacturing polishing wheels with micro abrasive grains, especially those smaller than 1~2 μm, is extremely difficult. When polishing wheels with larger abrasive grains are used in polishing, the polishing marks on the surface of the specimen are wider. The mirror-like surface can not easily obtained. It is more difficult to polish the machined micro holes. In view of such drawbacks, this study aims to enhance the surface quality and precision of machined parts.
In this study, three approaches improve the surface roughness and machining precision of stainless steel plate are proposed. Three approaches are the mirror surface polishing by using the electrophoretic deposition method, Electro-chemical micro drilling (ECMD) by using helical tool, ECMD and Electrophoretic Deposition (EPD) polishing complex micro-hole machining. For the first approach, the experimental results indicate not only that SiC particles of size 0.9~1.5 µm were used in EPD polishing, but also that the initial roughness of the turning and the EDM machined surface could be improved from 0.5 µm Ra and 1.67 µm Ra to 0.03 µm Ra and 0.05μm Ra respectively. The second approach using a micro helical tool as a novel solution in ECMD process to improve the machining accuracy. The reaction products can be squeezed out of the machining zone. The inlet and outlet diameters of the micro holes could be improved from 425 μm and 362 μm using micro cylindrical tool to 355 μm and 299 μm respectively. Finally, ECMD and EPD polishing complex micro-hole machining experiment was performed. The micro helical tool can be deposited with SiC particles in Phenolic Formaldehyde Resin solution as a hybrid micro-tool by electrophoretic deposition phenomenon. The hybrid micro-tool is used in ECMD and EPD polishing complex micro-hole machining.experiments. When the helical tool is used, the inner surface roughness of micro hole is 0.4 µm Ra. When the hybrid micro-tool is used, the inner surface roughness of micro hole declines markedly to 0.041 µm Ra. The inner surface roughness of micro hole can be significantly improved.
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Shyu, Pi-Tsung, and 徐碧聰. "The Electro Mechanical System Integration and Performance of Precision Machining Center." Thesis, 1999. http://ndltd.ncl.edu.tw/handle/68677622471419286977.
Full textAbstract:
碩士<br>國立雲林科技大學<br>機械工程技術研究所<br>87<br>The 3D microelements with dimension from a couple of micron to millimeter have been broadly used in the field of computer, precision instrument and various medicalapplications. The difficulty for making such products obtaining surface roughness under submicro require high precision machining center in level of micron. The high precision micro-EDM can reach the requirement, but the shape complexity and material are limited. For non-metal material, precision machining center are play the main role.
The purpose of the thesis are to integrate the electro mechanical system for a precision machining center of cutting preceding size, and to do the performance analysis of position stage for the precision machining center. To integrate electro mechanical system of the precision machining center include software development of manipulating interface, mechanism design, interface control technique quotation,pipelines allocation of peripheral devices, pneumatic and cooling system. In performance analysis include measurement and analysis of dimensional accuracy, geometry accuracy and dynamic performances for position stage. All the purpose of the research is to develop a precision micro-machining technique for 3D microelement fabrication in the future.
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Huang, Han-Kuan, and 黃瀚寬. "Nano-scale Tip Fabricated by Electro-chemical Machining for Nano Lithography." Thesis, 2014. http://ndltd.ncl.edu.tw/handle/26574672268392141439.
Full textAbstract:
碩士<br>國立雲林科技大學<br>機械工程系碩士班<br>102<br>As integrated circuits shrink, lithography is the main key steps. In order to produce nanoscale dimensions, the mask is very important. It is a important problem to produce mask by low price.
This thesis describes a sub-micron mask production. First to produce Three-dimensional inverted pyramid silicon mold by KOH etching, and then Turn to h-PDMS mold and coat a metal layer and the resist on h-PDMS. We remove the photoresistof the tip by dry etching and produce metal hole by Electrochemical etching. Currently the smallest aperture is 180nm.
A BPL system is successfully constructed to produce different patterns at sub-micrometer scale, with the potential to fabricate complicate patterns in optoelectronic and semiconductor industry.
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Alkhaleel, Abdallah H. "Generating nano-scale features by electro-machining using an atomic force microscope." 2009. http://proquest.umi.com/pqdweb?did=1720911381&sid=10&Fmt=2&clientId=14215&RQT=309&VName=PQD.
Full textAbstract:
Thesis (Ph.D.)--University of Nebraska-Lincoln, 2009.<br>Title from title screen (site viewed October 13, 2009). PDF text: xiii, 127, 11 p. : ill. (some col.) ; 6 Mb. UMI publication number: AAT 3352608. Includes bibliographical references. Also available in microfilm and microfiche formats.
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SHIH-WEI, HSU, and 許世瑋. "Dynamic Thrust Bearing Microfabrication Technique with UV-LIGA and Electro-Discharge-Machining." Thesis, 2003. http://ndltd.ncl.edu.tw/handle/33791033079496498287.
Full textAbstract:
碩士<br>國立臺灣大學<br>機械工程學研究所<br>91<br>The objective of the present thesis is to fabricate the herringbone grooves of dynamic thrust bearing with UV-LIGA and Electro-Discharge-Machining (EDM). The mold of microelectrode is fabricated by SU-8 thick film negative photoresist. Utilizing the microelectrode for EDM can fabricate the microgrooves.
The whole fabrication process of dynamic thrust bearing is divided into three stages, including fabricating SU-8 microstructure, micro electroplating, and EDM. we fabricate 250μm microstructure by SU-8 single layer coating. However, we also experiment on different recipes for soft bake, exposure, electroplate, and EDM processes to optimize machining resolution.
The precision of pattern transferring is discussed in the thesis. After lithography, micro electroplating, and EDM processes, the error of pattern transferring can be controlled within 5%. Therefore we can complete micromachining with complicated pattern in a very short time. Finally, a high efficiency and low cost microfabrication technique has been realized for dynamic thrust bearing.
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朱麒宇. "Development of a penetrating intra-cortical probe array by using micro electro-machining." Thesis, 2014. http://ndltd.ncl.edu.tw/handle/x7g934.
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Hsueh, Tsu-Chun, and 薛祖群. "The Study of parameters discussion of micro-electro tools made by Electrochemical Machining." Thesis, 2014. http://ndltd.ncl.edu.tw/handle/726epb.
Full textAbstract:
碩士<br>國立臺北科技大學<br>機電整合研究所<br>102<br>Using WEDG(Wire Electro Discharge Grinding) with OPED(One Pulse Electro Discharge) can fabricate micro spherical stylus, which is about 40μm in diameter, for Coordinate Measuring Machine(CMM)to use, but WEDG has low-efficiency grinding, and it is quite challenging to grind small-scale electric tools with diameters below 10μm which is easily slanted or broken during the processing stage。Therefore, this research was experimented with Electrochemical Machining(ECM) technique，at first，micro-scale tool was processed using electrochemical corrosion，secondly，super micro spherical stylus was formed using RC discharge method。
But the process of ECM of relative parameters still remain uncertain。
In this study，micro spherical stylus was made by electrochemical complex machining method，exploring the influence of micro spherical stylus made by ECM of processing time、processing speed and electrode rotational motion，hoping to provide reliable parameters to make micro spherical stylus and increase productivity as well as practicality for products。
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吳正仲. "The analysis and application for pulse trains in wire electro-discharge machining process." Thesis, 1997. http://ndltd.ncl.edu.tw/handle/13848329502984554428.
Full textAbstract:
博士<br>國立臺灣大學<br>機械工程學系研究所<br>85<br>Improvement of the machining performance of a wire electrical discharge
machine so as to increase its machining speed and stability is studied.
An approach to discriminate discharge pulses into normal, arc and short
sparks is proposed, and a pulse discriminating system is developed. In
addition, a method to estimate the average discharge gap
distance is established.
The effects of machining settings on the behaviors of pulse trains are
investigated, and they are interpreted physically. Based on the analysis of
pulse trains under various machining conditions, it is found that the energy
consumed per unit metal removal and the short ratio (ratio of the number of
short sparks to the total number of sparks in a specific sampling period)
can be used to evaluate the machining speed and stability of the process.
Fuzzy rules to regulate different circumstances which may occur during the
machining process are then formulated accordingly. Moreover, a spark monitoring
system which can sample and process discharge pulse data on-
line is developed, and a fuzzy control system is
implemented. In order
that a high cutting speed objective can be achieved while at the same time
maintaining the machining stability, feed is adjusted in accordance with the
reference sparking energy level, and off-time is regulated so that short ratio
will not exceed a specific value. By this approach, reference sparking energy
level is the only parameter needs to be provided while off time can be adjusted
automatically. Hence setting of machining conditions is greatly simplified.
This also makes the developed control system applicable to a wide range of
machining conditions. Experiments show that the proposed control strategy
results in very satisfactory transient response and steady state response as
compared with conventional control schemes.
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Woo, Jen Chung, and 吳正仲. "The analysis and application for pulse trains in wire electro- discharge machining process." Thesis, 1997. http://ndltd.ncl.edu.tw/handle/85818173820583732023.
Full textAbstract:
博士<br>國立臺灣大學<br>機械工程學系<br>85<br>Improvement of the machining performance of a wire electrical
discharge machine so as to increase its machining speed
and stability is studied.An approach to discriminate discharge
pulses into normal, arc and shortsparks is proposed, and a
pulse discriminating system is developed. Inaddition, a method
to estimate the average discharge gap distance is established.
The effects of machining settings on the behaviors of pulse
trains areinvestigated, and they are interpreted physically.
Based on the analysis ofpulse trains under various machining
conditions, it is found that the energy consumed per unit metal
removal and the short ratio (ratio of the number of short sparks
to the total number of sparks in a specific sampling period)can
be used to evaluate the machining speed and stability of the
process. Fuzzy rules to regulate different circumstances which
may occur during the machining process are then formulated
accordingly. Moreover, a spark monitoringsystem which can sample
and process discharge pulse data on-line is developed,
and a fuzzy control system is implemented. In order that a high
cutting speed objective can be achieved while at the same
timemaintaining the machining stability, feed is adjusted in
accordance with thereference sparking energy level, and off-time
is regulated so that short ratiowill not exceed a specific
value. By this approach, reference sparking energylevel is the
only parameter needs to be provided while off time can be
adjustedautomatically. Hence setting of machining conditions is
greatly simplified.This also makes the developed control system
applicable to a wide range ofmachining conditions. Experiments
show that the proposed control strategyresults in very
satisfactory transient response and steady state response
ascompared with conventional control schemes.
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Yu-Feng, Chang, and 張裕峰. "Study on the Technical Process of Fabricating Nano-Porous Silicon Structure Using Electro-Chemical Machining." Thesis, 2007. http://ndltd.ncl.edu.tw/handle/20181561999114883634.
Full textAbstract:
碩士<br>崑山科技大學<br>機械工程研究所<br>95<br>Recently the nano-technology was rapidly developed. The demanding needs of nano-scale materials were required more and more in the industrial. Therefore, it is important to investigate the fabrication process and method of nano-structure materials. Owing to the nano-porous structure material has some unique physical characteristic, likes larger ratio of surface area and volume, adjustable energy gap and high sensitivity properties, thus the porous material is very suited to become the raw material of the optical-electric components and micro-sensors. In another hand, the porous diameter and depth of nano-porous structure material can be improved more effectively by way of adapting non-traditional machining in fabrication.
After researching and reviewing the references, we conclude that the generous research used for fabrication of porous structure are all adapt either in horizontal or vertical electro-chemical reaction tanks, both have shown some discrepancy were not able to precisely control the corrosion area, density of electrical current and the distance between silicon and electrode. In order to control more precisely the parameters of experiment and refer mentioned above about the advantage and discrepancy of both chemical reaction tanks, the “modified electro-chemical reaction tank”, made of PTFE material, is developed to be experienced and verified the effect of tightness, corrosion, and operation. The modified vertical chemical reaction tank not only can prevent the leakage of HF solution but also is capable of controlling the parameters of nano-porous structure experiment more precisely. Then, Taguchi Method L9 orthogonal array were employed to layout experiment arrangement, and placed the silica wafer in the HF solution with electric current flowed into the solution in order to observe the results of its chemical action. The silica wafer was developed to porous structure due to corrosive action in the anode pole and all relative results could be acquired by utilizing the micro-balance and SEM. After calculating the S╱N ratios under various factors and levels, response tables and diagrams were generated as well as the main influencing and the optimal combination of parameters in fabricating of porous structure by electro-chemical. Based on the results of ANOVA analysis, the variation, deviation, and degree of contribution of parameters were found. Finally the optimal combination of parameters must be confirmed by confirmation experiment.
Based on the results of experiment, the porous silicon was influenced by the machining parameters of electro-chemical machining. The different type porous silicon will be obtained under different machining parameters. The machining parameters of electro-chemical machining included of the concentration of HF solution, the density of current, the distance between electrode and silicon wafer and the resistance of work piece. The poor machining parameters of electro-chemical machining will be produced failure porous structure or induced electro-polishing. The porous silicon, made by electro-chemical machining, with high optical performance could use as the electrical-optical components. In this study, we use the modified electro-chemical reaction equipment to obtain the main influencing parameter with Taguchi method, and it is effect to save experimental time and cost.
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LI, MING-HSING, and 李明興. "Fabrication for Curved Airfoil of Turbofan Engine by Multi-Axis Electro Discharge Machining on Inconel-718." Thesis, 2013. http://ndltd.ncl.edu.tw/handle/87cs57.
Full textAbstract:
碩士<br>國立高雄應用科技大學<br>模具系碩士在職專班<br>101<br>This research is about processing an aviation engine product made from Inconel -718 material that has 88 curved air foils by applying key experimental processes like 7-axial EDM and abrasive flow grinding.These experimental processes of have proved their feasibility of manufacturing aerospace turbine engine blades through the following inspections:1.CMM inspection was used to determine the size and geometrical dimensions of the 88 air foil side section (about 10 different sections from section C-C to M-M),such as leading edge thickness, maximum thickness, trailing edge thickness, contours,twist angles, and wing chord length.All the measurement data are determined to be within the dimension tolerances and conforming to the blueprint requirements after careful review and analysis.According to the process capability index analysis like Cpk and Cp, only section J-J and K-K process have an index number below 1.33 and need to be improved.All other geometrical section has an index number greater than 1.33 and showing the process stability meets the requirement.2.After 7-axial EDM and abrasive flow process, roughness inspection was done on the coupons of the front section air foil (10th airfoil), middle section air foil (44th airfoil) and back section air foil (88th airfoil).The roughness result is within Ra 8.4 µin, a value that is much better than the product requirement of Ra 32 µin.Microstructure inspection is also done by using optical microscope (OM) to check for recast layer and micro-cracks.None of the recast layer and micro-cracks was observed during the inspection and therefore meets the air foil surface microstructure requirements.By combining the inspection results listed above,it demonstrates that this experimental manufacturing process is able to replace the electro-chemical machining used in other countries comes that has high environmental impacts,and successfully introduced this product to domestic manufacturing.