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1
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.
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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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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.
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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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Stephenson, Richard C. "Comparing the Feasibility of Cutting Thin-Walled Sections from Five Commonly Used Metals Utilizing Wire Electric Discharge Machining." Diss., CLICK HERE for online access, 2007. http://contentdm.lib.byu.edu/ETD/image/etd1948.pdf.
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Rashid, Asif Bin. "An Experimental and Theoretical Study of Developing Methods for Machining Ceramic Materials by Electrical Discharge Machining (EDM) Process." Miami University / OhioLINK, 2020. http://rave.ohiolink.edu/etdc/view?acc_num=miami159426017923493.
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Blom, Ricky J. "Production and evaluation of rapid tooling for electric discharge machining using electroforming and spray metal deposition techniques." Thesis, Queensland University of Technology, 2005. https://eprints.qut.edu.au/16014/1/Ricky_Blom_Thesis.pdf.
Full textAbstract:
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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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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Alavi, Farshid. "Optimization of Process Parameters in Micro Electrical Discharge Machining (EDM) of TI-6AL-4V Alloy." TopSCHOLAR®, 2016. http://digitalcommons.wku.edu/theses/1568.
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Ti-6Al-4V has a wide range of applications such as in the automotive and aerospace industries. Nevertheless, titanium alloys are very difficult to machine by conventional methods. Micro-EDM is a non-conventional machining method that uses the thermal effect of precisely controlled sparks. Manufacturers are looking for the methods and optimal settings to increase the productivity of micro-EDM in terms of lessening machining time and tool wear. Moreover, surface integrity of the machined area is crucial for some products such as biomedical implants.
The objective of this study was to investigate the effects of the micro-EDM process parameters on response variables, in order to understand the behavior of each parameter as well as to determine their optimal values. Although, there is a substantial amount of literature studying different aspects of micro-EDM, most of them were designed based on the one-factor-at-a-time experiments instead of studying all factors, simultaneously. This research was conducted through a series of experiments using a full factorial design. An analysis of variance was employed to analyze the findings and to determine the effect and significance of each process parameters on the response variables.
The process parameters included voltage, capacitance, electrode rotational speed, and electrode coating. Voltage and capacitance were studied separately as well as in combination in terms of the discharge energy. Response variables consisted of machining time, tool wear, crater size, microhardness, and element characterization. The surface morphology and element characterization were studied through the application of SEM and EDS analysis.
The findings indicated that voltage had a decreasing effect on machining time, while it increased the crater size. Capacitance decreased machining time and tool wear. It had an increasing effect on the surface hardness. The effects of the TN-coating and electrode rotational speed were not statistically significant. Voltage and capacitance were the only parameters affecting element characterization. The affected elements included Ti, Al, C, and W. The optimal process parameters for two sets of response variables were determined using Minitab 17.
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Habovštiaková, Mária. "Elektroerozivní drátové řezání technické keramiky." Master's thesis, Vysoké učení technické v Brně. Fakulta strojního inženýrství, 2020. http://www.nusl.cz/ntk/nusl-417109.
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The presented diploma thesis deals with the issue of wire electrical discharge machining of SiSiC ceramics. The first part explains the principles of electrical discharge machining, describes the WEDM technology and presents the properties of the advanced ceramics. The second part consists of a detailed analysis of the cutting process of eighteen samples obtained with systematically changing process parameters. Based on the obtained results from EDX analysis, SEM electron microscopy and topography there was performed an analysis of the influence of process parameters on the cutting speed, surface roughness, kerf width and number of wire breaks with usage of the selected brass cutting wire. From the evaluated results it was possible to select a combination of parameters that ensured a stable machining process.
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Mouralová, Kateřina. "Trendy použití nekonvenční technologie elektroerozivního drátového řezání." Master's thesis, Vysoké učení technické v Brně. Fakulta strojního inženýrství, 2010. http://www.nusl.cz/ntk/nusl-229121.
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The aim of this dissertation are future trends of electrical discharge machining in conditions of a small tool factory. In the introduction is presented the theory of non-conventional machining. The practical part is focused on valuation the current level of electrical discharge machining, the importance of the use in a tool Nástrojárna Ryšavý. It also compares the level of leading global manufacturers of electrical discharge machines and future trends of electro-discharge technology.
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Macháčová, Veronika. "Rozbor výsledků z experimentálního elektroerozivního hloubení speciálních materiálů pro letecký průmysl." Master's thesis, Vysoké učení technické v Brně. Fakulta strojního inženýrství, 2020. http://www.nusl.cz/ntk/nusl-417090.
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The aim of this master's thesis is experimental electric discharge sinking of special materials for the aerospace industry. The first part is a general overview regarding the technology of electric discharge machining with emphasis on electric discharge sinking. Following this is a practical part devoted to the electric discharge sinking of the Nimonic 263 material with a copper tool electrode with a subsequent evaluation of surface and subsurface changes in this material. The wear of the tool electrode is also examined with the conclusion highlighting combination of machined material and tool electrode material behave in different working conditions and how the surface layer of machined material is affected.
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Kim, Sangseop. "Determination of Wall Thickness and Height when Cutting Various Materials with Wire Electric Discharge Machining Processes." BYU ScholarsArchive, 2005. https://scholarsarchive.byu.edu/etd/294.
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This thesis looks at the capabilities of cutting thin webs on Wire EDM machines that are difficult or impossible to machine using conventional methods. Covered is an investigation of how different material and web thickness affect the capability of machining thin-walled parts.
Five different metals are used for the test; Aluminum 6061 T6, Yellow Brass SS360, 420 Stainless Steel, D2 unheat-treated tool steel 25-30 RC, and D2 heat-treated tool steel 60-65 RC. The small parts were cut to a 6mm (0.2362 inch) height with six different wall thicknesses: 0.30mm (0.0118 inch), 0.25mm (0.0098 inch), 0.20mm (0.0078 inch), 0.15mm (0.0059 inch), 0.10mm (0.0039 inch), and 0.05mm (0.0020 inch). A Sodick AQ325L Wire EDM machine was utilized for testing.
The methods employed during the study include the following:
• Machine settings and offsets were limited to the default setting selected from the Sodick AQ325L database.
• Two different pre-test cuts were taken on the material to check for web bending during the cutting process.
• Hardness was tested for comparison of the web heights.
This thesis shows that bending increased as webs became thinner and that bending occurred toward the wire as the second side of the web was cut. Bending does affect the height of the web. Physical properties of materials also impacted the height of the web with the hardest material staying intact during the cutting process. This study shows that two factors, physical properties of materials and web thickness, significantly affect cutting results for thin web parts.
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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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Barabáš, Martin. "Aplikace technologie drátové elektroeroze." Master's thesis, Vysoké učení technické v Brně. Fakulta strojního inženýrství, 2014. http://www.nusl.cz/ntk/nusl-231508.
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This marter’s thesis deals with the technology of electrical discharge wire cutting. There is described the basic nature of the electrical erosion, EDM principle and WEDM principle. The main part deals with the application of wire cutting in the manufacture pulley 68-8M-130 with a description of technology on the wire cutter Excetek V 650. At the end of the work is devoted to the statistical evaluation of the precision machined surfaces.
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Qu, Jun. "Development of Cylindrical Wire Electrical Discharge Machining Process and Investigation of Surface Integrity and Mechanical Property of EDM Surface Layers." NCSU, 2002. http://www.lib.ncsu.edu/theses/available/etd-20020325-173441.
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<p>The cylindrical wire Electrical Discharge Machining (EDM) process was developed to generate precise cylindrical forms on hard, difficult-to-machine materials. A precise, flexible, and corrosion-resistant underwater rotary spindle was designed and added to a conventional two-axis wire EDM machine to enable the generation of free-form cylindrical geometries. A detailed spindle error analysis identified the major source of error at different frequencies. The mathematical models for material removal rate and surface finish were derived. Experimental results indicated that higher maximum material removal rate might be achieved in the cylindrical wire EDM than the 2D wire EDM. Effects of some key process parameters, wire feed rate, pulse on-time and part rotational speed, on the surface finish and roundness are explored. For WC-Co parts, an arithmetic average surface roughness and roundness as low as 0.68 and 1.7 mm, respectively, can be achieved. Surfaces of the cylindrical EDM parts were examined using Scanning Electron Microscopy (SEM) to identify the macro-ridges and craters on the surface. Cross-sections of the EDM parts are examined using the SEM to quantify the recast layer and heat-affected zone under various process parameters. This study also used nanoindentation to investigate the influence of cylindrical wire EDM process on the mechanical properties of WC-Co composite. Multiple indents were conducted on the cross-section of the recast layer, heat-affected zone, and bulk material. The SEM micrographs were used to correlate the individual nano-indent to the measured hardness and modulus of elasticity. The experimental results showed that the heat-affected zone had more compact microstructure less indentation cracking. The recast layer had lower hardness and modulus of elasticity than the original material and heat-affected zone. EDS X-ray and X-ray diffraction were used to analyze the material compositions of the heat-affected zone and recast layer and to understand the effects of wire EDM process on the machined WC-Co surface. The micro-blasting process has been applied to improve the surface integrity of the part machined by wire EDM. The surface roughness of WC-Co parts could be reduced significantly using micro-size SiC abrasives. The surface finish improvement was also shown by the SEM micrographs of the blasted surfaces and their cross-sections. The undesired recast layer, which has poor mechanical properties and irregular features, was eventually removed by micro-blasting. Compressive residual stress introduced by micro-blasting could increase the surface wear resistance. Experiments with different process parameters were conduced to study the efficiency and effectiveness of micro-blasting for surface property control. <P>
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Prokeš, Tomáš. "Optimalizace řídicích parametrů EDM stroje." Doctoral thesis, Vysoké učení technické v Brně. Fakulta strojního inženýrství, 2021. http://www.nusl.cz/ntk/nusl-446793.
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The dissertation thesis is focused on the optimization of control parameters of an EDM machine; the subject of optimization is cutting speed and surface topography. The first part of the thesis contains a research study on the technology of electrical discharge machining with the attention paid to the optimization methods use for control parameters of this process. The second part of the thesis is focused on real application of knowledge gained from studied sources. Here, a design of experiment aim at optimizing the parameters of the EDM machine is designed and carried on to maximize the cutting speed with the highest possible surface quallity. The result of the work is to build adequate regression models and find the optimal setting of machine control parameters.
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Svoboda, Jiří. "Nekonvenční technologie elektroerozivního drátového řezání." Master's thesis, Vysoké učení technické v Brně. Fakulta strojního inženýrství, 2010. http://www.nusl.cz/ntk/nusl-229332.
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This thesis deals with technology of electric discharge machining with emphasis on application of the principle of material removal on wire cut electric discharge machine. The main part is concentrated on wire cut electric discharge machining in terms of a small tool making shop. The goal of the thesis is to create a wire cut electric discharge machining workplace in the company with a focus on the production of cutting tools. The thesis defines requirements for each component of cutting tools and strategies for their machining. Machining of model part and subsequent technical - economic evaluation is included in the final part.
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Bednář, Šimon. "Materiál elektrod pro elektroerozivní obrábění." Master's thesis, Vysoké učení technické v Brně. Fakulta strojního inženýrství, 2018. http://www.nusl.cz/ntk/nusl-378984.
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Diplomová práce se zabývá problematikou volby grafitového materiálu využívaného pro výrobu nástrojových elektrod při elektroerozivní obrábění. Práce je rozdělena do třech částí. Teoretická rešerše nekonvenční technologie elektroerozivního obrábění vypracovaná dle uvedených zdrojů se nachází v první části práce. Dále je v práci proveden cenový průzkum EDM grafitových materiálů nabízených v České republice a na Slovensku. Čtyři odlišné stupně kvality grafitu (od stávajícího dodavatele firmy GAMARTIS TRADE s.r.o.) a jeden měděný materiál byly podrobeny experimentu, jehož účelem bylo zjištění závislosti mezi kvalitou grafitového materiálu (cena) a přesností vyhloubené kavity, opotřebením nástrojové elektrody, časem obrábění nebo také drsností povrchu.
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Santhosh, Sandhya. "Determination of surface finish and Metal Removal Rate by varying parameters in wirecut Electrical Discharge Machining and optimizing using genetic algorithm." Master's thesis, Alma Mater Studiorum - Università di Bologna, 2017.
Find full textAbstract:
Wire Electric Discharge Machining (WEDM) is one of the greatest innovations in the tooling and machining industry. This process has brought dramatic improvements in accuracy, quality, productivity and earnings. Before wire EDM, costly processes were often used to produce finished parts. Now with the aid of computer and wire EDM machines, extremely complicated shapes can be cut automatically, precisely and economically even in materials as hard as carbide. The selection of optimum machining parameters in WEDM is an important step. Improperly selected parameters may result in serious problems like short-circuiting of wire, wire breakage and work surface damage which is imposing certain limits on the production schedule and also reducing productivity.
The objective of the present work is to investigate the effects of the various Wire cut EDM process parameters on the surface quality, maximum material removal rates and obtain the optimal sets of process parameters so that the quality and MRR of machined parts can be optimized. Experiments will be conducted on the pieces by parameters. The material used for machining is Aluminium alloy. The process parameters considered are Pulse Time on, Pulse Time off, Input Power, Wire Feed, Servo Voltage and Wire Tension. The optimization will be done by using Genetic Algorithm.
The above work is performed in English at WinWill Technical Services, located in Hyderabad, India, for a period of 4months.
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Sedláček, Jiří. "Drátové elektroerozivní obrábění při výrobě nástrojů pro dřevoobrábění." Master's thesis, Vysoké učení technické v Brně. Fakulta strojního inženýrství, 2008. http://www.nusl.cz/ntk/nusl-228096.
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My thesis is aimed at the application of wire electical discharge machining technology in the production of woodworking tools. All of this in the conditions of Vydona company. There is a theory of machining method plus a well-aranged division of cutter tools for wood in the introduction. The practical part describes in detail the procedur of cutting shaped plate out of tungsten carbide. As a result of the technical and at the same time the economic evaluation is an establishment of hourly rate for machine.
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Galko, Adam. "Technologie drátového elektrojiskrového obrábění." Master's thesis, Vysoké učení technické v Brně. Fakulta strojního inženýrství, 2017. http://www.nusl.cz/ntk/nusl-318392.
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This thesis talk about practical application of wire electrical discharge machining (WEDM), which belongs to electro-erosion machining methods. This thesis is focused on the production of cutting dies produced by company FOR MIX s.r.o. Trenčín. We can consider the cutting die as a typical product of company´s product program. In the practical part of this diploma thesis, there is detail of technological aspects and operating costs for wire electrical discharge machining technology in specific condition of company FOR MIX s.r.o.
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Brázda, Radim. "Technologie elektrojiskrového drátového řezání." Master's thesis, Vysoké učení technické v Brně. Fakulta strojního inženýrství, 2013. http://www.nusl.cz/ntk/nusl-230788.
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This master´s thesis deals with unconventional technology of wire electrical discharge machining. There are described the principles and essence of electrical discharge machining and the principles related to wire electrical discharge machining with emphasis on the application of this technology in terms of medium-sized engineering company. There is also described the complete assembly of technolgy wire cutting and machining on wire cutter Excetek V 650. Then in the work there are statistically evaluated parameters precision machined surfaces, specifically to the belt pulley 116-8M-130. At the end of the work there is the technical-economic evaluation that addresses the hourly cost of machining on wire cutter Excetek V 650.
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Slouka, Radim. "Aplikace technologie elektroerozivního drátového řezání." Master's thesis, Vysoké učení technické v Brně. Fakulta strojního inženýrství, 2011. http://www.nusl.cz/ntk/nusl-229412.
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This master´s thesis focuses on the basic principles of the nonconventional technology of electrical discharge machining (EDM) with an emphasis on wire-cut electrical discharge machining performed in a mediumsized company. The thesis deals with manufacture of a belt pulley 75-8M-130, and checks of accuracy of wire-cut EDM machines. Following the study of the current status of electrical discharge machining in the engineering company, measures for assurance and increase of accuracy of wire-cut EDM machines are proposed.
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Tichý, Štěpán. "Technologie drátové elektroeroze." Master's thesis, Vysoké učení technické v Brně. Fakulta strojního inženýrství, 2015. http://www.nusl.cz/ntk/nusl-231987.
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This master’s thesis deals with technology of wire electrical discharge machining in theoretical and practical level. Theoretical part of the thesis explains in detail the principle of electrical discharge machining, describes functional parts and settings of a current wire EDM machines and also the possibility of using method for production of specific parts. Practical part of the thesis solves manufacturing of gearing on pinion manufactured by wire cutter EXCETEK V650 and statistically evaluates precision parameters on surfaces of the carriers taken by specific technological conditions with the same machine.
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Kudrna, Tomáš. "Elektroerozivní hloubení technické keramiky." Master's thesis, Vysoké učení technické v Brně. Fakulta strojního inženýrství, 2020. http://www.nusl.cz/ntk/nusl-417445.
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The master’s thesis deals with the topic of electrical discharge machining. The first part of the thesis contains a study of the die-sinking EDM. The die-sinking EDM of the silicon carbide ceramic is realized in the experimental part of the thesis. The result of this work was to explore the influence of the EDM sinking parameters, specifically pulse current, open-voltage and pulse on-time, on the machined surface. Furthermore, the analysis of the tool electrode was made. This analysis was focused on the wear in the corners, which has key influence on accuracy of the machining. The machining time was also examined.
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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.
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Yahya, Azli. "Digital control of an electro discharge machining (EDM) system." Thesis, Loughborough University, 2005. https://dspace.lboro.ac.uk/2134/13655.
Full textAbstract:
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.
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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.
Full textAbstract:
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).
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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.
Full text
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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.
Full textAbstract:
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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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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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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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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MERLA, Cristina. "Evaluation of Micro Electro Discharge Machining Performance: the Effect of Process Parameters and Electrode Material." Doctoral thesis, Università degli studi di Bergamo, 2015. http://hdl.handle.net/10446/48730.
Full textAbstract:
The miniaturization of components enhances the difficulties related to their production with conventional technologies. At the same time this miniaturization trend opens the possibility to employ new non-conventional technologies that, like micro-EDM, are able to fulfil the market requirements and the technological challenges associated with the realization of micro components.
Micro-EDM is able to machine any conductive material regardless of the hardness and high strength of the workpiece material and, thanks to the contact-less nature of the process, it leaves no residual stresses in the workpiece. This technology allows the realization of high aspect ratio micro features, especially micro holes, with an excellent surface finishing. The influence of the process parameters is of great importance for an effective control of the wear phenomenon and also because they have an influence on the final geometrical characteristics of the through holes and on the process performances.
The aim of the present work is to deepen the knowledge about the influence of the process parameters on the final geometrical characteristics of the holes and on the process performances.
A signal acquisition system, aimed at the recording and filtering of the process parameters, was implemented. The data collected with the acquisition system has been analysed, in order to obtain reliable information about peak current, peak voltage, number of sparks, energy and power exchanged during the process.
Once the data has been collected for all the electrode materials and diameters and for all the process parameters combinations, a regression analysis has been carried out. Predictive linear and non-linear equations based on the measured values of the process parameters were obtained in order to forecast the machining time and the electrode wear, as well as the geometrical characteristics of the holes.
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Treurnicht, N. F. "High speed cutting and electric discharge machining as complementary processes in the die and mould industry." Thesis, Stellenbosch : Stellenbosch University, 2003. http://hdl.handle.net/10019.1/53448.
Full textAbstract:
Thesis (MScEng) -- Stellenbosch University, 2003.<br>ENGLISH ABSTRACT: High Speed Cutting (HSC), specifically milling is a significant contemporary development in
machining. The Die and Mould industry is experiencing a difficult business climate. There
is competitive pressure for shorter lead times and lower prices. Companies worldwide, are
under financial pressure, to meet the challenges of a globalised business environment.
The conventional position of milling and Electric Discharge Machining (EDM / Erosion) is
discussed with the proposal to use HSC and EDM as complementary processes. Among
new developments the progress in computer infrastructure is prominent. There is also a
paradigm shift that should be made from experience based process planning to modern, up
to date knowledge based process planning. High Speed Cutting is now a mature process
capable of acceptable process security. The examples detailed include crankshaft-forging
tooling, injection moulding tooling and powder sintering tooling. A process chain is proposed
for the complementary HSC / EDM process with estimated illustrative time saving over the
conventional EDM dominated process. HSC will be the first process removing the bulk of
the material, finishing as far as possible and with EDM finally machining the features that will
be difficult or impossible with HSC.
To facilitate the use of the complementary processes a decision model to determine the
crossover point between HSC and EDM is proposed. The decision model is firstly
presented as a flow diagram to determine whether the task is a candidate for HSC only, EDM
only, or the complementary HSC / EDM process. The key parameters e.g tool H d ratio are
variables. This is in order that the flow diagram may be adapted to a specific machine tool
infrastructure and expertise level in a company. The second part is a HSC machining time
estimation model. The time is estimated per segment roughed, semi-finished, or finish
machined. The model is in an empirical form with constants that can be adapted to the
practices of a specific company. It is intended that the constants also be periodically revised
to reflect the development in HSC expertise that will occur during the use HSC in the
company. The model is practically evaluated with a case study, including the detail steps,
not included in the model. Conceptual guidelines are given for software implementation.
It is concluded that HSC and EDM are suitable complementary processes. It is a necessary
prerequisite to use pallets to avoid multiple set-ups. Complementary HSC and EDM is
especially appropriate for the gradual deployment and skill development for HSC. HSC and
complementary HSC / EDM is considered the opportunity for companies to make a major
breakthrough in lead time and operating expense if the necessary pallet/fixturing equipment,
CAx infrastructure and human capability is available.<br>AFRIKAANSE OPSOMMING: Hoe Spoed Masjinering (HSC), spesifiek frees is ‘n betekenisvolle ontwikkeling in
masjinering. Die Gereedskap en Gietvorm bedryf ervaar ‘n moelike besigheidsklimaat.
Daar is kompeterende druk vir korter lewertye en laer pryse. Maatskappye wereldwyd is
onder finansiele druk om in die geglobaliseerde besigheidsmilieu te presteer.
Die posisie van frees en Elektriese Ontladingsmasjinering (EDM / Vonkerosie) word
bespreek met die voorstel om HSC en EDM as komplementere prosesse te gebruik. Onder
die nuwe ontwikkelings is daar prominente vooruitgang in rekenaarinfrastruktuur. Daar is
ook ‘n paradigmaverskuiwing nodig van ondervinding gebaseerde na op datum kennis
gebaseerde proses beplanning. HSC is nou ‘n ontwikkelde proses met voldoende
prosessekerheid. Die voorbeelde sluit krukas smee gereedskap, inspuitgiet gereedskap, en
poeier-sinter persgereedskap in. ‘n Prosesketting word voorgestel vir die komplementere
HSC / EDM proses met ‘n beraamde illustratiewe tydbesparing oor die konvensionele EDM
gedomineerde proses. HSC sal die eerste proses wees wat die meerderheid van die
materiaal verwyder en oppervlaktes so ver as moontlik afwerk, met EDM wat die finale
afwerking doen en ook die masjinering wat vir moeilik haalbaar of onmoontlik is vir HSC.
Om die gebruik van die komplementere prosesse te fasiliteer, word ‘n beluitnemingsmodel vir
die oorgangspunt tussen HSC en EDM voorgestel. Dit word eerstens as vloeidiagram
gebruik om die taak te klassifiseer vir HSC alleen, EDM alleen of vir komplementere HSC en
EDM. Die sleutelparameters, bv die beitel 116 verhouding, is veranderlikes. Dit is sodat
die vloeidiagram aangepas kan word by ‘n spesifieke masjienvermoe en ‘n kundigheidsvlak
in ‘n maatskappy. Die tweede deel is ‘n HSC masjineringstyd model. Die tyd word beraam
per segment uitgerof, afgewerk, of finaal afgewerk. Die model is in empiriese vorm met
konstantes wat kan aangepas word by die praktyke van ‘n firma. Dit is die bedoeling dat die
konstantes periodiek aangepas word om die ontwikkeling te weerspieel wat in die
maatskappy plaasvind. Die model word prakties evalueer met ‘n gevallestudie, insluitend
die detailstappe, wat nie in die modelformulering ingesluit is nie. Konseptuele riglyne word
gegee vir programmatuur implementering.
Die gevolgtrekking word gemaak dat HSC en EDM geskikte komplementere prosesse is.
Dit is ‘n voorvereiste om pallette te gebruik om veelvuldige opstellings te vermy.
Komplementere HSC / EDM is veral toepaslik om HSC geleidelik in ‘n firma te ontplooi en
kundigheid te bou. Die HSC / EDM kombinasie word ook die geleentheid geag vir firmas om
‘n deurbraak te maak in lewertyd en bedryfsuitgawes as die nodige pallettoerusting, CAx
infrastruktuur en menslike vermoe beskikbaar is.
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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.
Full textAbstract:
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.
36
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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Smith, Jr Philip T. "CAPACITANCE METROLOGY OF CURVED SURFACES: STUDY AND CHARACTERIZATION OF A NOVEL PROBE DESIGN." UKnowledge, 2007. http://uknowledge.uky.edu/gradschool_diss/570.
Full textAbstract:
Capacitive sensors are frequently applied to curved target surfaces for precision displacement measurements. In most cases, these sensors have not been recalibrated to take the curvature of the target into consideration. This recalibration becomes more critical as the target surface becomes smaller in comparison to the sensor. Calibration data are presented for a variety of capacitance probe sizes with widely varying geometries. One target surface particularly difficult to characterize is the inner surface of small holes, less than one millimeter in diameter. Although contact probes can successfully measure the inner surface of a hole, these probes are often fragile and require additional sensors to determine when contact occurs. Probes may adhere to the wall of the hole, and only a small number of data points are collected. Direct capacitance measurement of small holes requires a completely new capacitance probe geometry and method of operation. A curved, elongated surface minimizes the gap between the sensor surface and the inner surface of the hole. Reduction in the size of the sensing area is weighed against electronics limitations. The performance of a particular probe geometry is studied using computer simulations to determine the optimal probe design. Multiple, overlapping passes are deconvolved to reveal finer features on the surface of the hole. A prototype sub-millimeter capacitance probe is machined from tungsten carbide, with four additional material layers added using ebeam deposition. Several techniques are studied to remove these layers and create a sensing area along one side of the probe. Both mechanical processes and photolithography are employed.
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Bartoš, Pavel. "Elektroerozivní drátové řezání." Master's thesis, Vysoké učení technické v Brně. Fakulta strojního inženýrství, 2011. http://www.nusl.cz/ntk/nusl-229873.
Full textAbstract:
This work deals with analysis of EDM wire cutting technology and aims to assess the current situation and the real possibilities of EDM wire cutting usage in a small engineering company. Furthermore, it addresses manufacturing technology of a model component and the subsequent economic evaluation.
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Dahmani, Rabah. "Optimisation d’un procédé d’usinage par microélectroérosion." Thesis, Lyon 1, 2015. http://www.theses.fr/2015LYO10058/document.
Full textAbstract:
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.
Full textAbstract:
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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Kalous, Ondřej. "Racionalizace technologie výroby forem." Master's thesis, Vysoké učení technické v Brně. Fakulta strojního inženýrství, 2014. http://www.nusl.cz/ntk/nusl-231505.
Full textAbstract:
The diploma thesis Rationalization technology of production tools is divided into two parts. The first part is focused on injection molding of plastic materials and analysis current status of production injection tools. The second part contains proposal of rationalization steps in the production process and evaluation of rationalization.
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Wen-Ming, Sheen, and 沈文銘. "The Study of Electric Discharge Machining Mold with ECM." Thesis, 1995. http://ndltd.ncl.edu.tw/handle/64385742991279708139.
Full textAbstract:
碩士<br>國立雲林科技大學<br>機械工程技術研究所<br>83<br>The electrolytic machining can be called electrochemical mach-
ining (ECM);It is install the metal workpieces at anode pole
and fixed the tool to cathode pole, when an electric current
is passed between two poles dipped into a liquid solution (elec
-trolysis) then obtain the shape、size and surface status that
we need from anode. The elect-rolytic polishing is surface
treatment technique of ECM.
In this context is discussion the factor of ECM by experiment,
The factor such as electrolytic time、current density、current
wave、even the kind and concentration of electrolysis etc.,
When the factors be various that may change the workpieces sur-
face roughness、shape or dimensions. We apply the results of
the experimental design method to get the best combination con-
dition, it can offer us some trend of parameter to develop the
ECM machine with Fuzzy control and Neural Network (NN).
Because the ECM phenomenon is very complicate, According to the
experimental results that indicate between the many factor rela-
tions have interaction each other to influence surface roughness.
Thus we must to do a great of experiments to obtain the optimal
parameter value.
The experiments contain two parts:
1. The electrolytic polishing of couple electrode.
2. The electrolytic polishing of electric discharge machining
(EDM) with practical used electrode.
Under the part 1, we find the current wave and the current density
interaction are most important and the pulse direct current (PDC)
polishing effect best than continuos direct current (CDC), the
electrolytic duration time influence slightly; Under the part 2,
let we know that when the PDC on time period was shortly then the
polishing effect will be grossly and/or the electrolytic fluid
resistance depends upon the mold shape especial at corner region
to drain the products (or sludge) is more diffucult. Finally,show
the electrolytic polishing can to improve the surface roughness
by the industrial used electrode at short time.
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Padhy, Durga Madhab. "A case study on Application of FUZZY logic in Electrical Discharge Machining(EDM)." Thesis, 2011. http://ethesis.nitrkl.ac.in/2431/1/Durga_thesis_FINAL.pdf.
Full textAbstract:
Electrical Discharge Machining (EDM) is one of the most accurate manufacturing processes available for creating complex or simple shapes and geometries within parts and assemblies. EDM works by eroding material in the path of electrical discharges that form an arc between an electrode tool and the work piece. EDM manufacturing is quite affordable and a very desirable manufacturing process
when low counts or high accuracy is required. Turn around time can be fast and depends on manufacturer back log. The EDM system consists of a shaped tool or wire electrode, and the part. The part is connected to a power supply. Sometimes to create a potential difference between the work piece and tool, the work piece is immersed in a dielectric (electrically non-conducting) fluid which is circulated to flush away debris.
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陳祈宏. "Development of a high-efficiency micro wire electrical discharge machining (w-EDM) power source." Thesis, 2014. http://ndltd.ncl.edu.tw/handle/89738792202670512195.
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Agarwal, Deepak Kumar. "GRA Coupled with Fuzzy Linguistic Reasoning for Quality Productivity Improvement in Electrical Discharge Machining (EDM)." Thesis, 2012. http://ethesis.nitrkl.ac.in/3368/1/Deepak_kumar_Agarwal_108ME026.pdf.
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In the present work, the use of the grey relational analysis and fuzzy logic combined with Taguchi method has been proposed for optimizing Electrical Discharge Machining (EDM) process with multiple responses involved. The study aims at simultaneous optimization of quality and productivity. Quality and productivity are correlated inversely. If product quality is intended to be increased then extent of productivity is to be compromised and vice versa. Therefore, a compatible balance is necessary between productivity and product quality. The study addresses a case study related to EDM in which material removal rate (MRR) and surface roughness (Ra value) of the machined work surface have been optimized.
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Behera, Umakanta. "Application of Fuzzy Logic and TOPSIS in the Taguchi Method for Multi-Response Optimization in Electrical Discharge Machining (EDM)." Thesis, 2012. http://ethesis.nitrkl.ac.in/3230/1/Umakant_Behera_Thesis_FINAL.pdf.
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Recently optimization of multi-response problems is a most focusing area of research. This study highlights application of fuzzy logic and TOPSIS in the Taguchi method to optimize a multi-response problem on Electrical Discharge Machining (EDM). In many manufacturing/production contexts, it is still necessary to rely on the engineering judgment to optimize the multi-response problem; therefore uncertainty seems to be increased during the decision-making process. Therefore, development of efficient multi-response optimization philosophies is indeed required. In this work, the experiment has been carried out by using 304L grade stainless steel as a work material and a copper as a tool electrode in EDM. Conversely, optimal process parameter setting has been selected successfully based on requirements of quality as well as productivity. A case study has been reported towards optimizing material removal rate (MRR) and roughness average of the EDM machined product in order to make a compromise balance between quality and productivity.
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Huang, YU-JU, and 黃玉如. "Computer Numerical Control Wire Electrical Discharge Machining (CNC Wire EDM) Process Design and Planning – A Case Study of C Company." Thesis, 2012. http://ndltd.ncl.edu.tw/handle/55498235825351424245.
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碩士<br>國立高雄應用科技大學<br>工業工程與管理系<br>100<br>Accumulation and application of knowledge and experience is the most important part of process design and planning. Computer Numerical control wire electrical discharge machining (CNC Wire EDM) is one of important machining method in Precise Manufacturing. Professional machining technology and skill, and properly planned and designed manufacturing process, is the key of accomplishing a high quality and high value work piece. If the professional skill and accumulated experiences of engineers can be preserved and used efficiently, it must be an important solution on process efficiency and enterprise competitiveness improving.
The advantage of information technology makes knowledge collecting, managing, and applying more efficient. As a result, this study investigates the functions such as knowledge preserving, retrieving, and sharing by product data management system, which for the technical documents of CNC Wire EDM and related information can be preserved and build CNC Wire EDM knowledge management system. The relevant personnel can refer to historical data and related resources to increase accumulation of knowledge and decrease learning time on the platform by granted permission. This study analyzes the CNC Wire EDM manufacturing process and describes the features of machining by gathering and compiling data from document and practical operation of case company. The practical machining case explained CNC Wire EDM process completely and detailed, and further analyzed how the machining process properly designed and planned by using product information management system. The machining knowledge management system which constructed according to product information management system can ensure the consistency and integrity and only of machining process knowledge data. Also, resource sharing and information synchronizing improved the standard of machining. During the appliance of aided process planning and designing, fully utilize the existing machining technology and designing experience, and learn from historical knowledge to stabilize the quality and shorten the time of process planning, is having practical reference value on improving the efficiency of CNC Wire EDM process planning and designing, and also accelerate enterprise integration toward electronic management.
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Soni, Pankaj Kumar, and Raju Gholley. "Study and analysis of residual stresses in electro-discharge machining(EDM)." Thesis, 2007. http://ethesis.nitrkl.ac.in/4224/1/Study_and_Analysis_of_Residual_Stresses_in_Electro-Discharge_Machining_(EDM)__22.pdf.
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Technological advances have led to an increasing use of high strength, high hardness materials in manufacturing industries. In machining of these materials, traditional manufacturing processes are increasingly being replaced by more advanced techniques such as electro-discharge machining (EDM), ultrasonic machining (USM), electric chemical machining (ECM) and laser machining. EDM has found widespread application in MEMS, tool and mould industries and aerospace industries. Therefore, promoting the quality of the EDM process by developing a thorough understanding of the relationship between the EDM parameters and the machined surface integrity has become a major research concern. Electric discharge machining removes materials by melting and vaporizing caused by the high heat within the discharge column. Furthermore, EDM can easily fabricate the precision and complicated parts by choosing the appropriate machining conditions to effectively control the amount of removed materials. Although EDM can obtain fine surface integrity and precise dimensions under finishing condition, the rough machining condition produces larger and deeper discharge craters since the great quantity of the melted material is removed. Furthermore, the melted material is not removed completely because the impulse force is insufficient to flush away the melted material at the end of discharge interval. The remaining melted material is solidified to form a recast layer that distributes micropores and cracks due to the effect of thermal stress during cooling. Thus, the microscopic feature of machined surface is severely coarse that significantly deteriorates the usage life and precision of machinery parts. EDM involves the complex interaction of many physical phenomena. The electric spark between the anode and the cathode generates a large amount of heat over a small area of the work-piece. A portion of this heat is conducted through the cathode, a fraction is conducted through the anode, and the rest is dissipated by the dielectric. The duration of the spark is of the order of microseconds and during this time, a plasma channel is formed between the tool and the work-piece. Electrons and ions travel through this plasma channel. The plasma channel induces a large amount of pressure on the work-piece surface as well. This pressure holds back the molten material in its place. As the plasma starts forming it displaces the dielectric fluid and a shock wave passes through the fluid. As soon as the spark duration time is over and the spark collapses, the dielectric gushes back to fill the void. This sudden removal of pressure results in a violent ejection of the molten and vaporized material from the work-piece surface. Ejected molten particles quickly solidify in contact with the colder fluid and are eventually flushed out by the dielectric. Small craters are formed at locations where material has been removed. Multiple craters overlap each other and the machined surface that is finally produced consists of numerous overlapping craters. Although molten material ejection is not the only means of material removal in EDM, it is, however, the dominant mode of material removal in case of metals. During machining the local temperature in the workpiece gets close to the vaporization temperature of the material. Thus, phase transformation from solid to liquid as well as liquid to vapor occurs during the heating cycle. Part of the transformed material is removed but the rest re-solidifies on the surface of the workpiece. This re-solidified layer is usually called the white layer, as it is not easily etchable. EDM processes carried out in hydrocarbon dielectrics lead to the partial breakdown of dielectrics and this further leads to some diffusion of carbon Below the re-solidified white layer lies a second layer that does not melt but is still affected by heat. For steels, during the cool-down cycle, solid-state transformations occur in this heat-affected zone because the highest temperature reaches beyond the austenite transformation temperature. Finally, all the non-uniform heating and cooling give rise to transient and residual stresses in the workpiece. As a result of these residual stresses surface cracks may be formed in the white layers. Usually, residual stresses are not high enough to cause sub-surface cracks in the parent material but may lead to detrimental effects when the machined work-piece is used in applications. This work is intended on analyzing the cause of residual stress in EDM process. It is also showing how current variation brings about a change in the surface characteristics and how the microstructure variation occurs because of subsequent sparks with constant magnitude. This is studied to draw a relationship between the micro structural change and the generation of residual stresses. Scanning Electron Microscope (SEM) images taken from the samples show the surface variation at different currents. A comparative study shows current variation is a factor for the craters developed at the EDMed surface, and that higher magnitude of current changes the grain structure of the sample drastically and intensifies the magnitude of residual stresses generated in EDMed sample. The solid-solid transformation is brought about at a higher temperature (at higher current) and sample EDMed at higher current is seen to have greater surface roughness.
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Chen, Yung-sheng, and 陳永昇. "Influence of Machining Parameters and Assistant Magnetic Force on Discharge Waveform using EDM." Thesis, 2005. http://ndltd.ncl.edu.tw/handle/02000675925737312568.
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碩士<br>中州技術學院<br>工程技術研究所<br>92<br>Waveform of normal discharge (ND), effect arc (Earc), arc (Arc), and short circuit (SC) by electrical discharge machining of SKD61 alloy were fully investigated in this study. Discussing processing parameters of this experiment and EDM method (M：Conventional、Assistant magnetic force), peak current (Ip：5、10、20 and 40A), pulse duration (p：50、150、450 and 800s) and no load voltage (V：120、160 and 200V) to influence electrical discharge waveforms. Besides, through analysis of variance (ANOVA) of signal to noise (S/N) ratio, the effects of machining waveform such as assistant magnetic method (M), peak current (Ip), auxiliary current (IH), pulse duration (p), no load voltage (V), and servo reference voltage (Sv) on machining waveform characteristics were determined. From this investigation, the relations between electrical discharge machining waveform characteristics and machining parameters of SKD61 alloy via EDM were established. Furthermore, the significant degree of each parameters affected the machining characteristics were explored, and the optimal combination levels of the machining parameters on normal discharge, effect arc, arc, and short circuit was determined. Moreover, the experimental results could be applied in industrial applications and academic researches.
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Nayak, Prashit Kumar. "Modelling and Experimental Investigation of HASTELLOY C-276 Using Electro Discharge Machining (Edm)." Thesis, 2016. http://ethesis.nitrkl.ac.in/9223/1/2016_MT_PKNayak.pdf.
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Due to advance in technology there is continuous need of compact, intricate, complex size products by advance machining process for various industries and production sector. These requirements are motivation for development of various non-traditional machining processes, among various advances non-traditional machining process EDM (Electro discharge machining) is unique one. EDM removes material via thermal erosion through a plasma arc. The machining process performs by using a high frequency current (typically through a fine wire or some other electrode) to an electrically conductive workpiece. The electrode is maintained small gap from the workpiece and the potential difference is applied through an insulating dielectric material such as deionized water, kerosene or oil. This short span supply of current generates a spark across the small gap between the electrode and workpiece, due to which material has melted and vaporized from both the tool and workpiece surface. The EDM process is used only for electrically conductive materials. The EDM process is also used in aerospace industries to manufacture of various parts of aero engine. The aerospace material has very unique feature, it should very efficient to resist very high temperature, mechanical and chemical weakness. Aerospace parts generally uses nickel based super-alloys, which has very high strength, very tough material properties, corrosion resistance characteristic and has a quality of thermal confliction also well in various engineering applications. Due to very difficult in nature the machinability has been studied by many researchers on this nickel based materials. This project shows the modelling and experimental investigation of HASTELLOY C – 276 in EDM process. The aim of this project is to examine the effect of input variables on the responses during EDM machining. The input parameters such as current (Ip), voltage (Vg), Pulse on time (Ton) and duty cycle (DC) have significant influenced on responses such as material removal rate (MRR),tool wear rate (TWR),radius of over cut (ROC) and surface roughness (Ra). A full factorial design of experiment (DOE) approach with threelevel, four factorials has been used to conduct this experiment. Mini tab 16 software has used to perform the ANOVA analysis. A Simple and lenient 3D thermal modelling for temperature distribution and 3D MRR modelling for single spark has been done by applying finite element method (FEM), this modelling has been done by using ANSYS 14.5 software.