Showing papers on "Electrical discharge machining published in 1997"
TL;DR: In this paper, electrical discharge machining (EDM) can be achieved in gas with the help of a high-pressure gas flow supplied through a thin-walled pipe electrode, which can be removed and flushed out of the working gap without being reattached to the electrode surfaces.
285 citations
TL;DR: In this article, a suitable selection of machining parameters for wire electrical discharge machining (WEDM) process relies heavily on the operators' technologies and experience because of their numerous and diverse range.
187 citations
01 Jan 1997-Precision Engineering-journal of The International Societies for Precision Engineering and Nanotechnology
TL;DR: In this paper, a feed-forward back-propagation neural network based on a central composite rotatable experimental design is developed to model the WEDM process, and an autoregressive AR(3) model is used to describe its stochastic component.
Abstract: Wire electrical discharge machining (WEDM) technology has been widely used in conductive material machining. The WEDM process, which is a combination of electrodynamic, electromagnetic, thermaldynamic, and hydrodynamic actions, exhibits a complex and stochastic nature. Its performance, in terms of surface finish and machining productivity, is affected by many factors. This paper presents an attempt at optimization of the process parametric combinations by modeling the process using artificial neural networks (ANN) and characterizes the WEDMed surface through time series techniques. A feed-forward back-propagation neural network based on a central composite rotatable experimental design is developed to model the machining process. Optimal parametric combinations are selected for the process. The periodic component of the surface texture is identified, and an autoregressive AR(3) model is used to describe its stochastic component.
158 citations
TL;DR: In this paper, a response surface model based on a central composite rotatable experimental design and a 4-16-3 size back-propagation neural network have been developed.
157 citations
TL;DR: A fundamental study of electro discharge machining (EDM) based on the physics of an arc and heat transfer theory has been carried out in this paper, where the field equations for electric potential and temperature in the spark region are simultaneously solved by employing the finite element method.
Abstract: A fundamental study of electro discharge machining (EDM) based on the physics of an arc and heat transfer theory has been carried out. The field equations for electric potential and temperature in the spark region are simultaneously solved by employing the finite element method. Using the criterion of constant current at any cross section of a spark, the arc radii at different cross sections are corrected until convergence. The final spark shape obtained is noncylindrical, and has different radii at different cross sections. Also, the percent of heat input absorbed by cathode, anode, and dielectric has been calculated. The computed relative electrode wear has been compared with experimental results.
125 citations
TL;DR: In this article, the authors studied the machinability of electrical discharge machining of metal matrix composite (MMC) materials for high performance applications such as aerospace vehicles and racing automobiles.
117 citations
TL;DR: In this paper, a feed-forward neural network is used to on-line monitor electrical discharge machining (EDM) processes, based on the neural network through the back-propagation learning algorithm.
110 citations
TL;DR: In this article, the main objective of the proposed research is the development of a production technology for three-dimensional micromechanical structures together with a study of the mechanical properties of these structures.
Abstract: Currently, nearly all microcomponents are fabricated by micro-electronic production technologies like etching, deposition and other (photo) lithographic techniques. In this way, main emphasis has been put on surface micromechanics. The major challenge for the future will be the development of real three-dimensional microstructures. The main objective of the proposed research is the development of a production technology for three-dimensional micromechanical structures together with a study of the mechanical properties of these structures. Electrodischarge machining (EDM) is a versatile technique which is very well suited for machining complex microstructures. This paper starts with an overview of EDM technology, the current state-of-the-art of micro EDM, and a comparison of EDM with other micromachining technologies. Afterwards, the basic parameters for EDM of silicon are derived. It will be demonstrated that EDM of silicon is not only feasible, but also forms an interesting, powerful and complementary alternative to traditional silicon micromachining.
108 citations
TL;DR: In this paper, the indispensable stabilizing role of gap debris in precision electrodischarge machining (EDM) has been investigated and it is shown that failure to evacuate surfeited debris in a spark gap results in arcing that damages the tool electrode as well as the work.
104 citations
TL;DR: In this paper, two types of advanced ceramics, Sialon and Al2O3 TiC, were machined successfully by the Wire-Cut EDM process.
98 citations
TL;DR: In this article, the requirements of the materials used for WEDM electrodes that will lead to the improvement of the performance of WEDMs have been investigated, and experiments have been conducted regarding the choice of suitable wire electrode materials.
TL;DR: In this paper, an investigation has been made into the combined technology of ultrasonic and wire electrical discharge machining (W-EDM), in which the design of the vibrating device is described.
TL;DR: In this paper, the performance of powder metallurgy (P/M) electrodes on various aspects of electrical discharge machining (EDM) operation is discussed in detail, and the properties of P/M electrodes can be controlled over a wide range by adjusting the compacting and sintering conditions.
Abstract: Electrodes in electrical discharge machining (EDM) can be compared with cutting tools in conventional machining. Tool performance is one of the important factors that determine the quality of the machined component. Due to the ease of manufacturing and control over the properties of electrodes, the powder metallurgy (P/M) technique has an advantage over other methods of electrode fabrication. P/M electrodes affect the micro- and macrovariables in EDM and the properties of P/M electrodes can be controlled over a wide range by adjusting the compacting and sintering conditions. The performance of P/M electrodes on various aspects of EDM operation is discussed in this paper.
TL;DR: In this paper, a new computer-aided pulse discrimination system based on the characteristics of voltage waveform during machining was developed, and a large amount of sparking frequency data during wire rupture process and under normal working conditions were collected and analyzed.
Abstract: Wire rupture in the Wire Electrical Discharge Machining (WEDM) process is a serious problem to manufacturers. A new computer-aided pulse discrimination system based on the characteristics of voltage waveform during machining was developed in this paper. With the use of this system, a large amount of sparking frequency data during wire rupture process and under normal working conditions were collected and analyzed. Two symptoms of wire rupture were identified: the excess of arc sparks, and a sudden rise of the total sparking frequency. The governing mechanisms of these two types of wire rupture were found from the SEM and EDAX analyses of the ruptured wire electrode. Furthermore, an index to monitor wire breaking was identified, and its relationships with the metal removal rate and machining parameters were found. Based on the results obtained in the paper, a control strategy to prevent wire from rupturing while at the same time improving the machining speed is proposed.
TL;DR: In this article, the machinability of ceramics is studied according to their physical properties and the effects on material removal rate, surface roughness and diameter of discharge points by various parameters are measured and discussed.
TL;DR: In this article, material-adapted machining technologies and their potential for advanced ceramic components are presented for production of advanced ceramics components, both in terms of component quality and process economics.
Abstract: New materials are vitally important in industrial development. They are mostly the start of a technology chain leading to the final product via a number of value-added stages. Application experience often produces feedback for improvement and optimization of the production process and the material itself. Machining ceramics makes high demands in terms of component quality and process economics. ‘Ceramic-adapted machining’ is therefore essential for production of advanced ceramic components. This includes both optimization of existing processes and development and testing of new machining technologies. This article presents material-adapted machining technologies and their potential for advanced ceramic components.
TL;DR: Experimental results have shown that EDM discharge pulses can be not only correctly but also quickly classified under varying cutting conditions using this approach.
Abstract: In this paper, the use of fuzzy set theory to construct a new pulse discriminator in electrical discharge machining (EDM) is reported. The classification of various discharge pulses in EDM is based on the features of the measured gap voltage and gap current. To obtain optimal classification performance, a machine learning method based on a simulated annealing algorithm is adopted to automatically synthesize the membership functions of the fuzzy pulse discriminator. Experimental results have shown that EDM discharge pulses can be not only correctly but also quickly classified under varying cutting conditions using this approach.
TL;DR: In this article, an analysis on the mechanisms of ultrasonic machining and electrical discharge machining has been carried out, and a technology which combines the advantages of both of them has been proposed in this paper.
Abstract: An analysis on the mechanisms of ultrasonic machining and electrical discharge machining has been carried out, and a technology, which combines the advantages of both of them, has been proposed in this paper. It can be used to machine all conductive hard and brittle materials with high efficiency and surface integrity. The mechanism of this combined technology has been studied by the authors. The experimental results show that the efficiency of it is over three times greater than that of ultrasonic machining, and the surface integrity is not significantly different.
TL;DR: In this article, the authors reviewed the research and development of advanced monitoring and control systems for die-sinking EDM and wire EDM during the last two decades, including different EDM gap monitoring systems, servo and pulse adaptive control systems and knowledge base control systems.
Abstract: The electrical discharge machining (EDM) process performance depends on maintaining an appropriate machining gap with a servo system and discharge pulse parameters with a pulse power generator. The integration of the state-of-the-art monitoring and control technologies can substantially improve the performance of the EDM process. This paper reviews the research and development of advanced monitoring and control systems for die-sinking EDM and wire EDM during the last two decades. Important research activities include different EDM gap monitoring systems, servo and pulse adaptive control systems, and knowledge base control systems.
TL;DR: In this paper, a D.C. power supply was used instead of the usual pulse power supply, the pulse discharge being produced by the relative motion between the tool and the workpiece.
TL;DR: In this article, the results of wire electro discharge machining (WEDM) were performed on two composites, SiC/2009Al alloy with 15% whiskers and with 20% particles reinforcement.
TL;DR: In this paper, the main advantages of micro-EDM are its low installation cost, high accuracy and large design freedom, which can indeed easily machine complex three-dimensional shapes that prove difficult for etching techniques.
Abstract: Micro electro-discharge machining (EDM) is introduced as a new technique to produce microstructures. The main advantages of micro-EDM are its low installation cost, high accuracy and large design freedom. Micro-EDM can indeed easily machine complex three-dimensional shapes that prove difficult for etching techniques. The primary applications of micro-EDM are in rapid prototyping and products with small batch sizes. However, the technique is versatile enough to be adapted to large series. Several examples are given of the possibilities of micro-EDM: an elastic force motor, micromirrors, an acceleration sensor and a microspring. Also the machine on which these structures were made is introduced. EDM requires electrodes as a tool. A reliable method for producing these electrodes, with custom shape and small sizes, is also presented.
TL;DR: In this article, a WEDM adaptive control system that optimizes on-line the sparking frequency by estimating the workpiece height with a new multiple input model is presented, which describes the dynamic and stochastic relationships between average gap feedback voltage and spark frequency and machine table feed rate.
TL;DR: In this article, the use of abductive networks to monitor the electrical discharge machining (EDM) process is described, where voltage and current across the gap between the tool and workpiece are fed into the developed networks for the recognition of various pulse types in EDM in a "winner-take-all" fashion.
Abstract: The paper describes the use of abductive networks to monitor the electrical discharge machining (EDM) process. The voltage and current across the gap between the tool and workpiece are fed into the developed networks for the recognition of various pulse types in EDM in a “winner-take-all” fashion. Experimental results have shown that EDM pulses can be clearly classified even with different machining conditions. Hence, a reliable technique has been developed to monitor the EDM process.
01 Aug 1997
TL;DR: In this article, a new process of machining polycrystalline diamond (PCD) using electrical discharge (ED) milling is presented, which employs a DC source instead of the pulse generator used in EDM, and uses a water-based emulsion as the machining fluid.
Abstract: Polycrystalline diamond (PCD) has been used widely in modern industry. However, the manufacture of PCD blanks is not an economical and efficient process. The shaping of PCD blanks with conventional machining methods (such as grinding), is a long, labour-intensive and costly process. Electromachining processes promise to be effective and economical techniques for the production of tools and parts from PCD blanks. Wire electric discharge machining is able to effectively slice PCD. Electrical discharge machining (EDM) and electrical discharge grinding (EDG) shape PCD blanks at a lower cost. However, EDM and EDG of a large surface area on PCD show lower efficiency. This paper presents a new process of machining PCD using electrical discharge (ED) milling. ED milling employs a DC source instead of the pulse generator used in EDM, and uses a water-based emulsion as the machining fluid. This process is able to effectively machine a large surface area on PCD, and effectively machine other advanced conduct...
TL;DR: In this article, cost-tolerance relationships for non-traditional machining processes, namely, electrical discharge wire machining and laser beam machining, were investigated and a third-degree polynomial function was found which gives the most representative fit to the data obtained.
Abstract: In recent years, non-traditional machining processes have been growing in popularity and their applications have continued to increase However, very limited research work has been carried out to investigate their economic implications on tolerance allocation This paper reports on cost-tolerance relationships for non-traditional processes, namely, electrical discharge wire machining and laser beam machining Medium carbon steel plates are machined using the two processes to obtain cost-tolerance data which are fitted to various mathematical models A third-degree polynomial function has been found which gives the most representative fit to the data obtained An example is presented to illustrate the application and to compare the cost implication of the two machining processes
Patent•
24 Apr 1997TL;DR: In this paper, a set of master parts in the shape of the EDM electrode is formed using stereolithography or other rapid prototyping techniques, and a flexible material is molded (109, 56, 57) in them to form a flexible mold.
Abstract: A rapid method for fabricating a precision electrical discharge machining (EDM) electrode (71). A set of master parts (31, 32) in the shape of the EDM electrode is formed using stereolithography or other rapid prototyping techniques (106). The master parts are assembled and a flexible material is molded (109, 56, 57) in them to form a flexible mold (111, 61). The flexible mold is then filled (115) with electrically conductive powder and the powder is cold isostatically pressed (117) to solidify it and form the EDM electrode.
Patent•
15 Jan 1997TL;DR: A surface treating method uses an electric discharge machining to form a coating layer having strong adhesion and excellent characteristics on a metal surface such as a hard metal as mentioned in this paper, where a discharge electrode is formed by powders containing metal hydride.
Abstract: A surface treating method uses an electric discharge machining to form a coating layer having strong adhesion and excellent characteristics on a metal surface such as a hard metal. A discharge electrode is formed by powders containing metal hydride. Electric discharge is generated in a working fluid containing carbon between the discharge electrode and a workpiece. Thus, a coating layer of the metal hydride is formed on a surface of the workpiece.
Journal Article•
TL;DR: In this article, pure axial fatigue tests have been carried out on individual membrane links of metallic membrane flexible couplings manufactured by laser-beam machining, abrasive water-jet cutting, electro-discharge machining (EDM), EDM and shot peening, and by the traditional process of stamping.
TL;DR: In this paper, surface modification of aluminum matrix composites was carried out by applying a new method named electrical discharge alloying, in which a conventional electrical discharge machine can be utilized.
Abstract: In order to improve friction and wear characteristics, surface modification of aluminum matrix composites was carried out by applying a new method named Electrical Discharge Alloying, in which a conventional electrical discharge machine can be utilized. Titanium contained in a green compact electrode, and also carbon and silicon decomposed from a working fluid are transferred to the substrate surface through a single discharged arc. An increase in the gap voltage widens the gap distance. Since the pressure due to the evaporation of working fluid in the vicinity of a discharged arc decreases with a gap distance widened, it is hard to blow off the top layer of discharged craters with enriched titanium and carbon if the gap voltage is high. Consequently, the volume fraction of TiC in the modified surface increases with increasing gap voltage, and then the hardness of modified surfaces becomes high. The process, electrical discharge alloying, makes it possible not only to coat a composite layer containing TiC precipitates with a thickness of nearly 80 μm within a few minutes, but also to get different volume fractions of TiC by changing the gap voltage, which is one of the process parameters. Hardness of the modified surface can be controlled to have any value of 7-14 GPa by varying the volume fraction of TiC. It is also recognized that the process improves wear resistance of the modified surfaces.