A review on current research trends in electrical discharge machining (EDM)

(BQ) This paper reviews the research trends in EDM on ultrasonic vibration, dry EDM machining, EDM with powder additives, EDM in water and modeling technique in predicting EDM performances
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A review on current research trends in electrical discharge machining (EDM)ARTICLE IN PRESSInternational Journal of Machine Tools & Manufacture 47 (2007) 1214–1228www.elsevier.com/locate/ijmactoolA review on current research trends in electrical discharge machining(EDM)Norliana Mohd AbbasÃ, Darius G. Solomon, Md. Fuad BahariFaculty of Mechanical Engineering, Universiti Teknologi MARA, 40450 Shah Alam, Selangor Darul Ehsan, MalaysiaReceived 15 November 2005; received in revised form 20 May 2006; accepted 17 August 2006Available online 17 November 2006AbstractElectrical discharge machining (EDM) is one of the earliest non-traditional machining processes. EDM process is based onthermoelectric energy between the work piece and an electrode. A pulse discharge occurs in a small gap between the work piece and theelectrode and removes the unwanted material from the parent metal through melting and vaporising. The electrode and the work piecemust have electrical conductivity in order to generate the spark. There are various types of products which can be produced using EDMsuch as dies and moulds. Parts of aerospace, automotive industry and surgical components can be finished by EDM. This paper reviewsthe research trends in EDM on ultrasonic vibration, dry EDM machining, EDM with powder additives, EDM in water and modelingtechnique in predicting EDM performances.r 2006 Elsevier Ltd. All rights reserved.Keywords: EDM; Ultrasonic vibration; Dry EDM; Powder additives; Dielectric; Modeling1. IntroductionElectrical discharge machining (EDM) is a non-traditional concept of machining which has been widely used toproduce dies and molds. It is also used for finishing partsfor aerospace and automotive industry and surgicalcomponents [1]. This technique has been developed in thelate 1940s [2] where the process is based on removingmaterial from a part by means of a series of repeatedelectrical discharges between tool called the electrode andthe work piece in the presence of a dielectric fluid [3]. Theelectrode is moved toward the work piece until the gap issmall enough so that the impressed voltage is great enoughto ionize the dielectric [4]. Short duration discharges aregenerated in a liquid dielectric gap, which separates tooland work piece. The material is removed with the erosiveeffect of the electrical discharges from tool and work piece[5]. EDM does not make direct contact between theelectrode and the work piece where it can eliminatemechanical stresses, chatter and vibration problems duringÃCorresponding author. Tel.: +60 16 218 6521; fax: +60 3 5543 5160.E-mail address: chelorot@lycos.com (N. Mohd Abbas).0890-6955/$ - see front matter r 2006 Elsevier Ltd. All rights reserved.doi:10.1016/j.ijmachtools.2006.08.026machining [1]. Materials of any hardness can be cut as longas the material can conduct electricity [6]. EDM techniqueshave developed in many areas. Trends on activities carriedout by researchers depend on the interest of the researchersand the availability of the technology. In a book publishedin 1994, Rajurkar [7] has indicated some future trendsactivities in EDM: machining advanced materials, mirrorsurface finish using powder additives, ultrasonic-assistedEDM and control and automation.However, the review presented in this paper is on currentEDM research trends carried out by researchers onmachining techniques viz. ultrasonic vibration, dry EDMmachining, EDM with powder additives and EDM inwater and modeling techniques in predicting EDMperformances. The areas are selected because of the noveltechniques employed (ultrasonic vibration and powderadditives), the environmental aspect (dry machining andEDM in water) and effort towards validating andpredicting EDM performance (modeling technique). Eachtopic will present the activities carried out by theresearchers and the development of the area that brings itto the current trends. Wire EDM is also discussed in eachtopic.ARTICLE IN PRESSN. Mohd Abbas et al. / International Journal of Machine Tools & Manufacture 47 (2007) 1214–12282. Ultrasonic vibrationIntroduction of ultrasonic vibration to the electrode isone of the methods used to expand the application of EDMand to improve the machining performance on difficult tomachine materials. The study of the effects on ultrasonicvibration of the electrode on EDM has been undertakensince mid 1980s. The higher efficiency gained by theemployment of ultrasonic vibration is mainly attributed tothe improvement in dielectric circulation which facilitatesthe debris removal and the creation of a large pressurechange between the electrode and the work piece, as anenhancement of molten metal ejection from the surface ofthe work piece [8]. Zhang et al. [9] proposed spark erosionwith ultrasonic frequency using a DC power supply insteadof the usual pulse power supply. The pulse discharge isproduced by the relative mo ...