Electrical discharge machining (EDM) is one of the earliest non-traditional machining processes. EDM process is based on thermoelectric energy between the work piece and an electrode. A pulse discharge occurs in a small gap between the work piece and the electrode and removes the unwanted material from the parent metal through melting and vaporising. The electrode and the work piece must have electrical conductivity in order to generate the spark. There are various types of products which can be produced using EDM such as dies and moulds. Parts of aerospace, automotive industry and surgical components can be finished by EDM. 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.

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

Surface modification by electrical discharge machining: A review

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Micro total analysis systems: latest achievements.

Parametric optimization of powder mixed electrical discharge machining by response surface methodology

Micro and Nano Machining by Electro-Physical and Chemical Processes

Machining characteristics of titanium alloy (Ti–6Al–4V) using a combination process of EDM with USM

Study of added powder in kerosene for the micro-slit machining of titanium alloy using electro-discharge machining

A study on the characterization of high nickel alloy micro-holes using micro-EDM and their applications

Electrochemical discharge machining (ECDM) is demonstrated to be a potential process for 3D microstructuring of Pyrex glass. However, the key to widening ECDM micromilling applications lies in how to improve the machining accuracy. To improve the machining quality of the ECDM micromilling process, microgroove machining experiments were conducted in this study. Three factors affecting ECDM micromilling performance—pulse voltage, tool rotational rate and travel rate of tool—were taken up as machining parameters to investigate their influences on machining performance. The results indicate that optimum combinations of both pulse voltage and tool rotational rate will realize better machining accuracy. The feasibility of three-dimensional microstructure machining was demonstrated by layer-by-layer ECDM micromilling machining. Complex structures were made to demonstrate the great potential for the 3D microstructuring of Pyrex glass of the ECDM micromilling process.

http://iopscience.iop.org/article/10.1088/0960-1317/17/5/016/pdf

3D microstructuring of Pyrex glass using the electrochemical discharge machining process

Electrochemical discharge machining (ECDM) is an emerging non-traditional processing technique that involves high-temperature melting and accelerated chemical etching under the high electrical energy discharged. However, there are still several obstacles to overcome. First, both machining time and hole entrance diameter were found to increase with increasing machining depth. In particular, the increase becomes drastic when machining depth exceeds 250 μm. In addition, achieving both high efficiency and accuracy in drilling a through hole in hard and brittle materials by ECDM poses even greater difficulty. To solve the above problems, this study proposed using a tool electrode with a spherical end whose diameter (150 μm) is larger than that of its cylindrical body (100 μm). Experimental results show that the curve surface of the spherical tool electrode reduces the contact area between the electrode and the workpiece, thus facilitating the flow of electrolyte to the electrode end, and enables rapid formation of gas film, resulting in efficient micro-hole drilling. Moreover, the curve surface does not cause excessive concentration of current density; and hence, bubbles grow at a more uniform speed; thus, increasing the discharge frequency. Comparison between machining depth of 500 μm achieved by conventional cylindrical tool electrode and the proposed spherical tool electrode shows that machining time was reduced by 83% while hole diameter was also decreased by 65%.

Biing Hwa Yan

Papers

Machining characteristics of titanium alloy (Ti–6Al–4V) using a combination process of EDM with USM

Study of added powder in kerosene for the micro-slit machining of titanium alloy using electro-discharge machining

A study on the characterization of high nickel alloy micro-holes using micro-EDM and their applications

3D microstructuring of Pyrex glass using the electrochemical discharge machining process

Enhancement of ECDM efficiency and accuracy by spherical tool electrode