Electrical discharge machining (EDM) is a well-established machining option for manufacturing geometrically complex or hard material parts that are extremely difficult-to-machine by conventional machining processes. The non-contact machining technique has been continuously evolving from a mere tool and die making process to a micro-scale application machining alternative attracting a significant amount of research interests. In recent years, EDM researchers have explored a number of ways to improve the sparking efficiency including some unique experimental concepts that depart from the EDM traditional sparking phenomenon. Despite a range of different approaches, this new research shares the same objectives of achieving more efficient metal removal coupled with a reduction in tool wear and improved surface quality. This paper reviews the research work carried out from the inception to the development of die-sinking EDM within the past decade. It reports on the EDM research relating to improving performance measures, optimising the process variables, monitoring and control the sparking process, simplifying the electrode design and manufacture. A range of EDM applications are highlighted together with the development of hybrid machining processes. The final part of the paper discusses these developments and outlines the trends for future EDM research.

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State of the art electrical discharge machining (EDM)

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

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

Relationship between EDM parameters and surface crack formation

Near-mirror-finish phenomenon in EDM using powder-mixed dielectric

Effect of TiC in copper–tungsten electrodes on EDM performance

Some recent advances made in the understanding of the solidification behaviour of molten metal during electrodischarge machining (EDM) of a range of commonly used tool steels are presented. In general, the recast layers produced by EDM can be classified into three structural types: thick multilayer, intermediate single layer, and thin featureless. The discharge energy affects the average thickness of the recast layer, and hence the distribution of the different types of recast layer formed during EDM. Detailed microstructural studies have shown that during EDM, solidification of the molten metal takes place simultaneously from the top interface with the dielectric and the bottom interface with the underlying metal into the melt, as well as from within the melt towards both interfaces. This leads to the formation of three distinctive sublayers withing each recast layer resolidified from a given pool of molten metal. The effects of steel composition and thermal properties on the solidification micr...

Y.S. Wong

Papers

Near-mirror-finish phenomenon in EDM using powder-mixed dielectric

Effect of TiC in copper–tungsten electrodes on EDM performance

Solidification microstructure of electrodischarge machined surfaces of tool steels

EDM performance of TiC/copper-based sintered electrodes

Crack susceptibility of electro-discharge machined surfaces