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)

A neutral-network approach for the on-line monitoring of the electrical discharge machining process

Electric discharge machining (EDM) is one of the leading edge machining processes successfully used to machine hard-to-cut materials in wide range of industrial applications. It is a non-conventional material removal process that can machine a complex shapes and geometries with high accuracy. The principle of the EDM technique is to use thermoelectric energy to erode conductive components by rapidly recurring sparks between the non-contacted electrode and workpiece. To improve EDM performance, the machine’s operating parameters need to be optimized. Studies related to the EDM have shown that the appropriate selection of the process, material, and operating parameters had considerably improved the process performance. This paper made a comprehensive review about the research studies on the EDM of different grades of titanium and its alloys. This review presents the experimental and theoretical studies on EDM that aimed to improve the process performance, including material removal rate, surface quality, and tool wear rate, among others. This paper also examines evaluation models and techniques used to determine the EDM process conditions. Moreover, the paper discusses the recent developments in EDM and outlines the progression for future research.

Electric discharge machining of titanium and its alloys: review

This paper aims at giving an insight into the wire electro discharge turning (WEDT) process, by analyzing the effect of machining parameters on material removal rate (MRR), surface roughness and roundness error, using the pulse train data acquired at the spark gap. To achieve this objective a simple and cost effective spindle is developed for the WEDT process. Pulse train data are acquired with a data acquisition system developed in the present work. A pulse discrimination algorithm has been developed for classifying the discharge pulses into open circuit, normal, arc and short circuit pulses. With the help of algorithm the number of arc regions, average ignition delay time, the width of the normal and arc regions in the data acquired can also be obtained. It has been observed that the rotation of the workpiece has significant influence on the type of the discharges occurring at the spark gap. Preliminary experiments conducted to compare the WEDM and WEDT processes disclosed that MRR is less in WEDT and the number of arcs and arc regions are more in WEDT. It has been observed that the surface roughness and roundness error of the WEDT components are influenced by the occurrence of arc regions, width of arc and normal discharge regions and average ignition delay time.

Pulse train data analysis to investigate the effect of machining parameters on the performance of wire electro discharge turning (WEDT) process

Electric discharge machining (EDM) is a material removal process that is especially useful for difficult-to-cut materials with complex shapes and is widely used in aerospace, automotive, surgical tools among other fields. EDM is one of the most efficient manufacturing processes and is used to achieve highly accurate production. It is a non-contact thermal energy process used to machine electrically conductive components irrespective of the material’s mechanical properties. Studies related to the EDM have shown that the process performance can be considerably improved by properly selecting the process material and operating parameters. This paper reviews research studies on the application of EDM to different grades of stainless steel materials and describes experimental and theoretical studies of EDM that have attempted to improve the process performance, by considering material removal rate, surface quality and tool wear rate, amongst others. In addition, this paper examines evaluation models and techniques used to determine the EDM process conditions. This review also presents a discussion on developments in EDM and outlines the likely trend for future research.

W. Dekeyser

Papers

Advanced Pulse Discriminating System for EDM Process Analysis and Control