Wire electrical discharge machining (WEDM) is an important technology, which demands high-speed cutting and high-precision machining to realize productivity and improved accuracy for manufacturing hard materials. WEDM has experienced explosive growth and complexity of equipment as well as rising demand for the basic process tool (the wire electrode). Greater taper angles, thicker workpieces, automatic wire threading, and long periods of unattended operation make the selection of the ideal wire a much more critical basis for achieving successful operation. This paper focuses on the evolution of EDM wire electrode technologies from using copper to the widely employed brass wire electrodes and from brass wire electrodes to the latest coated wire electrodes. Wire electrodes have been developed to help user demand and needs through maximum productivity and quantity by choosing the best wire. In the final part of the paper, the possible trends for future WEDM electrode research are discussed.

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Review of improvements in wire electrode properties for longer working time and utilization in wire EDM machining

In a wire electrical-discharge machining process an electrically conductive workpiece is eroded ahead of a continuous moving wire by spark discharges, which are identical with those in conventional...

High-performance wire electrodes for wire electrical-discharge machining – a review:

One of the major requirements of wire electrical discharge machining (WEDM) is to develop suitable technology for producing smooth surfaces. The main characteristic of WEDM is the development of the white layer. To ensure good surface quality, the white layer thickness (WLT) must be as thin as possible, homogeneous, and crack-free. Spark energy and wire electrode type are the most important parameters to experimentally investigate WLT. Experimental results show that the WLT increases linearly by 3 and 2 µm for every 20-µJ increase in the spark energy while using brass and coated wire, respectively.

1.9 Effect of Electrical Discharge Energy on White Layer Thickness of WEDM Process

In wire electrical discharge machining (wire-EDM) material is removed by the thermal energy of an electric spark that has been initiated between two electrodes (the wire and the workpiece), submerged in demineralised water. The use of high frequency current pulses for sparking leads to excellent machining performance, in terms of the work piece roughness, the material integrity of the cut and the material removal rate. To reach the highest frequencies, the wire-EDM generator mostly consists of a voltage source with an as low as possible internal inductance. The working current delivered to the spark and, hence, the material removal rate of the process depends on the total impedance of the electrical circuit. In this article the importance of the wire’s impedance will be shown. Due to the skin-effect, this impedance depends on the frequency of the current signal, especially for ferromagnetic wires, such as steel wire. Coatings will prove to be primordial to prevent the machining speed from dropping significantly.

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The skin-effect in ferromagnetic electrodes for wire-EDM

A wire cut electrical discharge machine is provided. The wire cut electrical discharge machine includes a base. At least two wire feeding and receiving components are disposed over the base. A working area is between the wire feeding and receiving components. At least two flaky wire electrodes are disposed in the working area, wherein ends of the flaky wire electrodes are respectively set on the wire feeding and receiving components.

Wire cut electrical discharge machine

An electrode for electric discharge machining comprises a high strength pearlitic steel wire having a carbon content higher than 0.6% and a tensile strength higher than 3000 N/mm2. The steel wire is coated with a copper free zinc or zinc alloy coating.The electrode is in particular suitable for high precision performance applications.

Danny Gonnissen

Papers

Electric discharge machining wire

Influence of coated steel wire on the machining performance of W-EDM