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Beryllium copper alloys with excellent features are widely used in many engineering fields, and their fabrication requires high machining speed. However, the fabrication of beryllium copper alloys by traditional processes has serious problems. In this study, high-speed electrochemical discharge drilling (HSECDD), a hybrid process containing electrical discharge machining (EDM) and electrochemical machining (ECM) in deionized water, was used to machine micro-holes on C17200 beryllium copper alloy. The material removal mechanism of HSECDD was studied and compared with traditional EDM. The performance of the process was investigated under different conductivities of peak current and pulse width. The results show that HSECDD is a high-efficiency method to machine C17200 beryllium copper alloy. During HSECDD, the material removal depends mainly on EDM. And, the ECM occurs at the entrance region of micro-holes machined by EDM. The function of ECM is to expand the gap between the electrode and the hole. The machining speed and average diameter of micro-holes increase with the increasing of peak current and pulse width. Increasing the pulse width will reduce the electrode wear. However, the taper angle will increase. In addition, the results also show that a value of 0.34-A peak current and 10-μs pulse width can be considered an ideal parameter for HSECDD to machine micro-holes on C17200 beryllium copper alloy. [ABSTRACT FROM AUTHOR]

Although helical electrodes have been proven to improve the EDM (electrical discharge machining) speed of small holes, there are few studies on the morphological characteristics of the machined small holes and the influence of electrode structures. In this paper, the influence of the helical electrode structure on the machining effect is studied by the method of orthogonal experiment, and the internal mechanism of the influence of the helical electrode on the machining is explained by the method of CFD (computational fluid dynamics) simulation. The results show that the larger depth and width of the helical groove and the helix angle of 60° are beneficial to increase the machining speed and reduce the relative loss rate, and at the same time, avoid serious defects in the small hole morphology. These conclusions provide a valuable reference for future researchers to choose the reasonable structure of the helical electrode, which is of great significance. [ABSTRACT FROM AUTHOR]

Tool electrode wear varying with different materials in electrical discharge machining (EDM) is unavoidable, thus inevitably reducing the machining quality and accuracy of microstructures. To convert this disadvantageous phenomenon into a beneficial process, the paper proposed a wear-variation EDM (WV-EDM) approach to fabricate a laminated disc electrode (LDE) with stable-shape micro channels on the outer edge surface; this electrode was subsequently used to machine micro grooves on workpieces by EDM. The WV-EDM formation of the LDE, the relationship between relative volume wear rate of the disc foils and the machining depth, and flow field distribution in the machining gap of the LDE during processing were investigated. The results show that the method proposed herein could reliably produce LDEs with stable micro channels on the outer edge surfaces that could subsequently be employed to continuously machine micro groove arrays with the same machining depth on the same material workpiece by EDM, and especially LDE reshaping was unnecessary. Additionally, the "pump effect" of the vortex, located in the flow field between micro channels on the LDE and workpiece, was beneficial for debris removal. Using the proposed method, micro groove arrays and columnar microstructures were successfully fabricated on Ti–6Al–4V alloy workpieces. [ABSTRACT FROM AUTHOR]

This study aimed to develop software for multi-axis electrical discharge machining (EDM) computer numerical control (CNC) systems using open CNC technology and soft CNC technology and to then apply the software to the machining of rimmed turbine blisks. Through the analysis of functional requirements, this study established the hierarchy structure of the software. On the basis of this structure, three main modules and their communications were established with Linux and RT-Linux as the development platforms. The software architecture was also constructed. Through the construction of the modules and communications and the realization of the functions, the multi-axis EDM CNC system software was developed and installed into a five-axis EDM CNC machine to realize the machining of rimmed turbine blisks. Machining results show that the architecture of the software is correct, harmonious, and reasonable. The software is also stable and reliable and features strong real-time capability and accurate movement control. [ABSTRACT FROM AUTHOR]

Abstract: This paper presents a new method to fabricate tungsten microelectrode instantaneously by means of the pressure difference of plasma between cathode and anode in a single electrical discharge. The influence of main machining parameters, such as electrode material, polarity, dielectric medium, discharge duration and peak current, is analyzed by detailed experiments to obtain the fabricating law of tungsten microelectrode. The fabricating principle is described clearly. As the result of experiments, a tungsten microelectrode about 350μm in length and 30μm in diameter can be fabricated on the top of the tungsten wire of 0.125mm in diameter by this method. At the tip of the tungsten microelectrode, its radius is about 100nm. This method can greatly shorten the microelectrode fabrication time and effectively improve the reliability of the microelectrode. Especially, this method can fabricate a nanometer level tip in general electrical discharge machining (EDM) machine tool and need not add any other apparatus. The fabricated microelectrode can be used as a drilling tool in micro-EDM or a probe for scanner and measurement devices. [Copyright &y& Elsevier]