The Experts below are selected from a list of 315 Experts worldwide ranked by ideXlab platform

Robert H. Siemann - One of the best experts on this subject based on the ideXlab platform.

P.j. Chou - One of the best experts on this subject based on the ideXlab platform.

H. Henke - One of the best experts on this subject based on the ideXlab platform.

Y S Wong - One of the best experts on this subject based on the ideXlab platform.

  • a review on the conventional and micro Electrodischarge Machining of tungsten carbide
    International Journal of Machine Tools & Manufacture, 2011
    Co-Authors: Muhammad P Jahan, M Rahman, Y S Wong
    Abstract:

    Abstract The capability of Machining intricate features with high dimensional accuracy in hard and difficult-to-cut material has made Electrodischarge Machining (EDM) process as an inevitable and one of the most popular non-conventional Machining processes. In recent years, both EDM and micro-EDM processes are being used extensively in the field of mould making, production of dies, cavities and complex 3D structures using difficult-to-cut tungsten carbide and its composites. The objective of this paper is to provide a state of the art in the field of EDM and micro-EDM of tungsten carbide and its composites. The review begins with a brief introduction on the EDM and micro-EDM processes. The research and developments in Electrodischarge Machining of tungsten carbide are grouped broadly into conventional EDM of tungsten carbide, micro-EDM of tungsten carbide and current research trends in EDM and micro-EDM of tungsten carbide. The problems and challenges in the area of conventional and micro-EDM of tungsten carbide and the importance of compound and hybrid Machining processes are discussed. A summary of the future research directions based on the review is presented at the final section.

  • An experimental investigation into the micro-Electrodischarge Machining behavior of p-type silicon
    The International Journal of Advanced Manufacturing Technology, 2011
    Co-Authors: Muhammad P Jahan, Y S Wong, T. W. Lieh, Mustafizur Rahman
    Abstract:

    The present study aims to investigate the feasibility of micro-structuring in p-type silicon, using conventional die-sinking Electrodischarge Machining (EDM). The EDM behavior of the silicon material is studied in terms of the effect of major operating parameters on the performance characteristics during the micro-hole Machining. In addition, microelectrodes are fabricated successfully on the conventional EDM machine for Machining different micro-structures in silicon. Three different types of micro-structures—micro-hole, blind slots, and through slots—are fabricated in p-type silicon successfully by using optimum parameters setting. It has been observed that p-type silicon is machinable by EDM using both the polarities. Moreover, like other Electrodischarge machinable materials, the selection of optimum operating parameters is very important for improved performance, as those parameters are found to influence the EDM performance of silicon significantly. Finally, it has been concluded that p-type silicon is machinable into different forms of micro-structures by understanding its Electrodischarge Machining behavior and by careful selection of optimum parameters.

Daniela Ghiculescu - One of the best experts on this subject based on the ideXlab platform.

  • multiphysics 3d finite element modelling of micro Electrodischarge Machining aided by ultrasonics
    2012
    Co-Authors: Daniel Ghiculescu, Sergiu Nanu, Niculae Marinescu, Daniela Ghiculescu
    Abstract:

    The paper deals with modelling through finite element analysis (FEA) of material removal mechanism of micro- Electrodischarge Machining (∝EDM) aided by ultrasonics (US). Some essential requirements of this hybrid variant of EDM and some experimental data which fulfil these prerequisites are presented, and starting from these, a strategic approach is formulated. In this context, a multiphysics modelling is achieved, comprising a thermal component, corresponding to EDM and a mechanical component, related to ultrasonically induced cavitation within the working gap. On this basis, some improvements of main output technological parameters of micro Electrodischarge Machining aided by longitudinal ultrasonic oscillations of the electrode-tool are proposed in terms of Machining rate and surface roughness.

  • TECHNOLOGICAL PARAMETERS COMPARATIVELY STUDIED BY FEM AT CLASSIC AND ULTRASONIC AIDED MICROElectrodischarge Machining
    2011
    Co-Authors: Daniel Ghiculescu, Sergiu Nanu, Daniela Ghiculescu
    Abstract:

    The paper deals with study through Finite Element Method (FEM) concerning the influence of technological parameters on material removal process at classic Electrodischarge Machining (EDM) finishing and micro()EDM aided by ultrasonics (US). The working parameters used at EDM were analyzed in comparison with classic EDM ones, identifying some weaknesses of EDM. Different initial microgeometries were considered in order to study the material removal process. Some recommendations resulted from FEM aiming at improving some technological performances at EDM+US were formulated.

  • Solutions for technological performances increasing at ultrasonic aided Electrodischarge Machining
    International Journal of Material Forming, 2009
    Co-Authors: N I Marinescu, Daniela Ghiculescu, Gheorghe Jitianu
    Abstract:

    The paper deals with researches concerning phenomenology and solutions for technological parameters improvement at finishing through Electrodischarge Machining (EDM) aided by ultrasonic (US) longitudinal vibrations of electrode-tool (EDM + US). The stability of EDM + US finishing process was obtained increasing the working gap through ignition voltage growing and amplitude decrease of US oscillations. Pulse energy minimization aimed to reduce the craters volumes produced by discharge. We used consumed power values to supply the acoustic chain ( PcUS ) so the created acoustic pressure was over the cavitation threshold, but simultaneously, the PcUS value was minimized in order to not damage the surface quality and even to reduce the surface roughness. The number of discharges within an oscillation period was maximized and thus, material amount removed by ultrasonically induced cavitation was increased. Machining high content carbon and alloy elements materials by frontal flat surface electrodes improves volumetric relative wear. The flexibility concerning acoustic chain construction can be increased by Computer Integrated Machining, CNC processing acoustic horns and electrodes, previously elaborated through CAD and CAE.

  • MODELLING ASPECTS OF REMOVAL MECHANISM AT ULTRASONIC AIDED Electrodischarge Machining
    International Journal of Material Forming, 2009
    Co-Authors: Daniela Ghiculescu, N I Marinescu, Sergiu Nanu
    Abstract:

    The paper deals with researches concerning modelling of material removal mechanism at microgeometric level by computer aided finite element method (FEM) of ultrasonic aided Electrodischarge Machining (EDM+US). Simplifying hypotheses, boundary conditions and the method of meshing are presented. The approached microgeometries modelling can be assimilated as results of previous Machinings: frontal milling, grinding, rough EDM etc. The microgeometries are parameterized to highlight the influence of various elementary surfaces and material characteristics on temperature distribution produced by discharges under conditions of ultrasonically aided EDM. At classic EDM finishing, FEM results emphasized the advantage of working with relaxation pulses, against commanded ones. When ultrasonic aiding of EDM finishing, commanded pulses become more effective compared to relaxation pulses. Moreover, commanded pulses can be produced within the ultrasonic semiperiod of liquid stretching, when working conditions facilitate the Machining rate increase. In all cases, ultrasonic contribution within removal mechanism enlarges 4-5 times the volume removed by a single discharge. The comparison between FEM results and previous experimental data pointed out that the removal mechanism modelling, taking into account disposal and machined microgeometry dimensions, is essential in progress of understanding the complex process of EDM+US.

  • influence of macro and microgeometry machined surface on ultrasonic aided Electrodischarge Machining
    International Journal of Material Forming, 2008
    Co-Authors: Daniela Ghiculescu, N I Marinescu, Sergiu Nanu
    Abstract:

    The paper deals with theoretical and experimental researches concerning specific mechanism of material removal process through Electrodischarge Machining (EDM) aided by ultrasonic (US) longitudinal-i.e. normal on machined surface–vibrations of electrode (EDM+US). The influence of machined surface shape at macro and microgeometric level on material removal process is highlighted through finite elements analysis (FEA) in agreement with experimental data obtained at finishing different kinds of surface types. The completion of optimisation conditions referring to input working parameters, specific to pulse types, achieves the improvement of all main output technological parameters comparatively with classic EDM.