High Spindle Speed Wire Electrical Discharge Grinding Using Electrostatic Induction Feeding Method

Yahagi, Yuna; Koyano, Tomohiro; Kunieda, Masanori; Yang, Xiao Dong

doi:10.4028/www.scientific.net/kem.447-448.268

Cited by 5 publications

(4 citation statements)

References 4 publications

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“…This occurs because the rotation at high speeds allows a more effective flushing of the debris particles and a faster cooling of the tool electrode surface. Moreover, in [7,8] it is demonstrated that the material removal rate and machining accuracy can be improved by increasing the rotational speed of tool electrode up to 50000 rpm. In [9] Kumagai et al improved the deep hole drilling process by using a new electrode made of a rod enclosed in a dielectric pipe to avoid secondary side sparks.…”

Section: Introductionmentioning

confidence: 99%

The Downsizing Effects in EDM Drilling of Micro Holes

D’Urso

Maccarini

Merla

2013

KEM

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The recent miniaturization trend in manufacturing, has enhanced the production of new and highly sophisticated systems in various industrial fields. In recent years, machining of the so called difficult to cut materials has become an important issue in several sectors. Micro Electrical Discharge Machining (micro-EDM) thanks to its contactless nature, is one of the most important technologies for the machining of this type of materials and it can be considered as one of the most promising manufacturing technologies for the fabrication of micro components. One of the most relevant applications of micro-EDM is micro-drilling. Micro holes in fact, are widely used for example in micro-electromechanical systems (MEMS), serving as channels or nozzles to connect two micro-features, and in micro-mechanical components. The present study is about micro drilling of metal plates by means of micro-EDM technology. In particular, the aim of this work is to investigate the effects of the downsizing of the micro holes diameter on the drilling performances. The influence of the reduction of the diameters in terms of both process performances (e.g., tool wear, taper rate, diametrical overcut) and general quality of the holes was investigated. Steel plates having thickness equal to 0.8 mm were taken into account. The drilling process was carried out using a micro-EDM machine Sarix SX 200 with carbide electrodes having diameter equal to 300, 200, 100 and 50 μm. Since the standard electrodes adopted in this study had a diameter equal to 300 μm, a wire EDM unit was used to obtain the other electrodes. The relationship between the process parameters considered the most significant and the final output, was studied. Furthermore, the geometrical and dimensional properties of the micro-holes were analyzed using both optical and scanning electron microscopes. In particular, it is demonstrated that the diameter size has a significant influence on the final value of the diametrical overcut while peak current and frequency parameters have a negligible effect.

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Section: Introductionmentioning

confidence: 99%

The Downsizing Effects in EDM Drilling of Micro Holes

D’Urso

Maccarini

Merla

2013

KEM

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“…On the other hand, the authors have developed the electrostatic induction feeding method [2][3][4] shown in Figure 1 to decrease the minimum discharge energy in micro electrical discharge machining (EDM). With this method, short pulse duration ranging from several ns to several tens of ns can easily be obtained by decreasing the feeding capacitance C 1 .…”

Section: Introductionmentioning

confidence: 99%

“…If this method is applied to micro ECM, use of an expensive ultra-short pulse generator may not be necessary. Moreover, with this method, non-contact feeding to the tool electrode is possible since the feeding capacitance C 1 can be formed in the gap between a feeding electrode and the tool electrode [2,4]. Thus this method enables feeding of electricity to…”

Section: Introductionmentioning

confidence: 99%

Electrochemical Micromachining Using Electrostatic Induction Feeding Method

Koyano

Kunieda

2012

KEM

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This paper describes micro electrochemical machining (ECM) using the electrostatic induction feeding method. In ECM, electrolytic dissolution can be localized in the area where the gap width is narrow by using pulse durations shorter than several tens of nano-seconds. With the electrostatic induction feeding method which has been developed for micro electrical discharge machining, the current pulse of such short durations can be obtained more easily compared with the conventional pulse generators. In this study, the influences of the pulse voltage of power supply and feeding capacitance on the machining current were investigated theoretically. It was found that the current pulse duration is nearly equal to the rise time and fall time regardless of the pulse-on time of the pulse voltage. Hence, ultra-short pulses can be obtained without a need to use an expensive pulse generator. Micro-hole drilling carried out in a sodium nitrate aqueous solution with current pulse duration of 30ns showed that significantly small side gap of 2μm could be obtained.

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“…In addition, because the interval between heat spots generated successively by pulse discharges increases with increasing relative sliding speed between the tool electrode and workpiece, the surface temperature on the electrodes can be lowered. In previous reports 2), 3) , it was shown that the material removal rate of micro drilling EDM can be increased by increasing the rotational speed up to 50,000rpm. However, since discharges occur with alternating polarity, the tool electrode wear rate was 40% 4) , which is higher than the conventional unipolarity pulse discharge, when the polarity of the workpiece was positive, leading to deteriorated machining accuracy.…”

Section: Introductionmentioning

confidence: 99%

Reduction of Tool Wear in Non-contact Electrostatic Induction Feeding EDM

Yahagi

Natsu

Koyano

et al. 2012

IJEM

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In this study, the authors aimed to decrease tool wear ratio in non-contact electrostatic induction feeding for micro electrical discharge machining (EDM). Since this electrostatic induction feeding method is capable of non-contact electric feeding to the tool electrode, the tool electrode can be rotated at a high speeds of 50,000rpm or more. Accordingly, both material removal rate and machining accuracy can be improved. With this method however, since discharges occur with alternating polarity, the tool electrode wear rate is higher than conventional unipolarity pulse discharge where the polarity of the workpiece is positive. Thus, in this study, circuit impedance was switched alternately to decrease the tool wear ratio, so that the discharge peak current becomes high when the workpiece is negatively charged, and low when positively charged. As a result, the tool wear ratio equivalent to conventional unipolarity discharge was achieved.

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High Spindle Speed Wire Electrical Discharge Grinding Using Electrostatic Induction Feeding Method

Cited by 5 publications

References 4 publications

The Downsizing Effects in EDM Drilling of Micro Holes

The Downsizing Effects in EDM Drilling of Micro Holes

Electrochemical Micromachining Using Electrostatic Induction Feeding Method

Reduction of Tool Wear in Non-contact Electrostatic Induction Feeding EDM

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