Development, Modeling, and Experimental Investigation of Low Frequency Workpiece Vibration-Assisted Micro-EDM of Tungsten Carbide

Abstract

This present study intends to investigate the feasibility of drilling deep microholes in difficult-to-cut tungsten carbide by means of low frequency workpiece vibration-assisted micro–electro-discharge machining (micro-EDM). A vibration device has been designed and developed in which the workpiece is subjected to vibration of up to a frequency of 1 kHz and an amplitude of 2.5 μm. An analytical approach is presented to explain the mechanism of workpiece vibration-assisted micro-EDM and how workpiece vibration improves the performance of micro-EDM drilling. The reasons for improving the overall flushing conditions are explained in terms of the behavior of debris in a vibrating workpiece, change in gap distance, and dielectric fluid pressure in the gap during vibration-assisted micro-EDM. In addition, the effects of vibration frequency, amplitude, and electrical parameters on the machining performance, as well as surface quality and accuracy of the microholes have been investigated. It has been found that the overall machining performance improves considerably with significant reduction of machining time, increase in MRR, and decrease in EWR. The improved flushing conditions, increased discharge ratio, and reduced percentage of ineffective pulses are found to be the contributing factors for improved performance of the vibration-assisted micro-EDM of tungsten carbide.

A review of hybrid manufacturing processes – state of the art and future perspectives

“…In the paper by Jia et al (1997), the mechanical signal was generated and transmitted to the tool-electrode, which was applied to remove material. On the other hand, Jahan et al (2010) attempted to drill micro-holes, where the tungsten carbide workpiece was being vibrated while the EDM process was carried out. Other studies employing similar configurations have been reported by Yeo and Tan (1999), Zhao et al (2002), Huang et al (2003), Sundaram et al (2008) and Yu et al (2009) for producing high aspect ratio of micro-holes on steel, stainless steel, titanium alloy and nitinol workpieces, respectively.…”

“…Although encouraging results have been shown, some issues still need to be solved. In the ultrasonic assisted machining processes, high frequency and amplitude vibration mechanisms are likely to deteriorate the surface quality and the dimensional accuracy of the machined parts (Jahan et al, 2010), and the machining energy only decreased 10%. In addition, with its high precision, laser processing has the potential to be incorporated in wider application areas.…”

“… EDM process has been widely used in the machining of tungsten carbide and stainless steels, but electrode deflection restricts its further development. Ultrasonic assisted EDM is capable of machining those hard materials with reduced electrode deflection effect (Jahan et al, 2010).  Long production time is always the major concern in forming processes.…”

Atomized Dielectric Spray-Based Electric Discharge Machining (Spray-EDM) for Sustainable Manufacturing

“…are employed [14]. They also tend to accelerate tool wear even though a higher material removal is achieved.…”

“…The application of low frequency vibration to the electrodes during the EDM process has been investigated in the past [83,84,14,85,13]. Ghoreishi and Atkin- the workpiece on the material removal rate, surface roughness and tool wear.…”