Influence of flushing holes on the machining performance of blasting erosion arc machining

Abstract

Blasting erosion arc machining is a novel electrical erosion process depending on the hydrodynamic arc-breaking mechanism to achieve a reliable high-efficiency machining. In blasting erosion arc machining, the high-velocity fluid field in the discharging gap is the precondition of the mechanism to control arc plasma to efficiently remove workpiece material. Therefore, this study mainly investigates the influence of flushing holes on the fluid field distribution directly and on the machining performance indirectly. Three multi-hole solid electrodes with different types of flushing holes are designed out according to the distributing principle. The influence of their flushing holes on the fluid field is conducted by a comparison fluid simulation which demonstrates that the electrode with flushing-hole diameters decreasing gradually from the inner to the outer in the radial direction attains the best flushing velocity distribution on the workpiece surface. Furthermore, the influence of their flushing holes on the blasting erosion arc machining performance is investigated by a comparison machining experiment in order to verify the comparison results of fluid field simulation. The experimental results illustrate that these electrodes have very different machining performance when machining nickel-based high-temperature alloy GH4169 (similar to Inconel 718) under the conditions of same discharge peak current and flushing inlet pressure. The electrode with the best flushing velocity distribution rather than with the highest velocity at a particular point achieves the best machining performance of the highest material removal rate, the least relative tool wear ratio and the least surface roughness (Ra), indicating an optimized design of flushing holes in the multi-hole solid electrode.

A Review on Porous EDM Electrodes

“…In porous electrode it will be a very good choice to use flushing through inside of the tool so that tool cool down fast air assisted multi hole tool support this idea by Singh et al [19]. Pour size will also affect the MRR larges the pour size higher the MRR and this idea is supported by Xu et al [16]. We can prepare porous electrode with the help of Borax to create diffusion bond between particles without creating reduction environment also borax will help in improving micro hardness of electrode if prepared with this technique this idea supported by Suarez et al [17].…”

“…Also decrease in the porous area can be helpful if sufficient flow of electrolyte can be achieved. Xu H, et al [16] researched on multi hole EDM electrodes with various size of hole diameters. The electrodes they used are made of graphite.…”

Electric discharge drilling with gas-assisted multi-hole slotted tool

“…Several studies [9][10][11] investigated the ability of liquid dielectric supply through the electrode to improve EDM performance. Gu et al [9] carried out EDM machining using a bundled electrode.…”

“…The reason for the improvement in flushing is probably because of the proposed tool effectiveness which reduces the concentration of debris in the electrodes gap. Xu et al [11] analyzed the impact of flushing through a multi-hole electrode during EDM operation. Their experimental and simulation results indicated that machining performance was significantly influenced by flushing velocity.…”

High efficiency blasting erosion arc machining of 50 vol.% SiC/Al matrix composites

“…16 Xu et al studied the influence of flushing holes on the machining performance of BEAM and machined nickel-based alloy with positive polarity BEAM utilizing a bundled electrode. 17,18 Chen et al researched the processing of titanium alloy with BEAM and machined a blade sample successfully. 19 In this paper, BEAM is adopted to machine 50 vol.% SiC/Al matrix composites with a rotatable cylinder electrode.…”