Relative Electrode Wear Rate Research Articles

The research of effect of various parameters on processing performance of compound machining of EDM milling and arc machining

As a new processing method for hard-to-cut materials, compound machining of EDM milling and arc machining has the extremely high processing efficiency. The study of machining parameters is indispensable to the research of the process performance. In this paper, a large number of single factor experiments under different processing parameters were carried out by using compound EDM arc milling machining technology. The effects of different peak current, arc pulse duration, arc pulse interval, spindle speed and the external diameter of the electrode on processing efficiency, the surface roughness(SR) and relative electrode wear rate(REWR) were obtained. More importantly, different optimal parameters to get the highest processing efficiency, minimal SR and REWR were also acquired to provide support for future research.

Experimental investigation of water-in-oil nanoemulsion in sinking electrical discharge machining

ABSTRACTThe most common dielectric in sinking electrical discharge machining (EDM) is kerosene. However, kerosene is inflammable; besides, it can be decomposed and release harmful gases during machining process. And, owing to its low viscosity, using kerosene in sinking EDM has low machining efficiency. Accordingly, conventional sinking EDM using kerosene as dielectric has poor safety, unfriendly environment impact, and low machining efficiency. A new water-in-oil (W/O) nanoemulsion is presented in this paper. This W/O nanoemulsion not only can eliminate the hazards from kerosene to operator and environment but also improve the machining performance of conventional sinking EDM. This research aims to experimentally investigate the machining performance of W/O nanoemulsion in comparison with kerosene in sinking EDM at relatively low discharge energy. The effects of electrode material, electrode polarity, peak current, and pulse duration on machining performance are studied. The machined surface and recast layer of workpiece are characterized as well. The experimental results demonstrate that compared with kerosene, using W/O nanoemulsion in sinking EDM can obtain a higher material removal rate (MRR), a lower relative electrode wear rate (REWR), and a machined workpiece with fewer defects and thinner recast layer.

Water-in-oil nanoemulsion dielectric for both rough and finishing electrical discharge machining

The modern industry which widely utilized sinking electrical discharge machining (EDM) with kerosene has many problems including low processing efficiency, unsafety, unfriendly environmental impact, and poor machined surface accompanying with recast layer. In this paper, a new water-in-oil (W/O) nanoemulsion dielectric is proposed to overcome these shortcomings of conventional sinking EDM. The machining performance and mechanism of sinking EDM using W/O nanoemulsion are investigated in both rough and finishing machining by comparing with kerosene. The main characteristic parameters for evaluating machining performance, including material removal rate (MRR) and relative electrode wear rate (REWR) in rough machining, and machined surface quality in finishing machining are studied. Compared with kerosene, using W/O nanoemulsion as a dielectric in sinking EDM, a nearly 34 times higher MRR and a relatively lower REWR are obtained in rough machining, and a better machined surface with no recast layer is attained in finishing machining.

High-speed compound sinking machining of Inconel 718 using water in oil nanoemulsion

This study proposes a novel water in oil (W/O) nanoemulsion dielectric for use in high-speed compound sinking machining. The compound machining is the combination of arc machining and electric discharge machining (EDM). The performance of the compound machining using the proposed W/O nanoemulsion is investigated systemically by comparing with that using the traditional water based dielectric. The influences of electrode polarity, peak current, and pulse duration on the material removal rate (MRR) and relative electrode wear rate (REWR) are studied. Moreover, the characteristics of machined surface are investigated using scanning electron microscopy (SEM), energy dispersive spectrometer (EDS), and micro hardness analysis. Experimental results demonstrate that compared with water based dielectric, machining with W/O nanoemulsion can obtain higher MRR, lower REWR, and better surface quality. Therefore, W/O nanoemulsion could be an alternative to water based dielectric in high-speed compound sinking machining applications.

High-efficient Dry Hybrid Machining of EDM and Arc Machining

EDM milling experiments on AISI 304 stainless steel (AISI 304 SS) using high-efficient hybrid machining with a high-speed air dielectric were conducted in this study. The novel and efficient hybrid machining is the arc machining and electrical discharge machining (EDM) working in parallel. AISI 304 SS can be quickly melted by significantly high machining energy and fast expelled by high-speed air flow and high-speed electrode rotation. The maximum material removal rate (MRR) of 5534 mm3/min was obtained, which was hundred times compared with that of conventional dry EDM. Comparative experiments on AISI 304 SS using high-efficient dry hybrid machining, dry arc machining, and dry EDM were conducted. The influences of air flow rate, peak current of arc machining, peak voltage of EDM, and electrode rotation speed on MRR, relative electrode wear rate and surface roughness were also studied. Moreover, the cross section and surface morphology were investigated. This study demonstrates that high-efficient dry hybrid machining is an efficient rough machining method in the processing fields that require removing vast materials.

Effects of an Electrode Material on a Novel Compound Machining of Inconel718

Compound machining (CM) compounded by arc machining and electrical discharge machining (EDM) milling is a new and fast processing method used to machine so-called “difficult-to-machine” materials. This method has an exciting maximum material removal rate that reaches 11,218 mm3/min with the relative electrode wear rate (REWR) of 1.54% when machining Inconel718. The electrode material is an important factor that affects the processing cost and quality of CM. Traditionally used electrode materials in arc machining and EDM, including pure tungsten (W), cerium tungsten (WCe20), copper (Cu), tungsten copper alloy (W80), and graphite (C), were used as electrode materials to process Inconel718. Experimental results show that tubular C is the best electrode material for CM. When tubular C is unavailable, WCe20 is the suitable electrode material for rough machining and W is a better choice in finish machining. Cu electrode is unsuitable for CM because of its low melting point. Results of this work provide guidance for selecting electrode materials for the industry application of efficient CM.

High-throughput electrical discharge milling of WC–8%Co

Experiments of high-throughput electrical discharge milling (HTED milling) of WC–8%Co at 600-A peak current and 4766 mm3/min material removal rate (MRR) using a 12-mm-external-diameter and 4-mm-internal-diameter tubular graphite electrode were conducted. The HTED milling process parameters, including peak current, electrode rotation speed, flushing pressure, and peak voltage, were studied to evaluate the effect on MRR, relative electrode wear rate, and diameter of overcut. The cross section, surface morphology, and microhardness of WC–8%Co for HTED milling were also investigated. Peak current has proven to be a critical factor for MRR. The MRR of HTED milling at peak current 600 A can be increased by ten times compared to that of HTED milling at peak current 100 A. Faster electrode rotation speed, larger flushing pressure, and higher peak voltage are essential to achieve low relative electrode wear rate (REWR) and high MRR. This study demonstrates that, using proper HTED milling process parameters and tubular graphite electrode, the HTED milling of WC–8%Co can be processed efficiently.

High-speed dry compound machining of Ti6Al4V

Milling experiments on Ti6Al4V using high-speed compound machining with high-speed air dielectric were conducted in this study. The new and efficient compound machining combines arc machining and electrical discharge machining (EDM) together, both of them are working in parallel. Ti6Al4V can be quickly melted by significantly high processing energy and rapidly expelled by high-speed air flow and high-speed electrode rotation. The maximum material removal rate (MRR) of 5862mm3/min was obtained, which was hundred times higher than that of conventional dry EDM. The influences of air flow rate, inner diameter of the tubular electrode, peak current of arc machining, peak voltage of EDM, and electrode rotation speed on MRR, relative electrode wear rate and surface roughness were studied. Moreover, the re-solidified layer, surface morphology and elementary composition were also investigated. This study demonstrates that high-speed dry compound machining of Ti6Al4V can be processed efficiently using the proper machining parameters.

A Novel Compound Machining of AISI 321 Stainless Steel Using Small Diameter Electrodes

Experiments of high-efficiently compound machining (CM) combined by EDM and arc machining of AISI 321 stainless steel at 658mm3/min material removal rate (MRR) using solid electrodes of different materials and different diameters of less than 5mm were conducted. The CM process parameters, including electrode rotation speed, peak current, electrode materials and electrode diameter, were studied to evaluate the effect on MRR, relative electrode wear rate (REWR) and width of overcut (WOC). The re-solidified layer of 321 for CM was also investigated. Faster electrode rotation speed, higher peak current, larger electrode diameter and pure tungsten electrode material are essential to achieve lower REWR and higher MRR. The processing conditions were bad using electrode diameter of 2mm. The re-solidified materials are significantly more densely than base materials.

Influence of Discharge Energy Parameters on S-03 High-Strength Steel for Aerospace Components

Optimizing the electrical discharge machining (EDM) discharge energy parameters and machine tool control parameters for processing S-03 high-strength steel aerospace components is studied. The aim of this paper was to improve the machining efficient, with regard to the requirements of the recast layer thickness and surface roughness. The design of experiments method was used in the experiments. First of all, peak discharge current (ie) was confirmed to fulfill the requirement of surface roughness and recast thickness, becausei e is the uppermost parameter affecting both factors. Secondly, pulse on-time (t on) and open-circuit voltage (U) were in turn to be confirmed. Finally, the machine tool control parameters were adjusted to achieve optimized results regarding the machining efficiency, surface roughness, and recast thickness. This promising technology was advanced for manufacturing the integrated turbine disk in S-03 material. The researched parameters and experiments results concerning machining time, relative electrode wear rate (θ), and the quality of the integrated turbine disk are presented. The results show that: peak current 20A, pulse on-time 42 µs, open-circuit voltage 100V, duty factor 70%, electrode jump motion speed 10m/min, and electrode jump motion height 6mm are the best optimized parameters for S-03 high-strength steel.

Sinking EDM in water-in-oil emulsion

In this paper, a new type of sinking electric discharge machining (EDM) dielectric–water-in-oil (W/O) emulsion is proposed, and the machining characteristics of W/O emulsion are investigated by comparing with that of kerosene. In the experiments, machining parameters such as the dielectric type, peak current, and pulse duration are changed to explore their effects on machining performance, including the material removal rate (MRR), relative electrode wear rate (REWR), and surface roughness. Experimental results revealed that W/O emulsion could be used as the dielectric fluid of sinking EDM and adopting long pulse duration and large peak current could lead to obtaining higher MRR than kerosene. Compared with kerosene, W/O emulsion is observed to cause lower carbon adhered to the electrode surface. Therefore, its REWR is higher. Statistics of the discharge waveform show that more stable discharge processes can be obtained by using W/O emulsion compared with kerosene. Furthermore, W/O emulsion is more economical and more environmentally friendly than kerosene, and it could be an alternative to kerosene in sinking EDM application.

The characteristics of cutting pipe mechanism with multi-electrodes in EDM

A new mechanism of cutting pipe combined with electrical discharge machining (EDM) is designed. The mechanism is set up on the working table of electrical discharge machine and used to investigate the effects of machining parameters such as material removal rate (MRR), relative electrode wear rate (REWR) on machining characteristics. The machining variables including machining polarity, peak current, pulse duration and the rotary speed of electrode have been chosen to explore the machining efficiency. The purpose of this study is to confirm the mechanism could not only increase material removal rates but also decrease the electrode wear rates in the EDM process.