Effect of Different Dielectrics on Material Removal Rate, Electrode Wear Rate and Microstructures in EDM

Niamat, Misbah; Sarfraz, Shoaib; Aziz, Haris; Jahanzaib, Mirza; Shehab, Essam; Wasim, Ahmad; Hussain, Salman

doi:10.1016/j.procir.2017.02.023

Cited by 58 publications

(15 citation statements)

References 18 publications

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“…All micrographs were taken in nanospace, keeping 101× magnification and 10 kV High Voltage (HV) value. Weight difference method was used for the measurement of MRR and EWR [46][47][48]. For this purpose, weight balance Mettler PE 1600 was used before and after the individual experiment.…”

Section: Methodsmentioning

confidence: 99%

Parametric Modelling and Multi-Objective Optimization of Electro Discharge Machining Process Parameters for Sustainable Production

et al. 2019

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Electro Discharge Machining (EDM) can be an element of a sustainable manufacturing system. In the present study, the sustainability implications of EDM of special-purpose steels are investigated. The machining quality (minimum surface roughness), productivity (material removal rate) improvement and cost (electrode wear rate) minimization are considered. The influence and correlation of the three most important machining parameters including pulse on time, current and pulse off time have been investigated on sustainable production. Empirical models have been established based on response surface methodology for material removal rate, electrode wear rate and surface roughness. The investigation, validation and deeper insights of developed models have been performed using ANOVA, validation experiments and microstructure analysis respectively. Pulse on time and current both appeared as the prominent process parameters having a significant influence on all three measured performance metrics. Multi-objective optimization has been performed in order to achieve sustainability by establishing a compromise between minimum quality, minimum cost and maximum productivity. Sustainability contour plots have been developed to select suitable desirability. The sustainability results indicated that a high level of 75.5% sustainable desirability can be achieved for AISI L3 tool steel. The developed models can be practiced on the shop floor practically to attain a certain desirability appropriate for particular machine limits.

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Section: Methodsmentioning

confidence: 99%

Parametric Modelling and Multi-Objective Optimization of Electro Discharge Machining Process Parameters for Sustainable Production

et al. 2019

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“…Simultaneously, it rises with the increased value of electrode peripheral speed and then again decreases when tool rotation, acoustic emission, and gap flushing techniques are employed Kerosene Cu/steel/ brass/Al CFRP Islam et al [23] observed that during the EDM operation of CFRP with different electrode materials like Al, Steel, and Cu, minimum unwanted burrs are found when machining was pursued with copper tool Brass Cu Prihandana et al [24] employed dielectric vibration to achieve improved MRR, because ultrasonic vibration helps additive dust particle to mix properly inside the entire volume of the dielectrics. It was observed that the amount of carbon wear particles on the machined surface was comparatively less in case of powder-mixed kerosene when compared to pure kerosene, which was detected by X-ray dispersive (XRD) analysis Kerosene Ti Cu-Be Yildiz et al [25] applied the concept of heat transfer and simulation technique to predict the optimum MRR with minimum possibilities of white layer formation TiC Wang et al [26] Niamata et al [30] assessed the performance of Al alloy using both kerosene and distilled water as dielectrics and observed that kerosene gives more stable and efficient machining performance than distilled water. It was also observed that higher value of input current caused improved MRR, but on the same side, it made the surface rough Titanium alloy and nickel alloy Maradiaa et al [31] concluded that better micro-EDM performance could be achieved on Ti alloy, Ni alloy, and steel with graphite and Cu electrodes using kerosene as a dielectric medium TiN, ZrB 2 , and TiB 2…”

Section: Graphite Powder-mixed Dielectricsmentioning

confidence: 99%

Feasibility assessment of some alternative dielectric mediums for sustainable electrical discharge machining: a review work

Das

Paul

Doloi

2020

J Braz. Soc. Mech. Sci. Eng.

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Low removal rate, high power consumption, and dependency on conventional fuels (kerosene as a dielectric) are some premier issues that keep the sustainability index of EDM low, though it has huge acceptability and popularity mostly in aviation sectors and biomedical instrumentation to machine some extensively hard ferrous and nonferrous metal/metal alloys. Besides these, the thermal agitation inside the fusion/machining zone partially burns the dielectrics and tool-workpiece-metal, which evolve some oxides/monoxides. These evolved gases promote an unhygienic breathing atmosphere, which is very much harmful to the operator's health. Sometimes because of inadequate flushing pressure and velocity, carbon particles deposited inside the crater makes the spark unstable and releases carbon monoxide when the temperature exceeds its melting point. According to ISO 14000, every manufacturing process must be comprised of the sustainability criteria, which maintains a compromised balance between the economic, environmental, and social aspects, including the issue of the operator's health. But in real practices, it is very tough to maintain a stoichiometric balance between all these constraints. The article intensely focuses on the issue of emergence of gases during machining and tries to promote the utility of some alternative vegetable oil-based dielectrics, which are experimentally justified as a potent alternative of conventional kerosene. Apart from these, it includes some comparative talks on dielectric nature and their impacts on the responses and surface properties. Finally, this article highlights some compromise solutions which are probably capable of mitigating the hurdles to some extent, so that the sustainable machining can be encouraged in real sense.

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“…In this case, when the degree of contamination is relatively small, such pulses may be identified by the control system as working, while in reality they lose a large fraction of their energy on removing and heating the electroerosion products. Although these processes have an adverse impact on the quality of the surface being machined [74], the control system still identifies the aforementioned pulses as working. In cases where refractory materials, such as composites of WC, TiC and Co hat conduct heat due to the presence of TiC in their composition [75], are being machined, the erroneous signal interpretation can lead to rapid wire melting and breakage due to the inability of the control system to timely increase the IEG to flush contaminants from the working zone [76,77].…”

Section: Introductionmentioning

confidence: 99%

Physicomechanical Nature of Acoustic Emission Preceding Wire Breakage during Wire Electrical Discharge Machining (WEDM) of Advanced Cutting Tool Materials

Grigoriev

Pivkin

Kozochkin

et al. 2021

Metals

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The field of applied wire electrical discharge machining (WEDM) is rapidly expanding due to rapidly increasing demand for parts made of hard-to-machine materials. Hard alloys composed of WC, TiC and Co are advanced cutting materials widely used in industry due to the excellent combination of hardness and toughness, providing them obvious advantages over other cutting materials, such as cubic boron nitride, ceramics, diamond or high-speed steel. A rational choice of the WEDM modes is extremely important to ensure the dimensional quality of the manufactured cutting inserts, while roughness of the machined surface on the cutting edge is of great importance with regards to the application of wear-resistant coatings, which increases tool life. However, the stock control systems of CNC WEDM machines, which are based on assessment of electrical parameters such as amperage and voltage, are unable to timely detect conditions at which a threat of wire breakage appears and to prevent wire breakage by stopping the electrode feed and flushing out the interelectrode gap (IEG) when hard alloys with high heat resistance and low heat conductivity, such as WC, TiC and Co composites, are being machined, due to the inability to distinguish the working pulses and pulses that expend a part of their energy heating and removing electroerosion products contaminating the working zone. In this paper, the physicomechanical nature of the WEDM of hard alloy WC 88% + TiC 6% + Co 6% was investigated, and the possibility of using acoustic emission parameters for controlling WEDM stability and productivity were explored. Acoustic emission (AE) signals were recorded in octave bands with central frequencies of 1–3 and 10–20 kHz. It was found that at the initial moment, when the dielectric fluid is virtually free of contaminants, the amplitude of the high-frequency component of the VA signal has its highest value. However, as the contamination of the working zone by electroerosion products increases, the amplitude of the high-frequency component of the AE signal decreases while the low-frequency component increases in an octave of 1–3 kHz. By the time of the wire breakage, the amplitude of the high-frequency component in the octave of 10–20 kHz had reduced by more than 5-fold, the amplitude of the low-frequency component in the octave of 1–3 kHz had increased by more than 2-fold, and their ratio, coefficient Kf, decreased by 12-fold. To evaluate the efficiency of Kf as a diagnostic parameter, the quality of the surface being machined was investigated. The analysis of residual irregularities on the surface at the electrode breakage point showed the presence of deep cracks and craters typical of short-circuit machining. It was also found that the workpiece surface was full of deposits/sticks, whose chemical composition was identical to that of the wire material. The presence of the deposits evidenced heating and melting of the wire due to the increased concentration of contaminants causing short circuits. It was also shown that the wire breakage was accompanied by the “neck” formation, which indicated simultaneous impacts of the local heating of the wire material and tensile forces. Due to the elevated temperature, the mechanical properties the wire material are quickly declining, a “neck” is being formed, and, finally, the wire breaks. At the wire breakage point, sticks/deposits of the workpiece material and electroerosion products were clearly visible, which evidenced a partial loss of the pulses’ energy on heating the electroerosion products and electrodes. A further increase in the contamination level led to short circuits and subsequent breakage of the wire electrode. It was shown that in contrast to the conventional controlling scheme, which is based on the assessment of amperage and voltage only, the analysis of VA signals clearly indicates the risk of wire breakage due to contamination of the working zone, discharge localization and subsequent short circuits. The monotonic dependence of WEDM productivity on AE parameters provides the possibility of adaptive adjustment of the wire electrode feed rate to the highest WEDM productivity at a given contamination level. As the concentration of contaminants increases, the feed rate of the wire electrode should decrease until the critical value of the diagnostic parameter Kf, at which the feed stops and the IEG flushes out, is reached. The link between the AE signals and physicomechanical nature of the WEDM of advanced cutting materials with high heat resistance and low heat conductivity in different cutting modes clearly shows that the monitoring of AE signals can be used as a main or supplementary component of control systems for CNC WEDM machines.

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Effect of Different Dielectrics on Material Removal Rate, Electrode Wear Rate and Microstructures in EDM

Cited by 58 publications

References 18 publications

Parametric Modelling and Multi-Objective Optimization of Electro Discharge Machining Process Parameters for Sustainable Production

Parametric Modelling and Multi-Objective Optimization of Electro Discharge Machining Process Parameters for Sustainable Production

Feasibility assessment of some alternative dielectric mediums for sustainable electrical discharge machining: a review work

Physicomechanical Nature of Acoustic Emission Preceding Wire Breakage during Wire Electrical Discharge Machining (WEDM) of Advanced Cutting Tool Materials

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