Dynamic Model of Electrical Discharge Machining and Algorithm of Extreme Control Through Acoustic Signal

Grigoriev, S. N.; Kozochkin, M. P.; Porvatov, Arthur; HtuM, Thein; Zhavoronsky, Pavel; Jiang, Xin; Pivkin, Petr M.

doi:10.1051/epjconf/201922405002

Cited by 9 publications

(4 citation statements)

References 44 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…The cerium Ce and nickel Ni react with zinc Zn of brass very actively with the formation of intermetallides. The reaction of nickel Ni and zinc Zn at temperatures above 1000 • C has an explosive character that can be observed as a series of sparks in the interelectrode gap during processing [26,44,53,155,156]. The reaction of cerium Ce and zinc Zn has a more violent character that is typical for cerium.…”

Section: Mediummentioning

confidence: 99%

Reviews and Advances in Materials Processing

2022

View full text Add to dashboard Cite

among the top 2.5% by ResearchGate and the top 1% in Stanford's list of researchers. To his credit are (i) the disintegrated melt deposition technique and (ii) hybrid microwave sintering technique, an energy efficient solid-state processing method used to synthesize alloys/microcomposites/nanocomposites. He has published over 600 peer-reviewed journal papers, co-authored 8 books, and owns 2 US patents. vii Citation: Gupta, M. Editorial for the Special Issue "Reviews and Advances in Materials Processing".

show abstract

Section: Mediummentioning

confidence: 99%

Reviews and Advances in Materials Processing

2022

View full text Add to dashboard Cite

show abstract

“…The pulses that have passed through the dielectric fluid (process S2 (t)) have a dynamic effect on the elastic system consisting of the workpiece and fixture, which has its own dynamic properties characterized by the modulus of the transfer function H2 (f). The dynamic impacts on the workpiece occur mainly due to evaporation of the workpiece material [10] and phase transitions in the workpiece material due to heating. The accelerometer installed on the workpiece side perceives vibrations (process S3 (t)) resulting from impacts of discharge pulses that have reached the workpiece surface and performed work associated with the formation of erosion craters.…”

Section: Assessment Of Vibroacoustic Emissions During Wedmmentioning

confidence: 99%

“…Based on this consideration, the amplitude of high-frequency vibrations (A) is related to the material removal rate (MRR) by the expression. In [10], experiments showed that simultaneous measurements of the dimensions of the craters formed via electroerosion and VA signals allow obtaining a monotonic dependence between the amplitude (A) of the high-frequency vibration signals and the MRR, determined by the volume of the craters:…”

Section: Materials Removal Rate (Mrr) Of the Wedmmentioning

confidence: 99%

“…Electrical discharge machining (EDM) is continuously expanding its presence in the industry due to the ability to perform high-precision processing of conductive materials regardless of their mechanical properties. The continuously increasing role of EDM makes research aimed at increasing the stability and productivity of the process and at creating the opportunities for the transition to "smart" EDM [1][2][3][4][5][6][7][8][9][10][11][12][13] operating in a fully automatic mode very interesting and important. In this work, EDM using wire-cut machines with an automatically adjustable interelectrode gap (IEG) was studied.…”

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

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

View full text Add to dashboard Cite

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.

show abstract

Application of Circuit Modeling in the Study of Spark Formation During Electroerosion Treatment

Porvatov¹,

Kozochkin²,

Minin³

et al. 2021

EPJ Web Conf.

Self Cite

View full text Add to dashboard Cite

Electrical discharge machining (EDM) of a workpiece is a complex, fast-flowing process characterized by alternating (intermittent) states: short circuit, idle and spark formation. The discontinuity of the EDM process means that the processing is carried out in single pulses, which are formed by a special pulse generator. The parameters of the generator pulses can be divided into time and electrical. The time period and duration of the pulses, as well as the difference between these two parameters (the “silence” interval), are considered temporary. The electric ones include the amplitude value of the voltage, the maximum permissible current, and the polarity of the pulses. in addition, depending on the device of the generator, the pulses can be composite, for example, have an igniting pulse with a higher voltage and a lower current than the main (working) pulse. In this work, we have developed a interelectrode gap model that allows not only to obtain values of electrical parameters, but also to evaluate and to optimize the electrical parameters of materials being processed with known electrical properties. The key advantage of this model is its modularity, which allows to add new functional blocks, which describe external and internal influences, for example, the concentration of erosion products, uneven electrical conductivity of the workpiece, and others, without changing its structure.

show abstract

Dynamic Model of Electrical Discharge Machining and Algorithm of Extreme Control Through Acoustic Signal

Cited by 9 publications

References 44 publications

Reviews and Advances in Materials Processing

Reviews and Advances in Materials Processing

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

Application of Circuit Modeling in the Study of Spark Formation During Electroerosion Treatment

Contact Info

Product

Resources

About