Justification in Selection of Voltage Pulse Durations at the Electrochemical Dimensional Micromachining with Nano- and M
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ification in Selection of Voltage Pulse Durations at the Electrochemical Dimensional Micromachining with Nano- and Microsecond Pulses V. V. Lyubimova, *, V. M. Volgina, and I. V. Gnidinaa aTula
State University, Tula, 300012 Russia *e-mail: [email protected]
Received July 22, 2019; revised September 17, 2019; accepted September 20, 2019
Abstract—The work is devoted to justifying the selection of a rational range of voltage pulse duration on the basis of comparing the time of the anodic dissolution start with the time of the electric double layer’s charging during electrochemical dimensional micromachining. The range of short circuit times as the limit of the maximum voltage pulse duration is justified. The simulation of dimensional electrochemical micromachining using ultrashort voltage pulses without taking into account the changes in the properties of the interelectrode environment is performed on the assumption that the anodic dissolution is determined by the Butler–Volmer equation. The zones of the current density, which have varying influence on the process of the dimensional electrochemical micromachining, are revealed. An approach to the selection of an effective voltage pulse duration based on the analysis of the character of the time zones of the process is proposed. Keywords: electrochemical micromachining, pulse duration, electric double layer, charging current, faradic current DOI: 10.3103/S1068375520050105
INTRODUCTION Electrochemical dimensional micromachining (ECDMM) is a highly effective method of processing modern structural materials, in particular, difficultto-cut materials [1–4]. Modern ECDMM is energetically and kinematically provided mainly in pulse or pulse-cycle mode [4–6]. As the mentioned modes of improving the processing accuracy are developed, less interelectrode gaps (IEGs) (to dozens of micrometers) and ultrashort voltage pulses are used [7, 8]. The decrease in the interelectrode gaps up to the indicated values caused a significant decrease in the working volume of the interelectrode spacing (IES), the growth in the amount of the anodic dissolution products in the IES volume unit, and the rise in the current density (to 200–2000 A/cm2) and the interelectrode medium temperature [7]. As a result of these phenomena, process instability and short circuits become more probable [9, 10]. The short circuits between the electrodes cause the destruction of the electrode tool and the electrode workpiece. This phenomenon has become the main shortcoming of the ECDMM. The existing methods for controlling short circuits at the ECDMM are mainly based on the interruption of the appeared short circuit [9, 10]. More radical is the exception to this phenomenon due to the application of shorter voltage pulses in comparison with
the time of the short circuit’s development and the selection of reasonable ranges of the voltage pulse ratios in the voltage pulse packet and the interpacket pulse ratio after the periodic control of the IEG. The time of the development of plasma channels in liquids was studied in
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