Abstract
The current density used in electrochemical machining can be increased only up to a certain value, above which the formation of electric sparks on the cathode (tool) is observed, whereby the latter is damaged and the anode surface becomes rough. The present work is devoted to the measurement of this critical density for small metal cathodes placed on the wall of a flow-through channel for Reynolds numbers from 1265 up to 5902 and static pressures ranging from 0.1 up to 1.0 MPa. The results are correlated by criterion equations which gave values of critical (sparking) cathodic current density,j s, with an average error of 7.1 % for laminar flow and 4.1 % for turbulent flow. The equations can be used for the calculation of the sparking current density for industrial flow-through cells for electrochemical machining.
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Abbreviations
- C pE :
-
specific heat of electrolyte (J kg−1 K−1)
- d E :
-
equivalent diameter of the inter electrode gap (m)
- h :
-
height of the inter electrode gap (channel) (m)
- I S :
-
limiting current for sparking (A)
- JS :
-
limiting current density for sparking (A m−2)
- K L,K T :
-
constants in Equations 1(a) and (b)
- L C :
-
characteristic length of the cathode (disc cathode diam.) (m)
- L D :
-
length of the channel downstream the cathode (m)
- Nu :
-
Nusselt number, Equation 2
- P :
-
static pressure in the interelectrode gap at the cathode (Pa)
- P 0 :
-
reference pressure (0.1 MPa)
- Pr :
-
Prandtl number, Equation 4
- R, S, U :
-
exponents, Equation 1(a) and (b)
- Re :
-
Reynolds number, Equation 3
- T B :
-
boiling point of the electrolyte at the given static pressure (K)
- T 0 :
-
temperature of the inlet electrolyte (K)
- θE :
-
linear velocity of electrolyte flow through interelectrode gap (channel) (m s−1)
- w :
-
width of the interelectrode gap (channel) (m)
- ΔP L, ΔP T :
-
pressure loss in the channel downstream the cathode (Pa)
- ΔT :
-
characteristic temperature difference (K)
- κE :
-
conductivity of electrolyte (ω−1m−1)
- λE :
-
heat conductivity of electrolyte (W m−1 K−1)
- σE :
-
dynamic viscosity of electrolyte (kg m−1 s−1)
- ϱE:
-
electrolyte density (kg m−3)
- L:
-
laminar flow (Re < 2300)
- T:
-
turbulent flow (Re > 2300)
References
J. F. Wilson, ‘Practice and Theory of Electrochemical Machining’, Wiley-Interscience, New York (1971) p. 11.
H. Degenhardt, ‘Elektrochemische Senkarbeit metallischer Werkstoffe’, Thesis, Technische Hochschule Aachen, Aachen (1972) p. 92.
R. A. Mirzoev, ‘Cathode Process During ECM’. Collected papers on ECM, Schtiinca, Kischinev (1971) (in Russian).
A. D. Davydov, V. D. Kaschtscheev and B. N. Kabanov,Elektron. Obrab. Mater. 6 (1969) 13.
M. Datta and D. Landolt,Electrochim. Acta 26 (1981) 899.
,,27 (1982) 385.
T. H. Drake and J. A. McGeough, Proceeding of Machine Tool Design and Research Conference, Macmillan (1981) p. 361.
P. Noväk, B. Sajdl, I. Rousar,Electrochim. Acta 30 (1985) 43.
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Roušar, I., Riedel, T. Sparking at cathode tools during electrochemical machining in flow-through cells. J Appl Electrochem 24, 767–771 (1994). https://doi.org/10.1007/BF00578092
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DOI: https://doi.org/10.1007/BF00578092