No abstract

No abstract

No abstract

Spark assisted chemical engraving (SACE) is an unconventional micromachining technology based on electrochemical discharge phenomena for glass and various ceramics. The limits of SACE with respect to small dimensions in the particular case of glass are explored. It is found, using a specially developed set-up based on an AFM, that even using extremely sharp tool-electrodes does not allow us to produce a smaller pattern than typically 25 µm. It is concluded that the gas film thickness, in which the electrochemical discharges take place, is the main limiting factor. Further experimental investigations on its formation are investigated. By adding surfactants to the electrolyte, in order to increase the wettability of the tool-electrode and therefore to reduce the gas film thickness, it is observed experimentally that the critical voltage reduces significantly. This observation may lead to a novel method of characterizing the gas film thickness in SACE.

No abstract

Gravity-feed drilling is the most commonly used method for micro-hole drilling in glass with spark assisted chemical engraving (SACE). This paper proposes a method allowing the systematic characterization of this drilling method. The influences of voltage, tool shape and force are investigated. It is found that SACE gravity-feed drilling shows two regimes depending on the drilling depth. During the first 200–300 µm, the discharge regime, controlled by the number of discharges inside the gas film, allows fast drilling (up to about 100 µm s−1). For deeper depths, the drilling is controlled by the hydrodynamic regime in which the drilling speed is limited by the flow of the electrolyte inside the micro-hole resulting in slow drilling of typically 10 µm s−1. Furthermore, it is shown how the gas film build-up time is limiting the drilling speed.

No abstract

No abstract