Improving the sparks assisted chemical engraving (SACE) for industrial application

TL;DR: In this article, an explanation model was developed to describe the SACE process, based on direct observation, optical emission spectroscopy and thermodynamic consideration, and a special attention has been devoted to the use of a square electrical signal with an offset.

Abstract: Parameters influencing the discharge phenomenon and the etch capability of Sparks-Assisted Chemical Engraving (SACE) have been investigated in last decade for a potential industrial application of this technology. Recently, Posalux SA, a company who evolves in the high-tech machine tool field, began the development of a commercial machine which uses the SACE process to etch glass. Since, the first commercialization of SACE, future customers’ needs have to be taken in account: the initial cost of the machine, the process cost, the machining speed, the reproducibility, the quality of the machining. The cost of the machine is determined by the company who work with customers to find a good compromise between the cost and the performances. This thesis focus on the three other characteristics (the process cost, the machining speed and the quality of the machining). Those characteristics can be improved by tuning the parameters used during the machining such as: propriety of the electrical signal, tool geometry, electrolyte type, electrolyte flow, machining strategy, etc. The optimization of those parameters has the benefit of not changing the mechanical structure of the commercial machine (not invasive). A special attention has been devoted to the use of a square electrical signal with an offset. Those variables have been empirically optimized to increase the machining quality and the machining speed. Based on those results, an explanation model was developed to describe the process. This explanation is based on direct observation, optical emission spectroscopy and thermodynamic consideration.