Investigating the effect of voltage signal waveforms on the gas film and machining during Spark-Assisted Chemical Engraving (SACE)

Spark-assisted chemical engraving (SACE) is a promising technique for microscale glass machining. However, the gas film surrounding the tool poses significant challenges, impacting the process's quality and consistency which limits its industrial applications. While several studies have explored the impact of SACE parameters on the gas film, the effect of voltage signal waveforms remains unexplored. This work addresses this gap by designing and evaluating voltage signal waveforms for their impact on gas film stability and machining outputs in SACE. The process feedback current was analyzed using signal and image processing techniques to measure gas film stability indicators. The sinusoidal signal waveform had the most significant impact on gas film stability. In subsequent experiments involving micro-machining holes on soda lime glass slides, sinusoidal signals improved hole quality at the expense of increased machining times. This discovery led to the development of a custom voltage signal waveform, resulting in enhanced hole quality and increased process efficiency.