Nature of drilling forces during spark assisted chemical engraving

Tool-substrate contact drilling forces proved to be promising for monitoring the SACE drilling progress. Although these forces were recently measured, their nature was never studied. This is investigated in the present work where it is found that a tool-glass bond is created while drilling. Preliminary investigations demonstrated that this bond does not break due to specific temperature drop and that it is formed just before tool-glass contact occurs. The bond is therefore expected to be chemically formed where more investigation is needed to further clarify this. The present results add up to the knowledge regarding the SACE machining mechanism.