Spark-assisted chemical engraving (SACE) is an unconventional micro-machining technology particularly suited for glass processing, taking advantage of electrochemical discharges. This technology distinguishes itself by its simplicity and flexibility, the possibility of machining high aspect ratio structures, the excellent surface qualities and the non-utilization of expensive clean room facilities. As the process is a serial one, the material removal rate becomes an important issue. It is shown that, by adequate tool vibration, it is possible to improve the mean material removal rate in gravity-feed drilling by a factor of 2. Micro-holes in glass with a depth of 300 µm are drilled in less than 10 s.