Local hardness and density variation in glass substrates machined with Spark Assisted Chemical Engraving (SACE)

Spark Assisted Chemical Engraving (SACE) is an unconventional technique for surface micro-machining of non-conductive materials specially glass. SACE offers many advantages for fabrication of microfluidic and Lab on Chip devices. However the exact mechanism of material removal in this technique is not fully understood. Besides, the changes in the properties of the machined sample have not been studied so far. In this letter, the material removed from glass surface is evaluated and the results of nano-indentation test for measurement of the hardness of machined micro-channels surface is reported. Based on the amount of removed mass during machining and results of nano-indentation test on machined samples it is concluded that hardness and density of the machined zones decrease during the process.