The capability of ECDM in creating effective microchannel on the PDMS

Abstract

Today, polydimethylsiloxane (PDMS) is widely used in medical and industrial applications. Lithographic processes are commonly used to create microchannels in PDMS, which have encountered several limitations such as high fabrication time and cost. In this study, the effect of tool characteristics (distance, geometry and diameter) and electrolyte properties (temperature and type) on the surface quality, surface roughness and dimensional accuracy of the created microchannel on PDMS through electrochemical discharge machining (ECDM) are investigated for the first time. The results stated the capability of ECDM in the formation of channels with the similar quality of created channels by lithography. In addition, it has been declared that increasing the tool/workpiece distance would lead to an increase in the surface roughness as well as deteriorated surface quality of the grooves due to the longer traveled distance by the particles and the subsequent energy increase by colliding the workpiece surface. According to the obtained results, increasing the mentioned distance from 20 μm to 150 μm was followed by a 356% increase in the surface roughness. Moreover, by the utilization of grooved tools instead of simple ones, thicker gas film would be formed at the vicinity of the tool, and consequently, intensified stray sparks and the resultant increased material removal area would be achieved. Furthermore, rising the electrolyte temperature from 25 °C to 65 °C led to an increase in surface roughness from 0.109 to 0.140 μm. Additionally, respective reductions of 33% and 3% in surface roughness and microchannel width were attained by 20% reduction in the tool diameter.