Optimization of photochemical machining process for fabrication of microchannels with obstacles

Abstract

ABSTRACT The microchannels are one of the most prominent components used in Lab on a chip device for mixing applications. For effective mixing, microchannels with obstacles are commonly used. Design and fabrication of a microchannel with obstacles (micro features) is a crucial one. By considering this motivation, a study on optimization of control parameters for fabrication of different microfeatures on copper and brass using photochemical machining (PCM) is carried out. The control parameters such as etchant concentration, etching temperature and time were considered to measure material removal rate (MRR), surface roughness (Ra) and the edge deviation (ED). In order to have better PCM performance, MRR desired to be higher, while Ra and ED are desired lesser. To obtain optimum conditions for attaining the higher MRR with lesser ED and Ra, Overall Evaluation Criteria (OEC) was articulated. Further, characterization has been carried out employing scanning electron microscopy. Finally, as an application of the study, different master molds of microchannels without and with triangular, semi-circular, and square obstacles were fabricated and using these molds, Polydimethylsiloxane (PDMS) microchannels were fabricated employing soft lithography technique. On the basis of fluid flow analysis, fabricated microchannels found to be suitable for the various microfluidic applications.