Cryogenic machining of PDMS fluidic channel using shrinkage compensation and surface roughness control

Abstract

Polydimethylsiloxane (PDMS) is widely used in the fabrication of fluidic chips. Recently, a direct mechanical micromilling process using cryogenic cooling was considered to cut PDMS in order to reduce development time and prototyping costs. In this paper, the characteristics of cryogenic machining of PDMS were experimentally studied. The machined surface was analyzed with a variety of machining parameters, such as spindle speed and feed per tooth, and their effects on cutting temperature were examined. To improve geometric accuracy, a tool path compensation method that takes into account the shrinkage of PDMS at cryogenic temperatures was developed. Based on the preliminary results, the fabrication of a PDMS fluidic chip demonstrated that fluidic flow can be controlled by differences in the flow friction.