Automatic aligning and bonding system of PDMS layer for the fabrication of 3D microfluidic channels

This paper describes a novel system for the aligning and bonding of patterned poly(dimethylsiloxane) (PDMS) layers for the fabrication of 3D microfluidic channels. The system has the following three moving parts: (1) a rough manual back-and-forth movement for the placing of upper layer onto the lower layer, (2) a precise XYZ movement to align lower and upper layers with one another, and (3) the rotational movement for the angular matching of patterns. After the aligning, the primary curing for the bonding of aligned layers was performed on a preset heater without movement of the sample. The alignment-tests were performed for four groups (novice/manual, novice/automatic, expert/manual, expert/automatic) by using various-sized triangular patterns. The experiments demonstrate the existence of a statistically significant improvement in aligning quality in the automatic aligning group. Even to the novices who have fewer than one months' aligning experience, the aligning accuracy is similar to the manual alignment of the expert group having more than 1 year's manual alignment experience. The system can be applied efficiently to the 3D fabrication of microfluidic channels in the laboratory.