Fabrication of a three-dimensional insect-wing model by micromolding of thermosetting resin with a thin elastmeric mold

For investigating insect flight, a low-cost micromolding technique using a thin polydimethylsiloxane (PDMS) mold to fabricate an artificial insect wing with a three-dimensional (3D) shape was developed. The wing consists of 3D polyurethane (PU) frames and a Parylene-C membrane. Using a low-viscosity thermosetting PU resin, this method can fabricate a wing frame with a thickness of 200 mu m and a length of more than 100 mm. To create a 3D mold channel for the PU resin, a thin PDMS mold was pressed along the curved surface of a rigid bottom mold. Depositing Parylene-C on the bottom mold made it possible to integrate the molded product with a Parylene film. To estimate the deformation rate of the PDMS mold during the pressing process, the height and width of the molded PU frames were compared with those of the original channels of the PDMS molds. It was found that both the height and width of the PU frame were more than 85% of those of the original channel when the aspect ratio of the channel ranged from 0.5 to 2.0. The length of the PU frame was also found to be related to the aspect ratio. Moreover, the maximum length was over 500 times bigger than the cross-sectional width.