Origami-Based Self-Folding Structure Fabrication Based on 3D Printing on Polystyrene Films

Abstract

Self-folding structures have unique advantages such as reconfiguration capability during their usage. Such advantages can be beneficial for a wide variety of applications including biomedical and electronics products. However, how to fabricate and actuate self-folding structures is still an ongoing research topic. In the paper a simple fabrication approach based on a 3D printing process is presented for the fabrication of self-folding structures that can be actuated using a constrain-based thermo responsive mechanism. A self-folding structure fabricated by our method is an origami sheet with multiple layers. The middle layer of the origami sheet is a pre-strained polystyrene film, which can have a large shrinkage when exposing to heat. Both its upper and bottom surfaces are covered with desired patterns in cured plastic resin. A foldable hinge is achieved by using the cured resin to constrain the shrinkage of the film on one side while the other side of the film is exposed to the heating environment. A model of the related folding mechanism is developed. Based on it, a hinge structure design method is presented for a given folding angle. Various experiments are performed to verify the folding control of designed self-folding structures. Possible applications of the developed self-folding structures are also demonstrated and discussed.