Shape-morphing structures are highly desirable for intelligent machines. Shape memory polymers (SMPs) are widely used in 3D/4D printing for fabricating shape-morphing systems, typically requiring a hot-programming step. Cold-programming, deforming the structure at room temperature, is simpler but has material constraints. This paper introduces grayscale digital light processing (g-DLP) 3D printing for fabricating cold-programmable shape-morphing structures. Using g-DLP's multimaterial capabilities, heterogeneous hinge modules are developed, cold-programmed by stretching. Different configurations are encoded during printing via hinge distribution and direction, enabling controllable independent morphing. Multi-shape morphing structures are demonstrated, showcasing g-DLP's potential for designing and fabricating shape-morphing structures.

Liang Yue, Xiaohao Sun, Luxia Yu, Mingzhe Li, S. Macrae Montgomery, Yuyang Song, Tsuyoshi Nomura, Masato Tanaka, H. Jerry Qi