Self‐Folding Metal Origami

Abstract

Origami‐based techniques for creating 3D shapes from 2D patterns via folding have moved from the domain of art to practical engineering. Flat sheets are an appealing starting material for the creation of 3D objects because of 1) the ability to efficiently store and ship stacks of sheets, 2) the compatibility of flat surfaces with a variety of patterning processes such as lithography, and 3) the ability to make sheets via high‐throughput manufacturing. Self‐folding is the ability of flat sheets of materials to respond to external stimuli (light, heat, magnetic fields, etc.) and rapidly change shape without human intervention. Herein, the self‐folding of metals is reviewed, which is particularly important for opening up new applications in robotics, medicine, and reconfigurable electronics. These applications rely on the superior thermal, mechanical, and electrical properties of metals compared with polymer alternatives. The field is reviewed from actuation mechanisms and materials to design approaches and common applications of technologies.

Engineering Origami: A Comprehensive Review of Recent Applications, Design Methods, and Tools

“…[43] Recent advances in self-folding technologies [21,44,45] could be of particular interest for the development of novel minimally invasive procedures, while the applicability of optimized 3D assembly methods based on bending, curving, and folding have also been investigated. [46] The application of reconfigurable origami-based self-folding designs encountering highly limited movements has been explored for human tissue engineering. [47,48] Because biological tissues are sensitive to contamination, self-folding structures are preferred over the use of external actuators to avoid contacts.…”

Miniaturized Origami Robots: Actuation Approaches and Potential Applications

“…Nowadays, most electric actuation miniaturized origami robots are based on SMA, which provides superior conductivity, toughness, mechanical strength, and ductility. [22] SMA is an intermetallic alloy that can be deformed, but will return to its original shape when heated. [23] Benefiting from the shape memory effect, SMA can transform Joule heat into mechanical energy to realize the self-folding of origami robots.…”

Metal Blossom: Laser Forming Complex and Freeform Metal Structures Imitating Flower Blooming

“…Laser-forming origami uses a laser to repeatedly induce localized thermoelastic expansion on metallic surfaces and generate plastic deformations that emulate folding, forming 3D metallic structures (4, 5) without human intervention (6). Laser-forming origami begins with the cutting of a net (7), a planar surface that can be continuously folded to transform into a goal shape under fine-tuned conditions for the speed, power, and laser beam size (8). Compared with traditional mechanical forming processes, laser forming with negligible springback (9) has seen use in fabricating sensitive electronics and as a forming tool for astronauts in zero-gravity environments (10,11).…”

“…Recent research has shown that laser-induced origami performed using budget laser cutters has potential in reducing fabrication costs of metallic (6), acrylic (14), and polyethylene terephthalate structures (15), increasing the accessibility of laser-induced origami to the general public. The problem faced is that a typical laser cutter is believed to be incapable of creating practical structures beyond those with a few folds as demonstrated by recent works (8,13), due to its limited degrees of freedom. Indeed, this limitation is universal to many origami or kirigami-based fabrication routes that use external light or focused ion beams (2).…”