Additive manufacturing-facilitated blow molding for functional thin-walled polymeric structures

Thin-walled structures capable of large, reversible deformation are key to multistability, origami, kirigami, and soft robotics. However, conventional fabrication techniques-including 3D printing, casting, and laser cutting-suffer from low durability, complex workflows, and restricted geometric freedom, hindering repeatable production. We introduce additive manufacturing-facilitated blow molding (AM-BM), combining the design flexibility of additive manufacturing with the robustness of blow molding. Replacing metal molds with additively manufactured resin ones enables rapid, low-cost fabrication of thin-walled components with tunable geometry and controllable wall thickness out of diverse thermoplastics. The thickness control allows thin-walled components to function as rigid load-bearing elements or compliant hinges. Demonstrations include multistable structures with geometry-controlled reconfigurability; origami and kirigami structures with extensive design freedom and uniform mechanical properties; and soft actuators and robots with ultrahigh load-to-weight ratios and rapid response. AM-BM offers a versatile, scalable route to thin-walled structures combining geometric freedom, mechanical functionality, and efficient production.