Predictable motion in soft robotics has traditionally depended on complex molds and multi-step fabrication processes, slowing design iteration and limiting customization. Researchers atHarvard Universityhave now introduced a multimaterial 3D printing approach that embeds actuation directly into flexible structures during fabrication, allowing soft robotic devices to be produced with built-in, programmable movement.
Reported inAdvanced Materials, the method uses additive manufacturing to create filament-based components with precisely engineered internal channels that enable controlled bending and deformation when pressurized with air, eliminating assembly steps and allowing faster prototyping, design freedom, and on-demand customization compared to conventional manufacturing. The new method is expected to accelerate the development of adaptive systems for surgical robotics, wearable assistive technologies, and flexible industrial automation.
The study was conducted by graduate student Jackson Wilt and former postdoctoral researcher Natalie Larson in Jennifer Lewis’s lab at Harvard SEAS, with support from theU.S. National Science Foundationand theArmy Research Office’s Multidisciplinary University Research Initiative (ARO MURI).
Rotational Multimaterial 3D Printing Approach
The fabrication method builds on a technology known as rotational multimaterial 3D printing, previously developed in the Lewis laboratory. This technique uses a single nozzle capable of depositing multiple materials at once. As the printing system rotates and shifts orientation, it deposits material in customizable configurations. Earlier work from the group used this strategy to create helical soft structures that function as artificial muscles and other adaptive components.
In the new study, the team produced filaments featuring a polyurethane outer layer combined with an internal channel formed from a poloxamer polymer commonly used in hair gels. These filaments could be arranged in linear configurations as well as flat or elevated patterns. By adjusting parameters such as nozzle geometry, rotational speed, and material flow rate, the researchers controlled the size, orientation, and geometry of each internal channel with high precision.
“We use two materials from a single outlet, which can be rotated to program the direction the robot bends when inflated,” Wilt said. “Our goals are aligned with creating soft, bio-inspired robots for various applications.”
After the outer shell hardened, the poloxamer core was removed through a washing process, leaving behind tubular structures with hollow interiors. These channels can be pressurized to enable directional bending, allowing the resulting devices to expand, contract, or grasp objects.
Streamlined Fabrication Without Molds
The technique introduces a simplified pathway for producing mechanically complex soft robotic systems. Conventional fabrication typically involves molding elastomeric materials, embedding pneumatic pathways onto surfaces, and sealing them beneath additional layers, a process that can be time-consuming and difficult to customize.
Source: 3D Printing Industry
