Additive manufacturing is becoming increasingly popular in robotics because it enables the design of flexible, customized, and more efficient devices. As new materials become compatible with a wider range of 3D printing processes, the possibilities continue to expand, making it possible to create flexible and even biocompatible robots. At Harvard, a team of researchers is focusing on 3D printing soft robots that can change shape, bend, and deform when inflated with air. Here’s how it works.
The concept is simple: the team developed a multi-material rotary 3D printing process that enables them to deposit multiple materials through a single nozzle along a precise path. The nozzle rotates as it extrudes the gel-like material. This motion not only allows for rapid material switching but also makes it possible to create both simple and highly complex shapes.
First, the team designs an internal channel made of poloxamer, a polymer commonly used in hair gels. By adjusting the 3D printer nozzle, its rotation speed, and the material flow rate, they were able to precisely control the shape, size, and orientation of each channel.
The structure is then coated with a polyurethane membrane. Once it solidifies, the researchers remove the inner poloxamer core. The result is a hollow shell that can be pressurized to bend into different shapes. This forms the foundation of a soft robotic device capable of contracting, gripping objects, or even expanding.
The rotary printing platform
Jackson Wilt, a Harvard graduate student and lead researcher on the project, explains:
We use two materials from a single outlet, which can be rotated to program the direction the robot bends when inflated. Our goals are aligned with creating soft, bio-inspired robots for various applications.
This multi-material printing method eliminates the need to create molds. Instead of pouring a flexible material, patterning pneumatic channels onto the mold surface, and encapsulating them in an additional layer, the process produces a structure that is ready to use and program. As a result, the robot can be deployed quickly and tailored to specific applications. For more information, click HERE.
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Photo credits: Harvard John A. Paulson School of Engineering and Applied Sciences