Soft robots made out of flexible, biocompatible materials are in high demand in industries including healthcare, but precisely designing and controlling such robots for specific purposes is a perennial challenge. What if you could 3D print a soft robot with predictable shape-morphing capabilities already built in?
Experts have shown it’s possible. A new fabrication method for printing robotic devices features long filaments with precisely placed hollow channels. When filled with air, the channels allow the device to bend and deform in predetermined ways.
The new approach is built on an innovation called rotational multimaterial 3D printing, in which one nozzle allows more than one material to be printed simultaneously. As the machine rotates and reorients, it extrudes ink in customizable patterns. The lab has used this type of 3D printing to make soft, helical structures that act as artificial muscles and other objects.
Using this general approach, the researchers created filaments made out of a polyurethane outer shell, and an inner channel made out of a polymer commonly found in hair gels, called a poloxamer. The filaments could be arranged in lines, and in both flat and raised patterns. Through precise control of the printer nozzle’s design, rotation speed, and rate of material flow, the researchers programmed the orientation, shape and size of each inner channel.
Once the outer shell solidified, the researchers then washed away the hair gel-like inner channel. The result: tubular structures with hollow channels that can be pressurized to bend in different directions and form the basis for soft devices that expand, contract, and grasp.
