Researchers from MIT have used a new 3D-printing method that works with both solids and liquids to create a six-legged, hydraulically-powered robot. The team from MIT's Computer Science and Artificial Intelligence Laboratory (CSAIL) created the bot using a commercially-available 3D printer. Several sets of tiny bellows power the robot's legs, and are filled with liquid deposited during the 22-hour printing process.

"All you have to do is stick in a battery and motor."

The bot's creation shows how 3D printing can advance from making individual components to whole active systems. CSAIL director Daniela Rus said in a press release that the research was a step towards "the rapid fabrication of functional machines." She added: "All you have to do is stick in a battery and motor, and you have a robot that can practically walk right out of the printer." The resulting bots weighs about 1.5 pounds and is just under six inches long. Future applications for such cheap robots could include exploring disaster sites where humans cannot easily go.

The process used to create the robot has been dubbed "printable hydraulics," and researchers say it's one of the trickiest 3D-printing methods to harness. The CSAIL researchers' solution is to use an inkjet printer to deposit small droplets of liquid material, then use high-intensity UV light to solidify the required parts. These droplets of material are tiny — just 20 to 30 microns in diameter, or less than half the width of a human hair. And then, like regular 3D printing, the end creation is built up layer by layer. As well as the hexapod robot, the researchers also made a fluid-filled robotic hand that can pick up delicate objects without breaking them.