MIT Can Now 3-D Print Robots Made of Both Solids and Liquids

Building a robot is hard work. But many of those obstacles melt away when you can 3-D print a robot with liquids and solids simultaneously. Their "printable hydraulics" method uses an inkjet printer to build up layer upon layer material less than half the width of a human hair one drop at a time. Several 3-D printed bellows use the fluid pressure of that pumping as a mechanical force, allowing the robot to move. The important thing to remember, though, is that it's a little plastic shuffling robot that took just 22 hours to print, with relatively small material cost.