Next, the Copier Will Reproduce Popsicles

Does the world need a computer printer that spits out ice sculptures? Ming Leu, Wei Zhang, and their fellow mechanical engineers at the University of Missouri-Rolla think so. These days, industrial designers do a lot of their brainstorming with 3-D computer programs. But then they need to build physical prototypes or make molds and casts. So Leu and Zhang invented a device that constructs a 3-D model out of ice in a matter of hours, using a technique they call rapid- freeze prototyping. Following specifications from the computer, the machine moves back and forth inside a refrigerated container, squeezing out water droplets where needed. The water freezes and accumulates, layer by layer, into the shape of the desired part or object. Zhang says the ice printer could also fabricate detailed 3-D models of patients' MRI scans, which could assist in surgery. "Then the doctor can see through the patient's organs ...