First of all, a living hinge is not a biological entity nor does it move on its own. Think of the top of a Tic Tac container where the lid and the cover are a single piece, and the thin plastic holding them together flexes to allow you to reach the candies disguised as mints. [Xiaoyu “Rayne” Zheng] at Virginia Tech designed a method of multimaterial programmable additive manufacturing which is fancy-ese for printing with more than one type of material.
The process works under the premise of printing a 3D latticework, similar to the “FILL” function of a consumer printer. Each segment of material is determined by the software and mixed on the spot by the printer and cured before moving onto the next segment. Like building a bridge one beam at a time, if that bridge were meant for tardigrades and many beams were fabricated each minute. Mixing up each segment as needed means that a different recipe results in a different rigidity, so it is possible to make a robotic leg with stiff “bones” and flexible “joints.”
We love printing in different materials, even if it is only one medium at a time. Printing in metal is useful and could be consumer level soon, but you can print in chocolate right now.
Via Phys.org. Thank you again for the tip, [Qes].








Some solutions come from no more than looking at two dissimilar things while in the right mindset, and realizing they can be mashed together. In this case I had recently segmented a large, hollow, 3D model into smaller 3D-printer-sized pieces and printed them all out, but found myself with a problem. I now had a large number of curved, thin-walled pieces that needed to be connected flush with one another. These were essentially butt joints on all sides — the weakest kind of joint — offering very little surface for gluing. On top of it all, the curved surfaces meant clamping was impractical, and any movement of the pieces while gluing would result in other pieces not lining up.