Hod Lipson, de la Cornell University, ha dado esta conferencia en varios sitios, explicando el futuro de la impresión en 3D.
Si no tienes paciencia para ver el vídeo, aquí va un resumen de la charla que dio Hod Lipson el 12 de abril en el congreso de la Materials Research Society (MRS). El tema dará que hablar.
Rapid prototyping—the ability to make a 3D model of any object by building it up in layers of material using a “3D printing” process—has made great strides in the last decade, according to Hod Lipson of Cornell University. In an informative and often humorous symposium X talk entitled, “Digital Matter—The Shape of Things to Come,” Lipson said the technique has gone from the lab to the home, with 3D printers available for hobbyists at a cost of about $1,000. These devices can print anything from “stainless steel to cheese,” Lipson said. You can download plans for thousands of objects from Web sites devoted to the craft. Got a broken gear in your bicycle? Download the details of the part from the web and print yourself a new gear instead of going to the bicycle repair shop, Lipson said. If a piece of tubing breaks in his own lab, he and his students are much more likely to print a new one than to walk down to the hall to the instrument shop, because “who wants to walk down the hall?” he said. Lipson predicts the end of machine shops in the future, although he admits that he is in the minority among colleagues on this subject. With the current state of technology, “complexity is free,” Lipson repeated several times during the talk.
The best 3D printers available print analog (continuous) patterns with a resolution of 10 microns at a rate of several layers per minute, depending on the area of each layer. Lipson showed printed objects ranging from a concrete bench capable of seating two people to a model of a medieval cathedral on the micron scale. The “inks” that can be printed include polymers, ceramics, metals, clay, wood dust, and glass, although left to their own devices many hobbyists seem to prefer food products like peanut butter, cheese and chocolate, including one successful effort to print a cake with frosting in its own pan. Lipson believes that the “killer app” that may finally make 3D printers an indispensable object in every home, like computers are today, just might be this type of creative food processing, though he admits it hard to know where the killer app might come from.
But Lipson and his group are scientists and engineers, not hobbyists. Having shown that virtually any inactive object can be fashioned using 3D printing, they are exploring ways to print active objects that contain actuators, valves, wires, and batteries, for example—a mixture of complex parts made of multiple materials, all printed in one machine in one continuous process. “We want to make battery-powered robots with the batteries included,” Lipson said. Printing a battery is proving to be challenge, because they contain a separating layer made of paper, and “ironically, we can print anything, but we can’t print paper,” Lipson said. His lab’s focus on robots got the attention of the New York Times several years back, which led to a headline containing words something like (I’m paraphrasing here) “A Robot that Makes its own Robots.” Lipson gave Evan Malone, one of his Ph.D. candidates, the task of printing a robot that would walk out of the printer on its own power as a condition for his graduation: “When the robot walks, he [Malone] walks,” Lipson said. In the end, the Malone produced a robot shaped like a fish that waddled out of the printer, and earned his Ph.D.
Lipson described many areas in which 3D printing has been scientifically successful. Archaeologists are able to duplicate cuneiform objects with the same weight, look, and feel as the original, thus making rare artifacts available to a wider body of students. In biomedicine, a leg scan can produce a design for a custom-fit prosthetic limb that fits the patient perfectly; a scan of an ear canal can similarly produce a custom-made hearing aid casing. Surgeons, who only get one chance to reassemble a mass of fractured and displaced bones in an accident victim, have called on Lipson to produce plastic models of the bones so they can practice putting the puzzle pieces back together before going into surgery. His team is also experimenting with printing living cells in hydrogels and then crosslinking them to form a replacement meniscus for a kneecap. As perhaps the ultimate biological challenge in this field, Lipson asked, “Can we print live cells into the desired location of a body in vivo?
From a materials point of view, a 3D printer should be able to make new materials by blending material “inks” in ways that are not possible using standard alloying or compounding methods. Perhaps the engineer in certain cases would not even have to specify which materials to use in advance. Lipson can envision a future in which the printer acts like a compiler. You give it high level instructions about what you want–say, a beam with desired flexing properties and stiffness—and it chooses the materials from its available inks based on a knowledge of the mechanical properties and phase diagrams of different ink combinations to produce the beam to your specifications. For mixtures of hard and soft materials, the properties depend on how you mix the two materials—checkerboard, stripes, or some random pattern? It should be possible, Lipson said, to “fabricate a lot of different patterns and have machine learning try to optimize and create models having the desired properties.”
Returning to the title of his talk, Lipson closed by discussing the ultimate switch from analog inks that are deposited in a continuous stream to discrete, digital matter (nanoparticles?) that would be “rapidly assembled” into 3D structures. “There is always a resistance in moving from analog to digital,” he said, citing computers and camera technology as examples, “but once the move was made, they never went back.”
