3D printing has revolutionized in the last years the industrial sector, of medicine or even of education. The traditional methods of this technology consist of building objects layer by layer. This process limits the speed of printing and in some cases causes defects that reduce the strength of the piece. Now a group of researchers has developed a new technique that eliminates the use of layers and prints the entire volume of an object at a time, according to a study published this Thursday in the scientific journal Science.
This procedure, called computerized axial lithography (CAL), offers new possibilities. In addition to faster printing than usual – from 30 to 120 seconds – it allows printing on very viscous or even solid starting materials and creating objects with very smooth surfaces. But the breakthrough, according to the researchers, is that with this new method you can print around a pre-existing solid object.
Until now, no machine could do it, as explained to EL PAÍS Antonio Sánchez, CEO of the company specializing in 3D printing AsorCad: "Today you first print and then you can put an object inside, but you can not print directly around an object". This expert, who has not participated in the study, also highlights the possibility offered by this method of "changing the characteristics of the material so that it has harder and softer areas and deciding which part to leave more gelatinous or more rigid".
Researchers have been able to print different centimetric objects with this technique in less than two minutes. For example, a diminutive version of The Thinker -One of the most famous sculptures of the French artist Auguste Rodin-, a small plane, a donut or a sphere. For this, they have used both engineering polymers and gelatin methacrylate hydrogel.
Hayden Taylor, co-author of the study and professor at the University of California, says that computerized axial lithography "works by rotating a container with light sensitive material while projecting a custom light pattern on it": "As the material rotates, the projected image changes. The accumulated amount of light that is absorbed in each location can be controlled independently and when the amount of light absorbed exceeds a certain threshold, the material solidifies. "
Uses of the new technique
"In general, we believe that computerized axial lithography could be used throughout the industry to manufacture a wide range of plastic components," says Taylor. This method could be particularly useful for manufacturing products that involve enclosing a pre-existing solid object in a custom plastic housing. The underlying object could have been made with a different material or manufacturing process. "For example, it could be a metallic structure produced in series and with this method the surrounding component could be produced", explains the researcher. The new method, he says, could mean an advance in the manufacture of prosthetic devices or tools.
The breakthrough, according to the researchers, is that with this new method you can print around a pre-existing solid object
The authors of the study have also managed to print components in very soft hydrogel materials. Now they intend to explore how these advances in tissue engineering can be used and look for new printable materials. But the main limitation of this method is the size of the printed figures. "He can not tackle very large pieces at once. In general all 3D prints have that limitation currently, "says Sanchez. For this reason, it is also essential for researchers to find the way to print larger objects.