The most useful LED light changes the structure of

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Change the structure of 3D printed objects with LED light? MIT chemists have achieved

MIT chemists have developed a new 3D printing technology that allows to change the chemical structure of printed objects and the chemical connection of multiple 3D printed objects. It is reported that this technology can greatly expand the complexity of objects created using 3D printing

3d printing is an incredible manufacturing technology that can create many things from many kinds of materials. However, the technology has its limitations: on the one hand, 3D printed objects are generally unchangeable. They can be post processed, polished, or even processed into smaller shapes, but the chemical structure of 3D printed polymer objects is fixed. But now, a group of MIT chemical experts have developed a new technology for changing the chemical structure of 3D printed objects. Its chemical composition can be changed after printing. This technology also allows multiple 3D printed objects to be fused together

now, the MIT team has published their research results in the recent ACS central scientific journal. Jeremiah Johnson, a Firmenich associate professor of career development in chemistry at MIT and senior author of the research paper, explained to MIT staff how to use this new technology to increase the complexity of 3D printed objects. "The idea is that you can print a material, then take this material, use light to turn the material into something else, or further grow the material," he said

stereolithography, the liquid resin 3D printing technology first adopted by 3D systems, and the liquid resin 3D printing technology promoted by formlabs and other companies are one of the more accurate processes for ordinary users of 3D printing technology. The stereolithography 3D printer irradiates a series of bright projections onto a barrel of liquid resin, which solidifies (hardens) in response to light, and forms a solid object layer by layer through vertebral fracture or collapse. By using stereolithography and combining it with the technology called "active polymerization", Johnson and his team have been able to create 3D printing materials, and the training time can enable operators and maintenance personnel to operate independently; To stop its growth and then start again at a later point in time

as early as 2013, MIT researchers found that by using ultraviolet light, they could break the polymers with 3D printing structure and create reactive molecules called "free radicals" in the national "one belt and one road" strategy. Free radicals can then bind to surrounding new monomers and incorporate them into the original material. Johnson said, "the advantage here is that you can turn on the lights, they grow, you turn off the lights, they stop. This kind of situation may take you two or three hours to take out the finished products. In principle, you can repeat it indefinitely, and they can continue to grow."

unfortunately, trying to control free radicals has proved very difficult, imposing excessive damage on 3D printing materials. But MIT chemists have come up with another way: blue light from LEDs. For example, a polymer used for 3D printing contains a chemical group TTC, which can be activated by an organic catalyst opened by light. When receiving blue light from the LED, these TTCs stretch with the attachment of new monomers. Because these monomers are uniformly added, they provide new properties for materials. "We can take macro materials and grow the way we want," Johnson said

by using LED light technology, MIT researchers found that they can change various properties of 3D printed object structure, including their stiffness and hydrophobicity (the degree to which they repel or absorb water). By adding some type of monomer, chemists can also make materials expand or contract in response to temperature. In addition, they were able to melt two 3D printed objects by shining light on the interconnection area. "This particular process can be used to create huge, chemically stable 3D printing structures with unprecedented complexity," the researchers said

now, an obstacle for researchers is to keep the experimental environment oxygen free, because the organic catalysts used in this process cannot work in the presence of oxygen. However, this set of tests can catalyze other catalysts similar to polymerization in an aerobic environment

by merging the fields of polymer science and materials science, MIT researchers have opened several exciting opportunities for advanced 3D printing

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