The new 3D printer uses light to turn gooey liquids into difficult hard objects within minutes.
The inventor was called a "replicator" – a Star Trek device that can implement any object on demand – a 3D printer can create smoother, more flexible and sophisticated objects than what is possible with traditional 3D printers. It can also overlay an existing object with new materials, such as attaching a handle to the metal screwdriver shaft that the current printers are trying to do.
Scientists say the technology is capable of transforming denture products into eyeglass lenses.
"I think this is the way to further massive objects, whether they are prostheses or jogging shoes," said Hayden Taylor, the professor of mechanical engineering at the University of California, Berkeley, and author of the oldest. describing the printer that is being displayed online today (January 31) in a magazine Science.
"The fact that you could make a metallic component or something from another manufacturing process and add it to customizable geometry, I think it can change the way products are designed," said Taylor.
Most 3D printers, including other light-based light, create a layer of 3D objects by layer. This leads to the “stair step” effect along the edges. They also find it difficult to create flexible items because the protruding materials can deform during the printing process, and support is required to print objects of certain shapes, such as arches.
The new printer is based on a viscous liquid that reacts to form a solid if it is exposed to a certain light threshold. Designing carefully-designed light patterns – basically "movies" – on a rotating fluid cylinder, which strengthens the desired shape "instantly."
"Essentially, you have a video game projector that I literally import from home, and then connect it to a laptop and use it to design a series of computed images while the engine turns the balloon that has the 3D printing resin," said Taylor. "Obviously, it has a lot of sophistication – how you formulate the resin and, first, how to calculate the images that will be projected, but the obstacle to creating a very simple version of this tool is not so high. ”
Taylor and the team used the printer to create a series of objects, from a small model of Rodin's 'Thinker' statue and a custom jaw bone model. Currently, they can produce objects with a diameter of up to four inches.
"This is the first case where we do not need to create custom layers of 3D layers by layer," said Brett Kelly, the first author on paper who completed work while a graduate who worked at UC Berkeley and Lawrence Livermore. National Laboratory. "It makes 3D printing truly three-dimensional."
CT scan – reverse
New printers were inspired by computed tomography (CT) scans that help doctors find tumors and fractures in the body.
CT scans projects from X-ray or other electromagnetic radiation into the body from all different angles. When analyzing the transmitted energy models, object geometry is revealed.
"Basically we changed this principle," said Taylor. "We are trying to create an object, not to measure an object, but in reality many of the theories that allow us to do this can be transformed from the theory underlying computerized tomography."
In addition to the light that requires complex calculations to obtain precise shapes and intensities, the second biggest challenge faced by researchers was to formulate material that remains liquid when exposed to light but reacts hard when exposed to a lot of light. .
"The liquid you don't want to cure will definitely pass through the light, so this transition from liquid to solid should be the threshold for light exposure," said Taylor.
The 3D printing resin consists of liquid polymers mixed with photosensitive molecules and dissolved oxygen. Light activates a photosensitive compound that reduces oxygen. Only in 3D regions where all the oxygen is spent, the polymers form a "cross-link" that converts the resin from liquid to solid. Unused resin can be recycled by heating it in an oxygen atmosphere, Taylor said.
"Our technique produces almost no material waste, and the raw material is 100% reusable," said Hossein Heidari, graduate of Taylor's laboratory at UC Berkeley and co-author. "This is another advantage of 3D printing."
Objects also need not be transparent. Researchers printed items that appear to be opaque using a dye that transmits light at the curing wavelength, but absorbs most of the other wavelengths.
"This is particularly satisfying for me because it creates a new volumetric or" one-time "3D printing system that we have started to build in recent years," said Maxim Shusteff, a Human Resources Engineer at Livermore. "We hope this will pave the way for many other researchers to explore this exciting technology field."
Indrasen Bhattacharya from UC Berkeley is the first author of the work. Other authors are Christopher M. Spadaccini of Lawrence Livermore National Laboratory.
This work was supported by UC Berkeley Faculty Start-up Funds, as well as laboratory-led R&D funds from Lawrence Livermore National Laboratory. The team has filed a patent application for this technique.