- Researchers use UV light instead of high heat to make glass that can be used for medical devices, microelectronics, and more
A group of Georgia Tech researchers has developed a new method for 3D printing glass lenses and other structures that could be used in medical devices and research. The process was carried out using ultraviolet light rather than extremely high temperatures.
The heat required to convert printed polymer resin to silica glass is reduced from 1,100 degrees Celsius to around 220 degrees Celsius, and the curing time is reduced from half a day or more to just five hours. They’ve used it to create a wide range of glass microstructures, including tiny lenses the width of a human hair that could be used for medical imaging inside the body.
The study is led by George W. Woodruff School of Mechanical Engineering, Professor H. Jerry Qi, and the team published their findings in the journal Science Advances on October 4.
3D Printing Glass Microstructures
These 3D printed glass structures could be used to create microfluidic devices, which are typically small computer chip-like devices with nano- or microscale channels used to study cells or biofluids in motion. According to the researchers, glass chips would have advantages over current polymer-based chips in terms of corrosion resistance from chemicals or bodily fluids.
“This is one of the exploratory examples showing that it is possible to fabricate ceramics at mild conditions, because silica is a kind of ceramic. It is a very challenging problem. We have a team that includes people from chemistry and materials science engaged in a data-driven approach to push the boundary and see if we can produce more ceramics with this approach.”– Professor H. Jerry Qi
According to Mingzhe Li, the study’s first author and a postdoctoral researcher in Qi’s lab, the low-temperature process would also enable the fabrication of microelectronics with glass structures.
Mingzhe Li explained, “We can print in situ, directly into microelectronics. Semiconductor materials used in microelectronics cannot withstand very high temperatures. If we want to print directly on a board, we have to do it at a low temperature, and 200 degrees C can definitely do this job.”
The team’s printing process offers a more environmentally friendly option for silica glass manufacturing. Polymer mixtures are typically used in glass additive manufacturing processes and must be burned away with heat once the desired shapes are formed. The Georgia Tech team’s method involves the use of a photoresin that is converted to glass using a type of ultraviolet light known as deep UV light. This allows for lower temperatures, which saves a significant amount of heating energy. And because they don’t need to add extra polymer material, they use fewer resources in the first place.
The researchers used a light-sensitive resin based on PDMS, a common soft polymer, and they did not need to add silica nanoparticles to their mix, as other 3D printing methods do. The end result is highly transparent glass without the potential optical issues that can arise when nanoparticles are added. Their glass lenses were as smooth as commercially produced fused silica glass.
At the moment, their process produces structures 200-300 micrometres in size, which is equivalent to the thickness of a piece of paper or the diameter of a human hair. They’ve begun work on scaling up the glass structures that can be 3D printed to the millimetre scale.
Qi stated that advances in 3D printing technology and interest in ceramics — inorganic, nonmetallic materials that are shaped, fired, hardened, and become heat- and corrosion-resistant — prompted the group to consider new manufacturing methods.
Qi added, “We really want to do the cutting-edge — things nobody has done before in the space of low-temperature conversion of polymers to ceramics within additive manufacturing. We were encouraged by the Office of Naval Research. They know the risk is high, but they gave us a lot of freedom to try new things.”
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