A team of researchers at the University of Utah has developed a new type of 3D printer that can create tiny, detailed objects in just one step.
Instead of building an object layer by layer like most 3D printers, the new system forms the entire shape at once using a special holographic laser.
The process takes only about 20 seconds, compared with the hours that many laser-based 3D printers need.
The research was published in the journal Nature Communications. The project was led by Professor Rajesh Menon from the University of Utah’s Department of Electrical and Computer Engineering, together with researcher Dajun Lin.
Traditional 3D printers make objects by adding one thin layer after another. While this method works well, it can leave tiny seams between layers. These weak spots may reduce the strength of the finished object.
The new printing method avoids this problem by creating the whole structure in a single step, producing a stronger and smoother result.
The new printer uses a very small device called a nanopatterned mask. This mask changes the path of laser light and turns it into a hologram that matches the shape the researchers want to create. The laser then hardens only the selected areas inside a special liquid-like material called SU-8. The parts that are not exposed to the laser remain soft and can simply be washed away, leaving the finished object behind.
SU-8 is already widely used in photolithography, a manufacturing process commonly used to make tiny electronic parts. The material contains long polymer chains that join together and become solid when they are exposed to laser light.
Printing in three dimensions is much more difficult than printing on a flat surface. As the laser travels through the material, the light can bend and scatter, making the final shape blurry. To solve this problem, the research team designed their nanopatterned mask to correct for this bending of light. This allows the laser to focus its energy exactly where it is needed inside the material.
To test their new system, the researchers printed a variety of tiny structures, including microtubule assemblies with individual tubes measuring only about 6 micrometers across. For comparison, a human hair is roughly 70 micrometers thick. They also produced long lattice-like structures with very high length-to-width ratios.
The team tested these printed structures by squeezing them to measure their strength. They also showed that the tiny tubes could move liquids through capillary action, the same natural process that allows water to travel through plant stems without pumps.
Although the technology is a major step forward, it is not yet capable of producing every kind of 3D shape. The researchers describe the current method as creating “extended 2D” objects because it offers excellent control over length and width, while the height is less flexible.
The team is now working on the next stage of the technology. Their goal is to create true three-dimensional objects with the same speed, strength, and accuracy, opening the door to faster manufacturing of tiny medical devices, electronic components, and other advanced products.
