While most research projects are funded and target a specific purpose, occasionally a professor will conduct an unfunded project that will still show definite benefits in several applications. For example, Mechanical & Aerospace Engineering Associate Professor Panos Shiakolas is currently experimenting with a novel process to quickly make micro-sized parts for microelectromechanical systems (MEMS).

Most micro-sized parts are created using the traditional photolithography process, where a photosensitive material (mask) is applied to a metal, exposed to a light that removes certain areas of the mask and then acid is used to etch away the exposed areas. This process is repeated over and over to remove more metal in the same place or in new areas.

Dr. Shiakolas’ process, on the other hand, adds layers of material instead of removing them to create parts. This process utilizes focused laser light and a two-part, liquid resin consisting of a monomer and a photoinitiator. The laser is programmed to fire short bursts through focusing lenses at targeted areas inside the liquid resin. Light striking the photoinitiator forms bonds in the resin, causing it to harden. The size of these solid areas can be varied by adjusting the pulse rate and power of the laser and the focus length of the lenses. The resin that isn’t hardened is poured off and reused, leaving behind a solid micro-structure or device.

This photo of a nozzle shows the complexity of microstructures the process is capable of producing.

Like forming a picture with individual pixels, individual points of hardened resin become a larger part. “You might call them volumetric pixels,” Dr. Shiakolas said. “One of the real benefits of this manufacturing method is that multiple identical parts can be formed at the same time simply by splitting the laser beam,” he continued. “We can accomplish the rapid prototyping of non-conventional structures in little time and expense and without chemical byproducts that need to be properly disposed.”

The parts constructed with this method are pure three-dimensional structures, with 3D curvatures and angles as well as interior cavities, as opposed to lithography where “two-and-a-half D” structures could be fabricated. Even though lithographic structures have length, width and depth, they lack the out-of-plane curvatures and angles of a true 3D composition.

Dr. Shiakolas is looking for collaborators to investigate uses for the process. “I can think of several possible applications in bioengineering, such as molds, nozzles and sieves,” he said. “We could also fabricate sensor, actuators, optical waveguides, splitters and prisms; well, just about any arbitrary solid shape with micro-nano features and resolution.”