The process, which is typically used for printed electronics applications, can fabricate parts with resolutions down to just 15 microns. This is virtually invisible to the human eye at about ⅕ the width of a human hair. Optomec has demonstrated its impressive Aerosol Jet capabilities with a whole host of material types, including polymers, composites, and even metals.
With the issuing of the new patents, the company’s IP portfolio now totals more 75 patents, and includes global protection across the US, Asia, and Europe.
Dr. Michael Renn, CTO of Optomec, has been attributed with the new patents, bringing his personal tally to more than 50. He states, “Optomec continues to invest heavily in its core technology, seeking to extend the already broad range of applications for its Aerosol Jet solution. The capability demonstrated with our 3D Printed Micro-structures work is already seeing potential applications in Semiconductor Packaging and Medical Device markets.”
How does Aerosol Jet work?
Aerosol Jet 3D printing works by precisely depositing small volumes of electronic inks onto substrates. The jettable ink is first placed in an atomizer, where a dense mist of ink droplets is created. Each droplet spans between 1 and 5 microns in diameter. The ink is then jetted out of a nozzle alongside a sheath gas, which works to surround the aerosol ink with a ring. Optomec systems typically use dry nitrogen or compressed air as the sheath gas.
As the gas and ink pass through the tip of the nozzle, they are accelerated and the 3D printing aerosol material focuses itself into a tight beam of droplets. Meanwhile, the sheath gas insulates the nozzle from any material contact, so clogging is never an issue.
Since the inks used in Aerosol Jet can be integrated with conductive silver nanoparticles, the 3D printing technique lends itself quite well to electronics applications. This includes components such as resistors, capacitors, antennas, sensors, and thin film transistors – all of which have been fabricated on Optomec systems in the past. The performances of these components can also be closely controlled via the printing parameters of the Aerosol Jet 3D printer.
Scaling down to the micron
Optomec’s new patents, including US Patent No. 10,994473, describe a method of 3D printing micro-structures by leveraging in-situ heating or UV illumination to modify the mechanical properties of the aerosol inks as they are deposited.
In the case of UV illumination, the light would partially cure the photopolymer ink droplets in-flight, while a heating element would cause solvent-based inks to rapidly dry via evaporation. According to the document, this has the effect of increasing the aerosol ink’s viscosity, enabling it to form miniscule, free-standing 3D structures. This technique has allowed Optomec to achieve lateral resolutions of 15 microns, along with layer thicknesses of 100 nanometers and aspect ratios of 100x for millimeter-tall structures.
Still, Aerosol Jet isn’t the only additive manufacturing technology capable of microstructure fabrication. Earlier this year, scientists from the University of Freiburg used two-photon-polymerization (2PP) technology from 3D printer manufacturer Nanoscribe to fabricate glass silica microstructures with a resolution of just a few tenths of a micrometer. Using the company’s novel ‘Glassomer’ polymer-based resin, the team 3D printed objects with a surface roughness of 6 nanometers, much less than the 40-200 nanometers seen in many other glass parts.
Elsewhere, 3D printer OEM Nanofabrica has also built a name for itself with its flagship Tera 250 microprinting system. The Tera 250 operates on a micro-DLP light engine and works by projecting UV light into a vat filled with polymer resin and curing it layer by layer into a 3D build. The system is capable of achieving an impressive one-micron resolution over a relatively sizable build volume measuring 50 x 50 x 100mm.
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Featured image shows microstructures 3D printed via Aerosol Jet. Image via Optomec.