Welsh Researchers Use Optomec Aerosol Jet Technology to 3D Print Hair-Sized Sensors

We hear a lot about 3D printing being used in aerospace, usually to print larger components. But researchers at Swansea University in Wales are finding that it’s also very useful in printing the smallest parts of an aircraft. The university’s Welsh Centre for Printing and Coating (WCPC) have been working with Optomec’s Aerosol Jet technology to print components the size of a human hair. What’s more, the minuscule strain sensors and optical creep sensors can be printed directly onto the surface of turbine blades.

The technology means a lot for aircraft maintenance. By printing sensors directly onto working blades, the research team was able to monitor each component in real time, which could potentially cut costs and time and allow for higher engine running temperatures and fuel efficiency. The team also developed a high temperature optical creep gauge sensor utilizing a laser inspection system and optical light management, allowing them to determine the degree of creep within a component down to 10nm.

If you’re unfamiliar with Aerosol Jet technology, here’s a quick rundown. A mist generator atomizes a conductive nano-platinum or nano-silver ink, the particles of which are then refined in a virtual impactor. The stream of material is then aerodynamically focused with a flow guidance deposition head, creating an annular flow of sheath gas to collimate the aerosol. A nozzle directed at the substrate focuses the stream to as small as a tenth of a size of the nozzle orifice, at which point CNC commands position the flow guidance head to deposit the material. The 5mm standoff distance from the deposition head to the substrate ensures that the material is deposited accurately on non-planar substrates, over existing structures and into channels.

Once the conductive ink is deposited, it undergoes thermal treatment to finalize its mechanical properties, electrical conduction and adhesion to the substrate, resulting in a thin, high-quality film as fine as 10nm with a high degree of edge definition and near-bulk properties. The researchers are also looking into the possibility of locally depositing the ink using a laser treatment process that would allow for the use of substrate materials with very low temperature tolerances.

According to the researchers, benefits of the technology include:

• Feature Sizes to 10 microns
• Thin Layer Deposition from 10nm
• Many Materials and Substrates can be used
• 3-D deposition
• Nanomaterial Deposition Capability

At the moment, the researchers are using conductive nano-silver ink which is stable up to temperatures of 250°C, but they’re working on developing a nano-platinum ink for high temperature components up to 1200°C. Eliminating temperature limitations on the sensors would be a major advancement for the aerospace industry. The team is also working on developing the smallest printed temperature sensors ever developed for aerospace components, sized as small as 30µm. The team’s research into printed electronics means a lot not just for the aerospace industry, but for consumer electronics in general.

Discuss these 3D printed sensors in the Optomec forum thread on 3DPB.com.