Using a variation of the technology the team was also able to create polymer-bonded magnets with intricate geometries and arbitrary shapes, which they say could open up new possibilities for manufacturing and product design.
The key to both, has been the use of an advanced form of 3D printing called direct write technology. Unlike conventional additive manufacturing, which uses lasers to fuse layers of fine metal powder into a solid object, direct write technology uses semisolid metal 'ink' that is extruded from a nozzle.
The UConn-UTRC scientists say this process allowed them to create fine lines of conductive silver filament that could be embedded into 3D printed machine components while they were made. The lines, which are capable of conducting electric current, act as wear sensors that can detect damage to the part.
According to the researchers, arallel lines of silver filament, each coupled with a tiny 3D printed resistor, are embedded into a component. The interconnected lines form an electrical circuit when voltage is applied. As lines are embedded deeper and deeper into a component from the surface, each new line and resistor are assigned an increasingly higher voltage value. Any damage to the component, such as wear or abrasion caused by friction from moving parts, would cut into one or more of the lines, breaking the circuit at that stage. The more lines that are broken, the greater the damage. Real-time voltage readings allow engineers to assess potential damage and wear to a component without having to take an entire machine apart.
The UConn-UTRC team was able to embed sensor lines that were just 15 microns wide and 50 microns apart to allow detection of very minute damage.
To develop the sensor, the team measured and optimised the flow properties of the silver-infused ink so that micron-sized lines could be reliably deposited without clogging the nozzle or causing substantial spreading after deposition.
The scientists also used direct write technology to create components with magnetic coatings or magnetic material embedded inside them. These polymer-bonded magnets are capable of conforming to any variety of shape, and eliminate the need for separate housings in machines requiring magnetic parts, the researchers say.
"This opens up a lot of exciting opportunities," claims Associate Professor Anson Maof UConn. "Imagine magnets that can take on different shapes and fit seamlessly between other functional components. Also, the resultant magnetic field that is created may be further manipulated and optimised by changing the shape of the magnets."
Current methods for creating custom 3D printed magnets rely on high-temperature curing, which reduces a material's magnetic properties. The scientists at UConn and UTRC overcame this problem by using low-temperature UV light to cure the magnets.
Embedding magnetic material directly into components could lead to new product designs that are more aerodynamic, lighter, and efficient, the researchers add.
