Scientists at the United Technologies Research Center and UConn are using advanced additive manufacturing technology to create ‘smart’ machine components that alert users when they are damaged or worn.
The researchers also applied a variation of the technology to create polymer-bonded magnets
Scientists at the United Technologies Research Center and UConn are using advanced additive manufacturing technology to create ‘smart’ machine components that alert users when they are damaged or worn.
The researchers also applied a variation of the technology to create polymer-bonded magnets with intricate geometries and arbitrary shapes, opening up new possibilities for manufacturing and product design.
This changes the way we look at manufacturing. — Sameh Dardona, UTRC
The key to both innovations is 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 viscosity of the metal ink looks like toothpaste being squeezed from a tube.
This process allowed the UConn-UTRC scientists to create fine lines of conductive silver filament that can be embedded into 3D printed machine components while they are being made. The lines, which are capable of conducting electric current, act as wear sensors that can detect damage to the part.
Here’s how they work. Parallel 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.
To get a better idea of how these micro sensors might be used, imagine them being embedded in the ceramic coating of a jet engine turbine fan blade. These blades are subjected to tremendous physical forces and heat. A microscopic crack in the protective coating could potentially be catastrophic to the blade’s performance, yet invisible to the naked eye. With the embedded sensors, mechanics would be alerted to any blade damage promptly so it can be addressed.
“This changes the way we look at manufacturing,” says Sameh Dardona, associate director of research and innovation at UTRC, which serves as the innovation engine for United Technologies Corp. “We can now integrate functions into components to make them more intelligent. These sensors can detect any kind of wear, even corrosion, and report that information to the end user. This helps us improve 