Scientists at UConn and UTRC used direct write technology, an advanced form of additive manufacturing, to create a novel sensor that can be embedded into machine components while they are being made. The sensors can detect and report wear and damage to a part to the machine's user. Source: Peter Morenus/UConn PhotoUsing an advanced form of 3D printing known as direct write technology, scientists have created ‘smart’ machine components that indicate their wear or damage with voltage readings. The benefits to end-users may be as simple as minimizing downtime and as significant as preventing severe injury and even death due to equipment malfunction.

Direct write technology uses semisolid metal 'ink' extruded from a nozzle, rather than lasers — the conventional method, to fuse layers of fine metal powder into a solid object.

Scientists at UConn and the United Technologies Research Center (UTRC) successfully used direct write technology to create fine lines of conductive silver filament. During the manufacturing process, these filaments are embedded into the components and form an electrical circuit when voltage is applied. Over the life of the component, any damage or wear cuts the lines, breaking the circuit. The greater the damage, the more lines are cut. Engineers can assess damage with real-time voltage readings. This means the machine housing the component does not need to be taken apart and there is no need to visually inspect the area in order to detect damage or wear.

At just 15 microns wide (an average human hair is 100 microns wide) and spaced 50 microns apart, the sensor lines that the UCONN-UTRC team embedded are able to detect very slight damage.

According to a UConn press release, embedding the micro sensors in the ceramic coating of jet engine turbine fan blades is one example of how this technology could be used. “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,” the press release states.

(On April 17, a Southwest Airlines Boeing 737 experienced a fan blade failure, which resulted in the loss of the engine inlet and cowling as well as the death of a passenger.)

"This changes the way we look at manufacturing," says Sameh Dardona, associate director of research and innovation at UTRC. "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 performance, avoid failures, and save costs."

More information on the fabrication of the wear sensors is available in Additive Manufacturing.