NASA Researchers Devise Method for Real-Time In-Situ Additive Manufacturing Inspection

NASA has made a wide range of forays into 3D printing—and for decades now. From 3D printed rocket engine parts that will pave the way for creating future components to continued efforts for developing 3D printed habitats on Mars, NASA has been and continues to be involved in advancing 3D printing technology.

Now, NASA engineers are getting involved in improving the 3D printing process itself, rather than just impressing us with what they are creating with the technology. Monitoring while printing has become a feature expected by savvy users today, especially from the desktop. But what about industrial processes—where often more is on the line in terms of material and product? Thanks to NASA, monitoring may soon be expanded further for additive manufacturing. This will allow for more opportunity to correct AM processes in real time, with the obvious benefits of less waste in materials and energy, and greater expediency overall. Users are able to pause the prints and make corrections as needed.

Interim inspection improves the quality of parts with intricate internal features like these fuel channels.

With the creation of a method for in situ dimensional inspection of AM parts, researchers at NASA Marshall Space Flight Center offer helpful technology for inspecting internal features like fluid channels and passages—areas that are difficult to check after printing. According to NASA, it also means the potential is there for including a closed-loop feedback system to make automatic corrections. The monitoring system employs cameras that are both visual and infrared, allowing the user to see the print in progress.

The IR cameras collect temperature data needed for validating thermal math models, and the visual cameras collect details for constructing precise models. This new technology will also reduce false positive readings.

Samples created through both laser-sintered plastic and metal processes have been tested by the NASA team:

“The technology detected errors due to stray powder sparking and material layer lifts. Furthermore, the technology has the potential to detect anomalies in the property profile that are caused by errors due to stress, power density issues, incomplete melting, voids, incomplete fill, and layer lift-up,” stated NASA. “Three-dimensional models of the printed parts were reconstructed using only the collected data, which demonstrates the success and potential of the technology to provide a deeper understanding of the laser-metal interactions.”

The monitoring system offers increased flexibility as it can be implemented in existing systems with reduction in time, energy, and waste for parts that are nonconforming. The IR and visual cameras allow for greater accuracy both thermally and spatially. NASA foresees the technology being useful in aerospace (for injectors, coolant components, heat exchangers), automotive (exhaust systems), and medical (orthopedic implants) applications. Discuss in the NASA forum at 3DPB.com.