By Simon Firth, HP Labs Correspondent — November 27, 2017
Multi-jet-fusion printed part on the left and a high resolution scan of the indicated portion of it on the right showing the micro surface structure used for authentication.
An HP Labs investigation into accurately identifying and authenticating 3D-printed objects is helping enable a future where parts for high performance machines like jet engines are routinely printed to order. It may also aid the development of new systems for tracking physical objects of any kind on a massive scale.
HP Labs Distinguished Technologist Stephen Pollard
“To use a 3D printed part in a machine like an aero-engine, you need to be able to confidently identify and track that part after it has been printed from a known and trusted printer,” observes Bristol, UK-based researcher Stephen Pollard.
One way to do that would be to add a unique identifier like a bar code to each printed item. But Pollard and his colleagues in HP’s Print Adjacencies and 3D Lab wanted to come up with an approach that added no processing or materials cost to the 3D printing process and that would also have applicability for 3D objects created via more conventional methods.
Their solution: a low cost, three-stage, automated identification and authentication system that doesn’t require a printed object to be readied for authentication in any way.
It works by first designating a small area of the object to be tracked as the location of a “virtual forensic mark.” This need only be a centimeter or so square and can easily be pre-assigned in the digital version of the 3D object before it is printed.
Once the item is printed, it is robotically scanned so that the location of the virtual forensic mark can be identified. Finally, a second, very high resolution scanner takes a measurement of that small area. It’s so accurate – detecting surface differences of just two thousandths of a millimeter - that it can establish a unique digital signature for every printed version of an identical 3D object.
With this identifying information on file, the object can be scanned again whenever a confirmation of the object’s specific identity is needed.
“It’s like a fingerprint scanner for physical objects,” says Pollard.
HP Labs research engineer Faisal Azhar
The team has already created prototypes for most of the elements in their system. They next plan to miniaturize and integrate them together into a single prototype device, creating a tool that does the work of instruments that currently cost tens of thousands of dollars for under $100 per machine.
One major challenge will be to place each of these elements together in way that allows the process to be fully automated, adds Labs researcher Faisal Azhar.
“The other hard problem we face is extracting reliable and repeatable signatures of the 3D parts,” Azhar says. “We are already able to make incredibly accurate scans but those scans need to be reliably repeatable to be confident that the object we identify right after printing is the same object we later want to place, for example, in a machine.”
At present, the system is optimized to scan the surface of objects created by HP 3D printers. But the Labs identification and authentication team plans to expand its capabilities to include objects made from a more diverse array of materials.
More broadly, they are also looking to measure properties of 3D objects beyond their shape, and devise methods for further enhancing production line integration and automated machine interactions with them. “This “forensic” level of authentication and identification will really come into its own when 3D printing moves from prototyping and into production, and manufacturers are printing millions and even billions of copies of any one part,” says Pollard.
