“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.