Researchers from the NYU Tandon School of Engineering have developed a method for proving where 3D printed parts come from and ensuring their design integrity by embedding QR code clouds into the 3D model in a new and clever way. That is, rather than simply sticking a QR bar code onto the 3D model’s surface, the research team has devised a way to convert QR codes into subtle 3D features which can be integrated into a given part without affecting its properties and, crucially, without being noticeable to counterfeiters.
One of the pressing concerns about utilizing 3D printing technologies to produce critical parts across a range of industries is ensuring that the 3D models of said parts are protected (in terms of IP) and are not compromised. Considering that experts believe up to 75% of new commercial and military aircrafts will integrate 3D printed engines, airframes and other parts by 2021, and that 3D printed medical implants will continue to grow by about 20% each year, the concern is real.
Elsewhere, the worry about unprotected 3D files spills over into the consumer goods market where brands exploring 3D printing want to ensure their designs won’t be ripped off or counterfeited.
In a bid to improve the security of 3D files and printed parts, a team of researchers from NYU Tandon School of Engineering have developed a way to prove the provenance of a 3D printed part using and putting a spin on QR code technology. The research study, recently published in the journal Advanced Engineering Materials, is led by Nikhil Gupta, an associate professor of mechanical engineering at NYU Tandon; doctoral student Fei Chen; and joint NYU Tandon and NYU Abu Dhabi researchers Nektarios Tsoutsos, Michail Maniatakos and Khaled Shahin.
The method employed by the research team consists of converting QR codes and other passive tags into three-dimensional features that can be integrated into and hidden in 3D printed parts, creating something they liken to a “game of 3D chess.” As the researchers explain, they developed a tool which effectively “explodes” a QR code within a CAD file. This results in the creation of a number of false QR codes which can be read by a micro-CT or other scanner.
The idea, in short, is that only a trusted end user would know how to properly scan the part (with the correct orientation) to read the original and legitimate QR code. Gupta explains further: “By converting a relatively simple two-dimensional tag into a complex 3D feature comprising hundreds of tiny elements dispersed within the printed component, we are able to create many ‘false faces,’ which lets us hide the correct QR code from anyone who doesn’t know where to look.”
In the research, the team tried out a number of different configurations for its exploded QRs, from distributing the code over three layers of the part to breaking the code into 500 tiny elements. They also tested various materials, including thermoplastics, photopolymers and metal alloys, and various 3D printing platforms.
Crucially, the 3D printed parts which embedded the hidden QR codes did not show significant signs of a compromised structural integrity when they underwent stress testing. “To create typical QR code contrasts that are readable to a scanner you have to embed the equivalent of empty spaces,” Chen explained. “But by dispersing these tiny flaws over many layers we were able to keep the part’s strength well within acceptable limits.”
The researchers believe their innovative method for integrating QR codes into 3D printed parts could be of significant benefit to the biomedical and aerospace sectors, which necessitate high quality, uncompromised parts for most if not all applications.