Major ‘fingerprint’ discovery could help us find who is making 3D-printed guns

19 Oct 2018

Image: © fotomek/

3D-printed guns are a growing concern for law enforcement, but researchers have found a way to ‘fingerprint’ their manufacturer.

While the industry still finds itself slowly entering the mainstream, the advent of affordable 3D printing is being seen as a threat by law enforcement agencies across the world. Where schematics for lethal firearms are available, it could be possible for someone to create a totally untraceable weapon and completely bypass any governmental checks.

However, a team from University at Buffalo believes it has found the first accurate method for tracing 3D-printed objects to the machine it came from, calling it PrinTracker.

Finding ‘wrinkles’

“3D printing has many wonderful uses, but it’s also a counterfeiter’s dream. Even more concerning, it has the potential to make firearms more readily available to people who are not allowed to possess them,” said the study’s lead author, Wenyao Xu.

To explain the method, the team said that it is all down to how a 3D printer works. Similar to a regular inkjet printer, a 3D printer will eject plastic filament in multiple layers.

During this process, it leaves submillimetre-sized ‘wrinkles’ called in-fill patterns, and these are supposed to be uniform. However, the printer’s model type, filament, nozzle size and other factors cause slight imperfections in the patterns, resulting in an object that doesn’t exactly match the design plan.

Like a fingerprint to a person, these imperfections are built into the system, leaving patterns that are unique, repeatable and traceable to a specific machine.

99.8pc accuracy

To test PrinTracker, the research team created five door keys, each from 14 common 3D printers including 10 fused deposition modelling printers and four stereolithography printers.

After creating a fingerprint database of the in-fill patterns for each of the 14 3D printers, they created an algorithm to align and calculate the variations of each key to verify their authenticity.

The results showed that it was able to identify which printer printed a particular key 99.8pc of the time. The team ran a separate series of tests 10 months later to determine if additional use of the printers would affect PrinTracker’s ability to match objects to their machine of origin, but it did not.

The researchers also ran experiments involving keys damaged in various ways to obscure their identity. PrinTracker was 92pc accurate in these tests. While not tested with 3D-printed guns, Wenyao said, it can be applied to any 3D-printed object.

“We’ve demonstrated that PrinTracker is an effective, robust and reliable way that law enforcement agencies, as well as businesses concerned about intellectual property, can trace the origin of 3D-printed goods,” he said.

Colm Gorey was a senior journalist with Silicon Republic