The researchers propose that every 3D printer holds unique fingerprinting features characterized by the thermodynamic properties of the extruder hot-end and that these can be used as a new way of 3D watermarking. This "fingerprint," say the researchers, can be used to address the increasing challenges of counterfeit detection and IP protection for 3D printing, where anyone with the digital design for an item can print out anything they want.
"So, what would be the best way to protect our intellectual property from someone else printing the same design using their own printer?" says Jin, associate professor in the Department of Computer Science and Engineering. "We wanted to find something internal. What would be the inherent signatures printed by my own 3D printer instead of another 3D printer?"
The researchers focused on the extruder used in 3D printers, which pushes the printing material along in successive layers to build an object. The extruder's hot end melts the material, and places it on the print bed to build the model.
Each extruder's hot end has its own unique heating properties that impact the precise way that the 3D model is constructed. As a result, say the researchers, those thermodynamic properties can be used to identify the specific extruder and, thus, the model of 3D printer, as uniquely as a human fingerprint - or "ThermoTag."
Because of the unique properties of each 3D printer’s extruder, a researcher can examine the specific manner in which a 3D-printed object was made and compare that to a database of various extruders until a match is made. The researchers say that by examining and comparing the ThermoTag features of 45 different extruders of the same model, they were able to correctly identify the source printer with an accuracy rate of 92%.
"This ThermoTag will behave like the fingerprint of the 3D printer," says Jin. "When you print out a new product, you can use watermarking."