To reduce illicit use of 3D printers, researchers are developing a way to track the origin of 3D-printed items. The technology would protect intellectual property from someone else printing the same design using their own printer.
3D printers build three-dimensional objects by adding successive layers of printing materials according to the digital design for a 3D model. Each 3D printer has an extruder that pushes the building material along. The extruder’s hot end then 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.
Those thermodynamic properties can be used to identify the specific extruder and the model of 3D printer as uniquely as a human fingerprint, or ThermoTag. The process is similar to using a laptop to write a letter. Because software exists that can track keystrokes, an observer can see every step that went into the letter including the writer’s unique writing style. Similarly, 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. From there, once the model printer is identified, the purchaser of said model can be tracked down if they had, for example, used the printer to build an illegal assault rifle.
By examining and comparing the ThermoTag features of 45 different extruders of the same model, the researchers were able to correctly identify the source printer with an accuracy rate of 92%. When printing out a new product, watermarking can be used to invisibly embed such information as the printer’s manufacturer, label, and serial number in the product. That would make the watermark of a particular product unique.