ThermoTag: A Hidden ID of 3D Printers for Fingerprinting and Watermarking

To address the increasing challenges of counterfeit detection and IP protection for 3D printing, we propose that every 3D printer holds unique fingerprinting features characterized by the thermodynamic properties of the extruder hot-end and can be used as a new way of 3D watermarking. We prove that these physical fingerprints resulting from manufacturing imperfections and system variations exhibit distinct heating responses, namely 'ThermoTag,' which can be represented as the distinguishable thermodynamic processes and, ultimately, the temperature readings during the preheating process. Experimental results show that, by only changing the hot-ends of the same model on the same 3D printer, we can achieve about 92% identification accuracy amongst 45 hot-ends. The permanence and robustness of ThermoTag for the same hot-end were examined, throughout a period of one month with hundreds of trials under different environmental temperature settings. Leveraging the hidden ThermoTag, an example of watermarking scheme in 3D printing is presented and evaluated.