While it’s perhaps fair to say that 3D printing has not been quite as transformative as was originally predicted, it is nonetheless achieving a reasonable scale in a short space of time. Indeed, data from Deloitte reveals that it is a multi-billion dollar sector at the moment.
“3D printing is experiencing the predicted inflection because companies in multiple industries are using it for more than just rapid prototyping,” they explain. “3D printers today are capable of printing a greater variety of materials. There is more 3D printing in metal and less plastic printing.”
As the sector grows, however, it becomes an increasingly attractive target for cybercriminals looking to capitalize on any vulnerabilities that exist. The problems were nicely encapsulated in a notable paper from researchers at the NYU Tandon School of Engineering, which highlighted the security challenges faced by 3D printing today.
The researchers focused on two particular forms of security risk found in the sector: the deliberate insertion of fine defects, and manipulating the orientation of the printer itself.
"Embedded defects in a 3D-printed specimen were found to be undetectable by ultrasonic inspection, though did not cause a decrease in the tensile strength," the researchers explain. "Similarly, alteration of the direction of printing in the material extrusion process was shown to significantly alter the strength and strain to failure of the test specimens."
Of course, it is also difficult to ensure the providence of any items produced via a 3D printer, leading to something of a wild west in which people are capable of producing whatever they want, regardless of whether they own the license to do so.
To overcome some of these challenges, it’s important to be able to accurately and reliably identify the materials produced by the printers. New research from the University at Buffalo proposes an approach that allows for the origins of each 3D printed item to be tracked and monitored.
The culture of 3D printing has evolved around a maker community that is quite open about sharing designs online. Indeed, a great many of the digital designs for items are available as open-source material that allows people to print anything they want, whether that’s toys or assault rifles.
As the movement matures, however, there are understandable concerns about protecting one’s intellectual property so that people can’t easily copy your design and print it on their own 3D printer. To overcome this, the researchers wanted to provide a kind of fingerprint that is unique to each printer so that it was clear where each item was produced (and by whom).
Building the signature
The researchers turned to the “extruder,” which is the part of the printer that pushes the building material through the printer so that each layer can be manufactured. The extruder has a hot plate that melts the material before placing it onto the print bed to gradually build the item.
What’s interesting is that each extruder has unique heating properties within this heating plate. These unique properties subtly impact the particular way in which each item is constructed by the printer. In essence it’s a kind of thermodynamic signature for the printer that leaves its mark on each item produced by it.
The researchers believe that these thermodynamic properties can therefore be used to identify the unique extruder used to make the item, and therefore also the model of the 3D printer. Indeed, it’s so unique that the researchers liken this “ThermoTag” with a human fingerprint.
The researchers liken the process to keystroke trackers on a laptop that can monitor every letter used in writing a letter. Indeed, such trackers can even identify the unique writing style of the author. They believe that their approach can perform a similar trick with 3D printers because each device has an extruder that has unique properties that allow the specific way in which each object was made to be tracked.
This can then be compared against a database containing the ThermoTag signatures of all extruders until a match is found, after which the owner of that printer can be tracked to ensure that they have the rights to develop the particular object or not.
When the approach was tested, the researchers found that examining the ThermoTag allowed to correctly identify the unique features of 45 different extruders of the same model of 3D printer with an accuracy rate of 92%. It’s an approach they are confident could be used to “watermark” each item so that it contains invisible characteristics, such as the manufacturer of a printer and the serial number of a product.
With the sector growing at a considerable pace, these kinds of approaches are likely to be increasingly important to ensure the security of the end product and the intellectual property of those involved is not compromised.