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When an operator does not know the specific print parameters such as print speed, triangulation (or poly count), print orientation, etc., design-embedded defects can reveal improper surface finish and even large gaps in component structures. The part on the left was printed under the correct additive manufacturing parameters; the part on the right was not.

Protecting additive manufacturing’s digital thread

According to National Transportation Safety Board (NTSB) data, counterfeit aircraft components have contributed to almost two dozen crashes since 2010. A review of the FAA records from 2011 to 2016, revealed 135 instances of unapproved components found in aircraft (including commercial airliners). These counterfeit components that bypass rigorous testing and certification often find their way into the supply chain because they’re cheaper and almost physically indistinguishable from the genuine article.

This past May, a U.S. Senate Armed Services Committee report based on a year-long investigation found more than one million suspected counterfeit components within the Department of Defense supply chain.

The prevalence of counterfeits, coupled with the critical nature of aviation components, has spawned an industry of supply chain verification technology and services. Some of the more basic processes include marking processes like labeling, chemical etching, inkjet stamping, and now recently laser marking. The latter, which provides a clean and energy efficient solution without contaminating component materials, can even leverage unique device identification (UDI) codes to connect various components with the industrial Internet of things (IIOT).

While the risk of counterfeit parts is ever-present, additive manufacturing (AM)—which relies heavily on digital files and digital communication throughout the supply chain—is especially prone to counterfeiting (not to mention product sabotage and IP vulnerability). The digital thread of an 3D-printed product runs from the design phase through manufacturing and product delivery, and possibly to the component’s service life and removal from service, depending on the monitoring systems utilized. Throughout a component’s digital thread exist multiple (potentially endless) touchpoints where an outsider could interact with the component; however, several companies have recently developed technologies to protect the integrity of 3D-printed aerospace components.

InfraTrac, a Maryland-based IP protection specialist, argues that requiring authorization on a 3D computer-aided design (CAD) file is not enough to prevent many forms of IP theft. By infusing AM polymers with a chemical fingerprint or “tag,” InfraTrac has developed a way to add verification codes to the actual 3D-printed components themselves.

The process includes introducing a unique chemical tag on sub-surface layers of a metal or polymer component as it is built up during the additive process. The company works with clients to find a unique chemical that is compatible with the component material and will not impact part performance. The tag location and formula is then kept confidential between InfraTrac and its clients. The tag can be scanned by an operator at any time with a handheld, of-the-shelf, near-IR spectrometer, allowing the operator to authenticate where the component was created and by whom.

While continuously available verification enables operators and installers to weed-out illegitimate lookalike components, researchers at NYU’s Tandon School of Engineering are working on a technique to foil a 3D manufacturer or counterfeiter using stolen designs.

When translating a CAD file into a stereolithography file for 3D printing, manufacturers need to define specific parameters such as print speed, triangulation (or poly count), and print orientation. By integrating condition-based flaws into the CAD file, a manufacturer must know the exact print parameters of the component for it to print as designed.

The flaws can be almost undetectable thanks to the complex nature of many 3D printed components. And although NYU researchers acknowledge network security should still be the first line of defense for securing a component’s digital thread, this method is likely to deter further IP theft or counterfeiting from a company if it decreases a counterfeiter’s production success rate.

“Cybersecurity tools can be applied as usual to make the files and cloud secure; however, in case the design files are stolen, there is nothing in the designs to deter printing a high-quality component,” said Nikhil Gupra, Associate Professor of mechanical engineering at NYU. “The new approach is designed to provide an advantage in this scenario and to make printing high-quality parts from stolen files difficult.”

In regards to directly protecting supply chain networks and companies’ IP, among the latest concepts is blockchain technology, a self-policing, three ledger accounting concept.

Wipro, a global information technology company, has developed four blockchain-based solutions for anti-counterfeiting, airworthiness certificate tracking, supply chain visibility, and AM. Products, digital files, labels, packaging, certifications, payments, or contracts would be registered on a blockchain registry and would be updated with status information as it passed to and from all partners on the supply chain. In doing so, proponents of blockchain solutions claim that business processes could be simplified, risk would be reduced, and transparency would increase.

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