Unique coding for authentication and anti-counterfeiting by controlled and random process variation in L-PBF and L-DED
Abstract
Additive manufacturing technologies enable various possibilities to create and modify the material composition and structure on a local level, but are often prone to undesired defects and inhomogeneities. This contribution makes use of such flaws to generate material-inherent, hidden codes and watermarks in metals for authentication and anti-counterfeiting applications. By controlled and random process variation, unique codes that can be read and authenticated by an eddy current device were produced with the processes of laser powder bed fusion (L-PBF) and laser directed energy deposition (L-DED). Two approaches are presented: First, volumetric, porous structures with a defined shape are manufactured with L-PBF. Second, coatings are fabricated by L-DED with alternating process parameters, leading to local deviations of the magnetic permeability. This non-deterministic coding approach generates a distinctive material structure that triggers high signal amplitudes in the eddy current measurement. Counterfeiting becomes impossible due to the irreproducible melt pool dynamics. Statistical hypothesis testing proves that the system is able to prevent false acceptance or rejection of a code with a certainty of 500 million to one. A low-cost setup for a novel locking system demonstrates that a code can be sensed reliably within one second. Show more
Permanent link
https://doi.org/10.3929/ethz-b-000420858Publication status
publishedExternal links
Journal / series
Additive ManufacturingVolume
Pages / Article No.
Publisher
ElsevierSubject
Powder bed fusion; Directed energy deposition; Coding; Anti-counterfeiting; Eddy current testingOrganisational unit
03641 - Wegener, Konrad (emeritus) / Wegener, Konrad (emeritus)
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