3D Printing

Plastic-layer thickness used to form unique IDs for 3D-printed objects

Plastic-layer thickness used t...
Scanned images of normally-deposited layers within a 3D-printed object (left) alongside layers printed utilizing the new technique
Scanned images of normally-deposited layers within a 3D-printed object (left) alongside layers printed utilizing the new technique
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Scanned images of normally-deposited layers within a 3D-printed object (left) alongside layers printed utilizing the new technique
Scanned images of normally-deposited layers within a 3D-printed object (left) alongside layers printed utilizing the new technique

As is the case with items that are manufactured in more traditional manners, it's certainly possible for 3D-printed products to be counterfeited. A new system could help identify such bogus goods, by printing a unique code right into objects.

Known as Fused Deposition Modelling, the most common form of 3D printing involves using a nozzle to lay down successive thin layers of molten plastic. That plastic then hardens to form the finished product, with the edges of the layers still visible on its exterior surfaces.

And ordinarily, all of those layers are of an equal thickness.

A team from Japan's Nara Institute of Science and Technology (NAIST), however, has developed a system in which a series of adjacent layers (in a certain part of the object) are deposited in specific subtly-different thicknesses. This is achieved by varying the plastic flow out of the 3D printer's nozzle, and it doesn't negatively affect the overall shape or structure of the item – after all, the same amount of plastic still ends up being deposited in the same places.

The result is a layer-thickness pattern that's almost like a barcode, which is unique to that product. And as long as it's on a flat part of the item, that code can be read simply by placing the object on a conventional document scanner, which images and analyzes the thickness of the layers in the relevant region.

In order to further thwart counterfeiters, the pattern can be applied to multiple parts of the item. This means that even if it's scraped, cut or melted off of one area, it will still be visible on others.

Along with embedding product-specific anti-counterfeiting IDs, it is thought that the technology could also be used to include information such as links to web services, or the identity of the specific printer that was used to manufacture a certain batch of items.

A paper on the research was recently published in the journal IEEE Transactions on Multimedia.

Source: NAIST via EurekAlert

If this kind of signal can be read by ordinary equipment it's plausible that it can be written with an ordinary printer. The G-code for doing it would be intensely simple, and could probably be handled by putting an ordinary print file through a fairly simple substitution script.
"In order to further thwart counterfeiters" This solution does not actually stop counterfeits. It could be used to identify an authentic product. I'm not really sure what problem is being solved? Maybe if a HW printer could print the object for the desired output. But if someone got ahold of the file and tried to print on a consumer 3D printer...and it produced an undesirable product.
Arnaud Delmotte
yes, it works with any FDM printer that take gcode as input (we used an prusa i3 MK3S). The goal was to develop a technique compatible with the most common printers and decodable without expensive equipment. It is equivalent to an invisible QR code. A few examples of application : It can be used to store data (batch number, object ID,...) for production and quality control. It can be used to tag the objects in case they get stolen (similar to datadot or alphadot) For copyright protection, it can not prevent a counterfeit but can help to detect and trace them. it can be used to prove the authenticity of an object (but of course, if the counterfeiter knows the method, he can reproduce the tag. Still, it requires more effort than a standard scan and print). It can also be used as traitor tracing (for prototypes under NDA). Online printing services can use it to trace the parts they printed. It can help police investigation if the printed objects (gun, TSA key, fake credit card reader) are used for criminal activities. (but of course, if you use your own opensource printer, no one can force you to add a tag with your ID on the object).
Ah. It makes much more sense as a tagging method in a relatively benign environment.
Bob Flint
Beside upsetting the "Z: direction in the new technique, "IT'S A 3D PRINTED PART" Nothing original about it...Lost Or Stolen hahaha..
Robert Schreib
??? Wouldn't implanting a tiny RFT, Radio Frequency Tag, inside of the artifact while it's being created, also enable you to tell if it's the real deal?
Arnaud Delmotte
@Robert Schreib : yes, it would works too. It's just an alternative method for similar application. the biggest default of RFID insertion in 3d print is that it requires more manual work (pause the print, insert the chip, continue the print). This could be done automatically but require printer modification such as : https://youtu.be/VUWhPr1E4YQ It would be interesting to be able to print the rfid directly. I think it's already doable but not with a common 3d printer. the proposed method was aimed to be totally automatic, working with the most common printer, and low cost for the decoding