Patterns in 3D-printed objects could replace bar codes

Researchers in the US have developed a way of building physical identification tags into 3D-printed products as an alternative to visible bar codes.

Altering the internal structure of a 3D-printed object can encode information about it for robotic manufacturing or inventory systems, without the need to disrupt printing to insert a radio-frequency identification (RFID) tag.

However, to read the tags, the scientists at Carnegie Mellon University and Microsoft Research who developed the system are relying on terahertz (THz) imaging systems, which can safely penetrate many common materials but are expensive.

‘You probably don’t want to have visible barcodes or QR codes on every object you make,’ said Karl Willis, a recent PhD graduate in computational design at Carnegie Mellon who helped conduct the proof-of-concept experiments.

He added that as THz technology matured and came down in price, smaller and more mobile readers could be used to read the tags, opening up the system to more applications.

The tags are created as part of the structure of the object as it is laid down, layer-by-layer, by the 3D printer. The information can be encoded using gaps or different materials in the structure that reflect THz radiation and can be used to make patterns or images.

‘The ability to embed 3D patterns gives designers new opportunities in creating objects that are meant to be sensed and tracked,’ said Andy Wilson, a principal researcher at Microsoft Research, who also worked on the project.

‘One idea is to embed a code just under the surface of the object, so that a THz beam can recover its position on the surface, wherever it strikes the object.’

THz radiation falls between microwaves and infrared light on the electromagnetic spectrum. It can penetrate many common plastics, papers and textiles but, unlike X-rays, does not harm biological tissues.

Other research into THz radiation has investigated its use in security scanners, medical imaging, scientific instruments such as spectrometers and communication.