Highly conducive material for 3D-printing of circuits

Scientists at A*STAR's Institute of Materials Research and Engineering (IMRE) have invented a new type of thermoplastic thread that can be used in 3D printers to create functional circuits for use in electrical gadgets.

"I believe this will revolutionise desk-top manufacturing for electronic gadgets," said Dr Johnson Goh, IMRE scientist and Head of the Science and Engineering Research Council's (SERC) Nanofabrication and Characterisation Group and Principal Investigator of this project.

Dr Goh and his team have successfully used this new material to print prototypes such as a USB connector that can light up a LED bulb, complex three-dimensional circuits, and a wearable flexible sensor.

The resistivity of IMRE's thermoplastic material is in the range of 0.5-1.0 Wcm, about 1,000 times more conductive than most commercially available plastic filaments for 3D printing. The filament is strong enough to stay intact throughout the 3D printing process in a conventional thermoplastic 3D printer.

"Objects in various colours, shapes and textures complete with functional circuits including wires, resistors and capacitors, could one day be printed in the comfort of one's home," said Dr Kwok Sen Wai, one of the key scientists in the team.

The team has found that using IMRE material to 3D print circuits rather than creating circuits through the conventional etching-and-soldering method is much safer, faster and cheaper. In addition, such circuits have highly uniform conductivity, with less than a 5 percent variation, compared to more than a hundred percent in commercially available conductive filaments.

"We believe that our material will encourage more innovation and entrepreneurship as it will empower people to make prototypes more easily and cheaply," added Dr Kwok.

IMRE is actively looking for industry partners to commercialise the technology. The new technology is now available for licensing through A*STAR's commercialisation arm, Exploit Technologies Pte Ltd (ETPL).

Notes:

1. This new material from IMRE made by blending carbon powder and polypropylene (commonly-used thermoplastic for many types of packaging and disposable plastic containers) thoroughly, and then producing this mixture as filaments.

2. As this new conductive thermoplastic has a resistivity of only 0.5-1.0 Wcm, and is 3D-printable in a low-cost conventional 3D printer, it is now possible to produce practical circuits based on conductive thermoplastics from low-cost conventional 3D printers.

3. The mechanical strength and heat resistance of this material is significantly higher than existing conductive filaments which are typically layers of conductive core and plastic outer coating. Thus, this new material is able to withstand the stress and high temperatures involved in 3D printing without degrading.

4. It sticks well to thermoplastic materials when used as solder.