Jeff's MCAD Blogging
Jeffrey Rowe has more than 40 years of experience in all aspects of industrial design, mechanical engineering, and manufacturing. On the publishing side, he has written well over 1,000 articles for CAD, CAM, CAE, and other technical publications, as well as consulting in many capacities in the … More »
Conductive Ink Expands Electrical Design Possibilities
December 3rd, 2015 by Jeff Rowe
This week Nano Dimension Technologies announced that it had filed a patent application with the U.S. Patent and Trademark Office for a proprietary copper ink that is used for printing electronic conductors.
The copper nanoparticle-based ink provides improved oxidation resistance with the ability to print copper with industrial 3D digital printers.
Copper, of course, is an electrically conductive metal, and its low price gives it a significant advantage when compared to silver (although copper is more electrically resistive than silver). However, copper nanoparticles rapidly oxidize upon contact with air that impairs electrical conductivity.
The patent application that the company has filed is an approach for overcoming the problem of copper nanoparticle oxidation. Overcoming this challenge introduces an effective and less costly method for industrial additive manufacturing of printed electronics by 3D printing.
Amit Dror, CEO of Nano Dimension, said, “Our conversations with companies across different industrial sectors indicate a strong demand for our 3D printed electronics technology. The demand is not limited to prototyping, but also includes industrial scale manufacturing applications.
The current global PCB market is estimated to be larger than $70 billion and is expected to reach about $100 billion in coming years. A high-performance copper nanoparticle ink presents an opportunity to significantly impact this huge market.”
Nano Dimension is focused on developing advanced 3D printed electronics systems, and its products combine three technologies: 3D inkjet, 3D software, and nanomaterials. The company’s primary products include a 3D printer for printing multi-layer PCBs (printed circuit boards), as well as nanotechnology-based conductive and dielectric inks.
Basically, conductive ink is an ink that conducts electricity. These types of inks usually contain conductive materials such as powdered or flaked silver, copper, and carbon materials, although polymeric conduction is also possible.
Below is a video of step-by-step instructions for brewing conductive liquid metal ink.
Brew Your Own Conductive Ink
Conductive inks can be a more economical way to lay down a modern conductive traces when compared to traditional industrial standards such as etching copper from copper plated substrates to form the same conductive traces on substrates. Conductive ink printing is a totally additive process that produces little to no waste that has to be be recovered or treated.
Conductive inks, and specifically, silver inks have multiple uses, such as printing RFID tags used in transit tickets, and repairing circuits on printed circuit boards. Computer keyboards contain membranes with printed circuits that sense when a key is pressed. Windshield defrosters consisting of resistive traces applied to the glass are also printed. Also, many cars now have conductive traces printed on rear windows that serve as the radio antenna.
For DIYers like me, conductive inks are a great substitute for soldering (which I’ve always been marginal doing, at best. OK, bad.). Sure, breadboards work, but by design, they constrain how you can arrange components and limit your options. On the other hand, in many cases, conductive inks/paints can open up a lot of possibilities.
Although conductive inks made from silver nanoparticles have been available for some time, a couple of years ago a group at Georgia Tech demonstrated a way to use them in inkjet printers to create custom circuits. Great concept, but they are pretty pricey, and I’m not sold on pumping metal through a 3D printer meant for plastics.
In contrast, conductive ink can be used in an ordinary roller-ball pen to draw circuit traces. I’ve thought that a fountain pen might work better, but I’ve never tried that. Pens are good in theory, but can be messy. I’ve had better luck with applying conductive inks/paints with a tiny brush.
While I do admire what companies like Nano Dimension are doing, I also appreciate what can be accomplished on a smaller and more affordable scale using relatively simple techniques and tools such as conductive ink and pens or brushes. And the best part is I don’t have to embarrass myself with my lack of soldering skills to create simple circuits.