Printed circuit board fabrication — especially in basements and garages — have been transformed by the computer revolution. Before that, people would use a permanent marker or little decals to layout circuit boards prior to etching. Sometimes, they’d do it on film and use a photo process, but they did make decals that you applied directly to the board to resist the etch. Now a team from Georgia Tech, University of Tokyo, Carnegie Mellon, and the University of Nebraska has brought things full circle. Their process inkjet prints silver traces on a substrate that they can then transfer to a circuit board — no etching required.
They start with a standard Epson inkjet with cartridges that have silver-bearing ink. The patterns print on a transfer paper that ensures the particles fuse so there’s no sintering step required to make sure the traces are all conductive. A sticky backing is applied and peels the pattern off the transfer paper. You can see more in the video below.
We don’t know what the cost of the ink is, but considering the excessive cost of regular ink we aren’t sure if we think it couldn’t possibly cost more even if the cost were astronomical. The paper talks about many different substrates depending on what you need. For example, they can transfer the pattern to Kapton.
We looked up the ink and found the following from the manufacturer:
Please note : Printing on other substrate such as glass, PCB, polyimide film other than Special media results in poor adhesion and no conductivity.
The trick, then, is in the paper. For the most part, the team used glossy photo papers from Kodak, Fujifilm, or Epson. They also printed on a PET film.