Ben Krasnow has a vision of future electronics: instead of the present PCB-screwed-into-a-plastic-box construction, flexible circuits will be deposited straight onto the plastic body of the device itself, merging the physical object and its electronics. There is existing copper-on-plastic technology, but Ben’s got something novel that he presents in this talk that you could implement yourself. You might also want a display, or at least something to blink, so he’s also working on some electroluminescent technology to complement it. If you were wondering why Ben is so interested in silkscreening photopolymers right now, watching this talk will pull a lot of interesting threads together.
Ben’s research here is truly cutting-edge. It’s prototype-able by the home gamer, but not yet production-ready for industry. Sure, there is an industrial technique for doing circuits on plastic right now. They’re not able to do plated through-holes, the plastic requires a special catalyst mixed in during injection molding, and the process requires a heavy-duty YAG laser. It’s expensive, so you could only use this process for high-margin items, and unless your garage looks different from ours, this is a non-starter for the home hacker.
This is what science in progress looks like
Ben’s goal is to “replace the expensive parts with cheap parts”. Instead of injection molding, he wants to be able to paint the catalyst onto a 3D-printed part, and he wants to be able to draw the circuits with a sub-$100 CO2 laser. There’s a lot of great experimentation behind the results presented here, but the end result is workflow that looks like this: coat the plastic with a PTFE bike-chain lubricant to keep the catalyst from adhering. Laser the lubricant off in places where you’d like copper traces, dip the part in a wetting agent to make the catalyst stick better where the laser has gone, and then dip in catalyst and in an electroless copper plating bath. Bam!
This process is novel, affordable, and it uses some of the tools we already have access to. After watching this talk, there is nothing stopping you from getting started on this. Ben has tested this out on 2D plastic surfaces, and the main stumbling block to fully 3D plated circuits seems to be getting a 5-axis laser machine. Note that using Ben’s technique, any areas that got hit with the laser will attract copper; if you can burn holes in the substrate with the laser, you get plated through-holes for free.
As promised, Ben shifts into blinky mode for the final part of the talk. He bought some off-the-shelf electroluminescent paint, but the stuff requires some high voltage. So he designed his own driver circuitry to delivery enough juice. If you were with us in Pasadena, you surely noticed his EL glove that he was wearing around all day before his talk. And if you were in the audience, you probably sang along as he Rickrolled the entire Supercon with painted high-voltage pixels.
Since the beginning of the 3D printing revolution, we’ve all been wondering if we could 3D-print circuits, resulting in a one-shot electromechanical design process. This talk outlines one way we could get there, and makes a few compelling arguments for why you might want to join Ben on his journey. Who is going to be the first to replicate this experiment in the home lab? Or take it to the next level with a fancier laser setup?