Here's a summary of the themes from the Hacker News discussion:
The Viability and Challenges of 3D Printed Electronics
A central theme is the exploration and debate around the practical feasibility of integrating electronic circuitry directly into 3D printed objects. While the concept is exciting, many users highlight significant technical hurdles and limitations compared to traditional PCB manufacturing.
- nickpinkston expressed skepticism, stating, "People have been doing this for a long time, but it feels a little too purist to me. The components will still be the same, so you'll still need some kind of pick-n-place functionality to make anything, so why not just have another print head for making the traces / doing the PnP?" He further elaborated on the limitations of current conductive materials: "unlike the low performance conductors made via conductive polymers as the OP's process imagines."
- crote was particularly direct about the limitations for non-trivial applications, saying, "3D Printing the PCB itself is pretty much impossible for any non-trivial application. Doing multi-layer PCBs with 0.20mm wide traces, spaced 0.20mm apart? Forget it, not happening - and requirements like those are standard for hobbyist-level chips like the RP2040 these days."
Alternative Conductor Deposition Methods
Beyond simple conductive filaments, the discussion delves into various methods for creating conductive traces, often involving wire manipulation or novel deposition techniques.
- nickpinkston suggested, "The head could lay copper wire/foil tape for conductors..."
- Aurornis countered this by calling it an "extremely hard problem to solve. You can't simply lay down wire or foil into arbitrary shapes on 3D surfaces."
- Lerc proposed a more nuanced approach: "If you printed channels for them to sit in, I think they could be placed." He later refined this idea: "I was thinking you'd print a channel where the wire would be placed, bend the wire to the shape of the channel, place it, and print over the top."
- joshmarinacci shared a relevant experience: "When I worked at Markforged we had a printer that could put solid carbon fiber threads into the print using a second extruder (on the same print head), so it's certainly possible. It was $20k, though. Getting this down to something accessible to hobbyists is the challenge."
- Xmd5a offered another idea: "Maybe lay chains instead of wires. Apply tension to the chain, ensuring that it conducts current and use fast solidifying glue to fix it in place/make it adhere to the surface/insulate it."
- pedalpete noted the emergence of actual metal filaments: "We are starting to see metal filaments and even this copper one[1]. Multi-filament fdm printers just might be able to make some rather large circuits."
The Role of Traditional Manufacturing Techniques and EDA Tools
Several participants draw parallels to existing manufacturing processes and emphasize the importance of supporting software tools for enabling this kind of integration.
- tdeck brought up historical context: "This reminds me a bit of Multiwire, a somewhat unusual circuit manufacturing technique from the 1980s. A machine laid down wires and then encased them in resin." They also provided a link to an image of a PERQ computer PCB using this method.
- zakqwy referenced academic work: "For this in 2D, see Sam's thesis, 6.3.3 (p. 86, CNC wire plotting). 3D would add a lot of challenges."
- seveibar highlighted the need for better tooling: "I think one of the things that is killing us is the tooling. One of the reasons I started building an autorouter was because I wanted to be able to have different 'build targets'- e.g. a build target that is a PCB with no vias and only 0 ohm resistors (jumpers). If our EDA tooling supported different build outputs, then we could have earlier prototypes built with less-than-ideal equipment..."
Practical Embodiments and DIY Approaches
The discussion includes specific DIY ideas and references to past projects that have attempted similar feats.
- p0px shared their own project, detailing how they used "tracks for dupoint wires in my model and used the GPIO pins to push through the wires to create connections" and created "THT connectors using the ends of the dupoint wire ends" for LED eyes.
- bitwrangler proposed a creative use of 3D printing as a masking agent: "Has anyone used dark color 3D filament printed onto copper clad PCB as photo resist or etch resist?"
- longtimelistnr commented on this, suggesting: "...much much easier to buy a cheap vinyl cutter, but interesting idea."
- fainpul added that "The toner transfer method uses a similar process and is probably easier. You don't need a 3D printer, but one of those laminating machines instead."
- monday_ outlined a more involved DIY approach: "A simpler and surprisingly workable solution appears to be adding a second printing head loaded with tin. ... Print PETG layers using a regular filament, but leave 'baths' for tin traces. ... After N layers, fill the baths from the tin head."
Potential and Concerns Regarding Future Integration
Looking ahead, participants acknowledge the potential benefits but also voice concerns about the long-term implications of highly integrated, potentially hard-to-inspect or repair electronics.
- xg15 expressed apprehension: "On the one hand, I like the idea. On the other hand, I dread a future where you need an X-Ray and/or MRT machine to be able to inspect any kind of electronic device. And don't even think of disassembling or repairing..."
- rkagerer recalled a cautionary tale: "Anyone remember the Next Dynamics NexD1 Kickstarter? It was pitched back in 2017 as a 'Multimaterial & Electronics' printer. Got to half a million or so in pledges before some of the backers uncovered serious red flags..."
Material Properties and Performance Limitations
A recurring theme is the performance gap between current 3D printable conductive materials and traditional copper traces, influencing design choices.
- monday_ stated: "Obviously, conductive filaments exist - but they are not remotely in the same category as copper." They also suggested how to compensate: "To offset the poor conductivity you can use thin, but very broad traces."
- pedalpete agreed about trace size: "I doubt we'll get down to 0.2mm tracers, but if size isn't an issue, we can do better than the conductive carbon tpu(?) filaments which are common today."