I'm Developing a New Circuit Board Manufacturing Technology

Comments · 1.2K

• HY

  @Hyo9000 · 1 year ago

  Hey friend, I’m a fan of electroplating and have been studying it for about 6 years. What you want to avoid that creeping copper growth is to do pulsed AC plating, and if possible, to force movement of the fluid through the WIP via. Here’s why:<br><br>0) By pulsed AC plating, I mean that instead of a constant current, you have a periodic cycle of “plate, plate, erode, rest”, for example. You have, say, 1A for 0.5s, then -1A for 0.25s, then 0A for 0.25s, and this repeats on and on.<br><br>1) Pulsed AC plating will, on average, deposit material (deposition is proportional to (average current) x time). In the eroding step, however, it will selectively erode the pointiest surfaces, because that’s where the current prefers to flow through. What this means for your VIAs is that you’ll erode the spurious dendritic growth that creeps towards the electrodes.<br><br>1.1) Pulsed AC plating will also help make a smoother, more consistent surface.<br><br>2) Forced movement will help you a lot here, because you need copper ions to successfully reach the surface and get plated. In normal circumstances, ion movement is mostly limited by diffusion. When ions get plated, new ions fill replace them by coming from some random direction in the fluid. In the case of the thin 0.3mm VIAs however, diffusion will have a hard time replenishing the plated ions inside the bore, because there is almost no direction where new ions can come from. In your setup, as it stands, that space gets starved of copper ions and stops conducting altogether.<br><br>Get a good flow of electrolyte solution through the bore, and you’ll see how much better the process behaves.<br><br>There’s a book on this from the German book shop Leuze Verlag, the book’s called Pulse Plating, it’s silver-colored and has a picture on the cover of electroplated vias that were successfully done using this precise approach.<br><br>Anyway. Cheers, friend. Your project looks epic. Please reach out if you want some help, I’ll gladly give you whatever info I can.

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• SE

  @SeanSaidThat · 1 year ago

  I absolutely loved seeing your negative results. I honestly learned more from this &quot;failure&quot;. Great work !

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• LE

  @Le_Sixx · 1 year ago

  Me listening to this as a mechanical engineer: &quot;Why does he know that ?&quot; &quot;How does he know about that?&quot; &quot;Wait where is his encoder for his position accuracy?&apos; &quot;Why does he know anything about pumps ?&quot;. This was awesome.

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• JO

  @jordini321 · 1 year ago

  Hey Levi, I&apos;m a process design engineer that deals specifically with electroplating metal into nanopores. Is the solution you are using a commercial solution with additives? You need to look into pulse plating, this will dramatically reduce the surface overplating you&apos;re experiencing.

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• LU

  @lutfijd · 1 year ago

  Nice of PCBWay to support their competition!!

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• SC

  @scruffy3121 · 1 year ago

  Btw. The design you came up with is called H-Bot. It&apos;s pretty common in industries. But you have to use proper guide length to force distance proportions

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• BA

  @BasketballHellMember · 1 year ago

  &quot;CoreXY vs H-bot&quot;.

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• EX

  @excitedbox · 1 year ago (edited)

  You can fix the electroplating problem. This is actually an issue which had to be solved in semiconductor etched trench filling. The diffusion blocking layers needed to coat the bottom and walls evenly and different coating processes are more directional than others.<br><br>Extend an insulation covered needle with only the tip uncoated into the center of the via, through the center of the tube. This will decrease the distance to the surface and the current path through the electrolyte solution. The proximity to the plating surface will also improve the directionality and placement accuracy. With the current flowing from the needle horizontally to the walls it is a straight path giving more even coverage.<br><br>You could feed an insulated solid core wire from your reservoir through the tube to avoid any risk of leaks. 3d print an X shaped electrode holder for the center of your tip and use it to center the electrode in the XYZ direction so when the tip seals against the PCB the tip of the wire is centered in the via.<br><br>I think for the final version you will still want to change the design to a multi-head or headless electroplating bath because even 90 sec per via could take days for a design like a raspberry pi.

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• VI

  @VinceAnido · 1 year ago

  Why bother with electroplating at all? This was developed specifically as a parallel way to do entire boards at once (as you explained very well.)<br><br>If you&apos;re already doing one at a time, maybe you could insert a simple wire filament through each hole then solder in place? Brass EDM wire comes in 0.25mm and there are already tons of documented ways of driving the stuff.<br><br>Cool project - keep it up! Subscribed

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• NO

  @notinsane · 1 year ago

  <a href="https://www.youtube.com/watch?v=0vtCyUHz1Mo&amp;t=286">4:46</a> &quot;i did some off camera mining&quot; ahh transition 😭

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• CA

  @calmlytech · 1 year ago

  Great video! Slight correction. &nbsp;As a former microfluidics researcher, you’re not using this term correctly. Microfluidics is not the term for small scale fluidics. &nbsp; Microfluidics is specifically about manipulating liquids in laminar flow state using microdevices. Usually the “tubes” (channels) in these devices have diameters below 0.5 mm or 500 microns (hence the term “micro”).

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• MA

  @mathdoc204 · 1 year ago

  That was cool! &nbsp; &nbsp;Chemist and machinist here, hear me out:<br><br>What if, instead of chemically depositing copper, you drilled the double layer board, slid in a piece of copper capillary tubing that is slightly longer than the board is thick, and riveted/pressed it in from both sides with custom dies that have centered guide pins + a concave face? Locking it in place and making contact on both sides, like a hollow rivet, you could even solder them on each side &nbsp; &nbsp; &nbsp; I bet you could pull it off

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