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Electroplating for electronics

An idea has occurred to me about how PC boards are currently made.

The normal process now is a destructive one, where unwanted copper is etched away.

What about figuring a way to electroplate the traces onto a substrate? Various toys and model parts are made of plastic, and yet have been electroplated with a cheap form of chrome. Why not apply that to PC boards?

I'm thinking that a photographically negative mask could be used in a photo-sensitive process to apply the conductive surface to a heat resistant substrate, and then the copper traces could be electroplated on.

Anyone have any thoughts on this, primarily at a hobbyist level?

**note - cross posted in tech.


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You're just reinvented so called "additive process" (in contrast to most widely used "subtractive"). Attempts to use pure additive process were made for decades. Main problem is that wires at the board have no common electrical connection, so they can't be electroplated. The only way to create them is chemical plating which is very slow and requires a lot of chemicals. There are also mixed versions of process, when thin layer of copper is deposited to entire PCB, then traces are made with electroplating and then initial layer is etched. Since it is very thin (few micrometers) etching is much simpler and faster. But this process is still much more complex than regular subtractive process.

Although etching most of the copper looks as unnecessary waste, it is possible to reuse it when proper etchant is used (not ferric chloride). In particular, any copper chloride-based etchant (or equivalent hydrochloric acid + hydrogen peroxide etchant) can be used for this purpose. Simple electrolytic tank (with etchant as a electrolyte), couple of electrodes and at the cathode you'll get pure copper which then can be reused for plating boards. Etchant also restores its ability to etch. No wastes anymore.

About through hole plating: there are processes which do not use platinum chloride but provide at least as good quality and still simple to use and productive. One of the versions of such a process adapted for home use I've published recently here, at Instructables.
NachoMahma6 years ago
.  As Steve has pointed out, plating/etching circuit boards involves the use of some pretty nasty (and expensive) chemicals. Disposing of the depleted chemicals properly can be problematic for DIYers.
.  As Steve also points out, you can have PCBs made reasonably cheap by pros who have the resources to dispose of the chemicals properly.
.  Making your own PCBs is one of those must-do learning experiences, but, in general, it's not something the average DIYer should want to do more than once or thrice.
 
.  Cross-posting is not necessary and just clutters things up.
charlie_r (author) 6 years ago
@ Steve --

Yes, i know that making the copper boards that we use is sometimes done by electroplating. Better control over how thick the copper is. However, a lot of the "hobbyist" boards are done with gluing copper foil to the substrate, which we then etch away wasting a lot of copper.


I understand the process. There must be a complete circuit for the plating process to work. Think about this: the more complex boards will usually have vias in quite a few traces. Why not use them as part of the plating process, by drilling just large enough to friction fit a wire? Do that to all the traces, whether it is a required via or just a dummy for the plating process. Join all the wires at your power supply, and you have divided your current needed to deposit the copper.

Failing finding a way for hobbyists to plate only the traces onto a substrate, there may be a way that can be found to recover the copper from the etchant.

Just something to think about......
Trouble is plating chemistry is nasty generally and/or expensive - one of the fundamental chemicals used is "Palladium Chloride" which is very expensive, in even small quantities.

I'm not sure I see a benefit from plating up your own board - the adhesion to the substrate is bound to be very weak.
charlie_r (author)  steveastrouk6 years ago
Steve, here is a site that explains how to plate your own vias.

http://www.thinktink.com/index.htm

From this, iI can only assume that my idea is not a new one. If you can plate your own vias, why not take it a step further and plate the traces as well?

I only scanned the site briefly, but saw no mention of Palladium Chloride in there.
If there is mention of it, i missed it.

In short, i think it is doable.

Now, how to convert the copper(II) and copper (III) in the Muratic acid+Hydrogen peroxide etchant into a usable plating solution, would be the next step. Do you see where I'm going with this? Recycle the copper we etch off of boards into plating onto new boards.
The link is a PCB prototyping process. AFAIR, the professional process uses palladium chloride.

I'm sorry, I just don't see the point - your proposed process is infinitely more difficult than the exisiting one - you still have to wire every trace together for the plating process, you still have a photomask, you have to screen on a conductive paint.....

Or you use the current process with cupric chloride etchant, and recover the copper for resale.

When I can buy a square foot of double sided PTH PCB, with masks and idents on both sides, with a gold flash for $35.00, I have to ask myself why bother with making them at home anymore ?
You can't electroplate the whole board, because all the tracks have to form part of the plating circuit.

Incidentally, A lot of the manufacture of a PCB IS electroplating - the PCB is drilled FIRST, then plated with electroless chemicals, then plated conventionally....


Steve
batman966 years ago
I had the EXACT same idea like a month ago!