They use an ion exchange membrane in the regeneration cell. I'm
not exactly sure what the membrane is doing in this situation.
Obviously its separating ions from anode to cathode.
Unfortunately the image showing the electrolytic cell is missing
from the web page. I'm sure PVC membranes can be purchased but I
figure the control system necessary to make this work would be
prohibitively complicated for a hobby. I'm not saying it couldn't
be done, but attempting to build such a system could end up being
a whole hobby in itself.
I have build the basics of a electro generative tank for alkaline
ammonia sulfate, but this enchant is only suitable for metal
plated etch resist, i.e tin or tin/lead plated tracks. The high
pH 9.0 ~ 10.0 of this enchant means it attacks standard
photoresists in just seconds. If you also wanted to make a tin
plating tank too then this enchant is excellent. Its about same
speed as air regenerated CuCl (bubble etch 25 minutes for "1 oz"
copper at 25°C). The problem is it smells of ammonia so it must
be in sealed tank, with small opening for the PCB. If bubbles are
passed through it then you must use recirculating air pump.
I don't think there is simple method to electrolytically
regenerate etchants. The alkaline ammonia is the simplest etchant
to regenerate electrolytically but its drawbacks are ammonia
smell and it limited to metal plating resists.
Here is another short article on etchant regeneration.
http://www.circuitree.com/CDA/ArticleInformation/features/BNP__Features__Item/0,2133,97639,00.htmlStefan Trethan wrote:
> <http://www.turi.org/publications/rep45.htm>
>
> also a few lines on chemical regeneration.
>
> discussion welcome on how and if one could build a electrolytical system.
>
> ST
>