curt_rxr wrote:
> Adam wrote:
>>
>> I was looking at an easier and more reliable way to etch PCBs. I know
>> from experience that bubble etching never produces acceptable
> uniformity
>> and often needs manual brushing to finish it off.
>>
>
> I've found that a simple covered, flat, rocking tank works pretty
> well. I made mine out of acrylic and use an eccentric on a gear motor
> to make the tank rock about twice a minute. The flow of the CuCl
> over the board is fairly uniform and my boards seem to etch evenly.
> You need to grip your PCB by two edges and have a deep enough tank to
> allow the etchant to flow over both sides of a double sided PCB.
>
Interesting. I wonder if this concept could be made to work in a
vertical tank. The PCB could be mounted to an plastic shaft that is
attached to some cam assembly at moderate speed. The circular
displacement might only be several mm , but the agitation could prove to
be uniform and vigorous. I assume any mechanical method would add a lot
of complexity, machining up bushes, wheels, brackets, et.
A cover plate is mandatory for bubble agitation since splashes go all
over the place otherwise. I found the cover plate also needs to have a
neat fit and recessed slightly so run off goes back into the bulk solution.
Adam