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Subject: Re: Spray etcher- technology of etching

From: "Dave Mucha" <dave_mucha@...>
Date: 2004-07-22

> A spray etcher is faster than most other methods, because it uses a
lot
> of force/agitation. It is basically a set of nozzles spraying
etchant
> at a board, and the nozzles move so it is distributed evenly.
> You get etch times around one minute or even less with it.
>
> If you etch in a bowl the "used" etchant will sit close to the
surface of
> the PCB, prolonging etch time. you will want to use some sort of
agitation
> (like moving the board or bubbles) to speed it up. But even with a
lot of
> agitation you don't get the speed of spray etching. (dunno why)
>
>
> ST


I think I read about surface tension of the etchant and exposure of
the coppper being different if it was submerged and bubbled and
sprayed. IIRC, spraying acutally allowed the etchant to be removed
down to the copper whereas the think film of etchant with bubbling
never really did.

Dave