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Subject: Re: [Homebrew_PCBs] mechanical etching

From: "Roy J. Tellason" <rtellason@...>
Date: 2004-04-28

On Tuesday 27 April 2004 10:45 pm, Dave Mucha wrote:
> > > I think the number of posts on the topics on here reflect the
> > > background and experiance and direction of the list members. 90%
> > > want to know about or handle chemcicals.
> >
> > Some of us don't. I for one have absolutely ∗no∗ interest in
> > chemical etching, and plan to do it with CNC once I can get something put
> > together.

> > Is there a problem with that?

> let's try to steer this back to more PCB related questions.
>
> There is a problem with chemical, getting rid of the fumes and
> chemicals.
>
> the bonus is you can do 100's of boards at the same time.

I can see where some people might end up doing that, depending on what you
were working on. I see making boards at all as simply being a way to augment
my hobby electronics stuff and make things a bit easier than the perfboard
routine I've been using for years.

> The benifit of mechanical etching is no chemicals.
> the down side is the expensive cutters that wear out quickly.

I have the impression that this is more of a problem with some board materials
than others, is that the case?

> A dull cutter will raise a burr on the copper and dependong on your
> hold-down method, will or will not effect the rest of the board.

I haven't yet begun to explore the possibilities of various holddown methods.
I can think of a few right off the top of my head, those being simple
clamps, some kind of a T-slot table (more clamps), or maybe a vacuum
holddown setup. What else is there?

> It will however require intervetion to be able to solder SMT parts.

That's someplace else I have no intention of going. That stuff does provide
some benefit, to be sure, in terms of component density and especially for
manufacturing in large quantities, but again, I don't see me getting into
any of that sort of thing.

> The other down side is how long it takes to make a board. the
> mechanical engravers cut one section of a trace at a time so the
> entire time is longer than chemical etching.

True, but it's not like I'd have to be sitting there doing it, once I got a
good setup going.

> Another plus for the CNC is drilled holes.

Yes, that's a big plus in my opinion. I'd ∗much∗ rather have the machine do
that than have to do it myself...