Homebrew PCBs

I just thought of something else regarding efficiency. Even though I 
don't make a lot of circuit boards, I have been etching two, and 
even, three boards at the same time.  This is very efficient and is 
only limitted by the size of the etching tank.  

Having been in shops of one type or another my entire adult life, I 
probably have been exposed to more toxins than I care to think 
about. So, fear of: acids, projectiles, and dust isn't an issue for 
me - been there done that sort of thing I guess.  Frankly, I am much 
more fearful of the dumb girl in the car in front of me talking on 
the cell phone and not paying attention to driving ;-(

A while ago I did read that article you mentioned, and you are 
right, they were not very positive at all about milling.  

Hmmm, makes me think of another possiblity though - laser etching?  
I know there are lasers that can focus their "cutting depth" which 
might allow for cutting through the copper and not the substrate.  I 
would have to guess that this sort of laser would require a bit of 
power though.  

Chris



--- In Homebrew_PCBs@yahoogroups.com, "Stefan Trethan" 
<stefan_trethan@g...> wrote:
>
> Mechanically milling PCBs is inferior. full stop.
> 
> It's done by people who have a unreasonable aversion to acids (and 
no fear  
> of high-speed debris projectiles or glassfiber dust strangely).
> There's no real advantage.
> You can read the paper on milling vs. etching by bungard (who 
sell  
> machines for both) and you'll see not even they like milling.
> 
> ST
> 
> 
> 
> On Thu, 08 Dec 2005 23:23:28 +0100, lcdpublishing  
> <lcdpublishing@y...> wrote:
> 
> > Okay, as you all know I am far from experienced with PCB 
making.  I
> >
> > have gone through a variety of trials with the toner transfer 
method
> >
> > and can appreciate it.  I can somewhat see it's limitations with
> >
> > regard to how small of a trace I could do using this process.
> >
> > However, if I ever need more detail, I could do the photoresist
> >
> > process.  The chemicals work good and efficient, all around, 
etching
> >
> > works very good.
> >
> >
> > Now about 6 months ago, I was wanting to do isolation milling as 
I
> >
> > believed it to be better.  However, I am pretty much now in the
> >
> > belief trying isolation milling will not show any advantages over
> >
> > what I am doing now.  I seriously doubt it would be faster than
> >
> > chemical etching.  I don't think the tool bits would last very 
long,
> >
> > so I would guess that the tooling costs would negate the costs of
> >
> > the chemicals. Even though you would be cutting with a very small
> >
> > diameter pointed tool, I don't think you could get better results
> >
> > (finer pitches and traces) using a milling process.
> >
> >
> > Is there something that I am not seeing in that process that 
would
> >
> > give it advantages over chemical etching?
> >
> >
> > Thanks guys
> >
> >
> > Chris
>