Homebrew PCBs

--- In Homebrew_PCBs@yahoogroups.com, "John Myszkowski" 
<myszka_us2000@y...> wrote:

> With the YAG, you could cut copper by pulsing and checking the 
light 
> return (feedback or reflection) from the material during the pulse. 
> There is always scattered light from the point where the laser 
> impacts. When much lower scattered light (reflection) is detected, 
> then you are through the copper layer. Just move to the next point 
> and start popping the copper.

Not too sure if I'd pulse here, depends on the power of the Yag
> 
> I think the best use of laser would be to vapourize the resist, 
which 
> could simply be a varnish or paint. That way you could easily use a 
> low power CO2 laser.

Dangerous! (I'd use paint or a graphite spray) That way you 
are 'basically' etching copper with a CO2.  Keep in mind all the 
mirrors in a CO2 are copper, because it reflects that part or the 
spectum (10600nm) *so* well.  (sure there are a few laysers of 
special coatings, but its the copper that actually reflecting)

The idea of the Yag for this, was to avoid chemicals, and be a bit 
quicker, 'etch' and drill all in one step.

Time to go find some surplus Yag crystals on E-Bay :)
But I think this is getting a bit out of hand/usefulness.
Maybe in time.....