Homebrew PCBs

>  One idea I have been noodling on (of which I have no idea whatsoever
>  how to do it) is lasers.  A number of years back I remember seeing a
>  laser marking machine that could mark a bunch of pieces with a lot of
>  characters in a couple of seconds.  I didn't have time to look at it,
>  understand it, watch it more than a couple of cycles, but I do know it
>  marked those stainless steel parts - FAST, VERY FAST!  As you would
>  expect from laser, with great precision too.
>
>  I know that burning through the copper would require a lot more power
>  than what this machine had and frankly, that machine was pretty big
>  and I wouldn't want it in my shop!
>
>  But, it's a method that interests me and who knows, maybe i will get
>  back in touch with that company someday soon and get a chance to
>  either play with the machine and do some tests, or just learn a bit
>  more about it.

I have worked with laser marking (engraving) and it actually is an oxidation 
process, requiring coated metals, either pre-coated, or with a coating that 
is sprayed on before going into the laser, and the coating is washed off 
after the item has been marked. Unfortunately, it doesn't actually cut the 
metal. There are some lasers that can, but you are looking at a very 
expensive piece of machienery, and you will end up cutting the board at the 
same time, as the material used for circuit boards is a much easier material 
to cut than the metal. 

Christopher Hart