Homebrew PCBs

Thanks for the answer.

Well, a CO2 laser can engrave the copper directly (I think). But It's
so much more expensive than a DVD-RW laser.

How does a CO2 laser tube cost? I saw How it works and it' so impresive.
 

--- In Homebrew_PCBs@yahoogroups.com, Mark Robinson
<mark.robinson@...> wrote:
> 
> A laser from a DVD burner should be quite adequate to expose
photoresist.
> 
> I played around with large argon lasers and scanners as a means of
resist 
> exposure rather a long time ago.
> 
> It was difficult to keep things square, the right size and in focus
but the 
> results were still rather acceptable.
> 
> A x-y plotter rig like those used with CO2 laser engravers would be
a much 
> better option and a great deal cheaper.
> 
> You'd probably want to use a considerably longer focal length lense.
> 
> X-Y CO2 laser engravers usually have the collimated laser statically
mounted 
> and shining along one axis hitting a travelling 45 degree mirror which 
> redirects the beam up the other axis to another travelling 45 degree
mirror 
> which in turn directs the beam down onto the work through a focusing
optic.
> 
> 
> DVD laser diodes are probably best mounted on the gantry aimed
directly at the 
> work.
>