Homebrew PCBs

The main problem I see is exposing the centre area of the spiral. You 
would need to align the disk axis so aligns within 50um of linear axis 
of the laser. I'm sure exposure intensity can easily be compensated in 
software for constant disk RPM.

Adam

Leslie Newell wrote:
>  
> 
> The tricky bit is keeping the exposure times reasonably equal. The disk
> would have to speed up as the laser approaches the center line. Nice
> idea though...
> 
> Les
> 
> javaguy11111 wrote:
>  >
>  > --- In Homebrew_PCBs@ yahoogroups. com 
> <mailto:Homebrew_PCBs%40yahoogroups.com>, "designer_craig" <cs6061@...> 
> wrote:
>  >> I looked into a couple of these but I believe they are for island 
> milling. Converting the xy moves from the gerber to the G-code is the 
> easy part the files are almost exactly the same syntax.
>  >>
>  >
>  > I wonder if instead of trying to do cartesian scans, put the board on 
> some sort of a spinning disk and run the laser in a radial direction or 
> a polar scan. Basically what is done on a DVD writer. You could keep the 
> .001 spot size and just spiral in.
>  > That way you are not wasting time with a bunch of stop and start 
> motion. May be easier to construct as well.
> 
>