PCB milling machines??

[jhaible]

> > I was paging through Electronic Design and saw a couple of ads for
desktop
> > PCB milling machines which basically goes from Gerber to drilled PCB by
> > milling away copper and drilling holes.  Has anybody used these or know
> > anything about them.

Terrible stuff, if you're asking me.
I know because I spent a lot of time looking for shorts on boards that were
done that way.
You always have the problem of adjusting the height of the tool, the board
never being
perfectly planar or even resonating at certain rotation speed of the tool.
So you end up
either removing too much copper - or the contrary. We used to look for
shorts that were
caused by copper connections that were too tiny to see them - decide which
traces are
shorted, and then burn away the connection with a strong current source.
A mere nightmare.

JH.