Homebrew PCBs

On Sat, 11 Jun 2005 16:13:28 +0200, David McNab <david@...>  
wrote:

> Hi all,
> Firstly, thanks to those who have helpfully responded to my earlier
> questions with suggestions to use CNC drills/routers.
> I'm forming ideas for the mechanics of a CNC transport:
>  - PIC micro controlling the thing, talking to PC via serial
>  - looting the x-y rotation counter bits from an old mouse
>  - implementing the x-y board transport via PWM-controlled motors,
>    driving threaded rods which have the mouse rotation counters attached
> I could see this achieving a resolution of 0.25mm or better.
> (Shame about the chicken/egg scenario - I'd love to have the CNC
> apparatus already in place to help me manufacture the PIC logic board it
> depends on  )
> Software on the PC side could then have basic primitives:
>  - goto (x,y) - board movement
>  - goto (z) - raise/lower drill or router
>  - calibrate (x,y) - allow user to check/adjust calibration relative
>    to a known 'origin' on board
>  - turn drill/router on/off
> Where I'm stuck is with the router - what kind of bit could I use to
> guarantee good results and clean polished cuts?
> And, any feedback on the above?
>



To me this approach seems harder than it needs to be.
Why not go with established concepts, like stepper motors and parallel  
port with step/direction signals?
And existing software that accepts drill files?

Why do you want to re-invent the wheel?


ST