Hi Guys,
I started a group to get more detailed about this type of machine,
but we really have not gotten a big start on discussing these.
http://groups.yahoo.com/group/CNC-PCB_Design/
To get into detail, you only need enough power to move the board. so
the energy needed is very light. Pretty much any steppers will work.
If you took a board and screwed on a pair of runners this could be
the basis of a really cheap home build.
NOTE: using wood would be good for a couple boards a month, and holes
on 0.1" centers. if you plan on high volume, or tight tolerances,
then something more ridged is needed.
Only one side needs to be the main guide. Make a plate for the top
of this that has more runners set so as to be able to slide over the
base. Some sort of plastic is needed to keep the wood from wearing.
This could be as simple as the plastic from a soda bottle. Testing
will show what wears too fast and what lasts longer.
Another section that would be mounted on this first would allow an X
and Y table movement. This would mean the drill would be stationary.
One would need to use the typical circuit board layout program to get
the Gerber files and drill files. The drill files are the key to
this work. My WinQcad saves all locations in 6 digits. 2 leading
and 4 decimal places. That means I can pull the drill file and turn
it into a G-Code for a low cost program like TurboCNC to run.
For manual holes, you just move the table to a stop, hand drill, the
move again. the beauty is perfectly lined up holes. The down side
it hand drilling.
My T-Tech PCB machine uses a solenoid to push the drill into the
part, and a foot that slides just over the part so the board does not
lift up if the drill gets stuck.
This section is where the real work would come in.
A heavy stepper motor, or even a car door window motor could work to
power the drill.
since you are not in the US, let me know what type of parts are
available to you.
Dave