Homebrew PCBs

starsnstripes_2003:
> I already had thought about a simple footswitch,
> But it would only turn on the Dremel.

Why the need for a footswitch to turn the drill on
and off?  I just turn on the drill, drill all the
holes, and then turn it off.

Dave Mucha:
> For the PCB drilling, which when done manually is
> boringly repetitive,

(One might also say that it is repetitive boring :-)

> I was thinking that if one used a solenoid to peck
> the drill into the board, it would leave your hands
> free to move the board.

One of the reasons I made the platform move up into
the drill, instead of the usual drill-moves-toward-
platform, is that you can position the board and
drill the holes while keeping both hands on the board.

For Starsnstripe's version, you could hold the drill
up with a spring, and pull the drill down using a wire
looped around your big toe.

> But, then I think a full CNC unit would be the most
> fun to make.
> Dave

Definitely :-)

Dan Mauch (http://www.seanet.com/~dmauch/) sells
CNC kits and has some great info on his site.  He
built a CNC drill machine which was described in
Nov 93 Nuts & Volts.  As I recall, he used a stepper
motor controlled X Y table, and a stepper motor to
raise and lower a Dremel tool.  He says he has drilled
200000 holes with it and is still using it.

If I was to build such a thing, I would move the PCB
in the X direction and the drill bit in the Y and Z
direction, using heavy-duty ball-bearing drawer slides
for the linear X and Y bearings, and a rotary bearing
on a long arm for the "Z" motion.  I think moving the
board and drill on separate bearings would give better
stiffness than having a Y bearing on top of an X bearing.
I would use a flexible drill shaft accessory (e.g.
Dremel) to hold the drill -- that would be a lot lighter
and easier to move around than the drill motor.

Stock Drive Products / Stirling Instruments
(http://www.sdp-si.com/) has some higher-precision parts
that could be used.  They also have some CNC products
and info under their Linear Motion Products tab.

Cheers,
- Jan



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