On Thu, 26 Aug 2004 04:52:24 -0000, Nick <
njacovou@...> wrote:
> Hello everyone.My name is Nick from Sydney Aust. My first post to
> this group.So this is probably a dumb question to you guys.I have
> managed to etch my first board after a few failures, but I came up
> with a real beauty(I think anyway).I drilled a board last week and i
> nearly went blind tryin to line up the bloody drill to the pads.So
> is there a way i can use a mirror or something to give me a better
> view of tiny drill to tiny pads. I am using a dremell mounted on a
> stand .The drilling is easy but lining up whilst looking through the
> magnifying glass is hard.Any tips would be appreciated.Thanks.
It helps if you etch a small hole in the copper. This small hole catches
the drill and centers it.
The professinal approach is to use a viewing apparatus, a optical system
looking
at the PCB from the other side. this apparatus has concentric rings on the
screen which
helps to align the pad.
Normally those machines feed the drill from below, and have a foot holding
down the pcb
so it doesn't get lifted up. A optical system looks from top, and has a
screen.
A "cheap" homebrew solution could be a small camera module and a old tv
screen.
Monunt the camera under the drill table, facing up through a hole.
(use a mirror and/or glass plate to keep the dust away from the cam lens).
I reckon this is easier to align for a electronics guy than a real optical
system and those
camera modules go for well below 50eur/usd. A tv can probably be found
somewhere.
It also allows for a unmodified drill stand with the drill fed from above
(and no pressure
foot needed).
Perhaps you will need compressed air or a fan to keep the dust away from
the mirror or glass plate.
You must ensure alignment is solid so the cam doesn't move relative to the
drill.
For around 500bucks you could buy a cnc drilling machine(-kit), and if you
are good with mechanics
you could build your own for a lot less. You put the pcb in and the
machine does the rest.
Of course a CNC is only useful if you have a certain number of PCBs,
otherwise is is too
expensive. (Also keep in mind setting up the machine will take time,
learnig how to generate
the drill files, aligning and chucking stuff etc. I believe for a small
imple PCB nothing beats
hand drilling (of course 100pcs./months with 200holes ea. are another
story).
ST