Re: [CAD_CAM_EDM_DRO] Double sided milling WAS Re: SuperCam & PCB Trace Milling Software

Good thought.

I know that is done at some of the printed circuit board house shops to
maintain
registration for silk-screening the component legend.

I have seen very high quality double sided circuit boards that were produced
by the engraving method. It definitely works.

I have found making a machine to engrave high density circuitry
requires a high level of precision, the devil is in the detail. If the
surface of the
table is more than a few thousands out of flat it will show up in the
engraving.
If either the X or Y axis are not perfectly parallel and perpendicular to
the
surface of the table it will show up in the engravings. A human hair under
a clad board to be engraved can change the results.

If the raw copper clad stock is held by squeezing from the side it will bow,
which
will show in the engraving.

I think using vacuum to hold down a board to be engraved has a lot of
advantages,
at least until the holes are drilled.

I am looking for a source of engraving cutters that can be used to engrave
circuit boards. If you know of any websites that sell them I'd sure like to
check them
out.

There are pictures of a machine I learned some of my lessons on at
http://www.super-tech.com/root/minirobo.htm Even with a low tolerance
machine it
is possible to make circuit boards with traces down to .015 width. I think
you would
have to be real finicky to make a machine that would permit traces between
the hole on
a DIP chip. The cutting kerf of the tool would have to be in the .010 inch
range.

Dennis

----- Original Message -----
From: Rick Dulas <drspiff@...>
To: <CAD_CAM_EDM_DRO@egroups.com>
Sent: Tuesday, October 17, 2000 7:49 AM
Subject: [CAD_CAM_EDM_DRO] Double sided milling WAS Re: SuperCam & PCB Trace
Milling Software


> Howdy! How 'bout a couple of through holes in the board to be used as
> locators. When the board is flipped over, use these 2 holes as "witness
> marks". Since you know their coordinates, you should be able to line up
> the board's coordinate system so the 2 sides are aligned. Just a
> thought.
>
> Rick Dulas
>
> Dennis Bohlke wrote:
>
> > I think engraving a double sided board would be a registration
> > nightmare, but do
> > able.
>
>
> [Non-text portions of this message have been removed]
>
>
>
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