Re: [CAD_CAM_EDM_DRO] Milling / drilling PC boards on home shop CNC equipment.

Alan Marconett and Larry Edington wrote:

> > The most important thing for isolation milling is a floating head. You want
> > the head to move down and put pressure on the PC board blank to help keep it
> > flat. Or to at least contact the board to ensure the bit penetrates into the
> > blank the same amount each time.
>
> >>>I was asking about that about a week or two ago.<<<

Alan,

I just thought I would post this link to my machines floating spindle.
http://www.data-cut.com/page5es.html
I am sure many of the fellows are familiar with these as they are found typically
on Computerized Engraving machines. They are a little on the expensive side but
plenty worth it. They will generally spin day in and day out up to 30K rpm. They
are available for 1/8", 11/64" and 1/4" diameter tooling, and the 1/4" is also
available with a top and bottom loading collet/drawbar setup. Just about ANY style
of a bit is available from: http://www.antaresinc.net/

I too have done some circuit board work without any problems though I am far from
an expert on the subject. When I do drill a hole in the center of a
pad............ it is in the center of a pad !!

My spindle is from a NewHermes 7200 machine. It costed around $500. There are
numerous different styles for less $$$.

If you look at the 3rd picture from the top, The floating spindle consists of only
the black portion seen on the top, NOT the whole aluminum Slug. I just use the
Slug to hold it in my clamp easily. These things mount real easy on a smaller
machine.
Swapping out the V-Groove pulley for a toothed one would make an excellent spindle
for some of these desktop mills.

Your typical setup of a bit ( in a top loading engraving spindle) would be to:

1. Set the built in Micrometer at the base of the spindle to 0.
2. Then adjust the spring tension prefered via the larger knurled section at the
bottom.
3. Then, jog the head down on top of your material ( the 5th picture shows one of
the many styles of "feet" available to "drag" on your material- this one with dust
collection), while watching for some "space" to show up just under the top pulley.

4. Then, loosen the setscrew in the brass "collar" on the top portion of the
tool.
5. Slide the tool and collar down thru the spindle from the top letting the tool
touch the material.
6. Turn the brass collar in Counterclockwise at the top.
7. Tighten the setscrew in the brass collar at the top of the tool.
8. Raise the Z axis.
9. "Dial" the Micrometer head in the bottom of the spindle UP to expose the amount
of tool you would like exposed.

Some day I need to install a 90 VDC motor with Feedback on my spindle in place of
the "sewing machine" motor.

If your ever interested in purchasing one, there are a few rebuilders on the
internet, but probably the best affordable source is Western Engravers.
http://westerneng.com/html/spindles.html

Careful though, Some DO NOT have a built in spring !!! Those are generally less
expensive.

It is one "accessory I can't do without !!!


Chris Luebke
DATA-CUT
http://www.data-cut.com/Index.html