Drilled solder paste stencils

Very nice. I tried this once on a CNC machine, but instead of drilling,
I used a fine drill rod to punch the holes in Lexan sheet. It worked
well enough, but your holes and the printed paste look better than
mine. How did you finish the holes so nicely? No burrs at all.

--
Joe Legris

Sanding.....Medium grit then fine.

J.A. Legris wrote:

oparr@hotmail.com writes:


Call me stupid, but I'm missing the key "how to do it" part.  Looks
like a stencil was cut, and then somhow solder wound up on the
boards.  How was that done?  I'm really curious to see how, since this
process looks really good in the pictures, and the best you could say
about my SMD soldering is that the solder joints tend to hold...
mostly...
--
Joseph J. Pfeiffer, Jr., Ph.D.       Phone -- (505) 646-1605
Department of Computer Science       FAX   -- (505) 646-1002
New Mexico State University          http://www.cs.nmsu.edu/~pfeiffer

    Looks like once the stencil is cut, you just swipe some paste over it
and it deposits through the holes.  So I would guess that you lay the
stencil over the board and use a small squeegee.  This would be almost
identical to silk screening.

Cheers!

Sir Charles W. Shults II, K.B.B.
Xenotech Research
321-206-1840

You align the stencil with the board/pads, hold it in place, dab solder
paste on the stencil then using either a rubber squeegee or flexible
plastic putty knife you ensure all the cutouts (holes in this case) are
filled flush with the stencil. Agreed, I could have taken more pictures
but just assumed this to be a well publicized no-brainer step. Here are
some links (BTW, it doesn't have to be as messy);

http://www.sparkfun.com/tutorial/SMD_Printing/SMD_Printing.htm

http://www.stencilsunlimited.com/

Joe Pfeiffer wrote:

oparr@hotmail.com writes:


Ah ha.  Definitely in the "now that I know the answer, it was obvious
enough I should have realised it" category.
--
Joseph J. Pfeiffer, Jr., Ph.D.       Phone -- (505) 646-1605
Department of Computer Science       FAX   -- (505) 646-1002
New Mexico State University          http://www.cs.nmsu.edu/~pfeiffer

But how do you get the pad coordinates so you know where to drill the
holes? Is there and easy way to extract it from gerber files?
Ringo


Joe Pfeiffer wrote:

I can only speak for Eagle. There is a file "smd-coordinate.ulp" in the
ULP folder that ouputs x-y coordinates of SMD pad centers. Since CNC
solder paste dispensing machines are still around, I suspect most PCB
CAD software provides some means to extract this info.

Ringo wrote:

Cool, I use eagle, so I'll have to give it a try. I currently get
Stencils made a Pololu for about $40, but this would be great for times
swhen you can't wait a week to get them.
Thanks

oparr@hotmail.com wrote:

Awesome work. The stencils always kept me from entering the SMD age, but
this may actually be the solution. Thanks for posting this!

What material did you use for the stencil?

Now if I could get my CNC machine to position the parts... . ;-)

   Matthias

Google >"solder paste stencils"<

Matthias Melcher wrote:

oparr@hotmail.com writes:


Having just googled, here's a good site on the subject that I found:

http://www.sparkfun.com/tutorial/SMD_Printing/SMD_Printing.htm

Lots of *really* good information there.

And to think the half-dozen SMD parts I've soldered have all been by
hand...
--
Joseph J. Pfeiffer, Jr., Ph.D.       Phone -- (505) 646-1605
Department of Computer Science       FAX   -- (505) 646-1002
New Mexico State University          http://www.cs.nmsu.edu/~pfeiffer

Awesome. I alreaddy decided for my first SMD project. I can finnaly get
my FTDI mounted and the USB-to-serial converter going ;-)

(Yes, I know, I can also solder that one by hand)

Matthias