Making SMD boards - wither paste stencils?

[Robert E. Seastrom]

Yeah, there is no shortage of folks who will gladly take your gerber
files and make you pc boards, with plated through holes and other
niceties.  Sure, you have to wait for them to show up, but it's a heck
of a lot less hassle than having yucky stuff like ferric chloride
around.

Eagle Light will do 4x3" PCBs (2 layer, 1 sheet of schematic), which
is enough for many projects.

-r


Tad G <tad at planetisuzoo.com> writes:

> Another option is to have someone else print it:
> http://www.pad2pad.com/
>
> -Tad
>
> ----- Original Message -----
> From: "Nan and Sandy Sanders" <radiodog77 at pobox.com>
> To: "Mike O'Dell" <mo at ccr.org>, "Tacos" <tacos at amrad.org>
> Sent: Sunday, November 14, 2010 11:29:52 PM
> Subject: Re: Making SMD boards - wither paste stencils?
>
> Mike, I have  done a lot of surface mount at both home and work, both 
> board house and toner-transfer. Almost all has been using a syringe ( 
> or sometimes a tooth pick). Of course most of the time the syringe 
> was hooked up to something like this http://www.zeph.com/zt-5100.htm 
> . Some where around 0603 or smaller it does not work as well as with 
> larger sizes. With fine pitch quad flat packs I just flood the pins 
> with solder and clean up with solder wick.
>       Sandy
>       WB5MMB
>
>
> At 08:46 PM 11/14/2010, Mike O'Dell wrote:
>>i've been thinking a lot about how one makes
>>PCBs for home-brew designs using SMDs.
>>
>>after talking with a number of folks,
>>the consensus seems to be that making a board
>>using toner-transfer (plus pen touch-ups)
>>and etching with ferric chloride will work
>>acceptably well.
>>
>>when i asked about making stencil for solder
>>paste, the 2.5 suggestions were: laser cutter,
>>vinyl cutter (a plotter with a sapphire scalpel
>>instead of a pen), or (.5) use a syringe and
>>dot the board manually.
>>
>>it seems to me that there should be a way to make
>>a paste stencil that isn't any more complex than
>>making the board, and the article i referenced
>>before on the "Ediburgh Etch" for intaglio print-making
>>may provide the answer. (I almost wrote "solution" but
>>stopped in time.) the trick is adding some citric acid
>>to the ferric chloride. it dramatically improves the
>>etching performance.
>>
>>using toner-transfer, one ought to be able to image
>>the stencil on very thin brass shim stock or even
>>heavy copper foil. paint the back and edges with
>>a resist and then let the etchant chew all the
>>way through the metal to make the stencil.
>>
>>i bring this up to ask if anyone knows of a better
>>approach before i try this out?
>>
>>while for small designs one can make a stencil
>>manually, there is something to be said for
>>a stencil that is made using the same tape-out
>>as the board.
>>
>>however, if people have manually made stencils
>>(like for the charleston SDR board??), what
>>techniques seem the best and where is the cross-over
>>between manual dotting with a paste syringe and
>>making a stencil?
>>
>>         -mo
>>_______________________________________________
>>Tacos mailing list
>>Tacos at amrad.org
>>http://www.amrad.org/mailman/listinfo/tacos
>
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