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Date: Tue, 29 Nov 2011 20:19:03 -0500
Message-ID: <CAPYb0EGx62k3hA9VTFJiG-tqaO=GbKCPh=ejjL5pdH=jajdFxw@mail.gmail.com>
Subject: Re: [geda-user] Re: I won't do BGA's
From: Bob Paddock <bob DOT paddock AT gmail DOT com>
To: geda-user AT delorie DOT com
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Precedence: bulk

> So, the layout can control the standoff height?

I'd like to know how myself?  Normally that is controlled by the paste stencil.

>Sounds like
> it might require depth controlled paste stencils -- where the thickness
> of the stencil varies -- they etch the stencil to different thicknesses
> to get things like that tuned up in production.

Stepped Stencils are one of those things  that is great in theory, but
doesn't work out all that well in practice.

As I've said in the past, talk to the people on the line at your
contractor.  They are more than willing to give feed back when asked.
The problem is usually getting past the sales and marketing folk to
get to the people doing the hands on work.
The line people will know what kind of tweeks it takes to work with
their equipment.
Stuff like you need to enlarge the aperture by 3% to get a clean
release with solder paste X etc.