Sent: Friday, December 14, 2001 2:45
PM
Subject: Re: [TN] Homeplate apertures,
how to use them
Hi Dave,
The goal is elimination of solder beads (the
balls at the sides of chipcomponents). At present we're cleaning all our
boards, which removes 99% of the solderbeads, but we want to anticipate on a
no-clean process that we may introduce in the future. From previous Technet
discussions I learned that the homeplate design is very effective in
removing solder beads. Maybe I should also try some alternatives, but the
question remains how to make an easy to use specification (to the stencil
supplier, or to our production engineers who orders the stencil) as to
what apertures should be changed to homeplate, and what apertures should be
left untouched (or should be changed in another way).
Daan Terstegge
----- Original Message -----
Sent: Saturday, December 15, 2001 1:09
AM
Subject: Re: [TN] Homeplate apertures,
how to use them
We do not routinely use
homeplate apertures. We only use homeplate
apertures in cases where
we need to reduce solder balling when using NC
fluxed pastes.
What
is your goal in using this aperture shape?
Dave Fish
-----
Original Message -----
From: "d. terstegge" <[log in to unmask]>
To:
<[log in to unmask]>
Sent:
Friday, December 14, 2001 6:05 AM
Subject: [TN] Homeplate apertures, how
to use them
> Dear Technetters,
>
> For our
stencils I have recently introduced the homeplate design for
the
apertures of chipcomponents larger than 1206.
> But now a
problem occurs with the guys who have to order the stencils: it
takes a
lot of time, by using Gerber data, partslist and assembly drawing
to
figure out which components are 1206, 1210, 1812. For a coil or
tantalumcaps
with such a footprint I don't want a homeplate aperture
because these parts
need a little more solder.
> So we end up with
a nice specification, but very unpractical for the
production
engineers.
>
> How do others deal with this ? Mabe you
have suggestions on how to make
an easier-to-use specification ? Or
ideas about easier ways to order a
stencil according to my spec ?
>
Should I keep it simple and say "use homeplate-apertures for
all
footprints larger than 1.5 * 1.5 mm ?"
>
> Daan
Terstegge
> SMT Centre
> Thales Communications
>
Unclassified mail
> Personal Website: http://www.smtinfo.net
>
>
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