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Reply To: | TechNet E-Mail Forum. |
Date: | Wed, 23 Feb 2000 11:40:52 +1100 |
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i'd concur with the "do not bend" notions,
but from learning the hard way episode
(changed to M-tron mil specked smd can from unmentionable thai fab
obscurity),
there is something else at play (discussed 1/2 year back here).
It's a shock/jar/nock/whatever ; the crystal can take only a few G's on
mounted tips,
before the tip shatters. Nock of board on edge over table is sufficient with
some brands,
as we validated (they even go to field , before they droll off completely
upon subsequent motions).
There is plenty of good smd's on market (M-tron i can speak of , after 6
months validations),
no excuses for Dilbert's prepping .
What 'm trying to say (in written English, hope) ; often this fragile factor
(generated alongside of the process),
distorts the say: prepping analysis .
Dropping a bag of crystals prior on concrete in store does not help.
Paul Klasek
ResMed
-----Original Message-----
From: [log in to unmask] [mailto:[log in to unmask]]
Sent: Tuesday, 22 February 2000 8:33
To: [log in to unmask]
Subject: [TN] ASSY: PTH -> SMT
Lately I have been seeing failure analysis that indicates the failures
were caused by trying to take a through hole component and bending
the leads up and around or under the component body to make it
a surface mount component. In one case a crystal seal was broken
and another the bends were just too "springy".
Is there a set of suggestions as to how and when and IF this can be
done to a through hole component?
Susan Mansilla
Technical Director
Robisan Lab
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