Geeze,

I have run into this time and time again.  Up front costs versus rework, in
field service, and acquiring a reputation for shoddy product.  Man, I can
tell you from experience you better fill that PTH all the way.  Also if it
is a large cap, you may want to anchor it to an even larger part via some
sort of RTV or other adhesive method.  Vibration can be a pain.  When we had
an issue with this, we ended up placing a piece of thin board laminate down
on the board, puttting the part in, clinching it, wave soldering it,
removing the laminate that was used as a temporary spacer and then using RTV
to attach it to a large transformer.

Mark Ross


-----Original Message-----
From: Jean-Francois Bissonnette [mailto:[log in to unmask]]
Sent: Wednesday, December 15, 1999 11:39 AM
To: [log in to unmask]
Subject: [TN] Ceramic capacitors


Hello technetters!

Well thank You for your enthousiastic answers concerning
your identities.  I'll give you some details about my
occupations ounce I get rid of some fires here (it's funny,
nobody mentioned firefighter!!!).

Some people here are getting pretty nervous about one
IPC-A-610 criteria here and honestly I dont know what
what to tell them to ease their worries.

Par. 3.2.4 says that class 1 & 2 permits coating meniscus
of capacitor to be mounted into PTH.  But is'nt there a
risk of preventing the solder to be conform to criteria
4.1 table 1 (saying that the solder must fill 75% of
the hole)?  What is the risk of not respecting this criteria
(3.2.4).  Personnaly I would fear craquing for the capacitor
on the long run (plus the solder fill), this thing will be submit
to constant vibrations (It goes on a train, near the braking system).
So I would prefer to have it above the meniscus.  But here they
are concerned with the overall costing... Well I guess I need
some of these 5000 years of experience now!

Thank You!  See you around!

JF

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