Subject: | |
From: | |
Date: | Thu, 17 Oct 96 17:45:12 cst |
Content-Type: | text/plain |
Parts/Attachments: |
|
|
Hi Ed-
There are not any major changes in store for terminal solderability
testing in the ANSIJ-STD-002 (components) specification (unless the
committee gets a suggestion to change something). However, there will
be some serious discussions in the 002/003 solderability committees on
the use of"R" flux versus some activated flux (an RMA) or a low
residue type flux for solderability testing. More info should be
available after the Naples IPC meeting. My experience with low residue
or no clean type fluxes (there is a difference) is that the amount and
type of activators used are much less aggressive, quicker to "burn"
off, and more soldering technique sensitive. After a short learning
curve period we have had very good success with using low residue
fluxes in manufacturing. Your terminal finish alloy is a high Sn
finish - tin preferentially oxidizes and thus the higher the tin
content the faster solderability will be impacted. Also bright acid
tin finishes tend to have more solderability problems because of
codeposition of the plating bath brighteners if not controled closely.
A 320 microinch thick finish should be enough to maintain
solderability unless the storage conditions are really bad. You might
try switching to a lower tin content alloy if your design permits it
or maybe some pretinning. Good luck.
Dave Hillman
Rockwell Collins
[log in to unmask]
______________________________ Reply Separator _________________________________
Subject: Terminal Solderability
Author: [log in to unmask] at ccmgw1
Date: 10/17/96 1:49 PM
In our switch to a low solids no-clean, we are having problems with
terminal solderability. I know from my reading that this is a problem
thoughout industry. ASTM spec. #B545-92 gives excellent criteria for
different classes. Ours being class three, we spedify the base material, a
barrier layer; 50microinches of nickle and final plating; 320 microinches
of tin or tin/lead(12%max lead). Terminals thus far with this
specification have performed great. However, previous designed terminals
have only required the terminal to be solderable. We are having a
difficult time finding suppliers who will sign-up to the solderablity
specification(dip test). We were lucky for many years because we used a
strong OA flux, and were able to solder terminals that were substandard.
We are an automotive supplier and the terminals in question are individual
terminals autoinserted into boards or terminals that are part of a
connector.
My questions:
--Is anyone else having this problem and how are you handling it?
--I have heard that there are some changes being made to the J-standards
specific to terminal solderablity
--Does anyone have any suggestions?
Thanks for your assistance
Ed Holton
Sr. Manufacturing Engineer
[log in to unmask]
***************************************************************************
* TechNet mail list is provided as a service by IPC using SmartList v3.05 *
***************************************************************************
* To unsubscribe from this list at any time, send a message to: *
* [log in to unmask] with <subject: unsubscribe> and no text. *
***************************************************************************
***************************************************************************
* TechNet mail list is provided as a service by IPC using SmartList v3.05 *
***************************************************************************
* To unsubscribe from this list at any time, send a message to: *
* [log in to unmask] with <subject: unsubscribe> and no text. *
***************************************************************************
|
|
|