I almost hate to admit this but in 1971 when I was
Genny,
I almost hate to admit this but in 1971 when I was working for Western
Electric we ran a non-controlled experiment in the lab and passed out
copper clad laminates to employees of different nationalities and told
them to put lots of finger prints on them and then we ran them on a
G.E.C. meniscogarph to see if we could find soldering differences. To
our surprise we couldn't determine and significant differences. Since
then I've been intimately involved with PCB soldering and solderability.
Although many of our factories didn't use gloves to handle OSP or
immersion solder PCBs we did encourage them to handle PCBs only by the
edge. We didn't discourage the use of gloves and in fact we encouraged
workers who did use gloves to handle PCBs only by the edge. One thing
you need to keep in mind most people wear gloves to protect their hands
not what they are handling. The outer surface of a glove is only clean
if you haven't handled something dirty before handing a PCB.
Regards,
George
George M. Wenger
Andrew Wireless Solutions
Senior Principal FMA / Reliability Engineer
40 Technology Drive, Warren, NJ 07059
(908) 546-4531 [Office] (732) 309-8964 [Cell]
[log in to unmask]
-----Original Message-----
From: TechNet [mailto:[log in to unmask]] On Behalf Of Genny Gibbard
Sent: Thursday, February 28, 2008 5:00 PM
To: [log in to unmask]
Subject: Re: [TN] OSP - protection
So no special paper required, like the silver saver paper recommended
for ImmAg finish boards?
We are trying to avoid writing separate procedures for handling
different finishes. We wanted to write one standard policy for storage
and handling of all our bare boards with just a few simple differences
noted, like the use of silver saver paper, that are specific to certain
finishes.
We thought we'd err on the side of caution and go to more strict levels
for all boards, whether or not they need it, unless it involves a
significant cost outlay.
Use of gloves, for instance - it isn't going to hurt a HASL board to be
handled with them, and the handlers already have gloves available for
handling boards, since we have told them to use gloves for ImmAg.
Storage in a sealed MBB. It is winter on the prairies and the air is
very dry around here, but a sealed MBB isn't going to hurt any board,
and it may potentially help when the spring thaw hits and humidity
shoots up. Not that we typically have much problem with moisture here
at any time of year.
-----Original Message-----
From: TechNet [mailto:[log in to unmask]] On Behalf Of Stadem, Richard D.
Sent: February 28, 2008 3:26 PM
To: [log in to unmask]
Subject: Re: [TN] OSP - protection
The salts from your fingerprints are the culprit. If assemblies are
washed immediately after handling, studies have shown that the
fingerprint oils containing the salts will usually be cleaned away.
However, after just a couple of days those same fingerprints actually
get much harder to clean off. Also, the salts from any snacks, not just
the oils, are bad news.
And you must never handle boards with your bare fingers (or any other
bare part of your body!) after the final wash just prior to conformal
coating, ROSE testing, and epoxy staking.
-----Original Message-----
From: TechNet [mailto:[log in to unmask]] On Behalf Of Nowland, Russell
Howard (Russell)
Sent: Thursday, February 28, 2008 2:37 PM
To: [log in to unmask]
Subject: Re: [TN] OSP - protection
George,
There are a few items that you missed and one was the heavy southern
draaawl.
The other is you don't need gloves but it is advisable to only hand the
boards from the card edges.
There are still some bad elements that can transfer to the board and can
cause some soldering difficulties. Most of the issues we found were
hand lotions and pop corn oil.
So no selling pop corn in the vending machines and no Avon or Mary Kay
parties in the cafeteria and you don't need gloves.
Russell Nowland
Alcatel-Lucent
Advanced Manufacturing Engineer
Address: 14000 Quail Spring Parkway, Suite 300 Oklahoma City, OK 73134
email: [log in to unmask]
Desk: 405-302-1660
Cell: 405-203-0034
Fax: 405-302-1622
-----Original Message-----
From: TechNet [mailto:[log in to unmask]] On Behalf Of Wenger, George M.
Sent: Thursday, February 28, 2008 2:27 PM
To: [log in to unmask]
Subject: Re: [TN] OSP - protection
You should point out that none of your customers found glov Lee,
You should point out that none of your customers found gloves necessary
with either OSP or immersion silver.
-----Original Message-----
From: TechNet [mailto:[log in to unmask]] On Behalf Of Lee parker
Sent: Thursday, February 28, 2008 3:01 PM
To: [log in to unmask]
Subject: Re: [TN] OSP - protection
Genny
We had over 20 years of experience at the AT&T facility in Richmond with
OSPs. Our customers stored the boards side by side with HASL boards and
experienced no adverse effects. I will also point out that while gloves
give added protection, none of our customers found them necessary.
Best regards
Lee
J. Lee Parker, Ph.D.
JLP Consultants LLC
804 779 3389
----- Original Message -----
From: "Genny Gibbard" <[log in to unmask]>
To: <[log in to unmask]>
Sent: Thursday, February 28, 2008 12:28 PM
Subject: [TN] OSP - protection
For immersion silver, we wear gloves when handling them prior to reflow,
and we interleave the silver saver paper and seal them in MBBs to store
them.
We are starting to work with OSP for the first time. What do you
recommend for OSP handling? Gloves is a given, but I am wondering about
storage.
Thanks in advance,
Genny.
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