I see ... And my question would be - what good would that do? I still think
we are dealing with flawed Fab drawing notes..... or a incompletely thought
out board design... hard to say though... all my info is second hand.
- Bill
-----Original Message-----
From: Howieson, Rick [mailto:[log in to unmask]]
Sent: Thursday, June 08, 2000 3:33 PM
To: [log in to unmask]
Subject: Re: [TN] still confused
Bill,
Helloooo....Ralph was talking about immersion gold NOT hard
electroplated gold as seen on connectors. Immersion gold can easily be
removed with an erasor, imagine what a corrosion from battery leakage
would do?
Rick
>-----Original Message-----
>From: Brooks Bill [SMTP:[log in to unmask]]
>Sent: Thursday, June 08, 2000 4:04 PM
>To: [log in to unmask]
>Subject: Re: [TN] still confused
>
>That's Different! He's absolutely correct! The gold plating in THAT area
>would be desirable, this is no different than a card edge connector. If the
>pad on the board is to act as a connector and they will NOT be soldering to
>it, I would highly recommend a gold over Ni surface. To rework, can you
>strip the solder from the pads and selective NI/gold plate there... and
>still protect the circuitry and components from contact with the chemicals?
>One alternative might be silver plating.... silver oxide is still very
>conductive... but I don't know if it's an option for the company you are
>dealing with...
>
>The risk of corrosion degrading the battery performance has to do with the
>contact of the battery to the pad on the board. Humidity in the air can
>condense between the nickel plating on the outside of the battery and the
>Tin/lead solder on the surface creating an electrolyte between dissimilar
>metals.... thus oxidation and corrosion will seep into the contact area
over
>time, reducing the conductivity between the battery and the board.
>
>
>Bill Brooks
>Senior PCB Designer - [log in to unmask] <mailto:[log in to unmask]>
>
>Zoneworx, Inc.
>40925 County Center Drive, STE 200
>Temecula, CA 92591
>http://www.zoneworx.com <http://www.zoneworx.com>
>Tel: (909) 296-1226 x 1037
>Co-Director / Education Officer / Webmaster
>for the San Diego Chapter of the IPC Designers Council
>http://www.ipc.org/SanDiego/index.html
><http://www.ipc.org/SanDiego/index.html>
>
>
>
>
>
>
>-----Original Message-----
>From: Ralph Richart [mailto:[log in to unmask]]
>Sent: Thursday, June 08, 2000 2:33 PM
>To: [log in to unmask]
>Subject: Re: [TN] still confused
>
>
>So here's the deal:
>
>They have two large circular pads (like about .750") that they use as
>battery
>contacts. He says that this is the place that he has corrosion risk. I
>can't tell if
>the corrosion risk is from battery leakage or environmental effects.
>Anyway, he says
>that corrosion significantly impacts the battery life.
>
>ralph
>
>David Hillman wrote:
>
>> Hi Ralph! Can you provide more information on what the customer
>> considers/experienced "corrosion" and what type of use environment he/she
>> was talking about?
>>
>> Dave Hillman
>> Rockwell Collins
>> [log in to unmask]
>>
>> Ralph Richart <[log in to unmask]>@IPC.ORG> on 06/08/2000 11:55:26 AM
>>
>> Please respond to "TechNet E-Mail Forum." <[log in to unmask]>; Please
>respond
>> to Ralph Richart <[log in to unmask]>
>>
>> Sent by: TechNet <[log in to unmask]>
>>
>> To: [log in to unmask]
>> cc:
>>
>> Subject: [TN] still confused
>>
>> We have answers....
>>
>> So I had a long talk with my customer this morning to provide input
>> based on the invaluable advice from you all.
>>
>> I said - "is there a specific reason for choosing 3-8u" of immersion
>> gold over tin/lead solder?"
>> He said - "absolutely, the gold provides corrosion resistance, the gold
>> does not"
>> I said - "even such a thin amount - only 3-8u"?"
>> He said - "definitely, all we need is the coverage, the thickness is
>> irrelevant"
>>
>> Is this true?
>>
>> Needless to say, we are rebuilding the parts as we speak. Rework sounds
>> difficult to say the least, although I may try to come up with some
>> scheme for fun as they have a bunch of boards that are no good right
>> now.
>>
>> thanks for all the help.....
>>
>> ralph
>>
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