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April 2010

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Subject:
From:
Mike Sewell <[log in to unmask]>
Reply To:
TechNet E-Mail Forum <[log in to unmask]>, Mike Sewell <[log in to unmask]>
Date:
Fri, 16 Apr 2010 08:00:18 -0500
Content-Type:
text/plain
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text/plain (366 lines)
Mid 30's 

Steve Gregory started me on Technet about ten years ago, back when I was
really green to the industry.  Steve has always been an outspoken
proponent (bordering on evangelism) of Technet and those that comprise
it.  Can't thank him enough.  

Y2K has passed, now it's the end of the calendar (the world?) in 2012!

Regards,
Mike

-----Original Message-----
From: TechNet [mailto:[log in to unmask]] On Behalf Of Guy Ramsey
Sent: Friday, April 16, 2010 7:32 AM
To: [log in to unmask]
Subject: Re: [TN] Question for "Old-Timers" about Gold

Late 50's 
I went back to the archives. I first learned of and monitored the
TechNet in
1995 or 1996. Our company didn't even have internet access. I monitored
from
home. In 1999, because of Y2K fears, the company moved from a DEC
mainframe
to a PC based network and we all got access. It was about that time I
started contributing. Remember Y2K?!


-----Original Message-----
From: TechNet [mailto:[log in to unmask]] On Behalf Of Bev Christian
Sent: Thursday, April 15, 2010 9:12 PM
To: [log in to unmask]
Subject: Re: [TN] Question for "Old-Timers" about Gold

Inge,
I missed this e-mail and went looking for it. I wanted to know what
started
the thread down memory lane. 

You are just being morose!

I mean people like:
Chris Mahanna
Doug Pauls
Dave Hillman
Joyce Koo
Lee Whitman
Karen Tellefsen
Graham Collins
Guy Ramsey
Steve Gregory

Are mostly in their forties.  So don't be so sure TechNet will disappear
when us older farts retire and/or die.  :)

Bev

-----Original Message-----
From: TechNet [mailto:[log in to unmask]] On Behalf Of Inge
Sent: Thursday, April 15, 2010 3:40 AM
To: [log in to unmask]
Subject: Re: [TN] Question for "Old-Timers" about Gold

Showing off?  It's just fun to share the little I know.  It's a
remarkable 
time we live in today.  There are no engineers left at my company,
engineers

who are interested in all about switches (and other electromechanical 
components).  On the other hand, I live partly in the past myself,
having 
very shallow knowledge about today's central technology with numerous 
applications based on semiconductors.  I've tried to understand how a
Intel 
processor works, but  must admit it's too advanced for my old skull. And
I 
would never be able to design a modern DSP or a X-band up/down
converter, to

take example.  I had a look at one of our library shelves the other day.
I 
estimated about 30 meters of technical literature for design of
electronics,

but only a few books about chemistry, mechanics and components !  It
seems 
as if old-timer's knowledge is not needed much today.

TN is still a exciting forum, all kind of themes are discussed.  I'm
very 
grateful to such persons as Brian Ellis, John Burke, Wayne Thayer, Dave 
Hillman, Iona Tempea, Steven Creswick, Victor Hernandez, George Wenger,
Mike

Fenner, John Maxwell III, Joyce Koo, Denny Fritz, Steve Gregory, Dewey 
Whittaker, It Depends,  and a dozen more.  You keep my curiosity alive. 
Thanks to you all.

I would like to see someone of you who started TN or have been members
from 
the very start, to write some kind of a retrospective essay about
TechNet, 
kind of baton for the change-over to next decade.  When those real 
enthusiasts retire, I'm afraid TN will distinguish.

Inge

--------------------------------------------------
From: "Jack Olson" <[log in to unmask]>
Sent: den 14 April 2010 15:43
To: <[log in to unmask]>
Subject: Re: [TN] Question for "Old-Timers" about Gold

> Well, now you are showing off!
>
> I believe the modern "impurity" is a .2% cobalt to add hardness,
>
> so I guess my questions for curiosity should have been
> "did standard knoop hardness change over the years?"
> and
> "has gold thickness been gradually reduced over the years?"
> but my REAL question is:
> "Has anyone experienced switch contact failures using the IPC
> recommended 150 knoop, 118uin. Nickel min, 31.5uin. Gold min.?"
> thanks,
> jack
>
> On Wed, Apr 14, 2010 at 5:19 PM, Inge <[log in to unmask]>
wrote:
>
>> Jack,
>> like you say, it's more to it....gold thickness is not the one and
only
>> parameter.  Other factors are contact asperity, contact geometry,
contact
>> area vs. current, wipe pressure, switch slide coefficient, underlying
>> plating, life expectancy and at least half a dozen more parameters. I
was
>> specialist on electromechanical and manual switches decades ago,
don't
>> remember all details, but I can tell you this: if you count on gold
>> thickness only, you don't know what you are shipping.  93.7% Au? We
did 
>> not
>> name that Gold at all. We talked about maximum 0.1% impurities.  The
more
>> impurities, the higher the friction coefficient. Well, I don't know
what
>> level of quality you speak for. I was in the HiRel, so maybe I'm too
>> demanding. Anyway,  My advice (which you will probably frown at) is
>> basic metal ?? your wiper
>> 300 uinches of pure Nickel
>> 25 uinches of Rhodium over Nickel
>> 5 uinches of soft gold (gold works as 'lubricant')
>>
>> The above based on a qualified switch mechanism.  If that is not the 
>> case,
>> not even 160 uinches of gold  will work for a very long life.  160 
>> uinches!
>> Never heard of such a lot of gold. When extrem current switching is 
>> actual,
>> one use to work with mercury switches, microswitches or like.
>>
>> Don't listen to me, I'm from an era when we dismantled switches and 
>> relays
>> and measured all contact parameters and stored the  test data for
minimum

>> 10
>> years. And all our own test equipments were sent to a qualfied
reference
>> lab. Madness?
>>
>> Inge
>>
>> --------------------------------------------------
>> From: "Jack Olson" <[log in to unmask]>
>> Sent: den 14 April 2010 14:14
>> To: <[log in to unmask]>
>> Subject: [TN] Question for "Old-Timers" about Gold
>>
>>   ya know, every time I think I know enough about a particular
subject,
>>> something comes along to make me realize there is more to it....
>>>
>>> I need to order some boards using a fabrication drawing that hasn't
been
>>> updated in over fifteen years.
>>> We need Hard Gold Electroplating for a rotary switch contacts.
>>> One of the notes calls for gold knoop hardness 200-300, thickness 
>>> 130-230
>>> uin. 93.7% purity
>>> The last FAI report showed gold thickness of 160 uin. All other 
>>> historical
>>> records are lost in the shifting sands of time
>>>
>>> Our vendor has knoop hardness 150, 99.7% purity and says gold 
>>> requirement
>>> is
>>> too thick.
>>>
>>> IPC says knoop 150, gold minimum 31.5 uin. for edge connector
fingers,
>>> which
>>> I assume is the same for contacts (doesn't seem to be addressed)
>>>
>>> Printed Circuits Handbook says knoop 150,  thickness 25-50 uin for
>>> non-military, 99.8% gold purity
>>>
>>> Has gold plating changed that much since then?
>>> Is there a danger of wear-out if I get 50uin. gold plating when our
old
>>> boards were 160 uin.?
>>>
>>> surfin' the learnin' curve,
>>> Jack
>>>
>>>
>>>
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>>
>
>
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