OH NO Bev not MoreRoHS....Please........8-) Happy Friday
John Burke
(408) 515 4992
-----Original Message-----
From: TechNet [mailto:[log in to unmask]] On Behalf Of Bev Christian
Sent: Thursday, April 15, 2010 6:12 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
>>>
>>>
>>> ____________________________________________________________________
>>> __ This email has been scanned by the MessageLabs Email Security
>>> System.
>>> For more information please contact helpdesk at x2960 or
>>> [log in to unmask]
>>> ____________________________________________________________________
>>> __
>>>
>>> ---------------------------------------------------
>>> Technet Mail List provided as a service by IPC using LISTSERV 15.0
>>> To unsubscribe, send a message to [log in to unmask] with following
>>> text in the BODY (NOT the subject field): SIGNOFF Technet To
>>> temporarily halt or (re-start) delivery of Technet send e-mail to
>>> [log in to unmask]: SET Technet NOMAIL or (MAIL) To receive ONE
>>> mailing per day of all the posts: send e-mail to
>>> [log in to unmask]: SET Technet Digest Search the archives of previous
>>> posts at:
>>> http://listserv.ipc.org/archives
>>> Please visit IPC web site
>>> http://www.ipc.org/contentpage.asp?Pageid=4.3.16 for additional
>>> information, or contact Keach Sasamori at [log in to unmask] or
>>> 847-615-7100
>>> ext.2815
>>> -----------------------------------------------------
>>>
>>
>>
>
>
> ______________________________________________________________________
> This email has been scanned by the MessageLabs Email Security System.
> For more information please contact helpdesk at x2960 or
> [log in to unmask]
> ______________________________________________________________________
>
> ---------------------------------------------------
> Technet Mail List provided as a service by IPC using LISTSERV 15.0 To
> unsubscribe, send a message to [log in to unmask] with following text in
> the BODY (NOT the subject field): SIGNOFF Technet To temporarily halt
> or (re-start) delivery of Technet send e-mail to
> [log in to unmask]: SET Technet NOMAIL or (MAIL) To receive ONE mailing
> per day of all the posts: send e-mail to
> [log in to unmask]: SET Technet Digest
> Search the archives of previous posts at:
> http://listserv.ipc.org/archives Please visit IPC web site
> http://www.ipc.org/contentpage.asp?Pageid=4.3.16
> for additional information, or contact Keach Sasamori at
> [log in to unmask] or
> 847-615-7100 ext.2815
> -----------------------------------------------------
______________________________________________________________________
This email has been scanned by the MessageLabs Email Security System.
For more information please contact helpdesk at x2960 or [log in to unmask]
______________________________________________________________________
---------------------------------------------------
Technet Mail List provided as a service by IPC using LISTSERV 15.0 To
unsubscribe, send a message to [log in to unmask] with following text in the
BODY (NOT the subject field): SIGNOFF Technet To temporarily halt or
(re-start) delivery of Technet send e-mail to
[log in to unmask]: SET Technet NOMAIL or (MAIL) To receive ONE mailing per
day of all the posts: send e-mail to
[log in to unmask]: SET Technet Digest
Search the archives of previous posts at: http://listserv.ipc.org/archives
Please visit IPC web site http://www.ipc.org/contentpage.asp?Pageid=4.3.16
for additional information, or contact Keach Sasamori at [log in to unmask] or
847-615-7100 ext.2815
-----------------------------------------------------
______________________________________________________________________
This email has been scanned by the MessageLabs Email Security System.
For more information please contact helpdesk at x2960 or [log in to unmask]
______________________________________________________________________
---------------------------------------------------
Technet Mail List provided as a service by IPC using LISTSERV 15.0 To
unsubscribe, send a message to [log in to unmask] with following text in the
BODY (NOT the subject field): SIGNOFF Technet To temporarily halt or
(re-start) delivery of Technet send e-mail to [log in to unmask]: SET Technet
NOMAIL or (MAIL) To receive ONE mailing per day of all the posts: send
e-mail to [log in to unmask]: SET Technet Digest Search the archives of
previous posts at: http://listserv.ipc.org/archives Please visit IPC web
site http://www.ipc.org/contentpage.asp?Pageid=4.3.16 for additional
information, or contact Keach Sasamori at [log in to unmask] or 847-615-7100
ext.2815
-----------------------------------------------------
______________________________________________________________________
This email has been scanned by the MessageLabs Email Security System.
For more information please contact helpdesk at x2960 or [log in to unmask]
______________________________________________________________________
---------------------------------------------------
Technet Mail List provided as a service by IPC using LISTSERV 15.0
To unsubscribe, send a message to [log in to unmask] with following text in
the BODY (NOT the subject field): SIGNOFF Technet
To temporarily halt or (re-start) delivery of Technet send e-mail to [log in to unmask]: SET Technet NOMAIL or (MAIL)
To receive ONE mailing per day of all the posts: send e-mail to [log in to unmask]: SET Technet Digest
Search the archives of previous posts at: http://listserv.ipc.org/archives
Please visit IPC web site http://www.ipc.org/contentpage.asp?Pageid=4.3.16 for additional information, or contact Keach Sasamori at [log in to unmask] or 847-615-7100 ext.2815
-----------------------------------------------------
|
