Randy
Will at Bell Laboratories I work quite a bit in bare copper on PCBs etc. At
first we had concerns about using bare copper for forced fit pins contacts
and other applications. We found this not to be a problem since copper, just
as aluminum, passivate's over time forming a very thin green coating. You
have probably seen this phenomena on roof tops and open copper aril wire
which is still widely used (miles and miles) by phone companies to
interconnect the system. Even in aggressive environments bare copper will
usually perform well as the affected coating is still very thin.
Best regards
Lee
J. Lee Parker, Ph.D.
JLP Consultants LLC
804 779 3389
----- Original Message -----
From: "Reed, Randy" <[log in to unmask]>
To: <[log in to unmask]>
Sent: Wednesday, February 06, 2008 12:51 PM
Subject: Re: [IPC-600-6012] Bare Copper as a Surface Finish
For those that use bare copper for RF application, I have a few
questions -
Does the RF board have a digital section and is the area a bare copper
final finish?
Do you have any concerns about corrosion or galvanic attack of the bare
copper finish in the PTHs for your applications?
I am trying to understand what cautions IPC-6012 would need for the bare
copper final finish without impacting those that use this finish.
Regards,
Randy Reed
Co-Chair IPC-6012
-----Original Message-----
From: IPC-600-6012 [mailto:[log in to unmask]] On Behalf Of Mike Hill
Sent: Tuesday, February 05, 2008 4:01 PM
To: [log in to unmask]
Subject: Re: [IPC-600-6012] Bare Copper as a Surface Finish
Yes,I have one customer that does use true bare copper.
mike
-----Original Message-----
From: IPC-600-6012 [mailto:[log in to unmask]]On Behalf Of Gordon,
Robert (J.)
Sent: Tuesday, February 05, 2008 6:06 PM
To: [log in to unmask]
Subject: Re: [IPC-600-6012] Bare Copper as a Surface Finish
You mean someone was using true bare copper? At Visteon we refer to an
OSP
finish as bare copper.
-----Original Message-----
From: IPC-600-6012 [mailto:[log in to unmask]] On Behalf Of Gandhi,
Mahendra (Space Technology)
Sent: Tuesday, February 05, 2008 9:51 AM
To: [log in to unmask]
Subject: Re: [IPC-600-6012] Bare Copper as a Surface Finish
Gordon,
OSP is a surface finish.
Mahendra
-----Original Message-----
From: IPC-600-6012 [mailto:[log in to unmask]] On Behalf Of Gordon,
Robert
(J.)
Sent: Monday, February 04, 2008 7:40 PM
To: [log in to unmask]
Subject: Re: [IPC-600-6012] Bare Copper as a Surface Finish
John,
We use OSP surface finishes for applications requiring a single
soldering
process. Generally, these boards are either single sided, non-plated
through hole boards, single sided silver jumper boards and double sided,
plated through hole boards. I would estimate that approximately 5% of
our
boards are OSP coated. Please do not remove it from tabel 3-2.
-----Original Message-----
From: IPC-600-6012 [mailto:[log in to unmask]] On Behalf Of John Perry
Sent: Monday, February 04, 2008 3:53 PM
To: [log in to unmask]
Subject: [IPC-600-6012] Bare Copper as a Surface Finish
Colleagues,
Our IPC-6012B specification provides for bare copper as a final finish
in
Table 3-2, Final Finish, Surface Plating and Coating Thickness
Requirements.
The task group is evaluating whether or not this should be removed from
Table 3-2 in the future IPC-6012 Revision C. Among the concerns with
bare
copper are instances of single-sided via protection that provides for
entrapment of chemistries that attack the bare copper in the hole wall.
If there are those of you out there who use bare copper as a surface
finish,
could you provide feedback to IPC as to how it is used in your
applications?
Thanks in advance,
John Perry
Technical Project Manager
IPC
3000 Lakeside Drive # 309S
Bannockburn, IL 60015
[log in to unmask]
1-847-597-2818 (P)
1-847-615-7105 (F)
1-847-615-7100 (Main)
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