Susan, you may be correct, but I had always thought that the purpose of
peel tests on foil lamination was to assure that the bond was strong enough
to survive assembly, therefore the after thermal stress values were used to
give some reasonable assurance that the foil wouldn't peel during assembly.
If cap construction is exempt from this testing, then one must assume that
the values and methods in the IPC-4000 series documents are valid, and
should be applied equally. Also, thanks for pointing out the loophole that
ENIG currently has in MIL-PRF-55110. We must point that out to DSCC, as
that's not a good thing at all. One word change can correct this.
Tom
Susan Hott
<[log in to unmask]
M> To
Sent by: [log in to unmask]
IPC-600-6012 cc
<IPC-600-6012@ipc
.org> Subject
Re: [IPC-600-6012] peel strength
04/26/2007 09:50
AM
Please respond to
"(Combined Forum
of D-33a and
7-31a
Subcommittees)"
<IPC-600-6012@IPC
.ORG>
If I remember correctly, the "after Thermal Stress" values were selected
because most boards had already been Hot Air Solder Leveled and this served
as a Thermal stress of the laminate. However, boards that have alternate
finishes have not been exposed to that type of Thermal excursion and the
playing field is no longer level.
If the 6012 group chooses to add the requirement to perform peel strength
testing, then we have the opportunity to have learned from the 55110/31032
requirements and adjust the method to make sense.
Currently the military specs state that solder and any other metallic
resist be removed prior to testing - the fact that ENIG can slip by without
being removed is only because it is not a "resist", but a surface finish.
The intent was to have bare copper to peel and that could be clearly
stated.
The issue to be addressed is - should all boards be treated equally since
some have seen the stress of HASL (at Pbfree temps) and others have seen NO
thermal stress?
Susan
Susan Hott
President
Robisan Laboratory, Inc
6502 E 21st Street
Indianapolis, IN 46219
317-353-6249 phone
317-917-2379 fax
www.robisan.com
-----Original Message-----
From: IPC-600-6012 [mailto:[log in to unmask]]On Behalf Of Thomas E.
Kemp
Sent: Thursday, April 26, 2007 9:31 AM
To: [log in to unmask]
Subject: Re: [IPC-600-6012] peel strength
1) I agree exactly with your first statement. We've got a void in our
documents. 2) MIL-PRF-55110 requires the after thermal stress values of the
applicable IPC- 4000 series document for the material type. While we don't
necessarily want to follow this document blindly, I believe they have set
the precedent, and I have not seen data to challenge it. I would recommend
the after thermal stress values of the applicable IPC- 4000 series document
for the material type. 3) I don't want to put actual values into the IPC
6000 series documents. Reference the material specs. 4) I believe the
original values came from MIL-P-13499, and were only changed when laminate
suppliers could not meet the old values. Dewey should be able to shed some
light on this subject?
Tom
Chris Mahanna
<CMahanna@ROBISAN
.COM> To
Sent by: [log in to unmask]
IPC-600-6012 cc
<IPC-600-6012@ipc
.org> Subject
Re: [IPC-600-6012] peel strength
04/26/2007 08:09
AM
Please respond to
"(Combined Forum
of D-33a and
7-31a
Subcommittees)"
<IPC-600-6012@IPC
.ORG>
The biggest problem that I see at the moment is that 6012 does not define
which requirement to use. As I mentioned in the original question, there
is a lot of precedence to use the after thermal stress requirement for
>0.5mm. For 4101/21,24,26 that's 1.05 N/mm or 6.00 lb/in. I think these
are the numbers we should use, but what's is the basis---today, if any?
Chris
-----Original Message-----
From: IPC-600-6012 [mailto:[log in to unmask]]On Behalf Of Thomas E.
Kemp
Sent: Wednesday, April 25, 2007 3:47 PM
To: [log in to unmask]
Subject: Re: [IPC-600-6012] peel strength
I don't believe we want to specify values in IPC-6012 and IPC-6018. We
would always be playing catch-up with IPC-4101 and IPC-4103 as they roll
revisions. I think we just want to say that product built using foil
lamination on outer circuits must meet the peel test values specified in
IPC-4101 and IPC-4103. We could list the peel strength test method as an
optional test for now in IPC-6012 and IPC-6018, until the QPL question is
answered. Just my thoughts on the subject.
Tom
Karl Sauter
<[log in to unmask]
COM> To
Sent by: [log in to unmask]
IPC-600-6012 cc
<IPC-600-6012@ipc
.org> Subject
Re: [IPC-600-6012] peel strength
04/25/2007 12:19
PM
Please respond to
[log in to unmask]
OM
Should a total of nine(9) Minimum Peel Strength values be specified in
IPC-6012 and IPC-6018?
For 2.0 oz. Copper Foil
* Min. Peel Strength when Std. Profile (Cu tooth roughness Rz, and RMA)
copper foil is used.
* Min. Peel Strength when Low Profile (Cu tooth roughness Rz, and RMA)
copper foil is used.
* Min. Peel Strength when Very Low Profile (Cu tooth roughness Rz, and
RMA) copper foil is used.
And the same for 1.0 oz. and Half oz. copper foils?
Karl Sauter
Semiconductor Packaging & PCB Technology
Sun Microsystems Inc.
Office: (650) 786-7663 / x87663
E-mail: [log in to unmask]
Thomas E. Kemp wrote On 04/25/07 07:55 AM,:
>What's going on with foil lamination? I received notice yesterday from
DSCC
>that we are going to have to qualify our foil lamination process for the
>next QPL! Thankfully, we have been using foil lamination on our
>qualification samples for some time now, so we won't see any change. But
>yes, to some extent we need to at least identify the minimum peel strength
>requirements of IPC-4101 and 4103 as being applicable to foil laminated
>product in IPC-6012 and possibly IPC-6018 for composite builds. I believe
>the testing requirements should wait until we decide on the possibility of
>the IPC QPL program.
>
>Tom Kemp
>QA Manager
>Rockwell Collins Printed Circuits
>319-295-1619
>
>
>
> Susan Hott
> <[log in to unmask]
> M> To
> Sent by: [log in to unmask]
> IPC-600-6012 cc
> <IPC-600-6012@ipc
> .org> Subject
> Re: [IPC-600-6012] peel strength
>
> 04/25/2007 09:30
> AM
>
>
> Please respond to
> "(Combined Forum
> of D-33a and
> 7-31a
> Subcommittees)"
> <IPC-600-6012@IPC
> .ORG>
>
>
>
>
>
>
>It isn't in 6012 - the only rigid board spec it appears in is 6016.
>
>Do we need to add it to IPC-6012 for next revision?
>
>Susan
>
>Susan Hott
>President
>Robisan Laboratory, Inc
>6502 E 21st Street
>Indianapolis, IN 46219
>
>317-353-6249 phone
>317-917-2379 fax
>
>www.robisan.com
>
>
>
>-----Original Message-----
>From: IPC-600-6012 [mailto:[log in to unmask]]On Behalf Of Chris
>Mahanna
>Sent: Tuesday, April 24, 2007 3:48 PM
>To: [log in to unmask]
>Subject: Re: [IPC-600-6012] peel strength
>
>
>Mahendra,
>Yep. That's where I get the 1.05 N/mm (using the military rules for which
>number to use). But, how is the requirement invoked -for foil lam
>conformance- from 6012? If at all?
>Chris
>
>-----Original Message-----
>From: IPC-600-6012 [mailto:[log in to unmask]]On Behalf Of Gandhi,
>Mahendra (Space Technology)
>Sent: Tuesday, April 24, 2007 3:27 PM
>To: [log in to unmask]
>Subject: Re: [IPC-600-6012] peel strength
>
>
>Chris,
>You need to look up IPC 4101 for this type of properties.
>
>Mahendra
>
>-----Original Message-----
>From: IPC-600-6012 [mailto:[log in to unmask]] On Behalf Of Chris
>Mahanna
>Sent: Tuesday, April 24, 2007 11:37 AM
>To: [log in to unmask]
>Subject: [IPC-600-6012] peel strength
>
>Hi all,
>
>I was recently ask to determine the conformance requirement for surface
>peel strength on a commercialized military board (foil lamination
>obviously). Knowing that it was FR-4 I quickly replied 1.05 N/mm. Then
>I pulled up 6012 and searched for peel, with zero results. ??? What's
>up with that?
>
>Thanks in advance,
>Chris
>
>Chris Mahanna
>Quality Manager
>Robisan Laboratory Inc.
>6502 E 21st Street
>Indianapolis, Indiana 46219
>317.353.6249
>
>
|
