Pete,

Indeed. As an independent lab:
"[panels with] multiple thin areas as non-conforming; panels with only one thin area would be conforming"

It is then up to our customer if they would like to sacrifice another 27 boards.  If they don't sacrifice another 27, I don't think lot conformance is determinable.

Chris

-----Original Message-----
From: IPC-600-6012 [mailto:[log in to unmask]]On Behalf Of Menuez,
Pete (IE) @ CIN
Sent: Tuesday, November 21, 2006 10:20 AM
To: [log in to unmask]
Subject: Re: [IPC-600-6012] 6012 plating void referee


Chris,

Two comments regarding your question.

I understand why you 'oversampled' but I don't agree that it is necessary or even allowed.  6012 para. 3.6 allows (prefers) the use of boards over coupons, and further says 'holes selected shall be equivalent to those specified for test coupons'.

I read that last sentence to mean hole size and quantity of holes.

I think that had 3.6 meant to include all layers it would have said so; (if my interpretation of this requirement is incorrect then we should update 6012 to clearly state that "each layer must be represented which may require multiple cross sections").

But you have looked at lots and lots of holes and found isolated thin areas - which by definition are less than .8 mils.  My understanding of 6012 is that if there is one such finding it's an isolated occurrence that does not reflect on the lot.  If the isolated area repeats within the panel then you would have to considered the panel to be non-conforming. If there are multiple occurrences then 4.2.2 would not come into play. By the fact there is more than one occurrence makes it more than a random occurrence.

Having said this if my board supplier (or lab) came to me with isolated thin spots in the copper plating I would be inclined to accept them- especially for class 2 product.  As a lab though I don't think you have much of a choice but to declare those panels with multiple thin areas as non-conforming; panels with only one thin area would be conforming.

My 2 cents worth...



Pete Menuez
Supplier Quality Engineer
L-3 Communications Cincinnati Electronics
7500 Innovation Way
Mason, Ohio 45040
[log in to unmask]

513-573-6401 Voice
513-573-6767 Fax





-----Original Message-----
From: IPC-600-6012 [mailto:[log in to unmask]]On Behalf Of Chris
Mahanna
Sent: Monday, November 20, 2006 10:20 AM
To: [log in to unmask]
Subject: [IPC-600-6012] 6012 plating void referee


Hello group,

We have a customer who is applying a fresh set of eyes to some 6012 details.
He bought ~1000 panels of class 2 product and ask us to perform structural integrity conformance testing.  There are no A-B coupons, so he sent 27 arrays.  We took one board from each array and pulled 4 rows of holes. We do this over sampling in an attempt to level the playing field with coupon work.  For instance there should be (at least) 12- layer 2 or N-1 plating connections to observe...
So anyway, although I don't remember exactly, there was about 20 holes per panel sectioned.
Great lookin boards, but... of the 27, 15 of them exhibited one isolated thin area of plating (a void) and 1 of the 27 had two isolated areas.

Although I have a opinion, I believe that there is not a unique answer to the proper "6012 disposition" of this lot.

Any ideas?  Don't forget section 4.2.2.

Thanks in advance,
Chris

Chris Mahanna
Quality Manager
Robisan Laboratory Inc.
6502 E 21st Street
Indianapolis, Indiana 46219
phone 317.353.6249
fax 317.917.2379