Jack,
I cannot speak for others but we try to rely on the IPC specs as much as possible.  However, occasionally we callout different or redundant requirements.  This occasionally happens because:

1.  We may have learned something and need to specify it prior to the IPC having it put into their documents.  Sometimes the IPC incorporation of new requirements might lag our learning of the problem by 2 years.  During those 2 years we will issue a lot of drawings.

2.  We utilize a parameter that the IPC eventually adopts but the IPC uses a wider or narrower tolerance and we already have history with what we have and are reluctant to change when many products are already qualified.

3.  The particular parameter is extremely important to us so we call it out.  Even if it exactly matches the IPC requirement we cannot guarantee the IPC does not change their limit in the future which would affect future procurements and might provide an opportunity to receive drawing and IPC compliant boards, but boards which don't meet our specific needs.

Bill

William Dieffenbacher
PWB Engineer, Platform Solutions

T  607-770-2961   F 607-770-2056   [log in to unmask]
BAE Systems  Johnson City, New York, USA




-----Original Message-----
From: IPC-600-6012 [mailto:[log in to unmask]] On Behalf Of Jack Olson
Sent: Thursday, February 24, 2011 12:50 PM
To: [log in to unmask]
Subject: Re: [IPC-600-6012] Document Sets

I have a follow-up question.

What led me to writing that last post was that I have collected many samples
of fab drawing notes as part of my working with the IPC-2610 series
committee, and I noticed that the MAJORITY of them call out both IPC-6011
and IPC-6012, so I thought I was onto something.

I' m trying to figure out why people are specifying things that are already
part of IPC-6012. For example, many people have a Bow and Twist note on
their fab drawings, but the maximum allowance they are calling out exactly
matches the one in 6012 (which in my mind, if its already in there, you
don't need to call it out separately, right?)

So my follow-up question is:
"Why do people do that?"

Jack


.
On Thu, Feb 24, 2011 at 11:17 AM, John Perry <[log in to unmask]> wrote:

> Hi Jack,
>
> I believe the words you are looking for in IPC-6012C are in section 3.1,
> General.  Here is the reference to meeting the generic requirements of
> IPC-6011.  So in the case of this document, the wording is a little farther
> in than the other documents, which has such language in section 1.
>
> John Perry
> Technical Project Manager
> IPC - Association Connecting Electronics Industries(r)
> 3000 Lakeside Drive # 309S
> Bannockburn, IL 60015-1249 USA
> +1 847-597-2818 (tel)
> +1 847-615-7105 (fax)
> +1 847-615-7100 (Main)
> [log in to unmask]
> www.ipc.org
>
> -----Original Message-----
> From: IPC-600-6012 [mailto:[log in to unmask]] On Behalf Of Jack Olson
> Sent: Thursday, February 24, 2011 11:13 AM
> To: Listserv IPC-600-6012
> Subject: [IPC-600-6012] Document Sets
>
> I have a question about how document sets are structured, in particular
> comparing the 6010 series with others like 2220 or 2610 series.
>
> IPC-2222 specifically incorporates all of the generic IPC-2221 with this
> statement:
>
> 1.1 Purpose The requirements contained herein are intended to establish
> specific design details that shall be used in conjunction with IPC-2221
>
> IPC-2614 (for example) incorporates everything in the generic IPC-2611
>
> 3 REQUIREMENTS The requirements of IPC-2611 are a mandatory part of this
> standard.
>
> What this says to me is that the documentation only needs to call out the
> specific standard to get the requirements of BOTH the specific and the
> genericl standards.
>
> Logically I assume that the same holds true for IPC-6011 and IPC-6012, but
> in my latest copy of 6012C (PROPOSED STANDARD FOR BALLOT - JANUARY 2010) I
> don't see any wording like this. Am I losing my mind? Do I have to call out
> BOTH of them on my fabrication drawing?
>
> onward thru the fog,
> Jack
>
> ______________________________________________________________________
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