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Date: | Thu, 29 May 2014 13:46:03 -0400 |
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Hello John,
The CH-65B document is more or less a handbook. It is not a standard. The
table you reference was designed as a basic set of guidelines and was never
intended as a standard for "assembly" cleanliness. Further, method 2.3.28
is the historical ion chromatography method and defines the process for
extracting the sample and calculating the data. It does not call out any
cleanliness limits for any ion species for any assembly or bare board.
Best Regards,
Joe Russeau
----- Original Message -----
From: "John Balchunas" <[log in to unmask]>
To: <[log in to unmask]>
Sent: Thursday, May 29, 2014 10:31 AM
Subject: Re: [TN] PCB Cleanliness Via Ion Chromatography Poll (informal)
Re:
">>...there
>> is a lot of subjectivity between the experts in defining what is
>> considered clean and not clean. IPC-5704 helps some with incoming board
>> cleanliness by setting up an industry standard that has been mutually
>> agreed upon within committee. However, no such standard exists for
>> assembly cleanliness..."
My 2 cents worth:
Table 6-4 of IPC-CH-65B July 2011 specifies contamination levels for
circuit board assemblies per IPC-TM-650, 2.3.28, Ion Chromatography.
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