Chris,

     From practical experience with both captive and contract assemblers,
     when component land patterns have been designed correctly and
     component placement observes minimum (IPC recommended) spacing rules,
     components don't touch after assembly. The contract assembler uses IPC
     610 exclusively, while the in-house assembly was based on a
     combination of IPC 610 and in-house spec's. This may indicate that the
     maximum component placement tolerances are rarely, if ever realized,
     that the assemblers take corrective action and do not report the
     problems, very efficient assemblers, good design practices (soldermask
     dams), etc. However, the potential still exists.

     On a slightly different vein, could this indicate that some of
     IPC-2221 is not DFM compliant?


______________________________ Reply Separator _________________________________
Subject: Re: [DC] IPC-A-610B,Class 2
Author:  "DesignerCouncil E-Mail Forum." <[log in to unmask]>
[log in to unmask] at Internet-Mail
Date:    10/13/98 5:28 PM


This is what I'm thinking... but I wanna know what someone building my
board, who says they quoted to IPC-A-610B, Class 2 does with it. Do they
scrap at no charge? Or do they say 'your design isn't laid out per the spec
we quoted to', or just what?
Thanks for the response,
-Chris-


My bet is that you get to assembly and testing -- it's unacceptable for
them
to touch.

Scott

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