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Date: | Tue, 28 Mar 2017 19:29:23 +0000 |
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I'm sorry, my post was to indicate the maximum warpage requirements are present in both IPC-A-600 and 610, not a method for straightening the board. Straightening is sometimes possible with the bare boards, but not after assembly because of the stresses applied to the components and solder joints. I suppose it also depends on the application and type. I have straightened commercial assemblies using straightening fixtures, re-fluxing, and sending the CCA back through reflow if there are no post-SMT components added that may not take the heat. This sometimes works because the solder joints are reflowed a second time, removing any stresses on the components. If the warpage after assembly is very minor, the one-time relaxation of Sn63 solder joints are typically not a reliability issue, but the same cannot be said of lead-free solder joints.
-----Original Message-----
From: TechNet [mailto:[log in to unmask]] On Behalf Of Jose A Rios
Sent: Tuesday, March 28, 2017 2:09 PM
To: [log in to unmask]
Subject: Re: [TN] IPC-TM-650, 2.4.22, Bow & Twist
I dont believe theres a PCBA method. If there was one you'd find it within section 2.4 of this:
https://www.ipc.org/test-methods.aspx
Sent from my iPhone
> On Mar 28, 2017, at 12:06 PM, "[log in to unmask]" <[log in to unmask]> wrote:
>
> Fellow TechNetters:
>
> Does the above stated TM applies to raw cards ONLY? Is there a standard for PCBA?
>
> Victor,
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