see IPC-9121 from Feb 2016

On Thu, Apr 19, 2018 at 9:26 AM, Robert Kondner <[log in to unmask]>
wrote:

> Hi,
>
>  The No Etchback sounds correct.
>
>  Does anyone have a cross section image that shows etch back. I would be
> interested in comparing the two images.
>
> Thanks,
> Bob K.
>
> -----Original Message-----
> From: TechNet <[log in to unmask]> On Behalf Of Wayne Showers
> Sent: Thursday, April 19, 2018 10:11 AM
> To: [log in to unmask]
> Subject: Re: [TN] R: [TN] R: [TN] PCB failure
>
> The real problem is that this PCB has no etchback, positive or negative
> (PCBs are defective).  As far as resin recession, yes the processing
> probably caused the separation, but once again, the PCB has no etchback.
>
> I would send that cross-section image to the PCB supplier and asked them
> if this is typical.  I suspect that they will realize it is a trap and
> either offer a crazy answer or admit that their is no etchback and offer to
> re-run/replace the PCBs.
>

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