May be the board has been reworked by powder polishing such as jet scrubbing or manual sanding (Al2O3 and Si2O4)
Thanks and best regards,
Ken Chow
OEM & Business Development Director,
Enthone, Cookson Electronics
Mobile: +852-9408-4736
From: Tan Geok Ang [[log in to unmask]]
Sent: 11/22/2011 10:04 ZE8
To: <[log in to unmask]>
Subject: Re: [TGAsia] Non-wetting on PTH top surface
From:
Sent: Monday, 21 November 2011
10:06 AM
To: [log in to unmask]
Subject: Re: [TGAsia] Non-wetting
on PTH top surface
Hi All,
I want to share a case
with you all here and collect your comments as I get a little stuck in
determining what is real root of the issue.
Referring to the photo
attached the solder pad was not fully covered by solder after manually solder,
not meeting the IPC-610 requirement of at minimum of 75% solder be covered
around the pad. observed under digit camera there some darkish residue remained
on there, and main elements spot by EDX as illustrated, to what surprise is where
did Al and SI come from since the used solder material do not contain these two
elements.
[log in to unmask]">
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