I agree, pin in paste could lead to such voids with improper profile and a "suboptimal" paste. Another root cause I have seen is poor barrel plating (porous) and moisture entrapped in the laminate evaporating through the barrel into the joint during soldering. One can proof whether this is the case by pre-baking the bare boards, populate+wave/selective solder and x-ray/cut sections afterwards and compare with boards that haven't been dried.

Gebhard






-----Ursprüngliche Nachricht-----
Von: TechNet [mailto:[log in to unmask]] Im Auftrag von Chris Mahanna
Gesendet: Mittwoch, 16. Mai 2012 15:24
An: [log in to unmask]
Betreff: Re: [TN] Through hole barrel voids

No industry standard requirements exist.
It is somewhat unusual to have full fillets with such severe voiding.
The condition is a relative reliability risk for severe environments (e.g. under hood).

However, from experience, I'd say wetting to the pin more likely correlates to the expected damage accumulation.
Often the dissolution of pin base metal into joint is poor when you have this kind of voiding.
That's what I'd check for.

Regardless, the hardware is very likely conformant, unless you have some customer specific requirements I haven't run into.
As for root cause, I'd check to see if they did pin-in-paste.

Chris

Chris Mahanna
Robisan Lab

-----Original Message-----
From: TechNet [mailto:[log in to unmask]] On Behalf Of Craig Sullivan
Sent: 2012/05/16 8:15 AM
To: [log in to unmask]
Subject: [TN] Through hole barrel voids

Hi everyone,



We have a certain board with several through hole connectors. The customer has provided us x ray images showing voiding in the barrels. Fillets on both sides are acceptable, and the solderability tests are ok. This seems to be isolated to this board because random sampling on other boards shows virtually no voiding. The only voiding "criteria" I can find is related to BGAs. Is there any published criteria / reference material for this type of defect?



Thank you,

Craig Sullivan

Manufacturing Engineer

MPL Incorporated

P: 607.266.0480

F: 607.266.0482

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