Thanks to all who have responded. I manage to convince the contractor to replace both the ICs.
Thanks and Regards,
~ Wee Mei ~
________________________________
From: Gobinathan Athimolom [mailto:[log in to unmask]]
Sent: Wed 9/22/2010 9:07 AM
To: TechNet E-Mail Forum; Lum Wee Mei
Subject: RE: [TN] Crack and oxidisation on IC leads
Hello Wee Mei,
Did you observe those cracks and/or oxidization on previous IC's batch or newer batch? If none, get the component supplier to clarify this observation or said predicament.
The crack can happen due to heterogeneous materials used. My understanding when there is a crack, there is a separation between the material which means there is a gap. Depend on the magnitude of the gap then we talk about the reliability and severity. The only way to find out thru cross-sections.
Regards,
Gobi
-----Original Message-----
From: TechNet [mailto:[log in to unmask]] On Behalf Of Lum Wee Mei
Sent: Saturday, September 18, 2010 1:46 AM
To: [log in to unmask]
Subject: Re: [TN] Crack and oxidisation on IC leads
The subcon will not remove the IC for a cross-section as they do not think the IC will have any reliability or functionality issue. They want me to waive off my observation so that the IC can stay on the board and to be used.
I have no reliability background but what I observed do disturb me. It has the potential to cause this PCBA to fail during its field operation. This is the rationale I reject this component. Unfortunately, the subcontractor is hard to convince.
Thanks and Regards,
~ Wee Mei ~
_____
From: TechNet on behalf of Werner Engelmaier
Sent: Sat 9/18/2010 1:28 AM
To: [log in to unmask]
Subject: Re: [TN] Crack and oxidisation on IC leads
Nee hao Wee Mei,
When beding leads over a small radius, surface cracks can occur if the lead material is not at least quarter-hard annealed or softer-these cracks typically do not cause any problems. HOWEVER, the photos you sent Steve show cracks substantially more severe-I concur with Vladimir that cross-sections are definitely called for to make a more accurate assessment.
Werner
-----Original Message-----
From: Lum Wee Mei <[log in to unmask]>
To: [log in to unmask]
Sent: Fri, Sep 17, 2010 8:07 am
Subject: [TN] Crack and oxidisation on IC leads
Dear All,
During PCBA inspection, we noticed cracked line across the entire IC lead width
at the knee location. It happen to the whole row on one side of the IC and we
consider it a reject. However, our production subcontractor do not concur the
component as reject. They said that the crack is only fine line and is unlikely
to cause any major physical issue to the leads itself.
In another IC, we noticed a small area of oxidation on one of the lead of about
1 - 1.5mm in size. Again the subcontractor do not accept our decision that it is
a reject. The reason given by them is that although the corrosion exposed the
base metal it is acceptable because the exposed surface is not part of the
required solder fillet.
I have tried to upload the photo on IPC Technet but not successfully. Hope from
your experience, you can provide some opinions.
Thanks and Regards,
~ Wee Mei ~
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