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May 2014

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Subject:
From:
"Stadem, Richard D." <[log in to unmask]>
Reply To:
TechNet E-Mail Forum <[log in to unmask]>, Stadem, Richard D.
Date:
Fri, 30 May 2014 18:46:25 +0000
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I cannot say for absolute certainty from just looking at the pictures, but it sure does look like RMA flux deposits from the tinning process that were not washed off completely. I can see the line of demarcation where it appears the tinning solder stopped just behind the flux.
Because the flux rides up the component lead when the component is immersed into the molten solder, it tends to collect at the inside bend of the lead of ICs like this. 
For mission critical applications, I would be concerned. 


-----Original Message-----
From: TechNet [mailto:[log in to unmask]] On Behalf Of Steve Gregory
Sent: Friday, May 30, 2014 1:34 PM
To: [log in to unmask]
Subject: Re: [TN] Component Lead Oxidisation

Hi Wee Mei,

I just want to apologize for not getting this posted sooner. I first saw your message on my phone and then got distracted by a bunch of other things and just forgot about getting your photos posted until you asked me about them.

I have them posted now:

 http://stevezeva.homestead.com/WeeMei_1.jpg

http://stevezeva.homestead.com/WeeMei_2.jpg

Is this a ceramic part? It looks like to me that some of the part encapsulate bled out beneath the lead shoulder and the lead did not get plated.



Steve 


-----Original Message-----

Steve,

I was looking at a batch of lead-formed part and noticed oxidisation or whatever you call them at the junction of the leads and component body.
This oxidisation is only found at the bottom side of the component. I look at the raw part (before the leads are form) and found some of them having the same issue. I need your assistance to post this file for the following advices.

1) If this is not oxidisation, what is the correct term for it?
2) How serious is this "oxidisation" as the parts are used in mission critical operation.
3) What is the cause of such "oxidisation"?

Regards,
~wee mei~
 

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