TECHNET Archives

May 2014

TechNet@IPC.ORG

Options: Use Monospaced Font
Show Text Part by Default
Show All Mail Headers

Message: [<< First] [< Prev] [Next >] [Last >>]
Topic: [<< First] [< Prev] [Next >] [Last >>]
Author: [<< First] [< Prev] [Next >] [Last >>]

Print Reply
Subject:
From:
Lum Wee Mei <[log in to unmask]>
Reply To:
TechNet E-Mail Forum <[log in to unmask]>, Lum Wee Mei <[log in to unmask]>
Date:
Sat, 31 May 2014 08:36:32 +0000
Content-Type:
text/plain
Parts/Attachments:
text/plain (100 lines)
Steve, thanks for the posting. Yes, the parts are ceramic and your reply sound reasonable.

Flux is ruled out because first picture is taken when the ICs are formed and cut. The second picture is taken with the ICs still in its holder (before formed and cut). They are not tinned at all when such "oxidisation" is noted.  

Regards,
~wee mei~
______________________________________
From: TechNet [[log in to unmask]] on behalf of Stadem, Richard D. [[log in to unmask]]
Sent: Saturday, May 31, 2014 3:58 AM
To: [log in to unmask]
Subject: Re: [TN] Component Lead Oxidisation

Wee Mei,
Poke it with a toadsticker. If it is flux, it should break off somewhat easily. Not so easily if it is oxidation. http://www.drinstruments.com/teasing-needles-6-pack.html



-----Original Message-----
From: Robert Kondner [mailto:[log in to unmask]]
Sent: Friday, May 30, 2014 2:45 PM
To: 'TechNet E-Mail Forum'; Stadem, Richard D.
Subject: RE: [TN] Component Lead Oxidisation

I agree, I thought flux when I was the image.

Question:

 If it was RMA flux what kind of failures can that flux reasonably lead to?
(Sorry for the Lead pun)

Thanks,
Bob K.

-----Original Message-----
From: TechNet [mailto:[log in to unmask]] On Behalf Of Stadem, Richard D.
Sent: Friday, May 30, 2014 2:46 PM
To: [log in to unmask]
Subject: Re: [TN] Component Lead Oxidisation

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~


______________________________________________________________________
This email has been scanned by the Symantec Email Security.cloud service.
For more information please contact helpdesk at x2960 or [log in to unmask] ______________________________________________________________________

______________________________________________________________________
This email has been scanned by the Symantec Email Security.cloud service.
For more information please contact helpdesk at x2960 or [log in to unmask] ______________________________________________________________________

______________________________________________________________________
This email has been scanned by the Symantec Email Security.cloud service.
For more information please contact helpdesk at x2960 or [log in to unmask]
______________________________________________________________________

______________________________________________________________________
This email has been scanned by the Symantec Email Security.cloud service.
For more information please contact helpdesk at x2960 or [log in to unmask] 
______________________________________________________________________

ATOM RSS1 RSS2