TECHNET Archives

March 2012

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:
"David D. Hillman" <[log in to unmask]>
Reply To:
TechNet E-Mail Forum <[log in to unmask]>, [log in to unmask]
Date:
Wed, 28 Mar 2012 07:15:24 -0500
Content-Type:
text/plain
Parts/Attachments:
text/plain (267 lines)
Hi Vlad - all true but you are not accounting for incidental transfer of 
tin from contact with the assembly or the soldering process. Just because 
the toe is most likely a shear surface and is not wettable, doesn't mean 
that an SEM analysis wouldn't pick up Sn.  Leland should be able to easily 
distinguish what surface he is analyzing by careful selection of SEM 
collection area.

Dave



"vladimir Igoshev" <[log in to unmask]> 
03/27/2012 05:30 PM
Please respond to
[log in to unmask]


To
[log in to unmask]
cc
"TechNet E-Mail Forum" <[log in to unmask]>
Subject
Re: [TN] Rework Concern and Question






Hi Dave,With all due respect I completely disagree. What you are saying is 
applicable in case the plating finish if thin (below 1 micron). But if 
someone analysts the toe of a lead, all the person should see is only the 
elements of the lead material, as there is no plating on the toe surface 
due to the way it's normally made.
VladimirSENTEC Testing Laboratory Inc.11 Canadian Road, Unit 
7.Scarborough, ON M1R 5G1Tel: (416) 899-1882Fax: (905) 
882-8812www.sentec.ca
From: [log in to unmask] 
Date: Tue, 27 Mar 2012 17:11:05 -0500
To: <[log in to unmask]>
Cc: TechNet E-Mail Forum<[log in to unmask]>
Subject: Re: [TN] Rework Concern and Question

Hi Vlad - it depends on the selected analysis location and the kV 
selection they used during the analysis. 

Dave 


"vladimir Igoshev" <[log in to unmask]> 
03/27/2012 03:25 PM 

Please respond to
[log in to unmask]


To
"TechNet E-Mail Forum" <[log in to unmask]>, [log in to unmask] 
cc

Subject
Re: [TN] Rework Concern and Question








Dave, if they did that then they wouldn't have seen Sn as leads are 
usually chopped off.
Vladimir

SENTEC Testing Laboratory Inc.
11 Canadian Road, Unit 7.
Scarborough, ON M1R 5G1
Tel: (416) 899-1882
Fax: (905) 882-8812
www.sentec.ca

-----Original Message-----
From: "David D. Hillman" <[log in to unmask]>
Sender: TechNet <[log in to unmask]>
Date: Tue, 27 Mar 2012 15:05:00 
To: <[log in to unmask]>
Reply-To: TechNet E-Mail Forum <[log in to unmask]>,
       <[log in to unmask]>
Subject: Re: [TN] Rework Concern and Question

Hi Leland - I recommend you find out the lead base metal composition. If 
you shot an SEM-EDS of the lead toe, you could be getting the Si from the 
base metal composition and not part of the solder alloy composition.

Dave Hillman
Rockwell Collins
[log in to unmask]



Leland Woodall <[log in to unmask]> 
Sent by: TechNet <[log in to unmask]>
03/27/2012 02:52 PM
Please respond to
TechNet E-Mail Forum <[log in to unmask]>; Please respond to
Leland Woodall  <[log in to unmask]>


To
<[log in to unmask]>
cc

Subject
Re: [TN] Rework Concern and Question






Vladimir,

We analyzed raw components straight out of the tape and reel packaging. 
The site selection was on the bottom side of the leads at the toe.

Leland

-----Original Message-----
From: TechNet [mailto:[log in to unmask]] On Behalf Of vladimir Igoshev
Sent: Tuesday, March 27, 2012 3:12 PM
To: [log in to unmask]
Subject: Re: [TN] Rework Concern and Question

Sorry Ben, it doesn't.
Leland,

What you are saying sounds strange. What does it mean: "We've analyzed the 

lead material beneath the SEM and it returns 98% tin and 2% silicone"? Did 

you analyzed leads or solder? Where the analysis was taken from? Did you 
analyzed leads with pads ripped off?

Regards,

Vladimir

SENTEC Testing Laboratory Inc.
11 Canadian Road, Unit 7.
Scarborough, ON M1R 5G1
Tel: (416) 899-1882
Fax: (905) 882-8812
www.sentec.ca

-----Original Message-----
From: "Gumpert, Ben" <[log in to unmask]>
Sender: TechNet <[log in to unmask]>
Date: Tue, 27 Mar 2012 18:58:21
To: <[log in to unmask]>
Reply-To: TechNet E-Mail Forum <[log in to unmask]>,
       "Gumpert, Ben"
       <[log in to unmask]>
Subject: Re: [TN] Rework Concern and Question

Leland,

I won't claim to be an expert, but this website seems to imply something 
along those lines.
http://resource.npl.co.uk/mtdata/phdiagrams/sisn.htm

Ben

-----Original Message-----
From: TechNet [mailto:[log in to unmask]] On Behalf Of Leland Woodall
Sent: Tuesday, March 27, 2012 2:18 PM
To: [log in to unmask]
Subject: EXTERNAL: [TN] Rework Concern and Question

Folks,

We've ran across a strange incident and I'd like a little advice from the 
group.

We recently underwent a component vendor change, and part of the first 
group of boards were misbuilt due to incorrect polarity (the part marking 
was misinterpreted by the vision operator).

Anyway, an attempt to remove the part by our Repair group resulted in 
lifted pads on 10 of the first 12 boards.  We've analyzed the lead 
material beneath the SEM and it returns 98% tin and 2% silicone.  The old 
style component comes off quite easily (within 3 seconds), and an analysis 

of its leads shows to be 100% tin.  It's a 6 pin diode with very little 
mass.

What's going on here?  Does a 2% silicone mix raise the melting point of 
solder by 200 degrees C?

Please help me understand.

Thanks,

Leland

________________________________

?Confidentiality Notice:
This transmission (including any attachments) may contain confidential 
information belonging to the sender and is intended only for the use of 
the party or entity to which it is addressed. If you are not the intended 
recipient, you are hereby notified that any disclosure, copying, 
distribution, retention or the taking of action in reliance on the 
contents of this transmission is strictly prohibited. If you have received 

this transmission in error, please immediately notify the sender and erase 

all information and attachments.?

______________________________________________________________________
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]
______________________________________________________________________

________________________________

?Confidentiality Notice:
This transmission (including any attachments) may contain confidential 
information belonging to the sender and is intended only for the use of 
the party or entity to which it is addressed. If you are not the intended 
recipient, you are hereby notified that any disclosure, copying, 
distribution, retention or the taking of action in reliance on the 
contents of this transmission is strictly prohibited. If you have received 

this transmission in error, please immediately notify the sender and erase 

all information and attachments.?

______________________________________________________________________
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