TECHNET Archives

September 2013

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:
Ed Popielarski <[log in to unmask]>
Reply To:
TechNet E-Mail Forum <[log in to unmask]>, Ed Popielarski <[log in to unmask]>
Date:
Wed, 11 Sep 2013 22:33:41 +0000
Content-Type:
text/plain
Parts/Attachments:
text/plain (127 lines)
Mr. Dewey,

Apparently Mr. Stadem has stepped up his stride as well. Humor seems to have become the http://en.wikipedia.org/wiki/Achilles%27_heel of Technet.

Ed Popielarski
Engineering Manager


                               970 NE 21st Ct.
                              Oak Harbor, Wa. 98277

                              Ph: 360-675-1322
                              Fx: 206-624-0965
                              Cl: 949-581-6601

https://maps.google.com/maps/myplaces?hl=en&ll=48.315753,-122.643578&spn=0.011188,0.033023&ctz=420&t=m&z=16&iwloc=A

-----Original Message-----
From: TechNet [mailto:[log in to unmask]] On Behalf Of Whittaker, Dewey (EHCOE)
Sent: Wednesday, September 11, 2013 1:13 PM
To: [log in to unmask]
Subject: Re: [TN] Gull wing solder joints and minimum electrical clearance

Sometimes my attempts at humor go down to defeat.
Dewey

-----Original Message-----
From: Stadem, Richard D. [mailto:[log in to unmask]]
Sent: Wednesday, September 11, 2013 1:04 PM
To: TechNet E-Mail Forum; Whittaker, Dewey (EHCOE)
Subject: RE: Gull wing solder joints and minimum electrical clearance

The stresses could be on the heel, sides, or toe, and any reliability issues would be seen only over time. This has been proven by Scholl's equation, which states that time wounds all heels, whether due to a sole source or multivariable pressure points.


-----Original Message-----
From: TechNet [mailto:[log in to unmask]] On Behalf Of Whittaker, Dewey (EHCOE)
Sent: Wednesday, September 11, 2013 2:19 PM
To: [log in to unmask]
Subject: Re: [TN] Gull wing solder joints and minimum electrical clearance

If the anomalies are between the heel and toe, the problems are due to a sole source.
Dewey

-----Original Message-----
From: TechNet [mailto:[log in to unmask]] On Behalf Of Peter Wong
Sent: Wednesday, September 11, 2013 12:06 PM
To: [log in to unmask]
Subject: Re: [TN] Gull wing solder joints and minimum electrical clearance

Yes, we have good wetting and the solder is wicking up the heel.  Without sending pictures, the bulge does occur more toward the heel end of the lead than the toe.

Thank
Peter

-----Original Message-----
From: TechNet [mailto:[log in to unmask]] On Behalf Of Wenger, George M. [Contractor]
Sent: Wednesday, September 11, 2013 12:00 PM
To: [log in to unmask]
Subject: Re: [TN] Gull wing solder joints and minimum electrical clearance

Richard makes a very good point about checking to see if the bulge might be a wetting issue.  Have you inspected the gull wing leads on any of the non-soldered components to see what the sides look like or have you run any solderability tests on the gull wing leads?  Unless you are using a very thick stencil or have a very wide aperture I would think that the heel of the gull wing leads, which are usually more solderable than the sides of the lead would allow the excess solder to wick up the heel and keep the side bulge to a minimum.

George
George M. Wenger
Failure Signature & Characterization Lab LLC
609 Cokesbury Road, High Bridge, NJ 08829
(908) 638-8771 Home (732) 309-8964 Mobile
E-mail: [log in to unmask]
[log in to unmask]

-----Original Message-----
From: TechNet [mailto:[log in to unmask]] On Behalf Of Stadem, Richard D.
Sent: Wednesday, September 11, 2013 2:48 PM
To: [log in to unmask]
Subject: Re: [TN] Gull wing solder joints and minimum electrical clearance

If the bulge is clearly due to excess solder, and good wetting away from the bulge is apparent (in other words, the bulge is not caused by a wetting issue), and minimum electrical clearance is not violated, then I do not see why they would need rework. The bulge of solder along the edges of the pad at the PWB level certainly is not going to affect the compliant portion of the lead above the heel.
You may also wish to look at the reflow profile. It is possible that a slightly hotter profile on top will draw more of the solder into the heel fillet, which is always good.

-----Original Message-----
From: TechNet [mailto:[log in to unmask]] On Behalf Of Peter Wong
Sent: Wednesday, September 11, 2013 1:06 PM
To: [log in to unmask]
Subject: [TN] Gull wing solder joints and minimum electrical clearance

We have assemblies where gull wing solder joints have so much solder that along the side joint, the solder connection extends out to the adjacent leads similar to Figure 5-1, Image C from IPC-A-610E.  "the solder connection to a termination may exhibit a wetting angle exceeding 90 degrees when it is created by the solder contour extending over the edge of the solderable termination area or solder resist" (We will be modifying our stencils to reduce the amount printed on these parts in the future).

There is no IPC-610 spec for this condition so we were thinking that if the spacing between the solder joints does not violate Minimum Electrical Clearance, they are acceptable.

Is this a correct acceptability criteria?

Thanks,
Peter

________________________________
The enclosed documents are proprietary items to Silicon Forest Electronics' (SFE) customers. They shall not be reproduced nor disclosed for any purpose except as specified in writing from an authorized agent of SFE. These documents may contain data restricted for export by the International Traffic in Arms Regulations (ITAR) section of the Arms Export Control Act (or the Export Administration Act). Violators are subject to severe criminal penalties.

______________________________________________________________________
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] ______________________________________________________________________

______________________________________________________________________
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