TECHNET Archives

April 2016

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:
Robert Kondner <[log in to unmask]>
Reply To:
Date:
Mon, 18 Apr 2016 18:15:33 -0400
Content-Type:
text/plain
Parts/Attachments:
text/plain (122 lines)
Hi,

Wow,  If this was just a CTE issue I do not think you would end up with such a large final fixed displacement. There appears to have been a large force that sheared the solder connection and caused the pin to pull to the left. Temperature cycling sure will not help but something was pulling that pin towards the left. Obviously the pin material is much stronger than the solder so the solder sheared.

Bob K.

-----Original Message-----
From: TechNet [mailto:[log in to unmask]] On Behalf Of Steve Gregory
Sent: Monday, April 18, 2016 5:47 PM
To: [log in to unmask]
Subject: Re: [TN] Solder Cracking After Thermal Cicling

Hi Ricardo,

I finally have your pictures up, they are here:

http://stevezeva.homestead.com/A15_Photos_of_pre__post_100_temp_cycling_CSC-10_SN12.pdf

Boy, that looks like a big CTE mis-match. A question; are the boards going through ESS? Vibration along with the temp cycling?

Steve

On Mon, Apr 18, 2016 at 2:35 PM, Ricardo Moncaglieri < [log in to unmask]> wrote:

> Steve,
> Attached arethe pictures.
> Thank you a lot.
> Await for your comments.
> brgds,Ricardo
>
> >>> Steve Gregory <[log in to unmask]> 18/04/2016 15:22 >>>
> Hi Ricardo,
>
> The Technet server strips the attachments, send your photo directly to 
> me and I'll get it posted...
>
> Steve
>
> On Mon, Apr 18, 2016 at 11:43 AM, Ricardo Moncaglieri < 
> [log in to unmask]> wrote:
>
> > Dear colleagues;
> >
> > Steve Gregory, could you please upload the enclosed picture?
> >
> > Solder become perturbated / cracked after thermal cicling:
> >
> > This picture corresponds to a plane (not circular) conector terminal 
> > solded to a pcb pad ENEPIG finished.
> > The connector terminal has been gold removed by twice pretin.
> > Solder used is Sn63Pb37.
> > Thermal cicling: 50°C to 125°C
> >
> > As picture showed there are stretch marks toward left direction and 
> > showed solder crack.
> >
> > Our provider reported temperature didnt pass over 125°C and solder 
> > used 63/37.
> >
> > Question:
> >
> > How could these kind of gooves or stretch marks have been produced 
> > taking into account they are just toward one direction (left) and of 
> > considerable length?
> > Just mecanic stress?
> > Temperature overpassing on any cicle?
> > Need of use of different alloy, ie.: In, Bi etc?
> > Provider reported the process is being useed from them since long 
> > ago (same solder alloy, temperature, pcb, terminal conector, thermal
> > cicling) but this is the first time they faced with such a cracking.
> >
> > Do you have any comment in order to anlyse/solve this trouble.
> >
> > Appreciate your feedback we are in middle of a providing acceptance 
> > tests space quality level (IPC class 3).
> >
> > brgds,Ricardo
> >
> >
> >
> > ____________________________________________________________________
> > __ 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 and any attachments are only for use by the intended
> recipient(s) and may contain legally privileged, confidential, 
> proprietary or otherwise private information. Any unauthorized use, 
> reproduction, dissemination, distribution or other disclosure of the 
> contents of this e-mail or its attachments is strictly prohibited. If 
> you have received this email in error, please notify the sender 
> immediately and delete the original.
>
> ______________________________________________________________________
> 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 and any attachments are only for use by the intended
recipient(s) and may contain legally privileged, confidential, proprietary or otherwise private information. Any unauthorized use, reproduction, dissemination, distribution or other disclosure of the contents of this e-mail or its attachments is strictly prohibited. If you have received this email in error, please notify the sender immediately and delete the original. 

______________________________________________________________________
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