As the amount of tin in a reflow and in a hand solder process is limited, to me it looks like copper dissolution is probably not the main cause of your issue...
Gebhard
-----Ursprüngliche Nachricht-----
Von: TechNet [mailto:[log in to unmask]] Im Auftrag von Joyce Koo
Gesendet: Donnerstag, 28. Juli 2011 04:23
An: [log in to unmask]
Betreff: Re: [TN] Missing PTH Barrels in Connector
What is the barrel thickness? Did you etch it and see how is the seed layer and subsequent 1st layer adhesion the the PWB? Any etchback can be observed? You do not need to answer my question. As long as you find out the answer.
--------------------------
Sent using BlackBerry
----- Original Message -----
From: Thomas Bauer [mailto:[log in to unmask]]
Sent: Wednesday, July 27, 2011 10:07 PM
To: [log in to unmask] <[log in to unmask]>
Subject: Re: [TN] Missing PTH Barrels in Connector
Hello
Do you know if there are inner layer pads helping secure the structural integrity of the pth? If not I could see how overheating during soldering could easily cause the barrel to pull out of the hole.
Thomas
On Jul 27, 2011, at 5:42 PM, "Tom Burek" <[log in to unmask]> wrote:
> Hello,
> I have a PCA that hand solders 6 connector pins to an 4 layer PCB
> assembly.
> The finish on the PCB is Lead Free HASL (SN100CL) and the solder used to
> hand solder the pins is SAC305. The hand soldering is performed as a
> secondary assembly operation after reflow.
> What happens to some of the assemblies, but not all of them, is that the
> solder will wick straight up the pin, thereby not allowing a Solder joint.
> The pin can be pulled right out of the hole, revealing a PTH with no
> inner barrel.
> Completely wiped out as if it was never there in the first place. This
> phenomenon is not present on every PCB or every pin of the same connector.
> The PCB's are part of a multi-board panel.
>
> As far as I know the PCB started out with a barrel, but I cannot rely on
> this being the case as I do not believe the technician checks 100% of the
> PTH's prior to inserting the pin.
>
> Am I looking at excessive heat causing complete Copper Dissolution of the
> PTH barrel?
> or
> A PCB that may not have a barrel in every hole, part of the PCB
> fabrication process?
> or
> Any other suggestion as to which direction to head would be appreciated.
>
> Thanks in advance.
>
>
> Tom Burek, CID+
>
>
>
> ______________________________________________________________________
> This email has been scanned by the MessageLabs Email Security System.
> For more information please contact helpdesk at x2960 or [log in to unmask]
> ______________________________________________________________________
>
> ---------------------------------------------------
> Technet Mail List provided as a service by IPC using LISTSERV 16.0
> To unsubscribe, send a message to [log in to unmask] with following text in
> the BODY (NOT the subject field): SIGNOFF Technet
> To temporarily halt or (re-start) delivery of Technet send e-mail to [log in to unmask]: SET Technet NOMAIL or (MAIL)
> To receive ONE mailing per day of all the posts: send e-mail to [log in to unmask]: SET Technet Digest
> Search the archives of previous posts at: http://listserv.ipc.org/archives
> For additional information, or contact Keach Sasamori at [log in to unmask] or 847-615-7100 ext.2815
> -----------------------------------------------------
______________________________________________________________________
This email has been scanned by the MessageLabs Email Security System.
For more information please contact helpdesk at x2960 or [log in to unmask]
______________________________________________________________________
---------------------------------------------------
Technet Mail List provided as a service by IPC using LISTSERV 16.0
To unsubscribe, send a message to [log in to unmask] with following text in
the BODY (NOT the subject field): SIGNOFF Technet
To temporarily halt or (re-start) delivery of Technet send e-mail to [log in to unmask]: SET Technet NOMAIL or (MAIL)
To receive ONE mailing per day of all the posts: send e-mail to [log in to unmask]: SET Technet Digest
Search the archives of previous posts at: http://listserv.ipc.org/archives
For additional information, or contact Keach Sasamori at [log in to unmask] or 847-615-7100 ext.2815
-----------------------------------------------------
---------------------------------------------------------------------
This transmission (including any attachments) may contain confidential information, privileged material (including material protected by the solicitor-client or other applicable privileges), or constitute non-public information. Any use of this information by anyone other than the intended recipient is prohibited. If you have received this transmission in error, please immediately reply to the sender and delete this information from your system. Use, dissemination, distribution, or reproduction of this transmission by unintended recipients is not authorized and may be unlawful.
______________________________________________________________________
This email has been scanned by the MessageLabs Email Security System.
For more information please contact helpdesk at x2960 or [log in to unmask]
______________________________________________________________________
---------------------------------------------------
Technet Mail List provided as a service by IPC using LISTSERV 16.0
To unsubscribe, send a message to [log in to unmask] with following text in
the BODY (NOT the subject field): SIGNOFF Technet
To temporarily halt or (re-start) delivery of Technet send e-mail to [log in to unmask]: SET Technet NOMAIL or (MAIL)
To receive ONE mailing per day of all the posts: send e-mail to [log in to unmask]: SET Technet Digest
Search the archives of previous posts at: http://listserv.ipc.org/archives
For additional information, or contact Keach Sasamori at [log in to unmask] or 847-615-7100 ext.2815
-----------------------------------------------------
**************************************************************************************** Note: If the reader of this message is not the intended recipient, or an employee or agent responsible for delivering this message to the intended recipient, you are hereby notified that any dissemination, distribution or copying of this communication is strictly prohibited. If you have received this communication in error, please notify us immediately by replying to the message and deleting it from your computer. Thank you. ****************************************************************************************
______________________________________________________________________
This email has been scanned by the MessageLabs Email Security System.
For more information please contact helpdesk at x2960 or [log in to unmask]
______________________________________________________________________
---------------------------------------------------
Technet Mail List provided as a service by IPC using LISTSERV 16.0
To unsubscribe, send a message to [log in to unmask] with following text in
the BODY (NOT the subject field): SIGNOFF Technet
To temporarily halt or (re-start) delivery of Technet send e-mail to [log in to unmask]: SET Technet NOMAIL or (MAIL)
To receive ONE mailing per day of all the posts: send e-mail to [log in to unmask]: SET Technet Digest
Search the archives of previous posts at: http://listserv.ipc.org/archives
For additional information, or contact Keach Sasamori at [log in to unmask] or 847-615-7100 ext.2815
-----------------------------------------------------
|
