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 -----------------------------------------------------