However, Were this the case you would see fracturing or voiding of the via. James Hofer Director of Operations Accurate Circuit Engineering 3019 S. Kilson Dr. Santa Ana Ca. 92707-4202 714-546-2162 work 714-473-6127 cell [log in to unmask] ----- Original Message ----- From: "Lee Parker" <[log in to unmask]> To: <[log in to unmask]> Sent: Friday, September 10, 2004 12:31 PM Subject: Re: [TN] Blow Holes -- Where the heck does the moisture come from anyway? > Carrie > > If you cross section the vias, remove the solder from the hole and look > at the copper barrels at very high magnification (use and SEM if > possible)you may see pin holes in the copper or glass bundles protruding > into the hole. This coupled with moisture in the dielectric which is > normal can create the mechanism. When the board is quickly heated in > assembly (reflow or wave solder) the moisture is pressurized and flows > out through the pin holes into the barrels blowing the molten solder in > the barrels out onto the board. > > Best regards > > Lee > > -----Original Message----- > From: TechNet [mailto:[log in to unmask]] On Behalf Of Morse, Carrie > Sent: Friday, September 10, 2004 2:33 PM > To: [log in to unmask] > Subject: [TN] Blow Holes -- Where the heck does the moisture come from > anyway? > > Just wondering a few things here at 2:30 on Friday Afternoon: > > 1. What else causes Blow Holes at wave on TH comps? Is it primarily > moisture? > 2. Where does the moisture come from? > 3. Are certain board materials more likely to sponge up the moisture in > the air? > 4. Can hole wall quality play a part in contributing to blow holes? > > -Carrie > > --------------------------------------------------- > Technet Mail List provided as a service by IPC using LISTSERV 1.8e > 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 > Please visit IPC web site > http://www.ipc.org/contentpage.asp?Pageid=4.3.16 for additional > information, or contact Keach Sasamori at [log in to unmask] or 847-509-9700 > ext.5315 > ----------------------------------------------------- > > --------------------------------------------------- > Technet Mail List provided as a service by IPC using LISTSERV 1.8e > 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 > Please visit IPC web site http://www.ipc.org/contentpage.asp?Pageid=4.3.16 for additional information, or contact Keach Sasamori at [log in to unmask] or 847-509-9700 ext.5315 > ----------------------------------------------------- > --------------------------------------------------- Technet Mail List provided as a service by IPC using LISTSERV 1.8e 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 Please visit IPC web site http://www.ipc.org/contentpage.asp?Pageid=4.3.16 for additional information, or contact Keach Sasamori at [log in to unmask] or 847-509-9700 ext.5315 -----------------------------------------------------