The plugs are inserted from the top side of the board and the problem occurs on both sides of the board. The problem that is driving this investigation is due to voids in the conformal coating Conap -1170 that we apply using an automated process. The vias with the copper appearance are the vias that cause voids in the conformal coating. When I began the investigation I found that they were conductive. -----Original Message----- From: Franklin D Asbell [mailto:[log in to unmask]] Sent: Friday, November 19, 2004 2:19 PM To: [log in to unmask] Subject: Re: [TN] Okay I'm curious now...what would you call a "standard" via? Franklin ----- Original Message ----- From: "Jeffrey Bush" <[log in to unmask]> To: <[log in to unmask]> Sent: Friday, November 19, 2004 12:56 PM Subject: Re: [TN] Vias that are required to be plugged and tented should not have this condition. Weak LPI at the knee is due to the LPI running into the barrel during coating, leaving a thin coating. On a standard via this is not normally an issue and many LPI materials have lower viscosity and present more of an issue for via coverage. Are the vias plugged and is the condition on the opposite side of the plug? Jeffrey Bush Director, Quality Assurance and Technical Support VERMONT CIRCUITS INCORPORATED 76 Technology Drive - POB 1890 Brattleboro, Vermont 05302 Voice: 802.257.4571.21 Fax: 802.257.0011 http://www.vtcircuits.com -----Original Message----- From: Chellis, Tammy [mailto:[log in to unmask]] Sent: Friday, November 19, 2004 12:33 PM To: [log in to unmask] Subject: [TN] We do incoming inspections on the PCB and we are having troubles with identifying if variations in the LPI layer is acceptable. We are having a problem with coverage on the Vias. I have a customer who specifies the vias are plugged and tented. I am getting boards with a copper color at some of the vias. I have tried to solder and it will not take the solder but using a DMM the via is not electrically isolated. I am not sure if this is a problem or not. Is a board in IPC compliance with out electrical isolation of a plugged and tented via? The tenting is to be done with the LPI layer and appears to be very thin on some vias. We are not trying to solder to them I just tiring to find out if it is a defect. The thing that does not make sense to me is the conductivity to the via. --------------------------------------------------- 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 847-615-7100 ext.2815 ----------------------------------------------------- --------------------------------------------------- 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 847-615-7100 ext.2815 ----------------------------------------------------- --------------------------------------------------- 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 847-615-7100 ext.2815 ----------------------------------------------------- --------------------------------------------------- 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 847-615-7100 ext.2815 -----------------------------------------------------