Everyone you are mistaken. At first when I read the comment I thought as you did. Plating thickness. 0.4mm is 15.7 mils. If you can make .016 of Cu connect there is a big problem here. I believe he is referring to the diameter of the hole. He has used the word barrel which is deceiving. What you have here my friend is a ring void. The fact that the PCB's have been processed with Immersion Tin finish is apparent the boards have not been through a thermal stress related process at the board vendors end. My recommendation is a solder float 5x @ 10 second intervals @ 500F. This will emulate the process of the wave soldering process when assembling the parts. It will also give you a good indication whether or not the vias can withstand that type of punishment. However most of the comments stated are true. 8 tenths of a mil is the minimum. 1 ounce (1.4mils) preferred. Merry X-Mas Everyone. Here's hoping 03 is better than 02. Regards, Damon A. DeSilva Engineering Manager Lazer-Tech Ltd. PH#(416)291-7727 EXT:271 FAX(416)291-0325 [log in to unmask] -----Original Message----- From: TechNet [mailto:[log in to unmask]]On Behalf Of [log in to unmask] Sent: Thursday, December 19, 2002 11:44 AM To: [log in to unmask]; [log in to unmask] Subject: [TN] Plated Through Holes Hi everyone Can anyone tell me what the recommended thickness of the barrels of PTH's is? We have a minor problem with 0.4mm dia. barrels not giving good ground from top of board to ground plane on underside. Boards are double sided PTFE / copper track / Emersion tin RF boards. Richard Brennan Manufacturing Support Manager Health & Safety Manager Aerial Facilities Ltd Aerial House Asheridge Road Chesham Bucks HP5 2QD 01494 777000 Direct line 01494 777052 [log in to unmask] --------------------------------------------------- Technet Mail List provided as a free 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/html/forum.htm for additional information, or contact Keach Sasamori at [log in to unmask] or 847-509-9700 ext.5315 ----------------------------------------------------- --------------------------------------------------- Technet Mail List provided as a free 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/html/forum.htm for additional information, or contact Keach Sasamori at [log in to unmask] or 847-509-9700 ext.5315 -----------------------------------------------------