Hi Paul, Are these bare boards or have they been assembled? Has anybody checked them out on an x-ray machine? Hans Air Force Material Command - We keep them flying! ~~~~~~~~ Hans M. Hinners WR-ALC/LYPME Bldg. 640 Materials Engineer 380 Second Street, Suite 104 Manufacturing Eng. Sec. Robins AFB GA 31098-1638 912-926-1970 (Voice) 468 - 1970 (DSN) 912-926-7974 (Fax) [log in to unmask] > -----Original Message----- > From: Chalmer, Paul [SMTP:[log in to unmask]] > Sent: Friday, June 11, 1999 03:53 > To: [log in to unmask] > Subject: Re: [TN] from jpl > > Here is some additional information on the suspected manufacturing problem > from NASA: > *** > we have some circuit boards that have developed open connections when we > apply pressure, heat or vibration. > > we destroyed one of the boards to create these cross sections. > > 40% of the via connections on one layer developed problems as depicted in > the cross section photos.the cross sections illustrate the anomalies. > > the boards were designed to mil-275 (ipc 2221). > material fr4 .093 > smallest trace is .008 air gaps .005 > 12 layers > vias are .025 pad / .010 hole / annular ring .0075 > > four of six parts look to have failed. > > ron ################################################################ TechNet E-Mail Forum provided as a free service by IPC using LISTSERV 1.8c ################################################################ To subscribe/unsubscribe, send a message to [log in to unmask] with following text in the body: To subscribe: SUBSCRIBE TechNet <your full name> To unsubscribe: SIGNOFF TechNet ################################################################ Please visit IPC's web site (http://www.ipc.org) "On-Line Services" section for additional information. For technical support contact Hugo Scaramuzza at [log in to unmask] or 847-509-9700 ext.312 ################################################################