All, Stick with me on this...it gets kind of lengthy.... About a year ago, I posted a problem to the Tech-net regarding solder fractures. At the time I got a lot of information on the subject. Enough to help guide me in the right direction. The PWB is a Polyimide material, .070" thick with 12 layers. All layers are 1oz copper. The PWB has a bonded stiffener, 6061-T6 aluminum @.040" thick. Board dimensions are 6" x 3.875". Some components are placed over the stiffener, some are not. The assemblies are prepared with straight through lead termination's and are wave soldered, some post assembly performed, cleaned, and inspected. All the assemblies exhibit good wetting and generally good solder characteristics at this point. The fractures all appear on gold plated, side brazed lead DIPs that are sitting directly on the stiffener. The fractures occur mostly at the lead fillet, but occasionally happen near the pad fillet Also worth noting is that the fractures occur on the side of the leads (the thin portion of the lead) with the more severe ones occurring near the ends of the DIPs and lessening as you move toward the middle. It turns out that because of the differences in Cte between the PWB and the bonded stiffener, the board is warping during wave solder. This warp is basically soldered in place which places the solder under constant loading as the board tries to return to it's room temperature dimensions. The side brazed DIPs do not provide sufficient stress relief and eventually the solder fatigues and fractures at the weakest point. Get to the point...what is your question you ask. Is there a way to eliminate this warp during wave solder or will attaching another material to the PWB only make things worse?? No we can't get rid of the side brazed DIPs because they are a military part only manufactured in that configuration. Any help you can provide will be greatly appreciated. Steve McBride Frontier Electronic Systems P.O. Box 1023 Stillwater Ok.74076 [log in to unmask] (405) 624-5281 ################################################################ 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 web site (http://jefry.ipc.org/forum.htm) for additional information. For the technical support contact Dmitriy Sklyar at [log in to unmask] or 847-509-9700 ext.311 ################################################################