To all you tech types, I imagine this question has been seen before, but here goes.... We are experiencing some problems with cracked solder joints on an assembly. 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 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 assemblies are then sent to our test department where they are subjected to 10 thermal cycles of -54 Deg. C to +95 Deg. C at a rate of 15 Deg. C. per minute (customers request). The assemblies are inspected and that is when the fractures appear. 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. My question is - What is causing the fractures and what can be done to eliminate it? I am pretty sure of the correct answer, so don't beat me up too much on this one, I had to ask. I need reassurance. Thanks in advance for your help!!! Steve McBride Manufacturing Engineer, Frontier Engineering Inc. (405) 624-6821 *************************************************************************** * TechNet mail list is provided as a service by IPC using SmartList v3.05 * *************************************************************************** * To subscribe/unsubscribe send a message <to: [log in to unmask]> * * with <subject: subscribe/unsubscribe> and no text in the body. * *************************************************************************** * If you are having a problem with the IPC TechNet forum please contact * * Dmitriy Sklyar at 847-509-9700 ext. 311 or email at [log in to unmask] * ***************************************************************************