Bill, I have experienced the condition you are describing when we were using similar process materials and equipment. We found RANDOM granular solder joint occurred were there was large thermal mass that resulted in very slow cooling of those joints. Solder joints at heavy voltage or ground planes, buss bars, and components that had large leads, would often result in this condition. We were able to reduce this some by providing additional cooling at the exit of the wave to help cool the assembly quicker and by dropping our processing temperatures a little. Dan Botts Hughes Training Inc. ------------------------ INTERNET MAIL ------------------------ From: "BROMLEY, Bill" <[log in to unmask]> Subject: ASSY:Grainy wave solder joints Date: Tue, 18 Mar 97 16:05 EST --------------------------------------------------------------------------- We are currently experiencing random grainular solder joints on double sided rigid PWB assemblies after wave solder. Our wave solder machine is an Electrovert Econopak 229, and we are using Alpha 615-25 (RMA-type) flux with Sn6337 solder per QQ-S-571. The PWB is GHN type per Mil-P-13949/5 with "C" type copper, and solder coated, with a dry film soldermask. We have made many process adjustments, including speed, top-side board temperature, wave bath temperature, etc. We have very recently verified that solder purity is within specifications. The graininess we are seeing in the solder joint (including the fillet area) is randomly distributed, and in some cases located one pad from a perfect solder joint. There is no consistent pattern from board to board. Can anyone offer some advice? Bill Bromley/Mike Polifrone Lucas Aerospace PSA 777 Lena Dr. Aurora OH 44202 USA voice: 216-995-1000 ex 7036 email: [log in to unmask] *************************************************************************** * 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] * *************************************************************************** *************************************************************************** * 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] * *************************************************************************** *************************************************************************** * 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] * ***************************************************************************