Hi Bill and Mike! Let me describe two conditions and then you will have to decide which you have: 1) a "disturbed" solder joint: a solder joint that has an "angular, faceted" appearance that is caused by the solder joint being moved as it solidified. 2) a "grainy" solder joint: a solder joint that has a rough, gritty appearance that is caused by the solder microstructure giving the solder joint surface relief. I am an advocate of NOT using visual appearance to define what a good and bad solder joint looks like - the number of hours spent by the specification community trying to define what a "disturbed or grainy" solder joint is would/should make all of us disturbed! But if you think you have a 'disturbed' situation go looking for equipment or fixture causes for the movement. If you have a 'grainy' situation you have two options: try to find a way to cool the solder joint faster and/or not get it so hot in the first place so that the solder joint microstructure is finer thus not giving you little solder joint surface relief or use some cross section analysis to prove that the 'graininess' is not a reliability issue. We did some extensive work in the 80's showing that a 'grainy' solder joint is not a bad solder joint - only different, reflecting some process or design parameter influence. Good luck. Dave Hillman Rockwell Collins [log in to unmask] ______________________________ Reply Separator _________________________________ Subject: ASSY:Grainy wave solder joints Author: [log in to unmask] at ccmgw1 Date: 3/18/97 4:27 PM 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] * ***************************************************************************