Dear Ted: While I cannot comment on your question regarding pwb reliability, I have performed (during a nine year peroid) close to one thousand copper purity, tensile strength, and elongation tests; from at least 20 different manufacturers, operating brightener systems from virtually all major vendors, and operating and maintaining their copper baths with a variety of different methods (type of anodes, anode/cathode ratios, filtration, frequency of carbon treat, etc.) . During this time, I have encountered only one bath which consistently failed the WS-6536 specs. (This does not include failures traced to poor sample preparation.) This failure occured with a Lea Ronnel additive system. But to their credit, Lea Ronnel did not dismiss the lab data as erroneous, and in a timely fashion determined the poor copper electroplating was due to poor rectification and not their additive system. While I have not accumulated this data in a single data base, if I were to segragate the data into "below average", "average", and "above average", it would be as follows: Elongation (%) Tensile Strength (psi) "below average" < 9 < 39,000 "average" 9-15 39,000 - 42,000 "above average" > 15 > 42,000 The best 10% of baths tested consistantly maintained greater than 20% elongation and 44,000 psi tensile strength. Hope you find this information useful. Regards, Ted Stern Circuit Research Corp. Edwards, Ted A (AZ75) wrote: > > At the recent IPC meeting in Tempe, AZ. on IPC 6012, Qualification and > Performance Specification for Rigid Printed Boards, I asked if Para 3.11.8 > b), which reads as follows, is realistic given todays thicker boards and > higher aspect ratios: > > b) When tested as specified in IPC-TM-650, method 2.4.18.1 ambient > using 50-100 micrometer (0.002-0.004 in) thick sample, the tensile strength > shall be no less than 245MPa (36,000 psi) and the elongation shall be no > less than 6%. > > The numbers appear to be directly from WS 6536 and unchanged over the years; > I personally do not think a 0.125 board with 16 mil holes if it were 6% > elongation would be very reliable. I also do not think anyone really would > try to be at 6%. BUT I have no data so when I said why not change to a > "real" number , the team members said show me the data. That leads me to > ask the following; anybody have any data? Is a value of 49,000 psi and 14% > , any better , or any worse, than a 42,000 psi and 22%? > > [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] * ***************************************************************************