In message <011301c61845$4dd6ca50$154d4d0a@MmPc21>, dated Fri, 13 Jan 2006, Piotr Galka <[email protected]> writes >With this 13 degrees C is it true? >What if my products are specified for -30 degrees (and often mounted >outdoors).
Form the Wikipedia entry for 'tin': Solid tin has two allotropes at normal pressure. At low temperatures it exists as gray or alpha tin, which has a cubic crystal structure similar to silicon and germanium. When warmed above 13.2 °C it changes into white or beta tin, which is metallic and has a tetragonal structure. It slowly changes back to the gray form when cooled, which is called the tin pest or tin disease. However, this transformation is affected by impurities such as aluminium and zinc and can be prevented from occurring through the addition of antimony or bismuth. You should talk to the solder supplier; maybe they have an alloy with bismuth added to overcome the problem. The problem with tin plague is that it's unpredictable. Everything may be OK for years, even, and then it happens. >To avoid problems with new technology we (small firm) decided to move >the production to contract manufacturer and supposed Pb-free technology >is no longer our problem. >Our standard warranty period is 3 years, and many devices sold 10 years >ago are still in use and I hope will be working for next 10 years (and >more). > >Should we change our warranty to say that Pb-free technology problems >are out of warranty ? That's something you management must decide for itself. -- OOO - Own Opinions Only. Try www.jmwa.demon.co.uk and www.isce.org.uk 2006 is YMMVI- Your mileage may vary immoderately. John Woodgate - This message is from the IEEE Product Safety Engineering Society emc-pstc discussion list. Website: http://www.ieee-pses.org/ To post a message to the list, send your e-mail to [email protected] Instructions: http://listserv.ieee.org/request/user-guide.html List rules: http://www.ieee-pses.org/listrules.html For help, send mail to the list administrators: Scott Douglas [email protected] Mike Cantwell [email protected] For policy questions, send mail to: Jim Bacher: [email protected] David Heald: [email protected] All emc-pstc postings are archived and searchable on the web at: http://www.ieeecommunities.org/emc-pstc
