"One reason is the lower temperature requirement for the Sn100 alloy," (vs. SAC305) Are you sure the cause of easier rework was temperature MP ~217C for SAC305 MP ~227C for SN100C Rex Waygood Technical Manager PartnerTech Poole Ltd Benson Road Poole Dorset BH17 0RY United Kingdom Tel: +44 (0)1202 674333 Fax: +44 (0)1202 678028 DDI: +44 (0)1202 338222 Mob: +44 (0)7887 997403 [log in to unmask] www.PartnerTech.co.uk -----Original Message----- From: TechNet [mailto:[log in to unmask]] On Behalf Of Stadem, Richard D. Sent: 18 August 2008 21:54 To: [log in to unmask] Subject: Re: [TN] FW: [LF] [TN] SN100 for Reflow Application Thanks, Keith. This is very informative, and goes hand-in-hand with my recent experiences with Sn100. I had an opportunity to work with Kester K100LD Sn100 wire solder and EasySpheres, and also Nihon Sn100CL "real RMA" cored flux wire and the SnCuNi +Ge eBalls while performing some laser solder process development and testing for a government customer three weeks ago. Last week I again used the Kester K100LD while performing rework/repair during IPC recertification at STI, during which I performed lots and lots of hand soldering and hot gas rework, so I became intimately familiar with Sn100 wire. I confirmed the instructor's observation that Sn100 alloy performs completely different from SAC305, SAC307, SAC407, etc, and is closest to 63/37. It proved to be much easier to solder in hot gas reflow, laser soldering during the development work, and when hand soldering it produced far superior solder joints from a wetting and appearance perspective than did the SAC305/405 alloy solders I found these two wire solders and solder ball products to be very similar to standard 63/37 while soldering and performing hand rework and BGA ball attach using laser and convection. Both Kester and Nihon Sn100 solders performed very well in vibration and shear testing, but not quite as good as Sn63/Pb37. I will get temperature cycling data in about 4-5 weeks. However, the laser-solder process with Sn100 from either Kester or Nihon had much better test results than any other lead-free alloy that was convection soldered, and also when the other Pb-free alloys were laser-soldered. This proved to be a big factor in the vibration and shear testing. After having fun performing rework on some very difficult-to-remove components that were soldered with SAC305 a few weeks ago, I can tell you it is much easier to rework the same components when they are soldered with Sn100. One reason is the lower temperature requirement for the Sn100 alloy, and the other is that a certain amount of ductility helps in removing the clinched leads without any pad or barrel damage. My observation is that the ductility of the Sn100 is much greater than SAC305, and for most purposes this would therefore be a better lead-free solution in terms of reliability than SAC305. The ease of rework says a lot for the use of Sn100, it presents less of a temperature shock than is required with SAC30X. But Sn63Pb37 is still the best choice in terms of reliability, if one is allowed to use it. How much more (or less) of a tin-whisker risk does Sn100CL present than the SAC alloys? ________________________________ ------------------------------------------------------------------------------- The information contained within this e-mail and any attachments contained therein may be confidential and/or legally privileged and is for the use of the intended recipient only. If you are not the intended recipient please delete it from your system and notify the sender by return e-mail. The content of this e-mail may not be copied or disclosed to any third parties without prior permission from the sender. E-mail is susceptible to data corruption, interception, tampering and viruses. We do not accept any liability for any such incidents or any consequences thereof. --------------------------------------------------- Technet Mail List provided as a service by IPC using LISTSERV 15.0 To unsubscribe, send a message to [log in to unmask] with following text in the BODY (NOT the subject field): SIGNOFF Technet To temporarily halt or (re-start) delivery of Technet send e-mail to [log in to unmask]: SET Technet NOMAIL or (MAIL) To receive ONE mailing per day of all the posts: send e-mail to [log in to unmask]: SET Technet Digest Search the archives of previous posts at: http://listserv.ipc.org/archives Please visit IPC web site http://www.ipc.org/contentpage.asp?Pageid=4.3.16 for additional information, or contact Keach Sasamori at [log in to unmask] or 847-615-7100 ext.2815 -----------------------------------------------------