Oh bumbles! Its that complicated math that always messes me up! Wait, weight percent is in metric right? That's my excuse - I am metrically impaired! No wonder I lose more tin in my solder wave with an extra 4%! Guess I better switch to Mt. Dew! Dave Doug Pauls <dopauls@rockwellc To: [log in to unmask] ollins.com> cc: Sent by: TechNet Subject: Re: [TN] SnPb Solder pot composition <[log in to unmask]> 12/04/2003 01:28 PM Please respond to "TechNet E-Mail Forum."; Please respond to dopauls Sasha, Dave is a superior metallurgist. We never knew just how superior he was until he came up with an alloy that is 104%. Dave, is it a company proprietary process that produces this 64 Sn/40Pb alloy? Four Diet Cokes and he is STILL not awake........ Doug Pauls Dave Hillman <ddhillma@rockwellc To: [log in to unmask] ollins.com> cc: Sent by: TechNet Subject: Re: [TN] SnPb Solder pot composition <[log in to unmask]> 12/04/2003 01:12 PM Please respond to "TechNet E-Mail Forum."; Please respond to ddhillma Hi Sasha! The tin composition of your wave solder bath is preferentially depleted because of two factors: a) Sn preferentially oxidizes in comparison to Pb so the wave solder dross is has a much higher Sn percentage than Pb percentage (this is the dominate loss mechanism); b) If you are using 64Sn/40Pb, you are using more tin in every solder joint than lead and tin forms an intermetallic with the copper pwb pads whereas lead does not. The JSTD-001 Handbook conveniently lists the Tin Depletion replenishment formulas (page 62 in the 001 Handbook with amendment revision). Dave Hillman Rockwell Collins [log in to unmask] Sasha Miladinovic <sasha.miladinovic@AM To: [log in to unmask] ERSHAM.COM> cc: Sent by: TechNet Subject: Re: [TN] SnPb Solder pot composition <[log in to unmask]> 12/04/2003 12:17 PM Please respond to "TechNet E-Mail Forum."; Please respond to Sasha Miladinovic Ed, I like Your declaration about "cold" joints... :) I had a minor war i a earlier life with a Q-department about the definition.. :) I'm not sure it any of us is right or wrong, but why would be Tin that drops? Isn't it density and temparature that is the governing factors in this case? Enyone outthere that can explain this? :) ************************************************************************* Sasha Miladinovic - Production Engineering Amersham Biosciences, PCB Production, Umeå Tel: +46 (0) 90 150 232 Fax: +46 (0) 90 138 372 E-mail: [log in to unmask] ************************************************************************* Ed Popielarski <[log in to unmask]> Sent by: TechNet <[log in to unmask]> 2003-12-04 18:40 Please respond to "TechNet E-Mail Forum."; Please respond to Ed Popielarski To: [log in to unmask] cc: Subject: Re: [TN] SnPb Solder pot composition Yordan, Deviation from 63/37 can cause increased solder shorts in a wave soldering machine. At 63/37 (eutectic) the melt point is minimum, and there is no plasticus range. As you drift from there the melt point increases and the plastic range increases. This is why hand solder is preferred at 60/40... there IS plastic range and makes it easier to judge the joint as you solder. This is also the main cause of "frosty" joints (I hate to say "cold" since it is a very inaccurate term). Another thought to add to the mix is the accuracy of the lab. I recommend using either Alpha Metals or Kester to do the analysis (Type C which is the "whole enchilada" variety) and perhaps to rule out other variables discussed in other's postings, take a few samples, from the static part of the pot, from the wave after running at temperature, etc. If all the samples come back relatively the same, then you are good to go, but if one or two stand out, there could be something worth looking into. Additionally, (yes, another variable) the tin is usually the element that drops, not the lead. This has me wondering as well. Why? Have a safe and happy holiday! Regards, Ed Popielarski QTA Machine 27291 Jardines Mission Viejo, Ca. 92692 Phone:949-581-6601 Fax: 949-581-2448 Cel: 949-337-2578 WWW.QTA.NET "Thank God for America... before it's too late!" --------------------------------------------------- Technet Mail List provided as a service by IPC using LISTSERV 1.8e 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 847-509-9700 ext.5315 ----------------------------------------------------- --------------------------------------------------- Technet Mail List provided as a service by IPC using LISTSERV 1.8e 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 847-509-9700 ext.5315 ----------------------------------------------------- --------------------------------------------------- Technet Mail List provided as a service by IPC using LISTSERV 1.8e 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 847-509-9700 ext.5315 ----------------------------------------------------- --------------------------------------------------- Technet Mail List provided as a service by IPC using LISTSERV 1.8e 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 847-509-9700 ext.5315 ----------------------------------------------------- --------------------------------------------------- Technet Mail List provided as a service by IPC using LISTSERV 1.8e 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 847-509-9700 ext.5315 -----------------------------------------------------