RE: [LF] Lead Free Wave Solder Alloy TemperaturesHello LF,
as there were a few more "leadfreers" interested in the presentation, let me give you a "sneak preview". It's only fair, as I worked in quite some information which I gained from this valuable forum. The PDF can be downloaded from
www.weichloeten.de/rutronik/ta-leadfree-1.pdf
I hope it works for you all - if not please tell me. By the way, it may take a while, it's ca. 5MB, due to many pictures. There are a few left over german comments in it, sorry for that, it was a little late last night when I translated it.
Best regards
Thomas Ahrens, Boostedt
e-mail [log in to unmask]
----- Original Message -----
From: Joe Lee
To: Thomi
Sent: Wednesday, May 26, 2004 9:34 PM
Subject: RE: [LF] Lead Free Wave Solder Alloy Temperatures
Mr. Ahrens:
I am interested in seeing the presentation in English.
Regards
Joe Lee
Nortel Networks
Phone: (613) 763-5916
Fax: (613) 763-1961
E-mail: [log in to unmask]
-----Original Message-----
From: Thomi [mailto:[log in to unmask]]
Sent: Wednesday, May 26, 2004 3:13 PM
To: [log in to unmask]
Subject: Re: [LF] Lead Free Wave Solder Alloy Temperatures
Hi Moss,
there have been nice investigations on wettability performed by my collegues group Mathias Nowottnick at IZM Berlin. Systematic parameter choice was temperatures of 5%, 10% and 15% (in degrees Kelvin) above melting for Sn-Bi, Sn-Pb-Ag, Sn-Ag-Cu, Sn-Ag and Sn-Cu. the results show that in order to achieve wetting within ca. 1 s (necessary for wave soldering), the temperature must be somewhat between 5 and 10%. For reference purposes, I have included the corresponding wetting diagram in a seminar presentation (in german language) on page 20 of the following document
http://www.weichloeten.de/themenschwerpunkte/online-quellen/14bleifrei-isit-
ta-2proseite.pdf.
This correlates well with the (absolute)minimum of 245°C for SAC and 255°C for Sn-Cu or Sn-Cu-Ni we found during our trials on commercial double wave soldering systems. For reflow, as there is longer time for wetting, the temperatures may be somewhat lower: After all, with vapour phase, we can solder SAC at 230°C. I will translate this presentation into english, as it will be given in Madrid (June 7), Lyon (June 23) and Paris (June 25) in the Rutronik seminar series on leadfree soldering (see www.rutronik.com). Lots of discussions we had in the past 7 sessions all over Germany and Switzerland, where astonishingly few electronics manufacturers seem to be aware that time is closing in at super sound speed with regard to the RoHS deadline. Tell me if there is interest in the presentation, then I can publish a link at the end of June for the english language version.
Best regards
Thomas Ahrens, Boostedt
e-mail [log in to unmask]
----- Original Message -----
From: "EMTC Ireland" <[log in to unmask]>
To: <[log in to unmask]>
Sent: Tuesday, May 25, 2004 7:42 PM
Subject: [LF] Lead Free Wave Solder Alloy Temperatures
Hi all
In reference to Howard H. Manko's book "Solders and Soldering" I'm just interested in learning from the metallugist fraternity out there his description of "Tin Pest" "When cooled to low temperatures, pure tin transforms from a white metallic material into a grey amorphous powder. In the past this transformation was called "tin pest", because tin articles for no explainable reason crumbled into dust." (13.2degC)
The paragraph continues to describe detrimental properties of tin - but can anyone comment for Sn0.7Cu or any high tin containing alloy if this is of concern.
Also has anyone Phase Diagrams for the SnCu and SAC alloys that show the "recommended alloy temperature during wetting" as presented in Manko's book (Fig 3.8) as opposed to the rule of thumb approx 40degC above liquidus?
All information/references appreciated,
Thanks in advance
Moss
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To unsubscribe, send a message to [log in to unmask] with following text in
the BODY (NOT the subject field): SIGNOFF Leadfree
To temporarily stop delivery of Leadree for vacation breaks send: SET Leadfree NOMAIL
Search previous postings 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
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