Bob, The best source for this information is the "IPC Roadmap: A Guide for Assembly of Lead-Free Electronics". http://www.leadfree.org/ Websites and links are contained within the document. (I'm too lazy to list all the web links.) Ryan Grant > -----Original Message----- > From: Bob Willis [SMTP:[log in to unmask]] > Sent: Thursday, December 07, 2000 1:12 AM > To: [log in to unmask] > Subject: Re: [LF] AW: [LF] Component Durability > > Where are the consortium papers referred to in a number of the emails ? > > I have a draft document on off form parts for pin in hole reflow which I > have run with lead free processes that may be added to this range of > papers. But where are they ? > > Bob Willis > www.bobwillis.co.uk <http://www.bobwillis.co.uk> > Tel: (44) 01245 351502 Fax: (44) 01245 496123 > > If you need to solve a soldering problem for free "Ask the Expert" at > www.solder-recovery.com <http://www.solder-recovery.com> > > ----- Original Message ----- > From: Ryan Grant <mailto:[log in to unmask]> > To: [log in to unmask] <mailto:[log in to unmask]> > Sent: Tuesday, December 05, 2000 9:12 PM > Subject: Re: [LF] AW: [LF] Component Durability > > Jim, > I must agree with Graham. I would dare say that MOST > companies are > currently wave soldering eutectic tin/lead with their solder pot > temperatures between 480 and 500 degrees Fahrenheit. > However, that still doesn't help the higher temperatures of > surface > mount. Ironically, many of the consortium's papers have indicated > that > problems with lead-free wave solder may push the industry to pure > SMT. > However, as Hans pointed out with electrolytic capacitors, this is > probably > unlikely since an easy way to overcome the high SMT temperatures is > to > revert back to through-hole. ("I shudder at the thought"). > > Ryan Grant > Advanced Technology Engineer > MCMS > (208) 898-1145 > [log in to unmask] <mailto:[log in to unmask]> > > > > -----Original Message----- > > From: Graham Collins [ SMTP:[log in to unmask] > <mailto:SMTP:[log in to unmask]>] > > Sent: Tuesday, December 05, 2000 1:44 PM > > To: [log in to unmask] <mailto:[log in to unmask]> > > Subject: Re: [LF] AW: [LF] Component Durability > > > > Jim > > I was both amused and puzzled by your email (I say this because > otherwise > > you might infer I was offended, not an applicable emotion in this > case) > > > > How do you read David's email as saying "many companies set their > wave > > solder temperatures much higher than necessary (or desirable)"???? > I do > > not read his email as saying that, he states that it is possible > to solder > > between not 450 - but doesn't offer an opinion that it is desired. > What > > the heck are you basing that on? Yes, I have heard of companies > running > > their wave at 450 or so, but to make the statement that higher > than that > > is not necessary - I'm not buying what you are selling. > > > > My wave solder is set at 500F. Why? Not based on a "lack of > knowledge" > > thanks very much. Now, I will admit I have only run experiments > down to > > 475F and up to 510, but not running experiments at 450 was a no > brainer > > for us, not based on some ignorance. If the results are bad at > 480 and > > get worse at 475 it's an odd leap of faith to assume 450 will be > better. > > If you think you can run 10 layer 2 oz copper boards at 450 F I > really > > want to know what kind of wave solder machine you are using. > > > > If or when we convert to lead free the operating temperatures will > be > > based on experiments, not on numbers picked out of the air. But > maybe we > > can get some of your local ballot counters to help with the math > :-) > > > > have a good week. > > > > regards > > > > Graham Collins > > Process Engineer, Litton Systems Canada, Atlantic Facility > > (902) 873-2000 ext 6215 > > > > >>> [log in to unmask] <mailto:[log in to unmask]> 12/05/00 > 02:52PM >>> > > David: > > > > I'm delighted you've weighed in with your excellent points. We can > > always count on your for scientific approaches to issues too often > > addressed via emotions. > > > > As you've noted, many companies already set their wave solder > > temperatures much higher than necessary (or desirable). They then > > experience problems ranging from distortion of circuit boards to > higher > > component failure rates. When the new solders are implemented, it > will > > not be possible to reduce temperatures to the 450?F range that > makes > > sense with current tin/lead. And I fear that those companies > already > > running at excessive temperatures will, in their lack of > knowledge, turn > > the heat even higher. > > > > Your other point about the higher tin content dissolving leads, > end caps > > and other metal parts is indeed cause for concern and not widely > > recognized. > > > > Summing up, then, it seems to me we end up with a process that is > not at > > all friendly to the components (regardless of whether the > environment is > > or is not better off). Would you concur? If not, what am I > overlooking? > > > > Jim Smith > > Managing Director > > Cambridge Management Sciences, Inc. > > 4285 45th St. S. > > St. Petersburg, FL 33711-4431 > > Tel: (727)866-6502 ext. 21 > > Fax: (727)867-7890 > > eMail: [log in to unmask] <mailto:[log in to unmask]> > > > > > > > > dsuraski wrote: > > > > > > Actually, there are several companies out there running > lead-free alloys > > in > > > wave soldering at a "drop-in" temperature as compared to Sn/Pb. > The > > reasons > > > for this are two-fold: First, many companies run Sn/Pb at a > higher > > > temperature than absolutely necessary. The operating window for > Sn/Pb > > in a > > > wave is about 425 to 500F, but most companies are at the very > high end > > of > > > this (490-500+F). In these cases, many lead-free alloys may be > used at > > the > > > same temp. Basically, the temperature range for lead-free > alloys begins > > > where the range for Sn/Pb ends, and there normally is crossover > (BTW, > > this > > > also is often the case with hand soldering). Second, one of the > reasons > > for > > > exceeding a solder's liquidus in wave soldering is to reduce the > > solder's > > > surface tension sufficiently to promote drainage, etc. As with > SMT, the > > > superheat temperature needed for most lead-free alloys is not as > high as > > > with Sn/Pb due to the surface tension characteristics of > lead-free > > alloys. > > > Therefore, it usually is possible to get by with a peak > temperature only > > > slightly above the liquidus. As with Sn/Pb, though, a higher > peak temp > > can > > > promote better wetting. > > > > > > As far as temperature concerns relating to lead-free alloys, the > > greatest > > > emphasis should be placed on SMT. My primary concerns for wave > > soldering > > > relate to the high tin content of lead-free alloys, which tend > to > > dissolve > > > the standard materials in wave soldering machines now. > Specifying a > > > "lead-free compatible" wave machine can help. Also, some alloys > such as > > > Sn/Cu offer poor wetting and sometimes require nitrogen and/or > very > > > aggressive flux chemistries to achieve adequate soldering. > > > ----- Original Message ----- > > > From: "Jim Smith" < [log in to unmask] > <mailto:[log in to unmask]>> > > > To: < [log in to unmask] <mailto:[log in to unmask]>> > > > Sent: Tuesday, December 05, 2000 1:16 PM > > > Subject: Re: [LF] AW: [LF] Component Durability > > > > > > Hans: > > > > > > You've confirmed my worst fears. As I point out in my note to > Doug Romm > > > here, wave soldering (if it survives the change in alloys) is an > even > > > more hostile environment than reflow ovens. How (or can) we > handle those > > > conditions? > > > > > > Jim Smith > > > Managing Director > > > Cambridge Management Sciences, Inc. > > > 4285 45th St. S. > > > St. Petersburg, FL 33711-4431 > > > Tel: (727)866-6502 ext. 21 > > > Fax: (727)867-7890 > > > eMail: [log in to unmask] <mailto:[log in to unmask]> > > > > > > "" wrote: > > > > > > > > ---------- > > > > Von: jsmith / unix ( [log in to unmask] > <mailto:[log in to unmask]>) > > > > An: [log in to unmask] <mailto:[log in to unmask]> > > > > Betreff: [LF] Component Durability > > > > Datum: Montag, 4. Dezember 2000 22:03 > > > > > > > > It is surely not the question, if component makers are able > ore unable > > > > to produce robust components (I?m sure they do their best), > it?s the > > > > simple physical limit: for all kinds of plastic capacitors the > melting > > > > point of the foil is not changeable, so this technology and > industry > > > > will be killed by the leadfree enthusiasts. Similar for the > > electrolytic > > > > capacitors, the boiling temperature of the electolyte is not > > manipulable > > > > as one wants. You mentioned the ceramics, it is also > wellknown, that > > all > > > > kind of ceramics are thermoshock sensitive, the higher the > solder > > tempe- > > > > rature, the higher the shock. Also the mismatch of the > different > > expansion > > > > coefficients, while the soldered component cools down on the > board > > from > > > > the higher soldering level leads to cracks. One question at > the end, > > > > if You buy a new car, do You prefer a "green" antiblocking > brakes > > system, > > > > or the "old" one? > > > > > > > > With kind regards, > > > > > > > > Hans Juergen Bauer > > > > Industrial Engineering > > > > Passive Components > > > > Qualification > > > > > > > > ALCATEL Stuttgart > > > > > > > > Pondering some recent postings on this forum, I began > questioning some > > > > of the assertions that eliminating lead is feasible. > Specifically, I > > > > wondered about the current inability (or, at least, lack of > rating) of > > > > many parts to survive temperatures in the 260?C range (many > larger > > > > ceramic capacitors, for example, are not warranted to survive > > immersion > > > > in solder above approximately 230?C for even a few seconds). > If lead > > is > > > > removed from solder, the components will be required to > survive at > > 260?C > > > > or higher for quite a large number of seconds. > > > > > > > > If the components can be made to tolerate higher temperatures > without > > > > degradation when new solder(s) with higher melting > temperature(s) are > > > > introduced, why haven't component manufacturers already made > their > > > > devices more robust? > > > > > > > > Jim Smith > > > > Managing Director > > > > Cambridge Management Sciences, Inc. > > > > 4285 45th St. S. > > > > St. Petersburg, FL 33711-4431 > > > > Tel: (727)866-6502 ext. 21 > > > > Fax: (727)867-7890 > > > > eMail: [log in to unmask] <mailto:[log in to unmask]> > > > > > > > > > ---------------------------------------------------------------------- > > > > ----------- > > > > Leadfee Mail List provided as a free service by IPC using > LISTSERV > > 1.8d > > > > To unsubscribe, send a message to [log in to unmask] > <mailto:[log in to unmask]> with following text > > in > > > > the BODY (NOT the subject field): SIGNOFF Leadfree > > > > Search previous postings at: www.ipc.org <http://www.ipc.org> > > On-Line Resources & > > > > Databases > E-mail Archives > > > > Please visit IPC web site ( < > <http://www.ipc.org/html/forum.htm>)> for > > > additional > > > > information, or contact Keach Sasamori at [log in to unmask] > <mailto:[log in to unmask]> or > > > > 847-509-9700 ext.5315 > > > > > ---------------------------------------------------------------------- > > > > ----------- > > > > > > > > > > > -------------------------------------------------------------------------- > > > ------- > > > > Leadfee Mail List provided as a free service by IPC using > LISTSERV > > 1.8d > > > > To unsubscribe, send a message to [log in to unmask] > <mailto:[log in to unmask]> with following text > > in > > > > the BODY (NOT the subject field): SIGNOFF Leadfree > > > > Search previous postings at: www.ipc.org <http://www.ipc.org> > > On-Line Resources & > > Databases > > > > E-mail Archives > > > > Please visit IPC web site ( < > <http://www.ipc.org/html/forum.htm>)> for > > > additional > > > > information, or contact Keach Sasamori at [log in to unmask] > <mailto:[log in to unmask]> or > > 847-509-9700 > > > ext.5315 > > > > > > > -------------------------------------------------------------------------- > > > ------- > > > > > > > > > -------------------------------------------------------------------------- > > -- > > > ----- > > > Leadfee Mail List provided as a free service by IPC using > LISTSERV 1.8d > > > To unsubscribe, send a message to [log in to unmask] > <mailto:[log in to unmask]> with following text > > in > > > the BODY (NOT the subject field): SIGNOFF Leadfree > > > Search previous postings at: www.ipc.org <http://www.ipc.org> > > On-Line Resources & Databases > > > > > > E-mail Archives > > > Please visit IPC web site ( < > <http://www.ipc.org/html/forum.htm>)> for > > additional > > > information, or contact Keach Sasamori at [log in to unmask] > <mailto:[log in to unmask]> or 847-509-9700 > > > ext.5315 > > > > > > -------------------------------------------------------------------------- > > -- > > > ----- > > > > > -------------------------------------------------------------------------- > > ------- > > Leadfee Mail List provided as a free service by IPC using LISTSERV > 1.8d > > To unsubscribe, send a message to [log in to unmask] > <mailto:[log in to unmask]> with following text in > > the BODY (NOT the subject field): SIGNOFF Leadfree > > Search previous postings at: www.ipc.org <http://www.ipc.org> > > On-Line Resources & Databases > > > E-mail Archives > > Please visit IPC web site ( < > <http://www.ipc.org/html/forum.htm>)> for > > additional > > information, or contact Keach Sasamori at [log in to unmask] > <mailto:[log in to unmask]> or 847-509-9700 > > ext.5315 > > > -------------------------------------------------------------------------- > > ------- > > > > > -------------------------------------------------------------------------- > ------- > Leadfee Mail List provided as a free service by IPC using LISTSERV > 1.8d > To unsubscribe, send a message to [log in to unmask] > <mailto:[log in to unmask]> with following text in > the BODY (NOT the subject field): SIGNOFF Leadfree > Search previous postings at: www.ipc.org <http://www.ipc.org> > > On-Line Resources & Databases > E-mail Archives > Please visit IPC web site ( <http://www.ipc.org/html/forum.htm>) for > additional > information, or contact Keach Sasamori at [log in to unmask] > <mailto:[log in to unmask]> or 847-509-9700 ext.5315 > > -------------------------------------------------------------------------- > ------- > --------------------------------------------------------------------------------- Leadfee Mail List provided as a free service by IPC using LISTSERV 1.8d To unsubscribe, send a message to [log in to unmask] with following text in the BODY (NOT the subject field): SIGNOFF Leadfree Search previous postings at: www.ipc.org > On-Line Resources & Databases > E-mail Archives Please visit IPC web site (http://www.ipc.org/html/forum.htm) for additional information, or contact Keach Sasamori at [log in to unmask] or 847-509-9700 ext.5315 ---------------------------------------------------------------------------------