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Why not use lead-free plumbing solders in electrical applications?

Joseph Holmes

#11683

Why not use lead-free plumbing solders in electrical applications? | 27 April, 1999

Another basic soldering question. I notice that lead-free solders have become required for plumbing applications due to legislation. In a local hardware store, I noticed the existence of lead-free solders (based upon tin-copper I think) with a melt temperature of 410-415 Farenheit. Why aren't these lead-free solutions adopted by the electronics industry? There must be very different requirements. Please let me know.

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Justin Medernach

#11684

Re: Why not use lead-free plumbing solders in electrical applications? | 27 April, 1999

| Another basic soldering question. I notice that lead-free solders have become required for plumbing applications due to legislation. In a local hardware store, I noticed the existence of lead-free solders (based upon tin-copper I think) with a melt temperature of 410-415 Farenheit. Why aren't these lead-free solutions adopted by the electronics industry? There must be very different requirements. Please let me know. | Joseph, They're already out there my man. These things exist. The goal is to go to a lead free PRODUCT. Not just solder, but the whole PRODUCT. That's where the delay is. I believe Nokia is making Lead Free Phones. I could be wrong but I know it's one of the major cellular mfrs. I think TI has a huge budget invested in this as well. Lead free changes everybody's process. Is it worth it? Hell yes. Keep that stuff in the ground where it belongs. Component mfrs., assembly houses, board shops, everybody involved has to go lead free. It's a comin' and it's not that far away.

Regards, Justin

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#11685

Re: Why not use lead-free plumbing solders in electrical applications? | 27 April, 1999

| Another basic soldering question. I notice that lead-free solders have become required for plumbing applications due to legislation. In a local hardware store, I noticed the existence of lead-free solders (based upon tin-copper I think) with a melt temperature of 410-415 Farenheit. Why aren't these lead-free solutions adopted by the electronics industry? There must be very different requirements. Please let me know. |

Jospeh,

Lead is the stuff in the solder that gives it ductility. Those tiny little joints actually take lots of stress when the components heat up in power cycles. The lead allows the solder joint to comply without cracking. The tin is what makes the nice bonds with the copper. The trick to finding a lead-free solder alloy is not to get one that bonds well (fairly easy - tin), or to get the exact right melting temperature (not too tough - use different %'s of alloys), but to get one with the right mechanical properties - that's the tricky part.

My guess is that plumbing applications don't have nearly as stringent requirements for thermal-stress cycling as electronics assemblies. So lead-free alloys for plumbing don't have to meet as many demands to be viable alternatives to the infamous Plumbum.

The best lead-free electronics solder right now is an alloy of four metals that's made by AIM. Lots of people are licensing it. I'll bet that's what's in those phones Justin is talking about. And he's right on with the point of needing not just a solder, but a product. Printable pastes with manageable profiles and good reworkability and data on extended life cycle tests and so on and so on.

Chrys

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Bernard Mulcahy

#11686

Re: Why not use lead-free plumbing solders in electrical applications? | 30 April, 1999

| |Hi all

This Debate on lead free soldering is really hotting up here in Europe. From 2004 the use of lead in components and assemblies will be banned here. Also flame retardent halogens will be banned(FR4 etc). While we all agree that we have to move away from lead the big problem is cost- changing processes, new equipment etc. and the fear that manufacturers will simply move their operations to countries with less stringent enviromental laws. But as Justin said 'its a coming' so the industry better be prepared. By the way the lead free phone is made by Nortel.

regards

Bernard

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Steve Gregory

#11687

Re: Why not use lead-free plumbing solders in electrical applications? | 30 April, 1999

| | |Hi all | | This Debate on lead free soldering is really hotting up here in Europe. From 2004 the use of lead in components and assemblies will be banned here. Also flame retardent halogens will be banned(FR4 etc). While we all agree that we have to move away from lead

Hi Bernard!

Well, this is a rather sore subject with me, because I truely believe that what once started out with the noble purpose of reducing or eliminating the toxics of lead, after I started looking closely at the whole issue, that can't possibly be the REAL reason.

I challenge any of you that is reading this, tell me that if we were all to stop using lead this VERY MINUTE, what difference it would make in our planet's problem with lead?

Use the INTERNET and find what percentage of lead our industry uses in comparison to the other industries...you'll see the same thing that myself and many others have discovered, that we use one fraction of a percent!

I don't know about anybody else, but in speaking for myself, the lead I use is logged, kept track of, and goes nowhere else but on printed circuit boards. Any other lead contaminated waste that I generate is recycled (dross), or disposed of properly as any hazardous waste should be.

Kids or people don't chew on printed circuit boards, so where are we contaminating the environment? There's studies done to show that any of the alternatives are JUST as TOXIC to the environment, maybe even more so!

I have a article that was published in SMT magazine as well as being presented at the Printed Circuits Expo in Long Beach that was done by engineers from K*Tec electronics that illustrates that point.

Another issue, is components. How many component manufacturers do you know that are using something other that tin/lead for the solderable surfaces? The only one I'm aware of that does it in a big way is Texas Instruments. How many threads have ya'll read about people having problems with their palladium finish? Temperature is another thing, most of the alternatives require that we'll have to use higher temperatures to reflow. As it stands now, many component vendors tell you that if you exceed 230-degrees centigrade all bets are off as far as guaranteeing reliability.

I wouldn't be so against something so sweeping as changing a primary substance that we all use in the products that we build and manufacture, if it would REALLY make a difference in the problem of lead pollution, or if someone could prove to me that by doing what we do REALLY contributes to the problem.

Everybody knows that lead is toxic and we shouldn't ingest it...hell, any 12-year old kid knows that. But I think the push to "lead free" lacks any real data that shows by doing what we are doing is harmfull.

Still, the train is coming and going to turn this industry upside down and create so many other issues that I'll bet when the train finally is running over us, we'll wish that it never happened!!

My humble opinion...

-Steve Gregory-

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