TIN/LEAD SOLDER & CHANGES UNDER EU REGS

RoHS products are being manufactured all over the world.

try Googling "rohs manufacturing"

Blimey, you are a bit late...

Just about everyone went over to lead free last year.(There are some exemptions e.g.Military I believe.)
Ah, I remember the good old days when solder melted and circuit boards would tin.

Actually it's all settled down now and the few teething troubles have been ironed out. Any supplier these days should be lead free.

_{(Don't tell anyone but I've got a reel of the old solder on my bench 'cos it's so much quicker and easier for prototyping...shhhhh)}

Del

For those of us in the military / space world, RoHS is just something that happens somewhere else. We're still inhaling those good old lead solder fumes, and our components still come with tin/lead soldered legs. It makes it hard to buy anything COTS, though.

Thanks guys,

Sleepy by name and Sleepy by Nature. If I were still at work I would be driving the change but I am not! So I am responding to cries from colleagues who have been similarly shocked and surprised!

There must still be problems.

1 Is everything sorted to use other types of Solder?

2 Is there one solution or many.

3 What is the preferred solution.?

4 If there is something to read which gives chapter and verse that would be good.

5 Presumably we have to change soldering Irons, solder and processes?

Also components and PCBs tinning of items to be soldered.

So if the above is catalogued and specified as to how and what with etc, that would be good to read.

I still come back to my other problem, how do we repair or modify older equipment?

It sounds like a lot of more throwing away - which is OK where we can afford it but where you cannot, how do we modify or repair both old and new equipment?

Cannot help the recycling game!

Particularly how do we modify/repair older equipment i.e more than a year old?

You hint Del That there are exceptions for the military; I can understand having worked in these fields myself but they, therefore, must have access to solder and other relevant materials. I presume that the military have a limited licence in this; they will have to go lead free eventually.

I am interested in how people like Radio Hams manage, often they have older kit to either keep going or to modify and there must be other areas maintenance of Electronic Organs and I could go on and on.

I have concluded, perhaps erroneously, that you cannot repair tin lead solderd equipment with silver solder or whatever the new solution is - unless someone has found a way?

In the last 72 hours I have talked to a lot of people who have a real concern in this matter, many have the odd few inches of tin/lead solder left and are using it very sparingly but do not know how long they can continue.

Who can I speak to about this - in Industry, in Government.... I have been officially retired for some years now and old contacts do wither unfoirtunately!

I would be grateful for any further thoughts, ideas, direction.

Thanks

Very Sleepy!!

Answers

1 Pretty much YES, as long as you sort out some of the other answers.
2 Many, but you will find a PBC supplier will generally have a preffered type of solder...you can't keep re-filling a flow solder machine. This was a big problem initially for these guys, as , until their bigest custome decided which solder to use they couldn't risk filling the bath....and of course no one would recomend which solder was best. Clasic catch 22.
3 See 2...the preferred solution is what everyone else uses. and by definition everyone uses the preffered solution!
4 Yeh, you sleepy git...use the internet like we did...check sloder manufactures web sites..phone a rep' get off your butt , talk to pcb suppliers etc.
5 If you have temperature adjustable irons you are ok. You will probably want new bits.

You can still repair using old solder...there may be migration issues and such...but like I say I keep a reel of the 'good old stuff' on my bench.

I dunno how you stayed away from this prob sooo long... but by now it should be very easy to just jump on board.

Del (must go have a cat nap )

Military usage of components, they don't go for the newest or greatest components, or soldering, if it works, don't change it (unless those obsolete TTL's are out of stock)

Here in the PCB testing industry, I am only lately seeing surface mounted components on Military PCB's, they are mostly thru hole and ceramic chips, but there are more of the later plastic chips starting to flow thru.

In the case of Soldering, there are still many issues, heat is the 1st, where components cannot be just put into the "Lead-free" enviroment as the soldering temperatures are quite a bit hotter, and that kills them, but there is also the problem of whiskering.

Whiskering is when you have a component soldered to a board, and little whiskers grow out of the solder joint.

Imagine a missile thats just launched, and the vibration moves a whisker and kills part of the targetting hardware, or worse, the detonation circuit, and the thing detonates in the launcher

With components getting smaller and IC's going to BGA's with a finer pitch denisty, a fine whisker can give no end of problems.

Or in Radio transmission circuits, all these little antennae growing inside your transmitter circuit sucking the power.

Also for board testing, you have to change your probe head style to a "Lead-Free" compatable head, as the older heads are too soft, and the life of your probes is sevearly dimished when they hit lead free solder.

Changing to Lead Free was a knee jerk reaction without understanding the consequances of the change, the Governments decided to go Lead Free in the belief that is would be a simple change over

As I understand it, Lead-free actually has ~8% Lead in it. FWIW.

Your question exposes a huge "can of worms" that many have struggled with. Temperature is the first hurdle that everyone sees, but that can be overcome with addition of other (rather exotic) materials that can provide lower melting points for the "solder" that is being used.

One common additive is Bismuth.

The huge variety of solders that have been introduced means that repair is fraught with reliability risk. The use of a "different" solder to perform a repair introduces potential brittle interfaces, especially when lead in any form is mixed with the non-lead solders.

Solder pad preservation for good soldering results has led to new "protective" coatings applied by the board manufacturer and designed to be removed by the soldering process. Some of those have restricted shelf life and some are unsiutable for what would be considered normal inventory handling. Like once OSP has been through one solder cycle, you'd better hope any additional soldering (like double sided SMT) is done within hours of the first pass.

Fluxes seem to be more aggressive, leading to cleaning concerns and then contaminated residue from that.

While lead may be a "nasty" material, I have real concerns relating to some of the other chemistries that are being used and the metals used in those. Relative to lead, some have very poor environmental credentials, but are "OK" since they are not lead.

And the final straw in my frustration with the change is the "smart alleck" companies that have patented specific solders. We know that solder baths and solder wires in general use change composition as the material from component leads dissolves during normal soldering process. The patents have been taken so that the "better" mixtures convert into these patented variants. (I won't rant on this, it's just a frustration)

The ultimate answer is to eliminate the material from the waste (garbage) stream so that all lead and such is recovered and then the solder that we have come to love and understand could still be used.

By the way, why was the old lead/tin solder chosen for electrical work?

I suspect it wasn't necessarily the best choice, just that when electrical experiments were happening way back in "the good old days" lead/tin solder was the cheapest available material (from the plumbers of the time) to joint copper, brass and tin plated components together. It worked and so no-one ever bothered to change it. (Except for the subtle 63/37 issue instead of 60/40)

Hi Guys,

"By the way, why was the old lead/tin solder chosen for electrical work?"

This combination of metals was chosen because it has the lowest melting temperature vs electrical conductivity which made fabricating components a little easier (plastics didn't were easier/cheaper to produce if they didn't have to be high heat resistant). At least, that's how it was explained to me by a university teacher way-back-when...

ROHS is good for the "BIC" products (all stuff made to be used and thrown away) but cannot be relied on (at least until now) for long term items. I'm in the simulator business and we have the same extension as the military and the aviation industry and it is all due to the longevity of our products (20+years) versus the whiskers.

When you think that the electronic industry comprises of only a few % of lead vs the lead battery industry which is almost totally lead, it becomes very hard to comprehend why we (electronic) have to adhere to this while they get a free pass for at least the foreseeable future.

Well, as it has been mentioned, RoHS is done and past, and everything we manufacture is now RoHS compliant ... Lead, plus 5 other 'nasties'.

BUT, as my tag line says, now 'they' have changed all the questions, and the restrictions are changing rapidly.

In the beginning of RoHS, the rules were 'fuzzy', at best, and few had the ability to measure, and fewer had the ability to regulate. Lots of certification labs made a lot of money, and suppliers were strong into the profit-taking mode. Almost all commodities went up on cost, and, because the RoHS directive was not world-wide, many brands chose then NOT to comply. It was hell for a while, keeping the RoHS and the non-RoHS inventories straight. Fortunately, today, all that has settled down, and everything is RoHS compliant.

Of course, there was an ever-changing list of products and groups who were exempt from the RoHS directives, because there was no way for them to comply (almost anything with a battery, for instance.)

During the same period, there was another directive, ELV, asked for a listing of all these same 'nasty' 6 by weight, so at the time of 'disposal',or End of Life, the disposer would at least know what was 'inside'.

Now, I have just learned, there is a new European agency, REACH, who asks for a COMLETE LIST OF ALL CHEMICAL COMPONENTS INSIDE ANY HOMOGENIOUS PART.

In Tandem with this, the major automakers are pushing the same under the heading of IMDS, or International Material Data Sheet.

Finally, there is a US IRS tax edict that actually taxes based on the use of Ozone Depleting Chemicals ANYWHERE in the manufacturing. I make a consumer product, I injection mold the ABS, I purchase the ABS pellets, the ABS converter buys raw materials ... sooner or later, down the food-chain there is crude oil, and if ANYBODY used any Ozone Depleting Chemicals, I'm supposed to report it.

We all want a safer planet ... I do ... but, after spending hundreds of man-hours documenting for only 6 substances and FINALLY (I think) getting all that under control, I'm not sure what it will take to comply with all these new laws.

We will ... we must ... just a major challenge.

Oh, and regarding your specific question about sorting out pre-RoHS and post-RoHS, at the PCB level, there is supposed to be an RoHS label. If you are repairing a pre-RoHS PCB, I'm not sure if even you CAN use lead-free solder. You are correct about temps.

It will be a PITA for decades, but still worth it, I think.

Take care ...

I work in the medical industry where the lead solder has not been banned yet. We have customers that insist in a leaded solder process to be used on ROHS compliant components for reliability reasons. Also the visual inspection of the solder joint is much easier with leaded solder.

Recently I came across an interesting article about the military industry:

http://mae.pennnet.com/articles/article_display.cfm?article_id=317447

We are still using tin/lead solders, there are exceptions in the EU rules that allow this for high volt applications. Our experience has been that we had problems with circuits not working as they should when soldered lead free. One problem identified was that the lead free flux seems to be slightly conductive.

Our PCBs are a bit unusual in that we might be taking 5 or 12 volt inputs & producing several outputs from a few hundred volts up to 30kV, currents are microamps & the boards are very sensitive to minor changes.

A reel of solder purchased in June 2008 from Maplins (usual disclaimer) claims to be a tin/copper mixture. It has worked well on electrical joints since beginning use of it. It seems to be resistant to the actions of Carr's Red Label flux (usual disclaimer) on brass-to-brass structural joints and a change to Carr's Orange Label is on the cards.

Thanks PWSlack,

Hmmm,

as of today, Maplin are refusing to acknowledge that tin/lead solder exists, it has disappeared from their product catalogue leaving quite a wide mixture of other solders available.

So I am still bothered, where do the Military, medical, space etc users get their supplies? There has to be a source which is approved for said uses.

And no Del, I have not had time today to spend on more than a few hours of seraches trying to catch up with you all!!

Thanks

Sleepy

Hello sleepy,

Tin lead solder still exists. Plumbers are still able to get 500g spools for pipe work.

Our facility is producing for an RoHs exemp market and we process around 10Kg of bar solder and 1Kg of wire solder per day. (All of this is the lead based material)

We have been ready to convert to lead free since 1998 and have our roadmap in place, but reliability risks/issues with tin whiskers and dendrites means that our customers require us to continue using lead based solder.

Someone mentioned IMDS system used for automotive industry. That is a great system when you get into it. All the component parts are already in there, along with other raw materials. This means that by inputting your BOM, the raw material "tree" is imported from those that have already done the hard yards. We've been in that system for three or four years now, entered information for some of the grades of steel used in springs and other components that we use and now those raw material "recipies" are available for any other user.

On the subject of lead in solder, per my previous note, 60/40 or even 63/37 may not have been the best choice all those years ago. The metalurgists around the world have made fantastic progress in this area in the last 15 years and soon the issues relating to the alternate solders will be solved (and prooven reliable).

The ultimate solution however is to eliminate the material from the scrap system and recover the inputs. If that is done properly, then the composition of solder is of little consequence.