Leaded or Lead free For wave solder Machine

[chris2006]

Hi All

I'm getting myself a wave soldering machine but I dont know which solder to go for

Alot of people dont seem to like the lead free and think the leaded is much better

Then some say the leaded wont stick to the ROHS compliaant components, I'm completely puzzled

[ataradov]

If you are at a point where wave soldering machine is justified, go for lead free, since you are probably a professional.

Leaded solder is much better for hand work, but I would not want to be close to a bath of a molten leaded solder for extended periods of time.

Both solders with both types of components work fine.

[CatalinaWOW]

Since wave soldering was on the way out when ROHS came in I suspect that you will be on your own for characterizing how to use your machine with lead free solder.  Lots of fun to be had learning where to put all of the process variables and controlling the chemistry of the material in the pot.  But if you have volume sufficient to justify wave soldering you won't be able to sell it with leaded solder, unless you are in one of the exempted markets.  Leaded solder will work with all of the ROHS through hole components I am familiar with.

Seems to me that you either use leaded solder or you bought a white elephant or a science project.

[chris2006]

Hi

Thanks for the replies

At the moment the product I'm using is exempt from ROHS but this could change soon

I have been purchasing my boards from another company that uses the leaded solder but have decided to try and go my own way to save costs

The wave machine I am going to purchase has an extraction system to take away the fumes

There are so many lead free solder bars I'm unsure which to purchase

Would these specifications be suitable

Product Type   
Lead-free solder bar
Composition
Sn 99.3Sn-0.7Cu
Melting Point/?
227?
WorkingTemperature/?
280-350?

Or would SAC305 be better ?

Many Thanks

[Neilm]

At the moment the product I'm using is exempt from ROHS but this could change soon

I thought that pretty much all exemptions will have expired by mid - 2019

The only ones left will be where reliable operation is required i.e. military and aircraft systems

[CatalinaWOW]

Yeah, reliability required systems.  Medical systems also, and probably a few more.

[HHaase]

If you're located in the EU  (I know, I know, that's a bit fluid of a situation for you right now),   then I'd start looking at lead-free right from the start.   As you stated, the exemptions are either expired or expiring soon,  so you'll be needing RoHS in the future either way.  Changing over the process can be expensive when you need to drain and refill a pot containing 1000-1500lbs of solder.  That and it's just easier to have an entirely lead-free process thus reducing the risk of mixing in leaded solder or components like can happen if you're running both processes.   Never had a problem soldering with lead solder and lead-free parts,  unless the parts were heavily oxidized.  Your flux choice will also have a huge effect on solder quality.   Make sure whichever flux you use is compatible with the higher temperatures of lead-free solder and be prepared for a BIG learning curve to adapt to the process.  Some PCB substrates can be horrible to get solder adhesion if you've had too much air exposure,  but wave soldering with HASL boards isn't a problem like fine-pitch SMT can be. 

It's a tough call between 100C and 305 for solders.   The 305 is generally more expensive due to the silver content but has a wider process window when it comes to temperature, makes a difference if you have big transformers or insufficient hole size compared to the component leads.   100c is cheaper, has a tighter process window, but is much less aggressive at eating away other metals.  They say it generates less dross but realistically you're going to make a LOT of dross with either type unless you have a nitrogen or other kind of inert environment like the Kirsten style oil bath.  Personally,  I went with 100C when I had to make the same choice.   Cost was a big factor in that choice.

And that's a big kicker you'll need to factor in,  dross.  You can sell that dross to a recovery company, but you're probably going to use up more solder as dross loss than actual production.  You also need to do regular solder samples and from time to time add supplements of trace minerals,  we add a few ounces of Germanium daily at my full-time employer.

[richardlawson1489]

I think lead free solder would be best for you to avoid corrosion of all machine parts that are in contact with alloy.

[Neilm]

Yeah, reliability required systems.  Medical systems also, and probably a few more.

I believe that the medical exemption expires next year.

[Mattylad]

Ideally, look at were your market is and see what the exemptions will be for that.

If it's going to be Mil or automotive (who ISTR will be exempt) then go with whats best for that.

[Mr. Scram]

The only ones left will be where reliable operation is required i.e. military and aircraft systems

The implication that reliability is not required in other systems amuses me.

[mac.6]

The only ones left will be where reliable operation is required i.e. military and aircraft systems

The implication that reliability is not required in other systems amuses me.

Well, aircraft are a different world on their own. Like plane crashing due to timer software overflow? simple: shutdown plane every xxx hours.

[Neilm]

The only ones left will be where reliable operation is required i.e. military and aircraft systems

The implication that reliability is not required in other systems amuses me.

Well, aircraft are a different world on their own. Like plane crashing due to timer software overflow? simple: shutdown plane every xxx hours.

There was a reort of a jet engine system where the user had to do just that - If it hadn't been completely turned off the counter overflowed. They found that out while the aircraft was flying. (fortunately it only affected 1 engine and teh jet landed safely)

[Mr. Scram]

Well, aircraft are a different world on their own. Like plane crashing due to timer software overflow? simple: shutdown plane every xxx hours.

That is not really acceptable for normal world devices either. If someone's phone reboots every day, or if a server does that, most people will consider that unacceptable. Of course, in aircraft, systems are made redundant several times. You can often lose 3 computers and continue without issue.

[Jeroen3]

Well, aircraft are a different world on their own. Like plane crashing due to timer software overflow? simple: shutdown plane every xxx hours.

If someone's phone reboots every day

They'll toss it out, and that is exactly the reason Rohs was invented.

[Monkeh]

The only ones left will be where reliable operation is required i.e. military and aircraft systems

The implication that reliability is not required in other systems amuses me.

Well, aircraft are a different world on their own. Like plane crashing due to timer software overflow? simple: shutdown plane every xxx hours.

There was a reort of a jet engine system where the user had to do just that - If it hadn't been completely turned off the counter overflowed. They found that out while the aircraft was flying. (fortunately it only affected 1 engine and teh jet landed safely)

I seem to recall hearing a story along those lines from a friend of mine who works on aircraft generators for Airbus. He had many very polite things to say about the software team.

[CatalinaWOW]

Aircraft reliability and phone reliability are totally different worlds.  If your phone locks up and requires a reboot once a month you are annoyed, but I and many other people have lived with this level of reliability in a phone.  If an airplane critical system does this there is an excellent chance that you will read about it in the news, with lawsuits to follow.  Even though there are examples of lockups in aircraft systems, the reason you and I are aware of them is they make headline news.  No one thinks they are OK, or a minor annoyance.

Another huge difference is that there are relatively few people in the world using a twenty year old phone, and an even tinier percentage using a twenty year old phone with significant electronic content (a wireless phone or cell phone).  But it is common to see twenty year old airplanes in use, and the average age of airplanes in use is measured in decades.

[Mr. Scram]

Aircraft reliability and phone reliability are totally different worlds.  If your phone locks up and requires a reboot once a month you are annoyed, but I and many other people have lived with this level of reliability in a phone.  If an airplane critical system does this there is an excellent chance that you will read about it in the news, with lawsuits to follow.  Even though there are examples of lockups in aircraft systems, the reason you and I are aware of them is they make headline news.  No one thinks they are OK, or a minor annoyance.

Another huge difference is that there are relatively few people in the world using a twenty year old phone, and an even tinier percentage using a twenty year old phone with significant electronic content (a wireless phone or cell phone).  But it is common to see twenty year old airplanes in use, and the average age of airplanes in use is measured in decades.

If only you knew how many things go almost wrong in aviation every day. That doesn't end up in newspapers, so this would neither. That's why they came up with redundancy in the first place. If you spend some time on an airport with the crews you hear all kinds of weird and wonderful things you never wanted to know.

Most aircraft parts have a predetermined operational life, after which they are discarded, even if the part seems to be fine. Even the hull is subject to this. Nothing is left to chance. That 20 year aircraft is probably mostly comprised of newer parts and has seen a series of full overhauls, where everything gets torn down and rebuilt.

[CatalinaWOW]

Aircraft reliability and phone reliability are totally different worlds.  If your phone locks up and requires a reboot once a month you are annoyed, but I and many other people have lived with this level of reliability in a phone.  If an airplane critical system does this there is an excellent chance that you will read about it in the news, with lawsuits to follow.  Even though there are examples of lockups in aircraft systems, the reason you and I are aware of them is they make headline news.  No one thinks they are OK, or a minor annoyance.

Another huge difference is that there are relatively few people in the world using a twenty year old phone, and an even tinier percentage using a twenty year old phone with significant electronic content (a wireless phone or cell phone).  But it is common to see twenty year old airplanes in use, and the average age of airplanes in use is measured in decades.

If only you knew how many things go almost wrong in aviation every day. That doesn't end up in newspapers, so this would neither. That's why they came up with redundancy in the first place. If you spend some time on an airport with the crews you hear all kinds of weird and wonderful things you never wanted to know.

Most aircraft parts have a predetermined operational life, after which they are discarded, even if the part seems to be fine. Even the hull is subject to this. Nothing is left to chance. That 20 year aircraft is probably mostly comprised of newer parts and has seen a series of full overhauls, where everything gets torn down and rebuilt.

As a lifelong aerospace fanatic, lifelong reader of AV&ST, retired aerospace professional, and father of an aerospace engineer and a certified A&P mechanic I can attest that all you say is true, but still assert that the required level of reliability is an entirely different thing in aviation than it is for consumer goods.  The fact that anomalies occur in spite of the intensive and expensive efforts to prevent them is why those who design aerospace systems (and presumably other systems which have high impact on human safety/well being) are so nervous about deliberately accepting known risks to reliability - like ROHS.  When Murphy is so effective at making the things you didn't know about go wrong, why be casual about the things you do know about?

[Mr. Scram]

As a lifelong aerospace fanatic, lifelong reader of AV&ST, retired aerospace professional, and father of an aerospace engineer and a certified A&P mechanic I can attest that all you say is true, but still assert that the required level of reliability is an entirely different thing in aviation than it is for consumer goods.  The fact that anomalies occur in spite of the intensive and expensive efforts to prevent them is why those who design aerospace systems (and presumably other systems which have high impact on human safety/well being) are so nervous about deliberately accepting known risks to reliability - like ROHS.  When Murphy is so effective at making the things you didn't know about go wrong, why be casual about the things you do know about?

We're straying a bit off-topic here, but the point was that it is amusing that in areas other than aviation, operation is implicitly deemed non-critical. These areas include medical and communications equipment. Obviously, it is easy to imagine how even the most mundane telephone could save a life under the right circumstances. Let's not even get started on medical equipment. And yes, I do very much understand the need for RoHS. Little bits add up.

[mac.6]

Back on ROHS solder, I just tried Sn100+NiGe from Felder, it' s a Sn99Cu1 solder with addition of Nickel (for fluidity) and germanium (prevent oxydation and micro-cracks).
Very nice solder, in fact the best lead free I ever used: nice shiny solder, good wettable, their clear flux is very nice to work with (no splatter, low fumes). Not as pleasant to work as SnPb, but close.

I have seen on manufacturer site that it is also prefered for wave soldering as germanium reduce dross formation, so maybe to try. It's also cheaper than Ag type solders.