Hi,
time is more critical than low temperature.
The slow melting response (as you correctly identified) indicates that you needed more temp.
You need some speed to reduce the conduction of heat down the connections into the device.
Now that you know that the 670degF indication suits 60/40 it gives you a start point for higher temp solders.
time is more critical than low temperature.
The slow melting response (as you correctly identified) indicates that you needed more temp.
You need some speed to reduce the conduction of heat down the connections into the device.
Now that you know that the 670degF indication suits 60/40 it gives you a start point for higher temp solders.
I have finally had a chance to try the new 99,7 stuff. It melts at a considerably high temperature as it has been mentioned, thus requiring everybody to throw their soldering irons away and buy new more powerful ones (who said pollution reduction?!?!?!). However, that's a very small drawback in comparison with the rest, because I can just use a variac to supply 250V or 260V to my irons and get some extra ºC.
The true bad news is that 99,7% solder sticks to component legs in a much poorer way than 63/37, is much less plastic when it comes to apply mechanical stress without cracking it, and it solidifies all at once in a very small fraction of a second (no matter how big the solder joint), thus leading to fissures and "false glueing" very easily.
In other words, solder without lead is mostly unusable for manual soldering and will cause a tremendous increase in failure rates on wave-soldered consumer electronics (leading to more pollution because any piece of consumer equipment that fails has great chances of end up in a dumpster). I will get as much supplies of the reliable 63/37 as I can.
BTW: Yesterday I visited an automotive sound installer and electrician friend of mine that did not know anything about RoHS. He solders 12V wires (and wires to connectors) almost always because that has proven to be far more reliable than mechanical connection approaches (he provides *full*lifetime* warranty against any wiring or installation defect). He had inadvertedly bought some amounts of the new 99.7% solder and was very angry. He was just going to phone the supplier to complain about "very poor solder quality" when I told him about RoHS. He became quite puzzled and told me that the "new" solder that he had just received was sticking very badly to the copper of the wires of the cars and was producing a terrible "false-solder-joint" look!! I even had to try it to believe!! Now he is also desperatly looking for supplies of the reliable 63/37 (and blaming those stupid European politicians).
The true bad news is that 99,7% solder sticks to component legs in a much poorer way than 63/37, is much less plastic when it comes to apply mechanical stress without cracking it, and it solidifies all at once in a very small fraction of a second (no matter how big the solder joint), thus leading to fissures and "false glueing" very easily.
In other words, solder without lead is mostly unusable for manual soldering and will cause a tremendous increase in failure rates on wave-soldered consumer electronics (leading to more pollution because any piece of consumer equipment that fails has great chances of end up in a dumpster). I will get as much supplies of the reliable 63/37 as I can.
BTW: Yesterday I visited an automotive sound installer and electrician friend of mine that did not know anything about RoHS. He solders 12V wires (and wires to connectors) almost always because that has proven to be far more reliable than mechanical connection approaches (he provides *full*lifetime* warranty against any wiring or installation defect). He had inadvertedly bought some amounts of the new 99.7% solder and was very angry. He was just going to phone the supplier to complain about "very poor solder quality" when I told him about RoHS. He became quite puzzled and told me that the "new" solder that he had just received was sticking very badly to the copper of the wires of the cars and was producing a terrible "false-solder-joint" look!! I even had to try it to believe!! Now he is also desperatly looking for supplies of the reliable 63/37 (and blaming those stupid European politicians).
I am most worried about BGA packages, soldering these well was a bit of an art at a manufacturing plant that went as far as x-raying every part. Even with 60/40 we had problems with board flex causing joints to crack.
Consumer devices like car and tv remotes that take a lot of abuse are going to be very unreliable. I have a Clarion car player that uses a single sided pcb for the control panel. It comes ourt once a year for re-soldering.
Consumer devices like car and tv remotes that take a lot of abuse are going to be very unreliable. I have a Clarion car player that uses a single sided pcb for the control panel. It comes ourt once a year for re-soldering.
mzzj said:
Sounds like you have some hippie-friendly flux in your solder
Old resin-based mildly activated flux worked very well with 60/40 but caused lots of allergies for workers. No-clean No-smoke, Antiallergic, hippie-friendly stuff they prefer to use doesnt work so well.
I was part of a test by the Health and Safety Executive on soldering hazards in service departments - apparently the only safety concerns were from the flux used?, which 'may' cause problems for a small number of asthma sufferers. From what I could make out, the potential problem numbers were EXTREMELY small, but prompted the requirement for fume extraction in production environments. The tests (on me and others) proved no requirement for fume extraction in a service environment.
Eva said:
Why use the 99.3/.7 stuff?? It's almost pure tin?? Are we gonna start a whole new wave of whisker and pest failures???
I've used pure tin, tin silver, tin lead, lead indium, all kinds of different solders and fluxes, and I've not found the problems you are mentioning.
I think you are experiencing thermal gradient failures. This is when the heat from the joint is being wicked by colder areas, this raises holy heck with the fluxing/cleaning process as well as differential shrinking.
Cheers, John
OK guys... I just got a RoHS job... 1700 boards... probably be about 150 parts each.
Spent all of yesterday reading up... Basically RoHS is going after the consumer junk. I don't know how it will be for boys in Europe to keep buying 63/37 solder... but it may not be that bad. Their are plenty of exceptions though and not ALL equipment has to be built RoHS compliant.
I think the bottom line is this:
1) Soldering irons with NO temp control are going to be a problem. Soldering irons WITH heat control, and POOR temp sensing (like ALL of them except METCAL), are going to be problematic as well. METCAL is going to be selling alot of irons I think.
2) We have all been spoiled by rosin and solder plated plated components. We will all need to learn about new fluxes etc... I have been doing testing and rework on SMT boards lately. I have only recently learned the joys of working with a bottle of liquid flux nearby to wet things down before you get to work.
3) Good solder joints won't be as shiny.
I'll be sure to report as I go along.
Spent all of yesterday reading up... Basically RoHS is going after the consumer junk. I don't know how it will be for boys in Europe to keep buying 63/37 solder... but it may not be that bad. Their are plenty of exceptions though and not ALL equipment has to be built RoHS compliant.
I think the bottom line is this:
1) Soldering irons with NO temp control are going to be a problem. Soldering irons WITH heat control, and POOR temp sensing (like ALL of them except METCAL), are going to be problematic as well. METCAL is going to be selling alot of irons I think.
2) We have all been spoiled by rosin and solder plated plated components. We will all need to learn about new fluxes etc... I have been doing testing and rework on SMT boards lately. I have only recently learned the joys of working with a bottle of liquid flux nearby to wet things down before you get to work.
3) Good solder joints won't be as shiny.
I'll be sure to report as I go along.
jneutron said:
Believe it or not Sn99.3/Cu0.7 is the alloy that politicians (and their friends at big companies) expect us to use now in Europe, as it's priced similarly to 63/37 or 60/40 and it's the only one widely available to the date, as opposed to others, like Sn96.5/Ag3/Cu0.5, that cost three times more and are quite hard to find. Furthermore, when you order/ask for the classic 63/37 or 60/40, they give/send you the 99.3/0.7 replacement instead, without even asking!!! It seems like nobody is informed!
The 99.3/0.7 melts at 227 ºC, 34 ºC higher than the usual 63/37, and even the ultra-expensive Sn96.5/Ag3/Cu0.5 melts at 217ºC so it's not a great improvement. Furthermore, the oviously poor mechanical properties of these alloys are conveniently left out of every data table that I have seen to the date.
Also, if the useful life of a solder tip is halved each time temperature is increased by 10ºC, how much are the tips going to last now? (Simple math tells at least 10 times less).
Poor or not depends on situationEva said:
I use Sn-Ag-Cu when I need strong solder joints. Sure higher mechanical strengt is a problem in wave soldering etc but mostly its a good thing 2 years or 20years tip life , I dont care. Both of my soldering irons(metcal and hakko) seem to have years of tip life even at higher temperatures.
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