Lead-Free (RoHS) and Reliability

[PeteS in CA]

Here is a page with several articles that deal with the reliability concerns in lead free components and assembly processes. While problems like CrapCaps are probably bigger, lead-free components and solder processes may cause even more headaches for users.

[japlytic]

Re: Lead-Free (RoHS) and Reliability

Another issue I have thought about is soldering irons. There should be a dedicated soldering iron for lead-free solder, and one for regular solder. Service centers should also be aware of equipment using lead-free solder before they even start soldering.

[PeteS in CA]

Re: Lead-Free (RoHS) and Reliability

The iron for the lead-free solder will have to be set to a higher temp, as that type of solder has a higher melting point. And of course, the bureaucrats "know" that components and PCBs won't be damaged by the extra heat during assembly and rework. I suspect RoHS-compliant products will have a special label to go with all the other safety agency marks and EMC compliance labels.

[arneson]

Re: Lead-Free (RoHS) and Reliability

Lead has it's place in certain applications, batteries have lead, solder has lead,pencils have lead.
This works for me. Lead in food, no, lead in housepaint, no ,lead in gasoline again, no.

Being one of those who for years have inhaled the fumes directly off the end of a hot iron, I jumped on the lead free solder. It would not melt and flow no matter what I tried. Maybe it was an early formula but it just seemed wrong so I threw the roll away.

[MD Willington]

Re: Lead-Free (RoHS) and Reliability

Pencils use graphite and polymers...last real LEAD pencil I used was in the 80's that I received from a Russian exchange student in elementary school...

[arneson]

Re: Lead-Free (RoHS) and Reliability

There's no lead in your pencil.
Oh no you dinin just say that.
Ha

[japlytic]

Re: Lead-Free (RoHS) and Reliability

I suspect RoHS-compliant products will have a special label to go with all the other safety agency marks and EMC compliance labels.

There should be at least a notice on each circuit board containing lead-free solder eg. "NOTE: LEAD FREE SOLDER IS USED ON THIS PCB - REFER TO SERVICE MANUAL FOR CORRECT TYPE OF SOLDER TO USE"

[PeteS in CA]

Re: Lead-Free (RoHS) and Reliability

Ah, the joys of, "Make it so!" bureacrats.

[gonzo0815]

Re: Lead-Free (RoHS) and Reliability

yes that will getting nice in EU, in several months only RoHS-compliant products will be availiable. I think especially TV`s and all kind of stuff which ist getting hot will lead to many failures. You can hardly differ between a cold solder point and a good one, with leadfree solder. But of course, thats not even the worsest regulation of Brussels bureaucrats .....i am sure, in 10 years it`s better in EU to be jobless. That would be the only posibility to not brake a law.... but ok, now we are leaving elektronic`s an wennt offtopic.

The funny thing i am sure, will be the whole cheap elektronic crap, which swaps from China to allover the world. It`S the same with UL, CE and VDE labels. E.g. I´ve opend an Powmax 420w psu, and i can`t find any x2 or y caps...instead simple ceramic ones. But the PSU has all required labels.... I could imagine, a service center repairs such an unit stated RoHS-compliant with the lead free soldering station....the that station was lead free....

[kc8adu]

Re: Lead-Free (RoHS) and Reliability

There should be at least a notice on each circuit board containing lead-free solder eg. "NOTE: LEAD FREE SOLDER IS USED ON THIS PCB - REFER TO SERVICE MANUAL FOR CORRECT TYPE OF SOLDER TO USE"

no.
a logo of a part being replaced with a circle/slash and another of the unit being tossed into the trash.

[willawake]

Re: Lead-Free (RoHS) and Reliability

i was curious why goot talk so much about the tips in their lead free RX-802AS.

Well the most popular lead free solder is SnAgCu otherwise known as SAC. This melts at about 217oC which is about 34oC higher than good old 60/40 tin/lead solder at 183oC. It is recommended to heat it to 40oC above the melting point. Other lead free range from 215-217oC

actual tip temperatures are about 343oC for lead free and 315oC for leaded. you might be wondering why we remove caps around 450oC, well the large ground planes in the motherboards, particularly p4 and later draw heat away from what you are trying to heat. ideally you should turn the iron down when you solder the new caps in but high temp with minimal dwell time doesnt seem to damage the new caps.

anyway one of the factors with lead free is increased temperature affecting tip life. that wont really affect us because we are soldering at higher temps already. it will be interesting to see if lead free soldering will not be possible at 450oC because more emphasis is placed on the flux.

unfortunately lead free solders have slower wetting so will require more active and corrosive fluxes and more amounts of them in the solder. this will also increase solder and flux spattering. they also require cleaner surfaces and longer dwell time.

tips for soldering are copper (high thermal conductivity) with iron plating (maintains the shape and prevents copper dissolution) but iron has poor thermal conductivity so is thin and all plating has defects. with the higher tin content of the lead free solder, the tip has shorter life because iron leaches or migrates to tin.

as regards to the person using the lead free solder, will it be more healthy? well actually the more agressive flux used will increase the requirement for fume extraction. there is actually no lead in fumes anyway, but it is not good at all to breathe flux.

will good old 60/40 continue to be available : yes

how do lead free joints look like?



lead



lead free

basically they look like cold solder joints need more info on how to spot bad lead free joints.

also apparently lead free solder is unforgiving and it is important to keep the iron tip very clean.

[Galvanized]

Re: Lead-Free (RoHS) and Reliability

I did read PeteS link in total. It was reminiscent of trying to read my brother's ASME Journals (metalergical engineer). Several of the internal links got my attention but one thing has me puzzeled.

Say caps are removed from a lead free board, What could/would happen to the joint if 60/40 were used to install new caps. Would the joint be satisfactory? The advantage would be less dwell time and less heat soak for the cap. Mmm.

I use to be pretty fair with gas, TIG & stick welding and this question came to mind. I know proper prep of any joint is very important and it's only a matter of scale.