RoHS compliance - having a good impact or not?

[M A V I C]

A friend of mine has been discussing a dead game console with another friend who was one of the main people who diagnoses console failures for the manufacture. It turns out his particular console failure was due to a common problem that has caused many of them to fail.

The root of the issue turns out to be RoHS compliance. Apparently the solder on the PCB has less lead in it to be RoHS compliant, and thus is less flexible. As the PCB heats and cools, eventually the solder cracks. Previous versions of this console were not RoHS compliant and thus didn't have this issue. While some of these consoles are repaired when this happens, most are thrown in the trash.

And that strikes me as odd. While the goal of RoHS was to cut down on toxic electronics being trashed, at least this implementation of it has greatly increased the rate at which PCBs fail.

I don't know enough about solder to know if there was some better way to do it. But I'm curious if anyone knows of any studies that have been done to see if this initiative is successful or not. From the numbers I've found, it seems like if the failure rate increases by more than about 2.5x, on average that means more lead (for example) end up in the dump than previously.

[Forrest]

First I want to clarify one thing - RoHS means there is NO lead in the solder - zero. Older, non-RoHS electronics typically used solder that was 63% tin/ 37% lead or 60% tin/ 40% lead.

RoHS also bans the use of a number of other chemicals/compounds that are dangerous to the environment.

If assembled properly, RoHS consumer electronics devices should last the same amount of time as their predecessors. The exception is devices that experience high-G's (think dropping a cellphone or aircraft). There are studies that show a dramatically DECREASED life in these applications - which is why the military, NASA and aircraft manufacturers have continued to require leaded solder.

[M A V I C]

Forrest wrote:
First I want to clarify one thing - RoHS means there is NO lead in the solder - zero.

Then why does the wikipedia say "The maximum permitted concentrations are 0.1% or 1000 ppm"?

If assembled properly, RoHS consumer electronics devices should last the same amount of time as their predecessors. The exception is devices that experience high-G's (think dropping a cellphone or aircraft). There are studies that show a dramatically DECREASED life in these applications - which is why the military, NASA and aircraft manufacturers have continued to require leaded solder.

So your saying the solder problem in the consoles is more so due to them being assembled improperly?

[JoeH]

I would say improper assembly and/or failure to change the assembly to take into account the lower flexibility of the near-zero lead content solder. Circuit boards that flex less, or have more supports to limit flexing are the way to go. Just changing out the solder to lead-free solder might meet RoHS, but is not sufficient to make a durable assembly.

[Forrest]

>0.1% maximum lead. I guess you and I can argue - but I'd call than zero. The old standard was 36% to 40% lead in each solder joint. Depending on the size of the circuit board - we're talking at least a few ounces per board.

I'd bet that RoHS assemblies made today probably last longer than those made 5 years ago. Yes - some far east manufacturers have been making them for than long. The fluxes and RoHS solders of 5 years ago required more process control and were more difficult to use than those made today.

[Racer X]

M A V I C wrote:
[quote=Forrest]
First I want to clarify one thing - RoHS means there is NO lead in the solder - zero.

Then why does the wikipedia say "The maximum permitted concentrations are 0.1% or 1000 ppm"?

If assembled properly, RoHS consumer electronics devices should last the same amount of time as their predecessors. The exception is devices that experience high-G's (think dropping a cellphone or aircraft). There are studies that show a dramatically DECREASED life in these applications - which is why the military, NASA and aircraft manufacturers have continued to require leaded solder.

So your saying the solder problem in the consoles is more so due to them being assembled improperly?
the vibrations and Gs generated during a space launch will break all but the most stringently designed components.

I worked on something that was subjected to 14,000Gs+. Yes fourteen thousand. It was causing insulation to strip off wires just like an old pair of socks falling down. Its a whole nother world.

Or a Navy fighter doing a carrier launches and landings.

I bet some 3rd party supplier, or outsourced assembler just thought they could swap out the solder and come in as lowest bidder. They got the contract, and with minimal thermal cycles they did pass quality control. Then the consumers did their own thermal cycling and vibration testing when the kids got their hands on them. My co worker worked at Nintendo building prototypes. They took stuff home and let their kids beat on them.

[Dick Moore]

I can tell you that repairing lead-free solder joints is very difficult regardless of how you do it, primarily due to lack of "wetting" at the joint. The joints are all ugly for sure. I think the failure rates of boards have increased and the repair rates of boards have dropped significantly. It's making me cautious about refurbs.

[mattkime]

>>It's making me cautious about refurbs.

non-sequitor?