[robomartin]

> It's the kind of stuff we should be embarrassed not to understand.

We understand it. Onset is stochastic. Mitigation is impossible given current regulations in consumer-land. Read my longer comment for further details.

EDIT: What I mean by "we understand it" is that we know that lead-free solder chemistry leads to tin whisker growth. When I was taking a deep dive into this many years back, the researchers I was working with at NASA told me "Growth onset can be 0 days to 3 years after manufacturing. Your guess is as good as mine.". And, BTW, you can have growth start in a few days in one corner of the PCB and a few months later elsewhere. It's a complex relationship of materials properties.

We know that tin whisker growth in lead-free solder is as much of a reality as gravity is between two celestial bodies. In other words, it will happen. We simply have no way to predict when or how quickly they will grow. It might just be too complex to compute/predict given the variables involved.

[gowld]

That sounds like not understanding it.

[robomartin]

Not quite. We understand that we can't build an anti-gravity device and don't even know how to go about thinking of one. Understanding that something is impossible (or likely impossible) is understanding. We might not like the answers (I sure didn't at the time) yet they are a based on knowledge and decades of research by some of the smartest scientists I have ever met.

[hulitu]

There are parts of the process which we do not underestand. Testing is expensive especially at this level and nobody wants to pay for things which _could_ happen.