[Robotgroup] lead free soldering advice

[vkonradi]

All consumer electronics sold in Europe are now lead-free, and have been for some time.  And a lot of stuff sold in the US is also lead-free right now, because these products are international in nature.  Any consumer product marked CE for instance must be lead-free.

There were problems at one time with tin whisker growth, and they maybe they aren't 100% solved.  But obviously they are largely solved, since your cell phone works.  Certain long-life items such as telcom equipment are currently exempted and may still contain lead.

Mechanical robustness of lead-free solder, and resistance to thermal expansion difficulties in extreme temperature are still issues.  That's why for instance automotive electronics currently have an exception and may contain lead.

Lead-free solder melts at a higher temperature.  It requires a higher temperature PCB.  Both reflow and wave soldering are a little trickier.  But these are essentially solved problems.

The point of all the above being we don't need to freak out about lead-free.  It is a current reality worldwide.

Hey, lets celebrate the fact that we won't be landfilling nearly as much lead for the acid rain to leach into the soil.

If anyone wants RoHS details, such as the actual European directives, classifications, exemptions, etc. please email me and I'll send them to you.  I have more information on this that you want to know.

----- Original Message ----
From: Def Egge <robodigest at innervate.com>
To: The Robot Group Mailing List <robotgroup at puremagic.com>
Sent: Thursday, May 24, 2007 10:01:34 AM
Subject: Re: [Robotgroup] lead free soldering advice


At 01:42  2007-05-24, you wrote:
>The following message is brought to you by Mr. Poo-Poo:
>
>I was talking to an engineer friend who designs circuit boards for a
>living the other day. He gave me some advice about lead free solder -
>don't use it. Apparently the lead keeps crystalline "whisker"
>formations in check. He said the lead free solder starts to corrode
>immediately after use, and in the process forms microscopic
>conductive whiskers that grow over time, eventually shorting with
>other traces. It is for this reason that the US military forbids the
>use of lead free solder. Apparently they don't want equipment failing
>in the field. Neither do I. Although in truth I rarely use my
>equipment these days anyway, much less out in a field.
>
>Bye now,
>Mr. Poo-Poo
>_______________________________________________
>Robotgroup mailing list
>Robotgroup at puremagic.com
>http://lists.puremagic.com/cgi-bin/mailman/listinfo/robotgroup


How rapidly do these tin whiskers grow?

I understand the continued use of lead-based solders in military and 
satellite applications where mission-critical considerations outweigh 
lead-free considerations.  Certainly, the assured recycling of 
electronic components (the mechanism is left as an exercise to the 
reader) would lessen the probability of exposure to lead, cadmium, 
mercury, etc.

Relatively speaking (compared to the MTBF for individual component 
points-of-failure), how likely are these to be the primary cause of 
consumer-grade electronics failures?  Is the expected useful life of 
your iPod, motherboard, HDTV likely to be affected?


All the best....

Mike


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