Re: gEDA-user: OT: lead-free question

[Steve Meier <smeier@xxxxxxxxxxxxxxxxxxx>]

There probably are issues that revolve around metal to metal interfaces.
High voltages might cause migration and leave surfaces expossed for
oxidation for example. I suspect that for normal voltage circuits the
true issues are the temperatures that devices can withstand during
assembly. To submit an older device to the higher temperature that is
required by new solders might cause older devices to fail.

Steve Meier


Given that Lead based solder melt at around 190 degrees C and silver
based solder melts at around 220 degrees C the tips of soldering irons
today are around 250 degrees C today  and are expected to rise to >300
degrees C for lead free.


Old part

focus.ti.com/lit/ds/symlink/opa2613.pdf

Max lead temperature 260 degrees C


New Part

focus.ti.com/lit/ds/symlink/buf602.pdf

Max Lead Temperature 300 degrees C






Stuart Brorson wrote:
>>I have heard that there exist lead free components that are not 
>>compatible with traditional lead based
>>processes, but I've yet to see one. In fact, every part that I've seen 
>>has a tin matte plating. I hear this
>>from vendors, but I have never see it (Other than parts that never were 
>>lead compatible even prior to
>>RoHS...). I am beginning to wonder how much of this is FUD..
>>
>>Stuart - Do you know anyone who has actually seen any...?... For that 
>>matter, has anyone on this list *actually*
>>seen it?
>>    
>
>I haven't seen any, but I haven't looked either.  
>
>My day job is at a company which stuck its head in the sand regarding
>RoHS for several years.  Then, we found an opt-out clause in the
>relevant EU directives which our lawyers interpreted as exempting us.
>Therefore, it isn't something I need to actively worry about.
>However, I do try to keep it on my radar screen and read about it when
>I need to.  But I haven no *practical* experience with any RoHS
>processes or issues. 
>
>Stuart
>
>
>