Re: gEDA-user: RoHS compliant fab & assy drawing notes

[Karel Kulhavy <clock@xxxxxxxxxxxxx>]

On Wed, Nov 30, 2005 at 10:23:37AM -0800, joeft wrote:
> 
> I have found similar info as what Steve has noted.  Many vendors are letting their parts automatically "roll over" to lead free compliant versions.  This means that if you manufacture something now (during the transition) you will have a mix 
> of RoHS and non-RoHS compliant parts.  Some will solder better than others depending on your assembly shop's process.  And you might find this leads to extra documentation overhead should someone want to know what your compliance status is down the road.
> 
> Lead free solders will be mostly tin with a small amount of other metals (usually bot not always silver), and they will indeed require higher soldering temperatures.
> 
> Board materials and plating will have to change if you were using HAL,
> as Steve points out.  Many shops will not have gold available as a
> plating option however and will use matte tin instead.  This brings
> into play the "tin whisker" problem which it seems not everyone has
> solved yet.  Gold does not always solder as well as you might like
> since it can actually diffuse out into your solder.  Unless your shop
> uses some really bizarre fire-retardant, the plating should be the
> only board material problem.

Do the whiskers form even if you solder under molten colophonium?

CL<