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First documented case of tin whisker formation

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Being a typically efficient Swiss based company Swatch start... - May 11, 2006 by Patrick Bruneel  

The link is broken. ... - May 17, 2006 by

#41486

First documented case of tin whisker formation | 11 May, 2006

Being a typically efficient Swiss based company Swatch started the task of RoHS conversion a year ago.

After 2 years of intensive research they implemented the process in mass production in June 2005, they started shipping and found massive problems with reliability due to tin whisker growth which caused them to stop shipping. They believe that this will be a problem with any pitch under 800 microns. They have switched back to tin lead solder, and have applied for an exemption the document is on public display at the EU web site.

Here's the link (you might have to try the link a couple of times the website is overloaded)

http://forum.europa.eu.int/irc/DownLoad/kseuATJFmmGCYxhSFE-5-dGmGt00dDlCqy3SRU-6gcnHB8-dCc0uQfZZNR6Fh-q9f433CHrobI-EmI60rCg0wc8E/A-1018%20Swatch.pdf

You might want to visit john's http://www.rohsusa.com for updates and latest info on lead-free

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#41489

First documented case of tin whisker formation | 11 May, 2006

Interesting read. Thanks for the link, Patrick.

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#41497

First documented case of tin whisker formation | 12 May, 2006

Interesting document. They are using a very high tin content alloy 99.5%SN, and suggest they can cange to a 90/10 PbSn alloy that will still mean they meet the RoHS Directive as alloys over 85% lead are exempt within RoHS. so if they used this they could not claim to be lea free but could claim RoHS compliance.

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#41507

First documented case of tin whisker formation | 12 May, 2006

Slain, A melting point of 300C would be a little too high for the components and tinny boards.

I just heard they will market the watches as Swiss "army" watches which makes them exempt.

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Rob

#41511

First documented case of tin whisker formation | 12 May, 2006

Great, just what we need - Psuedo science.

To paraphrase:

We tried 99.5Sn/0.5Cu & it didn't work so we couldn't be bothered to try any other lead free alloy. So give us an exemption else we'll bury you up to the neck in the stuff.

I have no problem in an exemption if Tin whiskers is the result of all Lead Free pastes, but at least show us some evidence of it.

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#41516

First documented case of tin whisker formation | 12 May, 2006

Rob,

I assume the exempt request is written by the legal department not by the technical department and translated from German to English.

Please tell me what evidence you are looking for and I will see what I can do.

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Rob

#41529

First documented case of tin whisker formation | 15 May, 2006

Hi Patrick,

Sorry, wrote it in a hurry on Friday afternoon, I meant show us evidence of a scientific trial on all or at least some other alloys.

I accept Tin whiskers and other similar phenomina exist, I even accept that the whole ROHS directive could have been written & implemented better by Jim Henson's finest, but what I do hate, and you could be right in that it's a translation problem, is lack of scientific evidence in the method (in this case apparently in the solder selection).

Sorry, rant over!

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#41561

First documented case of tin whisker formation | 16 May, 2006

Hi Rob,

Don't feel sorry I like these discussions make us think more thorough. This is the supporting scientific paper they used in support of the exemption request.

Effects of lead on tin whisker elimination By Wan Zhang and Felix Schwager.

http://forum.europa.eu.int/irc/DownLoad/kreXA5JLm_G0FfT2JBPRRqJVId74mSy04bN7Z2cY738UoPBcZ3RMoYoThtV2m-TtGV6O0rSQGpa3pFKW6ry-YV57c7tjPHUU/-/JES00C337.pdf

Interesting read (my head is still spinning)

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James

#41594

First documented case of tin whisker formation | 17 May, 2006

The link is broken.

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#41596

First documented case of tin whisker formation | 17 May, 2006

I just tried it works fine You might have to try the link a couple of times the servers are very busy hosting those papers, I wonder why.

I can also send you the pdf file by email just let me know

Patrick@interfluxusa.com

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#41603

First documented case of tin whisker formation | 17 May, 2006

Try from this link. Then you just need to select the link for the pdf document. http://forum.europa.eu.int/Public/irc/env/dir_2002_95/library?l=/stakeholders_comments/individual_business/rohsusa_inc/jes00c337pdf/_IT_1.0_

Patrick's link didn't work for me either, but I found it from the home page with a little poking around. When I actually got the doc open, the link Patrick gave was the address on the doc.

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#41605

First documented case of tin whisker formation | 17 May, 2006

Rob, it's not psuedo science, it's business. They have a problem, and have evidently tried a solution based on applying for an exemption. It's probably cheaper than trying every other possibility.

I think it's the EU with the psuedo science to back their politics.

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#41627

First documented case of tin whisker formation | 18 May, 2006

Stephen,

In addition to your comments The bothersome part is that NO environmental impact assessment report commissioned by the EU on the environmental impact of lead in solders and its alternatives exist.

The two environmental impact reports that are published: A) Solders in Electronics: A Life-Cycle Assessment (US EPA) B) White paper from the University of Stuttgart.

Both reports clearly states that lead-free alloys are worse for the environment in many different ways.

You would think that before writing a law, this new law would be based on scientific evidence.

Not on the fact that the average Jo thinks lead is bad.

Enough Rohaas (hate that word) science for today

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#41635

First documented case of tin whisker formation | 18 May, 2006

Here's a link to another analogy "get used to tin whiskers" http://www.reed-electronics.com/semiconductor/article/CA6332135?spacedesc=ne

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Rob

#41649

First documented case of tin whisker formation | 18 May, 2006

Hi Pat,

It's all going to be OK - they're giving us something else to occupy our minds:

http://www.electronicsweekly.com/Articles/Article.aspx?liArticleID=38641

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#41654

First documented case of tin whisker formation | 18 May, 2006

Rob,

Thanks for reminding me why I left Europe and moved to the US. I admit taxes were part of the reason too.

Cheers

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Rob

#41657

First documented case of tin whisker formation | 18 May, 2006

Strangely enough I'm in the process of getting measured up for my Crocodile Dundee hat.

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#41707

First documented case of tin whisker formation | 22 May, 2006

Hi Rob,

I'm not sure if you're kidding or not Are you moving to Australia?

Here's a link to the text John Burke used to write the EU commission for an exempt on lead in solders on environmental grounds. (Supporting documentation links on the bottom of the page) http://rohsusa.com/page20.html

And for people pronouncing Rohs as "Rohaas" From now on they will be lead (as in pointing too) in the right direction. http://www.rohaas.com/

Cheers Patrick

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Rob

#41708

First documented case of tin whisker formation | 22 May, 2006

Hi Pat,

The main driver for the UK on Lead-Free is to avoid leachate in our drinking water & in the food chain. Whilst John Burke's report is compelling & I agree with him on the points he has raised, regarding the leachate issue he has referenced a 1999 report from K-tech, which was written before the full scope of the WEEE directive was known (if in fact it is yet!). With a combination of WEEE & ROHS we should not only avoid putting heavy metals into the ground, we should be recycling the alternatives.

Here admittedly it kind of falls down, as:

1) If we recycled all of the electronics in the first place we wouldn't need to change to take the lead out.

2) We (UK) as a country take on most of Europe's nuclear waste...and we're talking of putting it where? in a big deep hole in the ground.

So yes Pat, in answer to your first question, I will be in a while, as I have no intention of raising a family in this nut house!

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#41718

First documented case of tin whisker formation | 23 May, 2006

3) other sources of lead.

Isn't electronics only a small souurce of lead in the enviroment? Although I"ve heard of steel being used in shotgun shot. But what about car batteries?

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