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lead free solder again
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Robert Baer
electronics forum Guru


Joined: 25 Mar 2005
Posts: 1159

PostPosted: Sat Jul 15, 2006 7:51 am    Post subject: Re: lead free solder again Reply with quote

Robert Latest wrote:

Quote:
On Fri, 14 Jul 2006 07:46:48 GMT,
Robert Baer <robertbaer@earthlink.net> wrote
in Msg. <IZHtg.4371$vO.4209@newsread4.news.pas.earthlink.net

Robert Latest wrote:


On Thu, 13 Jul 2006 02:44:25 GMT,
Robert Baer <robertbaer@earthlink.net> wrote
in Msg. <dsitg.3864$vO.1459@newsread4.news.pas.earthlink.net

Metal whiskers are very crystalline, and are hundreds if not
thousands times stronger than even pure metal sheet or rod.


What makes you think so? Single-crystal metals are much softer than
their multicrystalline forms -- that's the mechanism of work-hardening.

robert

i repeat, "softness" has *nothing* to do with strength.


So, in which sense do you think metal whiskers are "stronger" than pure
metal sheet or rod?

robert
Mostly in compression, so as it grows, it can puncture almost anything.
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I.F.
electronics forum Guru


Joined: 30 Mar 2006
Posts: 407

PostPosted: Sat Jul 15, 2006 6:07 pm    Post subject: Re: lead free solder again Reply with quote

"Frank Bemelman" <f.bemelmanq@xs4all.invalid.nl> wrote in message
news:44b8953d$0$7915$e4fe514c@dreader29.news.xs4all.nl...
Quote:
"Joerg" <notthisjoergsch@removethispacbell.net> schreef in bericht
news:rpWtg.66197$fb2.16987@newssvr27.news.prodigy.net...
Hello Ken,


Whiskers will poke right through conformal coat right above where they
are
initiating from, but they have difficulty poking back through the
conformal
coat. Also, the conformal coat yields additional protection from
whiskers
that have broken off and are just wandering around.


And then it's "whisker meets whisker". Bzzzt .... poof.

Look at the bright side. Most adjacent whiskers are on the
same net ;)

The downside is, that it can even endanger other equipment
that uses lead solder. Imagine whiskers growing out of
your RoHS compliant equipment, entering the ventholes of
your older non-RoHS stuff. Another KABOOM waiting around
the corner...

LOL

--
Thanks, Frank.
(remove 'q' and '.invalid' when replying by email)



What a pity you mock those who actually know what they're talking about! - I
hope your TV gets whiskers and burns your house down, then you might not be
so free and easy with the sarcastic remarks!
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Joerg
electronics forum Guru


Joined: 05 May 2005
Posts: 3533

PostPosted: Sat Jul 15, 2006 6:35 pm    Post subject: Re: lead free solder again Reply with quote

Hello Frank,

Quote:

And then it's "whisker meets whisker". Bzzzt .... poof.

Look at the bright side. Most adjacent whiskers are on the
same net ;)


Have you dealt with TSSOP packages or even smaller ones?

The real problem will be when a male whisker pokes through and see a
stunning female whisker ... :-)

--
Regards, Joerg

http://www.analogconsultants.com
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Frank Bemelman
electronics forum Guru


Joined: 05 May 2005
Posts: 501

PostPosted: Sat Jul 15, 2006 6:43 pm    Post subject: Re: lead free solder again Reply with quote

"ian field" <dai.ode@ntlworld.com> schreef in bericht
news:T9aug.9427$sz1.9057@newsfe6-gui.ntli.net...
Quote:

"Frank Bemelman" <f.bemelmanq@xs4all.invalid.nl> wrote in message
news:44b8953d$0$7915$e4fe514c@dreader29.news.xs4all.nl...
"Joerg" <notthisjoergsch@removethispacbell.net> schreef in bericht
news:rpWtg.66197$fb2.16987@newssvr27.news.prodigy.net...
Hello Ken,


Whiskers will poke right through conformal coat right above where
they
are
initiating from, but they have difficulty poking back through the
conformal
coat. Also, the conformal coat yields additional protection from
whiskers
that have broken off and are just wandering around.


And then it's "whisker meets whisker". Bzzzt .... poof.

Look at the bright side. Most adjacent whiskers are on the
same net ;)

The downside is, that it can even endanger other equipment
that uses lead solder. Imagine whiskers growing out of
your RoHS compliant equipment, entering the ventholes of
your older non-RoHS stuff. Another KABOOM waiting around
the corner...

LOL

--
Thanks, Frank.
(remove 'q' and '.invalid' when replying by email)



What a pity you mock those who actually know what they're talking about! -
I
hope your TV gets whiskers and burns your house down, then you might not
be
so free and easy with the sarcastic remarks!

Yes, I seriously doubt what Joerg is talking about. And myself, for that
matter. But I am confident about my next TV - those manufacturers do know
what they are dealing with, and I don't hear them complain.

But, even you would have to admit that most adjacent whiskers are on
the same net. So even if they do emerge, most of them will be pretty
harmless. The more I'm thinking about it, applying some coating on
the edges of TQFP's isn't such a crazy idea. At least it *is* an
idea. All I hear from Joerg is complaining about something he has
zero hands-on experience with.

--
Thanks, Frank.
(remove 'q' and '.invalid' when replying by email)
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Frank Bemelman
electronics forum Guru


Joined: 05 May 2005
Posts: 501

PostPosted: Sat Jul 15, 2006 6:46 pm    Post subject: Re: lead free solder again Reply with quote

"Joerg" <notthisjoergsch@removethispacbell.net> schreef in bericht
news:eAaug.5812$2v.953@newssvr25.news.prodigy.net...
Quote:
Hello Frank,


And then it's "whisker meets whisker". Bzzzt .... poof.

Look at the bright side. Most adjacent whiskers are on the
same net ;)


Have you dealt with TSSOP packages or even smaller ones?

No, TQFP is the smallest I have used.

Quote:
The real problem will be when a male whisker pokes through and see a
stunning female whisker ... Smile

Oops didn't think about that. Since I thought they were
actually hermafrodites, I suppose this is an advantage ;)

--
Thanks, Frank.
(remove 'q' and '.invalid' when replying by email)
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Joerg
electronics forum Guru


Joined: 05 May 2005
Posts: 3533

PostPosted: Sat Jul 15, 2006 7:43 pm    Post subject: Re: lead free solder again Reply with quote

Hello Frank,

Quote:
... All I hear from Joerg is complaining about something he has
zero hands-on experience with.


How do you know that?

FYI, I work in medical and there are areas where lead is not allowed. My
exposure to conductive bonding processes of such devices is about twelve
years by now. And we are talking mass production here. Ok, maybe that's
not enough by your standards.

--
Regards, Joerg

http://www.analogconsultants.com
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Eeyore
electronics forum Guru


Joined: 22 Jun 2006
Posts: 642

PostPosted: Sat Jul 15, 2006 8:13 pm    Post subject: Re: lead free solder again Reply with quote

ian field wrote:

Quote:
"Frank Bemelman" <f.bemelmanq@xs4all.invalid.nl> wrote in message
news:44b8953d$0$7915$e4fe514c@dreader29.news.xs4all.nl...
"Joerg" <notthisjoergsch@removethispacbell.net> schreef in bericht
news:rpWtg.66197$fb2.16987@newssvr27.news.prodigy.net...
Hello Ken,


Whiskers will poke right through conformal coat right above where they
are
initiating from, but they have difficulty poking back through the
conformal
coat. Also, the conformal coat yields additional protection from
whiskers
that have broken off and are just wandering around.


And then it's "whisker meets whisker". Bzzzt .... poof.

Look at the bright side. Most adjacent whiskers are on the
same net ;)

The downside is, that it can even endanger other equipment
that uses lead solder. Imagine whiskers growing out of
your RoHS compliant equipment, entering the ventholes of
your older non-RoHS stuff. Another KABOOM waiting around
the corner...

LOL

--
Thanks, Frank.
(remove 'q' and '.invalid' when replying by email)


What a pity you mock those who actually know what they're talking about! - I
hope your TV gets whiskers and burns your house down, then you might not be
so free and easy with the sarcastic remarks!

Well said, that man !

Graham
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Eeyore
electronics forum Guru


Joined: 22 Jun 2006
Posts: 642

PostPosted: Sat Jul 15, 2006 8:15 pm    Post subject: Re: lead free solder again Reply with quote

Frank Bemelman wrote:

Quote:
But I am confident about my next TV - those manufacturers do know
what they are dealing with, and I don't hear them complain.

Really ?

Before he vanished John Woodgate reported about the increasing failure rates of
TVs made with lead free processes !

And they were 'complaining' in an industry mag.

Graham
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Frank Bemelman
electronics forum Guru


Joined: 05 May 2005
Posts: 501

PostPosted: Sun Jul 16, 2006 12:46 am    Post subject: Re: lead free solder again Reply with quote

"Joerg" <notthisjoergsch@removethispacbell.net> schreef in bericht
news:Yzbug.173016$F_3.126081@newssvr29.news.prodigy.net...
Quote:
Hello Frank,

... All I hear from Joerg is complaining about something he has
zero hands-on experience with.


How do you know that?

FYI, I work in medical and there are areas where lead is not allowed. My
exposure to conductive bonding processes of such devices is about twelve
years by now. And we are talking mass production here. Ok, maybe that's
not enough by your standards.

Does that involve lead-free solder too? What is the trick to
prevent whiskers? Fill us in, with your 12 years experience
you must be able to give some advice, other than just complaining.

--
Thanks, Frank.
(remove 'q' and '.invalid' when replying by email)
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Robert Baer
electronics forum Guru


Joined: 25 Mar 2005
Posts: 1159

PostPosted: Sun Jul 16, 2006 7:40 am    Post subject: Re: lead free solder again Reply with quote

Frank Bemelman wrote:

Quote:
"ian field" <dai.ode@ntlworld.com> schreef in bericht
news:T9aug.9427$sz1.9057@newsfe6-gui.ntli.net...

"Frank Bemelman" <f.bemelmanq@xs4all.invalid.nl> wrote in message
news:44b8953d$0$7915$e4fe514c@dreader29.news.xs4all.nl...

"Joerg" <notthisjoergsch@removethispacbell.net> schreef in bericht
news:rpWtg.66197$fb2.16987@newssvr27.news.prodigy.net...

Hello Ken,


Whiskers will poke right through conformal coat right above where

they

are

initiating from, but they have difficulty poking back through the

conformal

coat. Also, the conformal coat yields additional protection from

whiskers

that have broken off and are just wandering around.


And then it's "whisker meets whisker". Bzzzt .... poof.

Look at the bright side. Most adjacent whiskers are on the
same net ;)

The downside is, that it can even endanger other equipment
that uses lead solder. Imagine whiskers growing out of
your RoHS compliant equipment, entering the ventholes of
your older non-RoHS stuff. Another KABOOM waiting around
the corner...

LOL

--
Thanks, Frank.
(remove 'q' and '.invalid' when replying by email)



What a pity you mock those who actually know what they're talking about! -

I

hope your TV gets whiskers and burns your house down, then you might not

be

so free and easy with the sarcastic remarks!


Yes, I seriously doubt what Joerg is talking about. And myself, for that
matter. But I am confident about my next TV - those manufacturers do know
what they are dealing with, and I don't hear them complain.

But, even you would have to admit that most adjacent whiskers are on
the same net. So even if they do emerge, most of them will be pretty
harmless. The more I'm thinking about it, applying some coating on
the edges of TQFP's isn't such a crazy idea. At least it *is* an
idea. All I hear from Joerg is complaining about something he has
zero hands-on experience with.

I repeat: coatings (of any kind) are *NOT* reliable!

There is *NO* known method to "cure" tin whiskers - other than not
using tin!
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Robert Baer
electronics forum Guru


Joined: 25 Mar 2005
Posts: 1159

PostPosted: Sun Jul 16, 2006 7:41 am    Post subject: Re: lead free solder again Reply with quote

Joerg wrote:

Quote:
Hello Frank,

... All I hear from Joerg is complaining about something he has
zero hands-on experience with.


How do you know that?

FYI, I work in medical and there are areas where lead is not allowed. My
exposure to conductive bonding processes of such devices is about twelve
years by now. And we are talking mass production here. Ok, maybe that's
not enough by your standards.

It would be helpful to disclose some of that information..
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Robert Baer
electronics forum Guru


Joined: 25 Mar 2005
Posts: 1159

PostPosted: Sun Jul 16, 2006 7:42 am    Post subject: Re: lead free solder again Reply with quote

Frank Bemelman wrote:

Quote:
"Joerg" <notthisjoergsch@removethispacbell.net> schreef in bericht
news:Yzbug.173016$F_3.126081@newssvr29.news.prodigy.net...

Hello Frank,


... All I hear from Joerg is complaining about something he has
zero hands-on experience with.


How do you know that?

FYI, I work in medical and there are areas where lead is not allowed. My
exposure to conductive bonding processes of such devices is about twelve
years by now. And we are talking mass production here. Ok, maybe that's
not enough by your standards.


Does that involve lead-free solder too? What is the trick to
prevent whiskers? Fill us in, with your 12 years experience
you must be able to give some advice, other than just complaining.

I second that.
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Roger Hamlett
electronics forum Guru


Joined: 28 Apr 2005
Posts: 302

PostPosted: Sun Jul 16, 2006 8:51 am    Post subject: Re: lead free solder again Reply with quote

"Robert Baer" <robertbaer@earthlink.net> wrote in message
news:F4mug.8805$PE1.5718@newsread2.news.pas.earthlink.net...
Quote:
Joerg wrote:

Hello Frank,

... All I hear from Joerg is complaining about something he has
zero hands-on experience with.


How do you know that?

FYI, I work in medical and there are areas where lead is not allowed.
My exposure to conductive bonding processes of such devices is about
twelve years by now. And we are talking mass production here. Ok, maybe
that's not enough by your standards.

It would be helpful to disclose some of that information..
Contact bonding has been used in a variety of places for years. Have a

look at:
http://ap.pennnet.com/Articles/Article_Display.cfm?Section=Archives&Subsection=Display&ARTICLE_ID=82206&KEYWORD=lead-free
For an overview of the advantages/disadvantages.
The IEEE site, also has a paper on this technology.
I have used it as an assembly process on a couple systems. It's biggest
weakness came at higher power, where the extra resistance, both
electrical, and thermal, does become a problem. Personally, I think the
chemicals involved in the epoxies are much nastier to handle than lead
solders, but of course, once the resin sets, they result is very inert
indeed.

Best Wishes
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Joerg
electronics forum Guru


Joined: 05 May 2005
Posts: 3533

PostPosted: Sun Jul 16, 2006 8:36 pm    Post subject: Re: lead free solder again Reply with quote

Hello Robert,

Quote:

... All I hear from Joerg is complaining about something he has
zero hands-on experience with.

How do you know that?

FYI, I work in medical and there are areas where lead is not allowed.
My exposure to conductive bonding processes of such devices is about
twelve years by now. And we are talking mass production here. Ok,
maybe that's not enough by your standards.

It would be helpful to disclose some of that information..


Sorry, but that isn't possible because it is a tightly guarded trade
secret. Just this much I can say: We have to stop thinking just about
solder to do connections, sometimes it isn't the right stuff. Especially
in very dense situations where whiskers do present a problem. Head in
the sand or "it'll all be ok because the legislators said so" like some
people seem to prefer is not the solution.

--
Regards, Joerg

http://www.analogconsultants.com
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Joerg
electronics forum Guru


Joined: 05 May 2005
Posts: 3533

PostPosted: Sun Jul 16, 2006 8:41 pm    Post subject: Re: lead free solder again Reply with quote

Hello Frank,

Quote:

... All I hear from Joerg is complaining about something he has
zero hands-on experience with.

How do you know that?

FYI, I work in medical and there are areas where lead is not allowed. My
exposure to conductive bonding processes of such devices is about twelve
years by now. And we are talking mass production here. Ok, maybe that's
not enough by your standards.

Does that involve lead-free solder too? What is the trick to
prevent whiskers? Fill us in, with your 12 years experience
you must be able to give some advice, other than just complaining.


Yes, it does but not the stuff that is sold in the stores now. Can't
reveal details as that would seriously damage a few companies'
competitive edge and I would be in breach of contract. Also, these
approaches would be far too expensive and cumbersome in "normal"
electronics assembly anyway. IOW, it would not help the cause here.

What I am complaining about is this: A legislative body has made a
decision and as far as I can tell there is no clear alternative path
they could point industry to. That's wrong. Before you make a law you
need to show your constituents how they are supposed to comply with it.

--
Regards, Joerg

http://www.analogconsultants.com
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