TECHNET Archives

August 2011

TechNet@IPC.ORG

Options: Use Monospaced Font
Show Text Part by Default
Show All Mail Headers

Message: [<< First] [< Prev] [Next >] [Last >>]
Topic: [<< First] [< Prev] [Next >] [Last >>]
Author: [<< First] [< Prev] [Next >] [Last >>]

Print Reply
Subject:
From:
Bob Landman <[log in to unmask]>
Reply To:
Date:
Tue, 9 Aug 2011 15:55:23 -0400
Content-Type:
text/plain
Parts/Attachments:
text/plain (94 lines)
Ron,

You failed to mention one very important negative factor.  It's not the lead-free solder (we in high rel continue to use tin/lead), it's being forced to accept the lead-free tin plating of the component leads.  That's the problem for high rel applications.  That is why NASA dips all their parts in molten lead, why they have to have incoming inspection of parts by XRF that must contain lead, why there is so much work being done to develop lead-free control plans in the aerospace and critical care medical device industries, and, why so many of us in the high rel industries spend an hour or two on a weekly TIN WHISKERS telecon hosted by Bill Rollins at Raytheon.  

Why do you neglect to acknowledge the trouble caused by tin whiskers?  Do you think they are a minor annoyance?  You think we are tilting at windmills, is that it?  

Have you gone to the NASA website and reviewed their very long list of publically admitted failures due to whiskers?  Have you spoken with Dr. Henning Leidecker?  Has he told you of the many other failures they have studied that they cannot list on the website because the reporting companies/federal agencies do not want the bad press?

Toyota had tin whiskers in 2002-2006 Camry accelerator pedals; that is a FACT.  The NASA/DOT report documented them with pictures after a customer's Camry experienced uncontrolled acceleration and she had it towed to the shop where they replaced the shorted pedal assembly.  She gave the defective assembly to the DOT who gave it to NASA.  Henning's group at Goddard Space Flight Center saw them then went to the junkyard and found more pedal assys containing whiskers SHORTING the three leads of the potentiometers.  NASA was stopped from continuing their investigation.  Why?  They'd barely gotten started!

Do you troubleshoot electronic equipment failures? I do. Tin whiskers are BIG trouble because they are very hard to find (max diameter 3 microns); they can cause intermittant failures.  They caused the failure of implanted Medtronic pacemakers forcing a FDA recall.  You want your chest cracked open because of a recall due to whiskers?  

I don't.

Bob Landman
H&L Instruments, LLC
LDF Coatings, LLC


-----Original Message-----
From: TechNet [mailto:[log in to unmask]] On Behalf Of Joyce Koo
Sent: Saturday, August 06, 2011 11:54 AM
To: [log in to unmask]
Subject: Re: [TN] Lead Free solder has performed well...

Ron, I agree with majority of what you said.  With two minor disagreement: (1) high rel wider temp range of harsh environment has been proven that lead free is inferior compare to the lead solder (either use high lead content or Cd containing solders).  (2) as for mobile device and small form factor, current components in processor or other speed critical package still using lead solder as flip chip.  It is under RoHS exemption.  I assume it is so far not proven can be replace cost effectively with form, fit, function in term of those devices. I am looking forward to be corrected if I am wrong on either issues.  My 2 cents.  
--------------------------
Sent using BlackBerry


----- Original Message -----
From: Ron Lasky [mailto:[log in to unmask]]
Sent: Saturday, August 06, 2011 10:36 AM
To: [log in to unmask] <[log in to unmask]>
Subject: Re: [TN] Lead Free solder has performed well...

Folks,

Since there has been much discussion about what it has been assumed that I said about lead-free solder,  it would seem to be reasonable to share my actual thoughts on the status of lead-free.  So here are some of them.

Lead-free is here.  It is not going away.  So let's understand how it affects us.  I don't have a problem with discussing lead-free's short comings, but spending a great deal of time acting like it will be repealed if we complain enough is a waste of time.  Let's discuss reliability, process challenges, concerns over silver and tin costs and supply, electrical use, etc.  But let the discussions be based on data and analysis, not emotions and name calling.

I agree that lead-free solder was and is not now needed to protect the environment or the citizens of the European Union.  It has never been demonstrated that lead containing solders are a threat in land-fills and it has been demonstrated that leaded solders can be safely recycled. In addition, establishing lead-free assembly cost upwards of $50B and continues to present challenges and require investment.

Although lead-free was not needed to protect consumers or the environment in the EU, since a large proportion of re-cycling is performed "illegally" in 3rd world countries, it is likely safer for the untrained and unregulated re-cylers of the 3rd world to recycle lead-free solders than leaded solders.

Reliability of lead-free assembled commercial type products has been demonstrated in the lab and in the field.  I am referring to 0 to 100C type thermal cycling and drop shock testing, with SAC alloys.  The experimental data of Henshall and Coyle presented last year at SMTAI support this.  Their work represents millions of dollars of testing by teams of major companies. Although RoHS is only 5 years old, Motorola has about 10 years of field data.  They claim equal or better reliability with lead-free.  Add this to the trillions of dollars of products manufactured since RoHS was enacted, with no major reliability problems and it would be hard to argue that commercial product reliability has not been demonstrated.

But, I agree, harsh environment, mission critical, long-life reliability of lead-free solder has not been demonstrated.
It would be hard to over state the benefit of lead-free solder's poorer spreading enabling high performance mobile products.  There are now 5.6 billion mobile phone subscriptions in a world of 7 billion people.  No electronic product has made such a market penetration.  Lead-free solder has aided this feat in enabling tremendous function in a small size.

More to follow.

Best wishes,
Ron

---------------------------------------------------
Technet Mail List provided as a service by IPC using LISTSERV 16.0 To unsubscribe, send a message to [log in to unmask] with following text in the BODY (NOT the subject field): SIGNOFF Technet To temporarily halt or (re-start) delivery of Technet send e-mail to [log in to unmask]: SET Technet NOMAIL or (MAIL) To receive ONE mailing per day of all the posts: send e-mail to [log in to unmask]: SET Technet Digest Search the archives of previous posts at: http://listserv.ipc.org/archives For additional information, or contact Keach Sasamori at [log in to unmask] or 847-615-7100 ext.2815
-----------------------------------------------------

---------------------------------------------------------------------
This transmission (including any attachments) may contain confidential information, privileged material (including material protected by the solicitor-client or other applicable privileges), or constitute non-public information. Any use of this information by anyone other than the intended recipient is prohibited. If you have received this transmission in error, please immediately reply to the sender and delete this information from your system. Use, dissemination, distribution, or reproduction of this transmission by unintended recipients is not authorized and may be unlawful.

______________________________________________________________________
This email has been scanned by the MessageLabs Email Security System.
For more information please contact helpdesk at x2960 or [log in to unmask] ______________________________________________________________________


---------------------------------------------------
Technet Mail List provided as a service by IPC using LISTSERV 16.0
To unsubscribe, send a message to [log in to unmask] with following text in
the BODY (NOT the subject field): SIGNOFF Technet
To temporarily halt or (re-start) delivery of Technet send e-mail to [log in to unmask]: SET Technet NOMAIL or (MAIL)
To receive ONE mailing per day of all the posts: send e-mail to [log in to unmask]: SET Technet Digest
Search the archives of previous posts at: http://listserv.ipc.org/archives
For additional information, or contact Keach Sasamori at [log in to unmask] or 847-615-7100 ext.2815
-----------------------------------------------------


______________________________________________________________________
This email has been scanned by the MessageLabs Email Security System.
For more information please contact helpdesk at x2960 or [log in to unmask] 
______________________________________________________________________

---------------------------------------------------
Technet Mail List provided as a service by IPC using LISTSERV 16.0
To unsubscribe, send a message to [log in to unmask] with following text in
the BODY (NOT the subject field): SIGNOFF Technet
To temporarily halt or (re-start) delivery of Technet send e-mail to [log in to unmask]: SET Technet NOMAIL or (MAIL)
To receive ONE mailing per day of all the posts: send e-mail to [log in to unmask]: SET Technet Digest
Search the archives of previous posts at: http://listserv.ipc.org/archives
For additional information, or contact Keach Sasamori at [log in to unmask] or 847-615-7100 ext.2815
-----------------------------------------------------

ATOM RSS1 RSS2