Hi David,
I would like to have a copy of your paper, pls advise..
Thanks & Regards
L.W.Foo
Engineer - Advanced Technology
Foo Loke Whong
Carsem Semiconductor Sdn Bhd
Email id : [log in to unmask]
Phone : +(6 05) 5262333 Ext : 530
Fax : +(6 05) 5265333
> ----------
> From: Cash, Alan[SMTP:[log in to unmask]]
> Reply To: Leadfree Electronics Assembly E-Mail Forum.;Cash, Alan
> Sent: Friday, June 01, 2001 2:55 AM
> To: [log in to unmask]
> Subject: Re: [LF] What is lead free...
>
> I would like a copy of your paper.
> Al Cash
> Northrop Grumman ESSS-DSD
> M/S H- 6185
> 600 HIcks Rd.
> Rolling Meadows, Il 60008
> E-mail: [log in to unmask] <mailto:[log in to unmask]>
> Tel: 847-259-9600 X-6764
>
> -----Original Message-----
> From: David Suraski [mailto:[log in to unmask]]
> Sent: Thursday, May 31, 2001 12:04 PM
> To: [log in to unmask]
> Subject: Re: [LF] What is lead free...
>
>
> I agree with Doug that the approach of utilizing a lead-free alloy with
> tin/lead coated parts as a first step in lead-free processing is being
> considered/taken by many. Unfortunately, this is an approach that could
> have negative results for some assemblies.
>
> Unfortunately, in the past the presence of lead in lead-free alloys has
> been
> presumed to be acceptable. The logic behind this often was that tin and
> lead are soluble in a lead-free system. However, what has been overlooked
> is that the intermetallic crystalline structures in lead-free systems are
> not soluble and will precipitate at lead boundaries. Thus, when using a
> lead-free alloy to solder to Sn/Pb coated component leads, Pb can actually
> create voids in the solder joint that can result in joint failure.
>
> To avoid problems related to this, the most prudent course of action is to
> eliminate/reduce the lead-free transition period to as short as possible.
> In other words, when a company implements a lead-free solder alloy, it
> should also implement lead-free component terminations and circuit board
> coatings. If these above guidelines are not followed, the reliability of
> the solder joint is risked.
>
> We've just completed a paper discussing the dynamics of this and showing
> real-world examples of failures caused by lead contamination of lead-free
> solders. This will be presented a Nepcon East/SMTA Boston this June, but
> if
> anyone would like to receive a copy of the paper before hand I'll be happy
> to send one along at your request.
>
>
> PS- I'm not advertising here, nor am I suggesting that anyone SHOULD go
> lead-free- just offering some research to the community!
>
> Best regards,
>
> David Suraski
> AIM
> T: 800-CALL-AIM / 401-463-5605, F: 401-463-0203
> www.aimsolder.com <http://www.aimsolder.com>
>
> ----- Original Message -----
> From: Romm, Doug <mailto:[log in to unmask]>
> To: [log in to unmask] <mailto:[log in to unmask]>
> Sent: Thursday, May 31, 2001 12:36 PM
> Subject: Re: [LF] What is lead free...
>
>
> Greg,
>
> You will probably get different inputs but here's mine.
>
> Many OEMs are stating that they will implement 'lead-free' in a staggered
> approach. The order of priority will be
>
> First: solder materials
> Second: printed circuit board finishes
> Third: components
>
> This is based on the % contribution of SnPb of each of the subsets
> (solder,
> pcb finishes, components) to the total solder joint (I believe).
>
> This approach is also being reflected in some end users roadmaps which
> show
> the requirement for 'high-temperature' capability of components and pcbs
> most immediately and then 'lead-free' as a follow-on step. This timing
> sequence is based on the fact that OEMs will convert to lead-free solders
> first (which may have a higher reflow temp requirement) and then will
> follow
> with lead-free PCBs and components.
>
> The goal (of those who choose to pure lead-free) is total lead-free in the
> entire system, but I believe the staggered approach is being followed by
> many.
>
>
>
> Doug Romm
>
>
> -----Original Message-----
> From: Greg Vance [ mailto:[log in to unmask]
> <mailto:[log in to unmask]> ]
> Sent: Thursday, May 31, 2001 10:46 AM
> To: [log in to unmask]
> Subject: [LF] What is lead free...
>
>
> Silly question, what defines lead free? Does this imply that there will
> be
> no lead in the assembly or we will use no lead solder, but PCB finish and
> some/all of the components may have SnPb plating on them... get my point?
>
> I ask this from the perspective of:
>
> 1) printed circuit board finishes
> 2) components
> 3) solder materials
>
> Greg Vance
> Rockwell Automation
> (330)487-6036
>
> --------------------------------------------------------------------------
> --
> -----
> Leadfee Mail List provided as a free service by IPC using LISTSERV 1.8d
> To unsubscribe, send a message to [log in to unmask] with following text in
> the BODY (NOT the subject field): SIGNOFF Leadfree
> To temporarily stop delivery of Leadree for vacation breaks send: SET
> Leadfree NOMAIL
> Search previous postings at: www.ipc.org > On-Line Resources & Databases >
> E-mail Archives
> Please visit IPC web site ( http://www.ipc.org/html/forum.htm
> <http://www.ipc.org/html/forum.htm> ) for additional
> information, or contact Keach Sasamori at [log in to unmask] or 847-509-9700
> ext.5315
> --------------------------------------------------------------------------
> --
> -----
>
> --------------------------------------------------------------------------
> -------
> Leadfee Mail List provided as a free service by IPC using LISTSERV 1.8d
> To unsubscribe, send a message to [log in to unmask] with following text in
> the BODY (NOT the subject field): SIGNOFF Leadfree
> To temporarily stop delivery of Leadree for vacation breaks send: SET
> Leadfree NOMAIL
> Search previous postings at: www.ipc.org > On-Line Resources & Databases >
> E-mail Archives
> Please visit IPC web site (http://www.ipc.org/html/forum.htm) for
> additional
> information, or contact Keach Sasamori at [log in to unmask] or 847-509-9700
> ext.5315
> --------------------------------------------------------------------------
> -------
>
---------------------------------------------------------------------------------
Leadfee Mail List provided as a free service by IPC using LISTSERV 1.8d
To unsubscribe, send a message to [log in to unmask] with following text in
the BODY (NOT the subject field): SIGNOFF Leadfree
To temporarily stop delivery of Leadree for vacation breaks send: SET Leadfree NOMAIL
Search previous postings at: www.ipc.org > On-Line Resources & Databases > E-mail Archives
Please visit IPC web site (http://www.ipc.org/html/forum.htm) for additional
information, or contact Keach Sasamori at [log in to unmask] or 847-509-9700 ext.5315
---------------------------------------------------------------------------------
|
