Hi TechNet land! We have completed a number of Pbfree solder joint thermal
cycle test investigations utilizing our existing printed wiring board
trace/pad/land guidelines and have had the same experience that several
other TechNet contributors are reporting - the existing
geometries/guidelines do not seem to impact the solder joint integrity for
the testing that has been conducted. However, the higher Pbfree soldering
temperatures are going to impact the plated thru hole and via structure
reliability to some level depending on what pwb laminate your design uses.
It will be interesting to see how much degradation is reported in the
industry investigations and how assembly laminate choices are impacted.
Dave Hillman
Rockwell Collins
[log in to unmask]
Thomi
<Thomas.Ahrens@T- To: [log in to unmask]
ONLINE.DE> cc:
Sent by: Leadfree Subject: Re: [LF] New to the group : Lead free landpatterns question
<[log in to unmask]
>
10/25/2003 05:03
PM
Please respond to
"(Leadfree
Electronics
Assembly Forum)";
Please respond to
Thomi
Hi Rene,
with regard to land patterns for leadfree electronics production, from all
we have tried and heard in various leadfree circles, we have not found a
necessity to change land patterns for better soldering results. One note,
though, on IPC-SM782 (and I am eager to responses to this from other
LEADFREE members, though this discussion might fit better in TECHNET) - I
am
not convinced that this is the most appropriate commonly available
landpattern standard. It is desperately lacking to distinguish between
reflow and wave pads, if I don't lack information regarding it's
interpretation.
For our layout, we prefer the Philips guidelines, as shown e. g. in the
reference
Klein Wassink, R. J., Verguld, M.M.F.: Manufacturing Techniques for Surface
Mounted Assemblies. Electrochemical Publications Ltd., Asahi House, Port
Erin, Isle of Man (1995).
(There are other comprehensive collections from Siemens, and further
component specific advisories).
But as mentioned, I'd like to find comments on this from others. I would
also like to get information on the next issue of IPC-A-610, which will be
revision D, if there will be special input on leadfree solder joints -
although I'd anticipate equal requirements for acceptability in terms of
wetting, smooth surface, concave shape, no opens, no bridges, no corrosive
residues and whats more...
Best regards
Thomas Ahrens, D-Boostedt
----- Original Message -----
From: "Rene Maas" <[log in to unmask]>
To: <[log in to unmask]>
Sent: Thursday, October 23, 2003 3:03 PM
Subject: [LF] New to the group : Lead free landpatterns question
> Hello to you all, I am investigating the impact on our product portfolio
if we have to adapt
> it for leadfree production. We currently use the IPC-SM-782+A1+A2
standard
for the definition
> of land patterns of components that we use. However, we would like to
prepare new designs for
> lead free production.
>
> Can anyone please advise for a standard/recommendation or website where I
can
> find details on the definition of lead free land patterns ?
>
> Thanks in advance,
>
> Rene Maas.
>
>
--------------------------------------------------------------------------
-----Leadfee Mail List provided as a 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: http://listserv.ipc.org/archives
> Please visit IPC web site
http://www.ipc.org/contentpage.asp?Pageid=4.3.16
for additional information, or contact Keach Sasamori at [log in to unmask] or
847-509-9700 ext.5315
>
--------------------------------------------------------------------------
-----
-------------------------------------------------------------------------------Leadfee
Mail List provided as a 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: http://listserv.ipc.org/archives
Please visit IPC web site http://www.ipc.org/contentpage.asp?Pageid=4.3.16
for additional information, or contact Keach Sasamori at [log in to unmask] or
847-509-9700 ext.5315
-------------------------------------------------------------------------------
-------------------------------------------------------------------------------Leadfee Mail List provided as a 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: http://listserv.ipc.org/archives
Please visit IPC web site http://www.ipc.org/contentpage.asp?Pageid=4.3.16 for additional information, or contact Keach Sasamori at [log in to unmask] or 847-509-9700 ext.5315
-------------------------------------------------------------------------------
|
