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 ---------------------------------------------------------------------------------