Hi Werner, if I got it right, one should design the landpattern the same size as the chip? That is for a 1206, the landpattern should be 120 mils overall length and 60 mils wide. Then, I am wondering how can one inspect the workmanship, not to mention eventual rework? And secondly, how could one control the height of the solder joint? Regards, Ioan > -----Original Message----- > From: TechNet [SMTP:[log in to unmask]] On Behalf Of Werner Engelmaier > Sent: Monday, June 13, 2005 5:15 PM > To: [log in to unmask] > Subject: Re: [TN] Ceramic MLCs and Leadfree, John Maxwell case? > > Hi John, > LF-solder are stronger, less ductile, and creep slower--all of these add up > to higher stresses in LF-SJs; ergo higher flex crack sensitivity. > For chip components I suggest getting rid of the fillets--they cause > component cracking, increasing the solder joint height under CCs and CRs, and reflow > soldering them. > > Werner Engelmaier > > --------------------------------------------------- > Technet Mail List provided as a service by IPC using LISTSERV 1.8e > 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 > 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 847-615-7100 ext.2815 > ----------------------------------------------------- --------------------------------------------------- Technet Mail List provided as a service by IPC using LISTSERV 1.8e 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 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 847-615-7100 ext.2815 -----------------------------------------------------