I guess you have to analyse the situation. Theoretically, tin on copper on iron should be readily solderable. Can we find why it isn't? Starting at the tin: is it massively oxidised? Was the copper properly prepared to receive the tin? Is it electroplated? If so, how pure is it? Is it porous? Are there organics co-deposited with the tin? Is it hot-tinned? If so, has it been wiped, so that the tin layer is non-existent, just an intermetallic layer? Has the intermetallic layer been properly formed? Going down to the copper, what is its thickness? What kind of plating bath was used? How pure is the copper? Has it been cleaned with abrasives? Are there organics co-deposited with the copper? Is it porous? By now, you should have found the cause but, if not and if the tin and copper plating is too thin, then it is just possible youmay find the problem at the copper/iron interface. No one here can solve your problem for you, we can only tell you where to start looking. Brian Poh Kong Hui wrote: > Hi Technetters, > > I would like to know if there is such kind of plating step. > The lead's base material is made of Iron (Fe), coated with Copper (Cu) and > next the outer with Tin (Sn). > > The issue faced is that the leads of the component has serious > solderability issue. > We do re-tin , but not 100% work. Some leads work fine and some are not. > > Please advise me if there is way to resolve the solderability. > > Thanks. > > Poh > > --------------------------------------------------- > 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 847-509-9700 ext.5315 > ----------------------------------------------------- > > --------------------------------------------------- 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 847-509-9700 ext.5315 -----------------------------------------------------