Hi Richard! We have a few boards that call out that too. From my point of view, as far as appearance, it looks the same as HASL. I've tried to think why Fused tin/lead would be called out instead of HASL, and my only guess is that someone didn't want the boards to be themally shocked by the HASL process. I might also add these were on 61-20 layer VME cards where everything was SMT, and the only PTH was press-fit connectors...so the boards didn't even see wave solder. Kind regards, -Steve Gregory- Senior Process Engineer LaBarge Incorporated Tulsa, Oklahoma (918) 459-2285 (918) 459-2350 FAX |---------+----------------------------> | | "Stadem, Richard"| | | <Richard.Stadem@G| | | D-AIS.COM> | | | Sent by: TechNet | | | <[log in to unmask]>| | | | | | | | | 09/20/2005 07:51 | | | AM | | | Please respond to| | | TechNet E-Mail | | | Forum | | | <[log in to unmask]>| | | ; Please respond | | | to "Stadem, | | | Richard" | | | <Richard.Stadem@G| | | D-AIS.COM> | | | | |---------+----------------------------> >--------------------------------------------------------------------------------------------------------------| | | | To: [log in to unmask]@SMTP@Exchange | | cc: (bcc: Stephen R Gregory/LABARGE) | | Subject: [TN] Fused tin lead plating versus HASL | >--------------------------------------------------------------------------------------------------------------| Hi, folks I have a pwb fab drawing that calls out fused tin-lead plating or solder coating. I know that the solder coating is HASL, but what is fused tin/lead? My understanding is that it is a tin/lead coating that is applied to the bare pwb using a reflow oven process. Does this provide a flat surface of tin/lead? If my only choice of finish is tin/lead, which process is better in terms of flatness and solderability? I have a fine-pitch BGA that is going to be assembled on this pwb. --------------------------------------------------- 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 ----------------------------------------------------- __________________________________________________________________ This message may contain information that is privileged and confidential to LaBarge, Inc. It is for use only by the individual or entity named above. If you are not the intended recipient, you may not copy, use or deliver this message to anyone. In such event, you should destroy the message and kindly notify the sender by reply e-mail. --------------------------------------------------- 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 -----------------------------------------------------