We currently use both no-clean and water soluble fluxes. The water soluble fluxes are more acidic and more aggressive. The flux residues need to be washed from the assembly to avoid corrosion. The WS flux that we are currently using at Wave Soldering is Alpha Metals 373 liquid flux. Let me know if you require further assistance, Paymon -----Original Message----- From: TechNet [mailto:[log in to unmask]] On Behalf Of Phil Nutting Sent: October 10, 2007 8:38 AM To: [log in to unmask] Subject: Re: [TN] RoHS solder and wetting plus thermal reliefs Paymon, What aggressive fluxes are you using? Phil -----Original Message----- From: TechNet [mailto:[log in to unmask]] On Behalf Of Paymon Sani Sent: Tuesday, October 09, 2007 4:51 PM To: [log in to unmask] Subject: Re: [TN] RoHS solder and wetting plus thermal reliefs Hello Phil, Guy is correct. You need to preheat the boards and use aggressive fluxes. We use the SnC100 with our wave soldering process and we get 100% barrel fill even-though we only need to meet the IPC specification! Paymon -----Original Message----- From: TechNet [mailto:[log in to unmask]] On Behalf Of Guy Ramsey Sent: October 9, 2007 3:46 PM To: [log in to unmask] Subject: Re: [TN] RoHS solder and wetting plus thermal reliefs We are doing 100% vertical fill on 5 mm thick 32 layer boards with multiple ground planes, Pb-Free solder. It requires preheat. -----Original Message----- From: TechNet [mailto:[log in to unmask]] On Behalf Of Phil Nutting Sent: Tuesday, October 09, 2007 3:10 PM To: [log in to unmask] Subject: [TN] RoHS solder and wetting plus thermal reliefs Hello Technetters, Let me see if I can explain the problem. We build some PTH boards with 4 oz. copper and connect some high power IGBT devices with thermal reliefs on the pads. In the past with tin/lead everything worked well. More of our designs are being converted over to RoHS (SAC 305). It appears we are not getting as much flow through or wetting on these devices. So there is a two fold concern. During a specific failure mode the thermal reliefs act like a fuse causing arcing until enough copper vaporizes to make a large enough gap that the voltage can no longer jump. One solution is remove the thermal reliefs. Part two is the amount of current passing through the PTH. We can't rely on the barrel for full current carrying capacity so 100% barrel fill is desired with a good fillet top and bottom. Here is where we are having issues with RoHS solder not fully wetting or filling the PTH. I'm concerned that removing the thermal reliefs will generate other problems. I'm thinking we should use a different configuration relief. If the RoHS solder does not fill the hole we would typically go back and top solder the connection. I know the industry considers this a no-no. Any recommendations? Thanks in advance. Phil Nutting --------------------------------------------------- Technet Mail List provided as a service by IPC using LISTSERV 15.0 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 15.0 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 15.0 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 15.0 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 15.0 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 -----------------------------------------------------