---- Begin Forwarded Message Return-Path: <[log in to unmask]> Received: from simon.ipc.org (IPC.ORG [168.113.24.64]) by ixmail3.ix.netcom.com (8.7.5/SMI-4.1/Netcom) id IAA25383; Tue, 10 Dec 1996 08:48:30 -0800 (PST) Received: from ipc.org by simon.ipc.org via SMTP (940816.SGI.8.6.9/940406.SGI) id KAA07703; Tue, 10 Dec 1996 10:39:36 -0800 Resent-Date: Tue, 10 Dec 1996 10:39:36 -0800 Received: by ipc.org (Smail3.1.28.1 #2) id m0vXUjn-0000VUC; Tue, 10 Dec 96 10:08 CST Resent-Sender: [log in to unmask] Old-Return-Path: <[log in to unmask]> Message-Id: <[log in to unmask]> Comments: Authenticated sender is <[log in to unmask]> From: "Tom Rapp" <[log in to unmask]> Organization: Comptronix Corporation; Guntersville, AL To: [log in to unmask] Date: Tue, 10 Dec 1996 10:03:25 -0600 Subject: (ASSEM) Wave soldering SOT-23 Priority: urgent X-mailer: Pegasus Mail for Windows (v2.23) Resent-Message-ID: <"rsXuN.0.cWI.qhOho"@ipc> Resent-From: [log in to unmask] X-Mailing-List: <[log in to unmask]> archive/latest/8399 X-Loop: [log in to unmask] Precedence: list Resent-Sender: [log in to unmask] Good Morning Tom, I have seen many successfull sot wave soldering operations using assorted fluxes (water soluble and rosin) and pad geometries, however, nearly all cases were utilizing "dual wave" soldering machines. The pricipal here is to solder the pcb first with a turbulent wave biased towards the exit end of the machine, producing less than optimum results (bridges) yet overcoming the "shadowing" effect of the component. This is followed by the more conventional asymetrical wave with high forward velocity, and flat exit portion, matching the velocity of the wave to pcb. Corrective action might be to retrofit a dual wave to your existing system (we do that sort of thing, by the way) or upgrading to a new machine. Another culprit could be the volatile carriers of your flux are not being evaporated during the preheat process. This would be very evident by excessive sizzling and popping as the pcb hits the wave. Corrective action might be to evaluate proper topside temp (200-225 F) just prior to entering the wave. If you are using a water based flux, you might want to evaluate alchohol based formulas which are much easier to drive off the volatiles. Regards, Ed Popielarski QTA Machine [log in to unmask] (714) 364-6614 We are having problems wave soldering SOT's located on the bottom side of the boards. The SOT's have insufficient or no solder after waving. I have several questions reagarding this problem. 1. Is there a recommended wave profile? 2. Is there a recommended pad geometry for SOT's? 3. Is there a recommened flux? 4. Does anyone have any reports or technical articles on this issue? Thank You, Tom Rapp QE [log in to unmask] 205-582-1800 Ext 1240 ************************************************************************ *** * TechNet mail list is provided as a service by IPC using SmartList v3.05 * ************************************************************************ *** * To unsubscribe from this list at any time, send a message to: * * [log in to unmask] with <subject: unsubscribe> and no text. * ************************************************************************ *** * If you are having a problem with the IPC TechNet forum please contact * * Dmitriy Sklyar at 847-509-9700 ext. 311 or email at [log in to unmask] * ************************************************************************ *** *************************************************************************** * TechNet mail list is provided as a service by IPC using SmartList v3.05 * *************************************************************************** * To unsubscribe from this list at any time, send a message to: * * [log in to unmask] with <subject: unsubscribe> and no text. * *************************************************************************** * If you are having a problem with the IPC TechNet forum please contact * * Dmitriy Sklyar at 847-509-9700 ext. 311 or email at [log in to unmask] * ***************************************************************************