Hi, I have used both same size pads and different size pads for reflow/wave soldering and have come to the conclusion that slightly longer pads (0.5 mm) show advantages on wave soldering compared to reflow. This is because taller components tend to shield the footprint from the chip wave which can lead to skipped or open joints. The longer pads help to capture the solder and lead it into the joint. If you are wave soldering in-line gull wing devices, then orientate them so that each footprint/lead goes through the solder wave one after the other. This will prevent shielding one side of the device. Extra pads at the output end, known as 'solder thieves' will aid drainage of the molten solder and help prevent shorts. Orientation of these devices on the reflow side is not an issue. My experience also says that reflow soldering inherently gives lower defect levels so I try to design wave soldering out of the equation. Double sided reflow and pin in hole reflow help here. Regards Eric Dawson > -----Original Message----- > From: Cathy Killen [SMTP:[log in to unmask]] > Sent: 10 August 2001 13:48 > To: [log in to unmask] > Subject: [TN] SMT Pads > > Hi, > Is there a difference in SMT pad/land size at the design stage if the PCB > is > to be reflowed or wave soldered? > Cathy Killen > Training Instructor > [log in to unmask] <mailto:[log in to unmask]> > An Oasis of Training Excellence > * 028 38314305 > > -------------------------------------------------------------------------- > ------- > Technet Mail List provided as a free service by IPC using LISTSERV 1.8d > 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 delivery of Technet send the following message: SET > Technet NOMAIL > Search previous postings at: www.ipc.org > On-Line Resources & Databases > > E-mail Archives > Please visit IPC web site (http://www.ipc.org/html/forum.htm) for > additional > information, or contact Keach Sasamori at [log in to unmask] or 847-509-9700 > ext.5315 > -------------------------------------------------------------------------- > ------- --------------------------------------------------------------------------------- Technet Mail List provided as a free service by IPC using LISTSERV 1.8d 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 delivery of Technet send the following message: SET Technet NOMAIL Search previous postings at: www.ipc.org > On-Line Resources & Databases > E-mail Archives Please visit IPC web site (http://www.ipc.org/html/forum.htm) for additional information, or contact Keach Sasamori at [log in to unmask] or 847-509-9700 ext.5315 --------------------------------------------------------------------------------- --------------------------------------------------------------------------------- Technet Mail List provided as a free service by IPC using LISTSERV 1.8d 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 delivery of Technet send the following message: SET Technet NOMAIL Search previous postings at: www.ipc.org > On-Line Resources & Databases > E-mail Archives Please visit IPC web site (http://www.ipc.org/html/forum.htm) for additional information, or contact Keach Sasamori at [log in to unmask] or 847-509-9700 ext.5315 ---------------------------------------------------------------------------------