It was difficult to tell from your description which actual direction the leads are presented to the wave. If they are crossing through the wave individually (one after the other) with the bridge between the middle and last lead, adding a 'thieving' or 'robber' pad should eliminate the problem. This is a solid pad behind your last lead, the same width as your part pad diameter and about x2 in length. The sole purpose is to provide an additional area for the solder to 'pull away' from the last two leads of your device which are shorting. Hopefully you haven't bought 50,000 fabs already and can convince your design group of the production cost savings versus the cost of rolling the fab.... Mike McMonagle PCA Process Engineering Supervisor K*Tec Electronics 1111 Gillingham Lane Sugar Land, TX 77478 (281) 243-5639 Phone (281) 243-5539 Fax [log in to unmask] > -----Original Message----- > From: WM Cheng [SMTP:[log in to unmask]] > Sent: Wednesday, December 09, 1998 10:19 PM > To: [log in to unmask] > Subject: [TN] Short solder problem of TO220 > > Dear Technetters, > > Recently one of our customer request us to further > improve the wave solder ppm (target 200ppm), the major > defect found is the TO220 package component which > contribute over 80% of the total failure, the component > is not preformed and is inserted to the PCB with all the > three leads lie in straight line parallel to the wave > soldering direction, the defect symptom is short solder > between the middle and the last lead. My question is : > > 1. Will shorten the leads help? Current lead extension > from the bottom of PCB is 2 to 2.5mm . > > 2. What hole and land size/pattern should be used? Does > any IPC standard mention about this? > > 3. What is/are the process parameter (wave soldering > process) contribute the problem and what should be > changed to improve this? > > Hope someone can help. > > Thanks, > WM Cheng > E-mail : [log in to unmask] > > ################################################################ > TechNet E-Mail Forum provided as a free service by IPC using LISTSERV > 1.8c > ################################################################ > To subscribe/unsubscribe, send a message to [log in to unmask] with > following text in the body: > To subscribe: SUBSCRIBE TechNet <your full name> > To unsubscribe: SIGNOFF TechNet > ################################################################ > Please visit IPC's web site (http://www.ipc.org) "On-Line Services" > section for additional information. > For technical support contact Hugo Scaramuzza at [log in to unmask] or > 847-509-9700 ext.312 > ################################################################ ################################################################ TechNet E-Mail Forum provided as a free service by IPC using LISTSERV 1.8c ################################################################ To subscribe/unsubscribe, send a message to [log in to unmask] with following text in the body: To subscribe: SUBSCRIBE TechNet <your full name> To unsubscribe: SIGNOFF TechNet ################################################################ Please visit IPC's web site (http://www.ipc.org) "On-Line Services" section for additional information. For technical support contact Hugo Scaramuzza at [log in to unmask] or 847-509-9700 ext.312 ################################################################