Stella What do you mean with side concave fillet? If you have no solder on the sides of the terminations of your component don't bother. If you have no fillet at the ends you might run into a problem with your customer. These fillets do contribute to a certain extend to the reliability of the solder joint. Thermal cycling tests show, that cracks are growing simultaneously in the layer between the component as well as in the fillet due to the local CTE mismatch component/solder. The crack under the component keeps on growing more or less horizontally through the fillet once it exits the gap between component and pad, the other grows vertically along the cap. The failure occurs in pure thermal cycling if the two cracks meet or, in conjunction with vibrations, if the load bearing area is to small to hold the component in place.To decide whether or not the boards can be used, it is important to know whether the extra number of cycles (as an estimate I'd say without vibrations max. 1000 cycles with a temperature-swing of 120 deg C when the average lifetime of "normal" solder-joints is approx. 9000 cycles) is essential for the reliability of the assembly. Remember, that the number of cycles to failure goes approx. with the square of the temperature swing. This means, if you half the swing you have four times more cycles to failure. On the other hand it is very likely that these solder-joints are more reliable than hand-soldered repairs and lets face it, if the board relies on the additional cycles to failure given by a filet at the end it is anyway on the edge to cause reliability problems. Best regards Guenter ################################################################ 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 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 ################################################################