Thank you all for your responses about this issue. Main points were: - temperature (too high or too low) - flux activity - contact time - possible shadowing - clealiness of the pads - diffused nickel - turbulence I still haven't checked all that though. Does anybody know about a good course/tutorial for engineers about wave soldering ? I need it. I checked with IPC, EMPF and SMTA and I didn't see anything in a near future. Thank you. ############################################################## TechNet Mail List 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 web site (http://www.ipc.org/html/forum.htm) for additional information. For the technical support contact Dmitriy Sklyar at [log in to unmask] or 847-509-9700 ext.311 ##############################################################