REGARDING Reflow problem Hello Technetters, I am experiencing a 'little reflow' problem with an assembly. The PCB is quite large 21" x 21", this restricts the supplier in using an all over solder reflow process during manufacture, as apposed to SMOBC. There is no active devices on the board, all are passives. I use a vapour phase machine for reflow. Heres the problem. Tin/lead is wicking from under soldermask near plated thru holes and forming solderballs/bridges between conductive elements. I am seeing this on both sides of the board, in particular the bottom side as Tin/lead seems to be accumulating on the underside (assumming gravity is taking its toll on the process). This seems to suggest an excessive amount of tin/lead (thickness) under the soldermask. I am told by the supplier that it is very difficult to control this amount of tin/lead and SMOBC is not feasible due to board size. Any suggestions, comments. Can I do anything in reflow process to reduce this, anybody else come accross similar issue in the past - with an identified solution. Regards John O'Sullivan. ############################################################## 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 ##############################################################