Hi Technetters! Looking through the IPC, ANSI spec's, I cannot find anything that references a recommended via size for multi-layer (up to 6 layers) boards. These particular boards may or may not have surfcae mount on top-side, and all are wave soldered, .062" thick, with LPI solder mask both sides. Currently our vias are .018" +\- .003" finished hole size, solder-mask plugged from the solder side. We are discussing eliminating the plugging and going to .021", and relying on the wave to fill the holes with solder...... Can you share your thoughts on what plated-thru via size works well for you, (also, do you solder-mask plug, no plug but wave solder fill, etc.???) Thanx in advance, oh guru's of the industry!! Jeff Hempton United Technologies Electronic Controls ############################################################## 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. If you need assistance - contact Gayatri Sardeshpande at [log in to unmask] or 847-509-9700 ext.5365 ##############################################################