With regard to conductor width 6012 states that the tolerance is 20%. Suppliers have responded that at 4 thou (mil) track and gap that this isn't a viable tolerance. Does IPC-6012 run out of steam at certain tracking densities? Minimum annular ring class three is 0.050mm (outer). Does this apply to blind via/multiple laminataion technology? Is there anyway to go beyond the "Tangent is acceptable" statements? If tangent is acceptable on sample, then there are bound to be breakouts on boards not checked. Regards Edward Brunker ############################################################## 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 Keach Sasamori at [log in to unmask] or 847-509-9700 ext.5315 ##############################################################