HI ALL !!!! I HAVE A BACKPLANE WITH 14 LAYERS. THE PANEL IS 6.8mm THICK. IPC CAT 3 REQUIRES 75% FILL ON PECS WHICH ARE UP TO 3.8mm THICK ? MY QUESTION IS, WHAT DICTATES THE REASON FOR 75% FILL ? I WOULD LIKE TO ACCEPT THE PANEL WITH ONLY 40% FILL. THIS WOULD STILL HAVE A FILLET OF 2.72mm. WOULD THIS FAIL IPC-610 CAT 3 ? Regards - Roger Deakin. EMAIL [log in to unmask] TEL +44 (0)1983 202632 FAX +44 (0)1983 202106 COMPANY BRITISH AEROSPACE LAND AND SEA SYSTEMS NEWPORT ROAD COWES ISLE OF WIGHT PO31 8PF ENGLAND ############################################################## 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 ##############################################################