Per IPC 2222 (Feb 1998): Page 6, table 4-2 lists a selection chart for various Registered FR4 types. I am familiar with FR4-04 and -06, however, it appears that for boards requiring to be very flat while still trying to watch cost, I would be better off specifying something like FR-4-17 or -19. It appears that the cost for 17 is middle of the road and cost for 19 is good. The kicker is that the farther down the table I go, it appears that the minus is the laminate is more difficult to drill. Is there articles anywhere out there regarding costs once we leave the FR-04-06, FR-04-04 material and start going into the -17 or 19 etc? What about the accuracy of the chart? It states material availability is good. Anyone out there had experience with this? Reason I ask, I have a 488 pin BGA 1 inch square I have to solder and they are asking me what to spec. Thanks in advance. _________________________________________________________________ Send and receive Hotmail on your mobile device: http://mobile.msn.com --------------------------------------------------------------------------------- Technet Mail List provided as a free service by IPC using LISTSERV 1.8d To unsubscribe, send a message to [log in to unmask] with following text in the BODY (NOT the subject field): SIGNOFF Technet To temporarily halt delivery of Technet send e-mail to [log in to unmask]: SET Technet NOMAIL To receive ONE mailing per day of all the posts: send e-mail to [log in to unmask]: SET Technet Digest Search previous postings at: www.ipc.org > On-Line Resources & Databases > E-mail Archives Please visit IPC web site http://www.ipc.org/html/forum.htm for additional information, or contact Keach Sasamori at [log in to unmask] or 847-509-9700 ext.5315 ---------------------------------------------------------------------------------