Is there a materials expert out there that can answer Mike's question below? B-stage epoxy resin is somewhat of a mystery to many designers. Perhaps someone can clarify the reference to "High Resin Content" as apposed to ? what other options are available and how they affect the construction of the FR4 board. Please copy to the group too so we can all learn from this. Bill Brooks PCB Design Engineer , C.I.D., C.I.I. Tel: (760)597-1500 Ext 3772 Fax: (760)597-1510 http://pcbwizards.com -----Original Message----- From: Mike Valle [mailto:[log in to unmask]] Sent: Tuesday, May 18, 2004 12:24 PM To: [log in to unmask] Subject: [DC] Core Constructions Hi, I need some help trying to find some information on FR-4 construction and thickness. I've come across a 4-layer stackup on a cross-section detail on one of our drawings and I can't seem to find it in IPC-4121. Our b-stage construction calls out for 1 ply of b-stage HRC (high resin content) 7628 .0068. Another detail on another drawing calls out for 1 ply of b-stage HRC (high resin content) 7628 .008. What I've been finding in IPC-4121 is that there is a FR-4 11 (7.087) 7628 40% RC and a HFR-4 11 (7.087) 40% RC, which is a high tg. So, my question is - is there such a thing as HRC - high resin content with varying thicknesses? Thanks, Mike Valle Project Engineer, PCB Design Shure Inc. (847)424-4616 [log in to unmask] ---------------------------------------------------------------------------- ----- DesignerCouncil 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 DesignerCouncil. To set a vacation stop for delivery of DesignerCouncil send: SET DesignerCouncil NOMAIL Search previous postings at: www.ipc.org > On-Line Resources & Databases > E-mail Archives Please visit IPC web site http://www.ipc.org/contentpage.asp?Pageid=4.3.16 for additional information, or contact Keach Sasamori at [log in to unmask] or 847-509-9700 ext.5315 ---------------------------------------------------------------------------- ----- --------------------------------------------------- Technet Mail List provided as a service by IPC using LISTSERV 1.8e 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 or (re-start) delivery of Technet send e-mail to [log in to unmask]: SET Technet NOMAIL or (MAIL) To receive ONE mailing per day of all the posts: send e-mail to [log in to unmask]: SET Technet Digest Search the archives of previous posts at: http://listserv.ipc.org/archives Please visit IPC web site http://www.ipc.org/contentpage.asp?Pageid=4.3.16 for additional information, or contact Keach Sasamori at [log in to unmask] or 847-509-9700 ext.5315 -----------------------------------------------------