Hi Ted, > Is there any data that suggests that conductive epoxies or fillers > shouldn't be used at a specific aspect ratio? > A: No data like that in the public domain, at least. > What are the chances that the conductive epoxy is increasing hole wall pull > away, damaging the barrel? > A: None, Hole wall pull away, ot resin ressesion, is the result of hydro-static [actually resin-static] pressure surrounding the via barrel trying to collapse it, and partially succeeding in terms of plastic deformation of the Cu barrel wall—putting anything into the via reduces the collapsing depending on the CTE of the fill material. > Can non-conductive fillers act as an insulator when it comes to heat > transfer within the barrel? > A: Non-conductive filler will provide better heat transfer than air, but less than any other type of filler. Werner ************************************** See what's new at http://www.aol.com --------------------------------------------------- Technet Mail List provided as a service by IPC using LISTSERV 15.0 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 847-615-7100 ext.2815 -----------------------------------------------------