At the last IPC EXPO, I presented a paper that mathematically models the electroplating process for through holes using the Navia Stokes equations for fluid flow and Faraday's law for electroplating . The parameters of first order importance which were identified by this analysis are (hole diameter/aspect ratio)-squared (not aspect ratio alone), current density, concentration and agitation speed. Unfortunately, most of these parameters suggest that improvements in the hole wall uniformity require additional expense. As we all know, improved reliability, often requires a more expensive process. Best regards Lee J. Lee Parker, Ph.D. JLP Consultants LLC 804 779 3389 --------------------------------------------------- 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 -----------------------------------------------------