Hi Edward: Sorry for the late response. Your inquiry is quite interesting. Lowering your ASF to 10 may put a strain on your brightner system as some go out of control at that current density over a long period of time. Lowering your ASF is sure to improve the throwing power, especially on those 10:1 aspect ratio panels. However, to improve surface distribution you must get the anode/cathode distance further apart. If space is a factor as you mentioned, you may consider using smaller diameter anodes and more of them. Make sure to keep your voltage high enough as again, you may imbalance your brightner and loosen your anode film. Good luck! ______________________________ Reply Separator _________________________________ Subject: Pattern plating considerations Author: [log in to unmask] at corp Date: 3/19/97 4:57 AM Hi Technetters ! We are in preliminary stage of design the expansion of the existing pattern plating line ( acid copper + tin-lead ) . Most of our PCB are SMT and back planes , up to 2.4 mm thick , 0.30 mm drilled vias , 4 - 5 mill conductors on the outer layers . The external pattern is not equal , lot of isolated pads and conductors . The next goal is 3.6 mm thich and 0.25 mm drilled vias . The existing cathode - anode distance is only 4 inch . Most of the boards are plated with current dencities in range approx. 20 ASF 60 minutes . More complicated and with high aspect ratio : double time and half of current dencity . Normally , we are traing to compensate uneven pattern by adding non - functional pads on the outer layers . Since the available space for further expansion is limited , we have to decide which one of basic approaches should be considered : 1 ) Keep the existing cathode - anode distance , but to plate with low current dencity ( 10 ASF ) 120 minutes . 2 ) Go to larger anode-cathode distance ( say 10 inches ) , keep the existing plating time ( 60 minutes ) and the current dencity ( 20 ASF ) Basic points for decision : 1 ) Better surface - hole plated copper distribution in high aspect ratios 2 ) Better surface distribution to avoid overplating on isolated pads and conductors to avoid severe overplating problems . Your comments will be very appreciated ! Edward Szpruch Eltek Ltd - Israel Tel 972 3 9395050 Fax 972 3 9309581 E-mail : [log in to unmask] *************************************************************************** * TechNet mail list is provided as a service by IPC using SmartList v3.05 * *************************************************************************** * To subscribe/unsubscribe send a message <to: [log in to unmask]> * * with <subject: subscribe/unsubscribe> and no text in the body. * *************************************************************************** * If you are having a problem with the IPC TechNet forum please contact * * Dmitriy Sklyar at 847-509-9700 ext. 311 or email at [log in to unmask] * *************************************************************************** *************************************************************************** * TechNet mail list is provided as a service by IPC using SmartList v3.05 * *************************************************************************** * To subscribe/unsubscribe send a message <to: [log in to unmask]> * * with <subject: subscribe/unsubscribe> and no text in the body. * *************************************************************************** * If you are having a problem with the IPC TechNet forum please contact * * Dmitriy Sklyar at 847-509-9700 ext. 311 or email at [log in to unmask] * ***************************************************************************