Let me preface this by saying that my experience has been only with panel and pattern copper plating. There are many literature references pertaining to periodic reverse pulse plating. They state several advantages including: - porosity reduction - lower gas content - high purity - fine-grained deposits - deposits having low electrical resistance - higher average cathodic current density - better surface to hole thickness ratio - uniform plating In my experience, some (if not all) of these advantages can be achieved with pulse plating. However, some possible negatives should also be considered: - cost of the power supplies - size and placement of the power supplies. The supplies that I have worked with generate a fair amount of heat (some of them were liquid cooled), but needed to be placed close to the plating cell to prevent inductive coupling of anodic and cathodic lines (twisted pair cables, etc.) - perhaps requires a special brightener system (if used). The higher current densities may destroy traditional brighteners. Lea Ronal used to make a system for pulse plating. - possible trouble with anodes "polarizing" after a period of time, causing high voltages. I believe that someone at Hughes may have done some work on this a while back. I am neither for or against pulse plating. These are just some observations. Dave Anderson *************************************************************************** * TechNet mail list is provided as a service by IPC using SmartList v3.05 * *************************************************************************** * To unsubscribe from this list at any time, send a message to: * * [log in to unmask] with <subject: unsubscribe> and no text. * *************************************************************************** * 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] * ***************************************************************************