At 09:30 AM 1/22/98 PST, you wrote: > Hi all, > > Our ammonia etcher is followed by a replenisher rinse consists of 4 > cascade rinse chambers. As I understand, all ammonia etchers are > followed by some cinfiguration of replenisher rinse, and when I ask > what is the purpose of it, I was told that the rep. rinse is to > 1) Decrease the copper content in the subsequent rinse water > 2) Increase the copper content in the etchant that enter the etcher > 3) Give a finishing touch to the etched panels > > I understand point#1, but not #2 and 3. Why would one want to increase > the copper concentration in incoming etchant? Won't that defeat the > purpose of feeding "fresh" etchant? And how does rinsing in cold, > fresh etchant give a finishing touch to the etched panels? > > Regards, > > Yee T.G. > Hadco Corp. The main reason for the cascade rinses is to reduce the copper in the rinse water going to the waste treatment system. Any other benifits are a extra benefit. Ed ############################################################## TechNet Mail List provided as a free service by IPC using LISTSERV 1.8c ############################################################## To subscribe/unsubscribe, send a message to [log in to unmask] with following text in the body: To subscribe: SUBSCRIBE TECHNET <your full name> To unsubscribe: SIGNOFF TECHNET ############################################################## Please visit IPC web site (http://www.ipc.org/html/forum.htm) for additional information. For the technical support contact Dmitriy Sklyar at [log in to unmask] or 847-509-9700 ext.311 ##############################################################