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
##############################################################