Mike-

In a previous life we had a black sludge build up in an ammoniacal etch.
Played havoc with the chloride levels and reduced etch performance.
Turned out it was zinc and a few other metals from the double treat foil we
used.
Just wondering if you had it analyzed, don't now what type of foil your
using or if
it could be the same type of situation.






At 07:26 12/16/1999 -0800, you wrote:
>We recently installed a new DES line using cupric chloride with sodium
>chlorate regeneration.  We have been experiencing a blue/black residue that
>coats the etch filters and seems to find it's way into the spray nozzles
>etc. etc.  We beat the fluoride theory and seal degradation to death and
>have found nothing substantial.  I have been told that others have
>experienced this problem and have attributed it to various causes such as
>developer drag-in, anti-foam contamination and leaching of dryfilm organics.
>I've also heard of others that have retrofitted carbon filtering systems on
>to their etchant recirculation pumps. I should note that this is brand new
>"high end" equipment with plenty of water rinse stations and blow-off
>modules.  Does anyone have any experiences they would care to share? Thanks
>in advance.
>
>Mike Bailey
>Director of Engineering
>McCurdy Circuits Inc.
>4900 E. Hunter Ave.
>Anaheim, CA  92870
>Phone: 714 507-4900 Ext 253
>FAX: 714 507-4911
>e-mail: [log in to unmask] <mailto:[log in to unmask]>
>
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Ian A. McMillan
Engineer
Herco Technology
13330 Evening Creek Dr. North
San Diego Ca. 92128
Ph# (858) 679-2800
Fax# (858) 679-7565

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