We saw this recently and traced it back to a nylon smear from the
deburring brushes that were not dressed properly. Hope this helps.
Rick Howieson
GTC

>-----Original Message-----
>From:  Julie Dixon [SMTP:[log in to unmask]]
>Sent:  Wednesday, March 22, 2000 12:38 PM
>To:    [log in to unmask]
>Subject:       [TN] Low Current Density Smut
>
>Dear Net,
>
>1. Is there a name, we use smut, for the slimy, dark brown-black deposit in
>low
>current density areas on panels in acid copper plating? It wipes off as a goo
>down
>to the foil copper.
>2. Is it related to DML boards only? Palladium on surface issue?
>Or is it related to DML's reaction with the brightner system in the plating
>bath?
>I've been told it's brightner related, but it never occurs on anything not
>DML'd.
>
> -Cold panels 70 F almost always manifest it.
> - But recently we saw it on 74 F panels plated at 35 asf for the first 5
>minutes.
>   a. bath had been inactive for 5 days, but continuously filtered, and air
>agitation
>       had been on for 2 hours prior to plate. Anode film?
>   b. design was a horrendous mismatch of copper area. We panelized best we
>could
>        front side-   1-9"         9-18"     the front 1-9" area smutted.
>Other area were ok.
>                         10x            1x
>                         copper area
>        back side-   1-9"         9-18"
>                           1x           10x
>
>Any experience with this? We thought we'd shelved this prob. with 98 F rinses
>in the
>pre plate. Sulfuric dip and plating bath are at the mercy of ambient
>conditions, typic
>74 F.
>
>Thanks,
>Julie
>
>##############################################################
>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.
>If you need assistance - contact Keach Sasamori at [log in to unmask] or
>847-509-9700 ext.5315
>##############################################################

##############################################################
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.
If you need assistance - contact Keach Sasamori at [log in to unmask] or
847-509-9700 ext.5315
##############################################################