TECHNET Archives

November 1997

TechNet@IPC.ORG

Options: Use Monospaced Font
Show Text Part by Default
Show All Mail Headers

Message: [<< First] [< Prev] [Next >] [Last >>]
Topic: [<< First] [< Prev] [Next >] [Last >>]
Author: [<< First] [< Prev] [Next >] [Last >>]

Print Reply
Subject:
From:
Lenny Kurup <[log in to unmask]>
Reply To:
TechNet Mail Forum.
Date:
Thu, 20 Nov 1997 17:21:56 -0500
Content-Type:
TEXT/PLAIN
Parts/Attachments:
TEXT/PLAIN (73 lines)
Hi Roger,

It seems as though your gold deposit is contaminated, or you are plating an
alloy higher in nickel than normal along with metallic impurities such as
iron, lead and even copper. You may even be co-depositing organics, by
entrapment. The thermal stress from the oven will result in blooming of
impurities to the surface and hence, discoloration.

When was the last time you analysed the gold bath for contamination, both
metallic and organic. Have your gold supplier analyse the bath, if you do
not have the resources.

Good Luck,
Lenny Kurup
EMX Enterprises Ltd.
905-475-8000ext240.

On Thu, 20 Nov 1997, [log in to unmask] wrote:

> Can anyone shed any light on the cause and cure of the following problem?
> Some test panels with edge connectors were gold plated on a tab plater:-
>
>         Electropolish - phosphoric acid
>         rinse
>         activate - 10% sulphuric acid
>         rinse
>         gold plate - nickel hardener
>         rinse
>         dry
>
> These boards were then passed through a conveyorized solder resist curing oven.
>
> The area  exposed to the tab plater solution turned a red/ purple colour.
>
> Other boards also tab plated were washed in a post hasl cleaner, passed through a 3%
> caustic soda coveyorized resist stripper and finally passed through a brushing machine.
>
> When passed through the the resist curing oven the area exposed to the tab plater
> solutions turned red/purple.
>
> When I tested the insulation resistance between the edge connector fingers on the
> stained boards at 1000 volts it was 145 gigohms.
>
> Some of the stain can be removed with acetone but not other solvents.
>
> Thankyou in advance
>
> Roger Hammond
>
> ##############################################################
> 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
> ##############################################################
>

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


ATOM RSS1 RSS2