Danger Will Robinson. Danger.

voltage + humidity + silver + close proximity = ?

check your textbook if you don't know how to spell migration

(Feb '92 issue of SMT "Conductive Epoxy Adhesives to Replace Solder" last
paragraph)

i am personally in the middle of an ugly one right now related to this.  we
unwittingly spec'd an ink with ~30% silver content onto a phone keypad.

the application had nominally 10 mil spacing and 3.3vdc applied.  classic
migration shows and keypad stops working after 3-4 weeks at 50C/95%RH.

Bummer.  That's about ambient in India during Monsoon season.  Guess where
our beta was?  =8-0

good news is it's early in the program and we're recovering fine.

bottom line: if it's got silver and it's not encapsulated (e.g. s/m or
conformal coat) you won't see me signing off on it.

see ya,
dwight
staff qe

At 6:37 PM 11/14/96, Aric Parr wrote:
>     We have multiple single sided panels with carbon ink keypads. To avoid
>     going double sided, or using multiple jumpers, we used the same carbon
>     ink as conductor traces over the solder mask. No reliability or yield
>     issues to date.
>
>
>______________________________ Reply Separator
>_________________________________
>Subject: Silver Ink Screen Print.
>Author:  [log in to unmask] at internet
>Date:    11/14/96 9:01 AM
>
>
>Does anyone have any experiencies or information relating to "Silver Ink
>Screen Print" (or any other form of screen printed conductors).
>
>We have a situation where we have a number of PCA designs which have only
>a few minor modifications required. These will be picked up at the next
>CAD revision, but in the mean time, we would like to investigate
>screen printing additional connections accross the boards, without the
>need to hand wire.
>
>Any comments are appreciated.
>  ________________________________________________________________________
> | [log in to unmask]         David Tandy. EDA Specialist.   GenRad ADS. |
> | Tel: (+44) 161 491 9191     Orion Business Park, Bird Hall Lane,       |
> | Fax: (+44) 161 491 9292     Stockport, Cheshire, SK3 0XG, England.     |
> |________________________________________________________________________|
>
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