Why would you want that portion of the flex, where is exits from the rigid board, to have nickel plating? That is typically under the polyimide layer and is also typically covered with a bead of epoxy along the edge.

-----Original Message-----
From: Hernandez, Victor G <[log in to unmask]> 
Sent: Thursday, May 27, 2021 9:33 AM
To: TechNet E-Mail Forum <[log in to unmask]>; Stadem, Richard D <[log in to unmask]>
Cc: Hernandez, Victor G <[log in to unmask]>
Subject: RE: [TN] ENIG plating Flex Circuit

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Folks,

    I want to be clear that my main concern at this time is the FLEX Circuit portion as it exits the Rigid Flex termination region of the Rigid Flex Board.
I was not aware that nickel could withstand flexing/bending.   Nickel is brittle.  A 90 degree bend on a flex circuit with a distance of 0.122 inch.
I will conduct x-sec to see if I find any copper/ENIG conductor anomalies.

Victor,

-----Original Message-----
From: TechNet <[log in to unmask]> On Behalf Of [log in to unmask]
Sent: Thursday, May 27, 2021 9:18 AM
To: [log in to unmask]
Subject: Re: [TN] ENIG plating Flex Circuit


[EXTERNAL EMAIL] 

Me neither. It takes a very sharp bend in the flex to affect most ENIG-finished individual component pads, and most larger ground planes/traces are typically not finished (covered with polyimide).
And (again, typically) once the components are soldered in place it is pretty darn hard to bend the flex sharply enough to do any damage. You would have to try really hard. The components would crack before any damage was done to the soldered pads. 
ENIG is one of the most common flex circuit finishes.
Odin
-----Original Message-----
From: TechNet <[log in to unmask]> On Behalf Of Larry Brophy
Sent: Thursday, May 27, 2021 8:04 AM
To: [log in to unmask]
Subject: Re: [TN] ENIG plating Flex Circuit

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Never had a problem with it Victor.

Regards,

Larry

-----Original Message-----
From: TechNet <[log in to unmask]> On Behalf Of Hernandez, Victor G
Sent: Thursday 27 May 2021 14:03
To: [log in to unmask]
Subject: [TN] ENIG plating Flex Circuit

Fellow TechNetters:

   Is ENIG surface plating finish suitable for a flexible circuit in a Rigid
Flex application?   Nickel is brittle.

Victor,