Fully route the rigid portions, and leave small connecting tabs on only the inner layer flex layers.  Then you can simply use an xacto or other type blade to separate the flex-rigid simply by cutting the flex tabs.

-----Original Message-----
From: Pradeep Menon [mailto:[log in to unmask]] 
Sent: Wednesday, January 16, 2013 10:53 AM
To: [log in to unmask]
Subject: Re: [TN] V scoring of Rigid flex PCB

Thanks for the inputs. But my query is more specific on Rigid flex V scoring. We do V scoring at our end as well. 

The issue is with Rigid flex ( or flex rigid) PCBs wherein there will be flex polyimide layers ( mostly at the center,  with the rigid portion towards the outer layers. For a 1.6mm thick rigid PCB, we usually do a 0.6mm depth V cut on either side which means there is a web of 0.4mm. This is easily 'breakable' since it is rigid. But if we have a flex in the remaining web portion, it is not breakable. Hence the doubt on any accepted practice or method for Rigid flex V scoring.

Rgds

Pradeep


-----Original Message-----
From: Nutting, Phil [mailto:[log in to unmask]]
Sent: Wednesday, January 16, 2013 8:35 PM
To: TechNet E-Mail Forum; Pradeep Menon
Subject: RE: V scoring of Rigid flex PCB

Pradeep,

You will find several discussions on V-scoring in the Technet Archives.  V-scoring is discussed in IPC 2222.

The Internet has many locations that discuss it, for example: http://www.pcbstandards.com/forums/showthread.php?t=2261

To separate the boards at the V-score typically a sharp wheeled device (like a pizza cutter) is drawn over the V-score and does a very nice job of cutting the boards apart.  Bending the boards so they break at the v-score works but is a VERY BAD PRACTICE as it puts large stress on components near the edges which possibly causes failures of the circuit with broken components or cracked etches.

See http://www.cab.de/en/electronics/pcb-separators/ for pcb separators.

Good luck,

Phil Nutting

-----Original Message-----
From: TechNet [mailto:[log in to unmask]] On Behalf Of Pradeep Menon
Sent: Wednesday, January 16, 2013 8:19 AM
To: [log in to unmask]
Subject: [TN] V scoring of Rigid flex PCB
Importance: High

Sir/Madam,

We have a customer who has asked for v scoring of rigid flex pcb. We are wondering how the PCB will be separated later, once we supply to them. Our customer has a drawing which calls for it, but they are also not very clear on this. We wanted to know whether there is a separate IPC standard or guidelines for V-scoring of rigid flex PCBs.

Tgds

Pradeep



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