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How does one go about creating a board file for a board with both "normal" PCB material, and flex materal? I have a project where I want the PCB and a flex bus to be seamlessly joined, like: http://www.globalsources.com/gsol/I/Rigid-flex-PCB/p/sm/1055505035.htm

Do you suppose that is one board file? Is the bus defined as a separate part, or is it PCB with different attributes?

I realize that different fab houses may take different schemes for doing this in board files, and there are clearly different kinds of flex fabrication, but I'm wondering if there is a typical or obvious way this would be done / not really sure where to start.

Purrell
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    Most likely it'll be one board file with a polygon defining where the board should be rigid. I don't think EAGLE has a default layer for this, but it's easy to create and add it to your gerber output. The complete answer to this will be highly board house dependent. – Samuel Oct 23 '13 at 15:46
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    This is definitely something you'll have to work out with the board fabricator -- find out exactly what they need in terms of Gerber files. Eagle is flexible enough that it should be easy to set it up to generate whatever they want. My guess would be that they'll need two separate "outline" drawings, but they'll have to tell you how to name the files. – Dave Tweed Oct 23 '13 at 15:56
  • I e4xpect that you would need two separate PCB files. Few board shops will be capable of making a flex cable, as the flex portion will require very a different process than the normal rigid board. In any case, discuss this with your board shop _before_ doing much work on the board layout. – Peter Bennett Oct 23 '13 at 16:21

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A PCB fabrication house I am familiar with treats such "hybrid" board designs as two PCBs, with the junction as an array of traces on each side, to be soldered as per their normal process. This is similar to how a regular FFC would connect to a regular FR4 PCB.

The board files, including copper and mechanical outline layers need to be separate for the two PCBs, with annotation to indicate alignment for assembly / soldering.

Other fabricators might offer different options, though it seems a little unlikely that a single board file would be accepted: The actual FPC and FR4 boards would be etched and routed in separate processes, so combining the design into a single board file leaves the separating out of the two parts into separate outline, copper, resist etc in the hands of somebody at the fab shop.

Anindo Ghosh
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