# Rigid-Flex Layer Preference

**URL:** <https://sierraconnect.protoexpress.com/t/rigid-flex-layer-preference/4340>\
**Category:** Flex and rigid-flex\
**Created:** [August 7, 2026, 10:54am UTC](https://sierraconnect.protoexpress.com/t/rigid-flex-layer-preference/4340 "2026-08-07T10:54:28Z")\
**Posts on this page:** 4\
**Page:** 1

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**Author:** ![phil.holden](https://avatars.discourse-cdn.com/v4/letter/p/e47774/32.png) [@phil.holden](https://sierraconnect.protoexpress.com/u/phil.holden)\
**Post date:** [August 7, 2026, 10:54am UTC](https://sierraconnect.protoexpress.com/t/rigid-flex-layer-preference/4340/1 "2026-08-07T10:54:28Z")

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For a 2-layer rigid-flex with a single-layer flex limb, do you have a fabrication preference for whether the flex copper continues from the top or bottom rigid layer, or is either acceptable?

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**Author:** ![lucy.sierracircuits](https://sea2.discourse-cdn.com/sierraconnect/user_avatar/sierraconnect.protoexpress.com/lucy.sierracircuits/32/8_2.png) [@lucy.sierracircuits](https://sierraconnect.protoexpress.com/u/lucy.sierracircuits)\
**Post date:** [August 7, 2026, 8:49pm UTC](https://sierraconnect.protoexpress.com/t/rigid-flex-layer-preference/4340/2 "2026-08-07T20:49:00Z")

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Hey Phil,

Thanks for posting. So our senior design engineer Greg Albers says, “There is no such thing as a rigid-flex 2-layer board.” He’s asking if he can call you to discuss. you can send me your number at [lucyi@protoexpress.com](mailto:lucyi@protoexpress.com).

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**Author:** ![phil.holden](https://avatars.discourse-cdn.com/v4/letter/p/e47774/32.png) [@phil.holden](https://sierraconnect.protoexpress.com/u/phil.holden)\
**Post date:** [August 10, 2026, 7:46am UTC](https://sierraconnect.protoexpress.com/t/rigid-flex-layer-preference/4340/3 "2026-08-10T07:46:28Z")

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Hi Lucy,

Thanks for the follow-up. I think there’s a terminology misunderstanding. I’m referring to a rigid-flex construction where the rigid section is 2-layer, with a single copper layer continuing into the flex limb.  
My question is simply whether, from your fabrication process point of view, you have a preference for that flex layer to originate from the top or bottom rigid copper layer.

Thanks,

Phil

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**Author:** ![lucy.sierracircuits](https://sea2.discourse-cdn.com/sierraconnect/user_avatar/sierraconnect.protoexpress.com/lucy.sierracircuits/32/8_2.png) [@lucy.sierracircuits](https://sierraconnect.protoexpress.com/u/lucy.sierracircuits)\
**Post date:** [August 12, 2026, 1:41pm UTC](https://sierraconnect.protoexpress.com/t/rigid-flex-layer-preference/4340/4 "2026-08-12T13:41:49Z")

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Hi Phil,

I’m currently on vacation but our team is looking at your reply.