Stress Relief for Potted Flexible Cable

[SysDev]

Hello,

I have an application in which a thin flexible cable is jumpered between two ciruit boards that reside in potted metal housings. The flexible cable is embedded in a hard inelastic epoxy due to the nature of the application. I am finding through time that I am losing communication between the two circuits and recognize that there is vulnerability at the interface between the two board containers.

I am searching for recommendations on how to relieve the flex cable stress at the interface between the two containers. I have attached a picture for your consideration.

Please note the following:
The flex cable is approximately 1.5 mm wide and .1 mm thick.
I have limited flexibility to change the dimensions of the entrance / exit slots but will if I can find a compelling solution.

Thanks for any feedback you can provide.

 

[MikeHalloran]

A photograph would be more helpful than your picture.

That's a whisker, not a cable.

Do I understand correctly; there are no connectors, the cable ends are potted into the cans, and soldered to the boards within the cans? If that conjecture is correct, I would further conjecture that the cable is being used as a handle to carry the two boxes.




Mike Halloran
Pembroke Pines, FL, USA

 

[SysDev]

Unfortunately a photograph cannot be provided due to the nature of the equipment. I will provide additional details...

- The top housing and bottom housing are bolted together.
- As noted in the previous message, "thin flexible cable is jumpered between two ciruit boards that reside in potted metal housings"
- The flex circuit is fully embedded in inelastic potting compound.
- The problem is occurring at the interface between A & B.

Regards

 

[MikeHalloran]

>>- The flex circuit is fully embedded in inelastic potting compound.<<

Flex circuits are designed to flex.
If you embed them in, e.g. concrete, then strain the concrete, you will probably fracture the circuit.

Would it be possible to cover the flex circuit with something flexible, like self-leveling RTV, before potting the attached cards?



Mike Halloran
Pembroke Pines, FL, USA

 

[SysDev]

Mike,

that's exactly the type of solution I've been hoping for. We've expended some energy trying to design a flexible circuit sleeve that would create a pocket around the flexible circuit; however, due to the geometric constraints, this has proven challenging. The idea of using a self leveling RTV prior to pocket may be the ticket. I'll test this out and get back to you.

Best