Can an FFC cable be fold to make a 90° angle?

Question

I'm talking about a standard flexible FFC cable, like this one as example.

I need to make a planar 90 degrees angle: the connectors are on the same PCB but rotated of a right angle.

I tried with a real cable and unless you firmly press the bending area it bends very easily.

I'm looking in the datasheet for any parameters or indications related to this (mis-?)use but I find nothing relevant.

Is this a specific feature I need to look for? Or I can do this without problems?

I'm aware there are cables with this specific shape but they are less available and customizable.

EDIT

Looking at the comments I believe I wasn't so clear in the first sentence. The datasheet I linked was just an example. I didn't select that specific model, my question is general for any FFC cable.

What I'm asking is which parameter (if any) I have to look for in the datasheets to be sure I can bend the cable as described.

Answer 1

There appears to be a specification relating to flex, bend, and cycle life.

From the datasheet:

The counts are likely minimum cycle lifetimes for the various grades of product. R5 might be a bend radius, 240 could be an angle (degrees?), 40mm might be length (of the cable tested? of the section flexed?).

Without a definition of these parameters, they aren't very useful.

Beyond this, I cannot help -- contact the manufacturer for more details.

If this is not sufficient information for your purpose, and contact isn't feasible, I would suggest shopping other brands, or distributors, until you find one adequately specified.

Alternately, set up a bending/flexing jig, and perform parts-receiving testing as a part of your own quality program. This is generally a Big Deal and best avoided (and left to those skilled in the matter, the manufacturer themselves), but it's worth mentioning for completeness.

If you only need a one-time crease, it's probably fine, but preferably should be kept above a minimum bend radius, and may be best with strain relief or a stiffening rib. Most datasheets specify this -- again, due to the language differences and general terseness of this datasheet, it's not clear to me if they do here, or omit it entirely.

Answer 2

FPC cables and circuits are, by default, intended for static applications and dynamic bends or sharp bends can cause failures.

Typically you should keep a minimum bend radius of a few mm (5 or 6 should be safe) and limit repeated flexing as much as possible. You do not want to make a sharp fold. Those two constraints may conflict in your case, especially if you have vibration. You may have to wrap the cable around a plastic post or something like that and glue it to both fasten it down to prevent flexing and to control the minimum bend radius.

The manufacturer should be able to provide more specific guidance for their products.

There are FPC techniques that produce circuits capable of dynamic flexing with reasonable life, and that's an extra-value feature that will be mentioned in the data. The Megastar (Zhaoxing Precision Electronics) product you linked to appears to be such a component- they are using copper that is manufactured to be particularly resistant to cracking unlike a typical FPC.

Answer 3

I had an application where I needed a 90deg bend upon asking the manufacturer (epic tech) they recommended at least 2x the thickness for a bend radius on the 90° bend. Which I think amounted to about 3-6 mil. The band could only be performed once after that there was no guarantees on copper performance. If the bend radius was increased you could bend it several times.

I would first talk to the manufacturer if they have no experience in this arena then perform experiments yourself, I would think you need a very high resolution x-ray to see if the copper was cracking and to what degree.