Reccomendations for fine pitch ribbon/flex/flat cable?

Question

Hi - I need to connect two PCBs together. They will move relative to each other constantly. I'd like to find a fine pitch (maybe 1mm or so) flat cable to connect between them - preferrably one that will be able to tolerate this movement. I should mention this is not a production item - under 10 of these will be made. I'd like it to be some sort of flat cable that can easily have connectors added on to it.

So I see two major possibilities for connectors. The first I think is called "insulation displacement connectors" - the kind of connector that punches into a ribbon cable. The other possibility I see is what you often see connecting the laser in an optical drive to the main board - where there is a clear cable and the connector is just a stiffer bit on the end of the cable. Is it possible to make such cables? Or does that have to be done by machine?

Any suggestions? Thanks!

-M. Noone

Pooh Bear · Accepted Answer

I assume you're familiar with 0.05" pitch ribbon cable ?

There is a high density version on 0.025" pitch. I used it once where space was *very* tight. Yamaichi made it under the 'Nanoflex' trade name. I'm sure there are likely to be other suppliers now too.

We had the cable assemblies made by the supplier. I don't mind doing 0.05" pitch in a machine vice but I reckon you're better off getting assemblies made by the experts with the high density stuff.

Other possibilities exist but are unlikely to be practical for a qty of 10.

Graham

Tim Hubberstey · Answer

IDC cables are, generally, not intended to be used in applications where they will be subjected to a lot of flexing. The 0.025" stuff is even less flexible.

There are stock flex cables available from several manufacturers. These are standard versions using similar construction to your "laser cable". Take apart any laptop and you'll probably see a bunch of them.

There are 2 main versions (and many variations):

Has pins crimped onto both ends for soldering directly onto PCB or inserting into connectors.
Has flat, tinned pads at the cable ends. Mates with a connector that looks similar to a PCB edge connector but has a locking mechanism to hold the cable.

My guess is that type 2 will probably stand up to repeated flexing better than the type 1. For examples of both cables and connectors, see pages 52 & 53 of the *Canadian* Digi-Key catalog:

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I assume the US catalog has the same (or similar) parts available.

Reccomendations for fine pitch ribbon/flex/flat cable?

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