About FFC cable use in 3d printers

It appears that increasing number of 3d printer manufacturers starting to use Flexible Flat ribbon Cables (FFC) in their printer designs. Here is an example (screenshot taken from 3DMN's Youtube channel https://www.youtube.com/watch?v=nP_b0sfnuAA)

I think FFC are more reliable comparing to another trend that uses VGA cables with D-sub connectors. Also, FFCs look much "cleaner" than regular cables ending with header (or similar) connectors.

I want to modify my printers and use FFCs for bringing power to print-heads and X-motors of IDEX printer, but I'm unsure about amount of current such cables can carry. I was able to find FFC voltage ratings, but nothing about max current. Out of 0.5 and 1.0 mm pitch options, I'd definitely choose the latter, but will a single pair of pins be enough to carry 3.4 Amps consumed by 40W heater?

I'd appreciate if you share your thoughts/expertise regarding this.


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I would say no, found here a datasheet with Current Ratings;


@BerndJM Thanks for the link!
Looks like I will need to choose option with 2mm pitch where each conductor has 2A rating. Two pairs of pins connected in parallel should be sufficient for heaters (2x3 would be even better). As for the rest, including motors - single conductor per wire should be enough.

I have few TearTime printers that use flatflex cables and compared to most prc 3d printer manufacturers these ppl almost know what they are doing ..

they are using "puny" 18W heaters and 19V as main voltage (heaters, motors..) but even for them they are running double tracks for heaters, so they only run 0.5A per track

now from some other use of flat flex I know they go from .03 to .1mm thickness and that's a lot of difference for current carrying capability for same width.. I assume higher thickness reduces elasticity so you need to find balance

Good point! I did not think about that. Thanks for the info.

Oh man, you beat me to it. There's no way I'd power a hotend from such a tiny wire.

I've had my experiences there. My first printer was a Velleman K8200. The whole wiring was done with "normal" ribbon cable.
2 x 3 wires for the Hotend that was already very borderline, at the latest when one or two wires break.... :fire:

The mentioned cable type 6 of the data sheet with 2mm pitch and 0.1mm thickness could work, but that's also stiff, almost 3 times as thick as a standard cable. How well - and above all how often - can this be bent? I don't know.

That's just a question of operational safety vs. beauty. :innocent:

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They also used them for the heat bed and I actually had that wire break there...

Thanks to all for your replies. I'll take them as your unanimous advise against using FFC.

I have to say, on UP Plus 2 there are 2 flatflex cables and one normal flat, 2 flatflex (maybe 3 don't remember) power 2 motors and heated bed and sensors from the bed and limit switches and... and there is one normal flat cable (10x1mm2 or 10x0.7mm2 can't say for sure they are too similar) that runs extruder motor, 2 fans, extruder heater and sensor, and after many years the flat flex cables are still operating 100% while the normal flat cable died once and now (started misbehaving 10min ago) is dead again .. has nothing to do with current carrying capacity, it did not burn, just wire got loose (last time fan wire, now it is sensor wire in the flat cable) ... and the flat cable is moving and bending a lot less than flatflex cables ... so .. dunno, have very limited experience in my designs with moving flatflex, I use them a lot but the movement is minor (during assembly or repair only)... but e.g. the ones on up plus 2 or up mini work without a problem for many years (wrt bending, wrt current carrying capacity they go with under 500mA per track)

ohh yeah ... I totaly forgot about this adventurous wiring :stuck_out_tongue_closed_eyes:

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Yes - but I learned most about practical 3D printing with that printer.

The actual reason I started this topic was sagging print-head cable in my newly built printer, but looks like I found the better solution than replacing the cables.
I bought 10 Ft. Spring-Steel Drain & Trap Cleaner in Harbor Freight for $3.99, 3d-printed 2 pieces that hold the ends of the spring and attached them to DB15 plastic hoods with 2 screws. My custom built print-head cables terminate with DB15 connectors. Spring and wires are placed into Split Loom 1/2" Tubing and keep perfect arc shape. :smiley:

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Formbot/Vivedino also went away from FFC cables and use usual ones with a spring:

If Tesla were still alive today he'd be delivering power to the hotend via a frickin' tesla coil...

...like a boss.