I am planning to use Ribbon cable for my 3D printer

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(Selvakumaran Ganesan) #1

I am planning to use Ribbon cable for my 3D printer. I am trying to connect the hot end cables (Heater cartridge, Cooling fan, Thermistor) cables to that Ribbon cable. What type connector can be used? Any consideration is required?

Is there any standard to get a Ribbon cable? Also, what is the difference between Ribbon cable and FFC?

Any suggestions please.

(Mano Biletsky (Open MAKER)) #2

What thickness are the copper wires in the ribnon cable? Also ribbon cable is not meant to bend. If you bent it several times, the copper core will break

(Alexey Volkov) #3

@Mano_Biletsky_Open_M ? Flexible ribbon cables used in many automation applications including robotics with no issues. Yes, the sharp bend would break quite fast, but for a wide loop it would work berret than standard wite in a flex track.

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(Alexey Volkov) #4

@Alexey_Volkov sorry, better than stadnard wire. Freaking autocorrect :sunglasses:

(ThantiK) #5

Don’t use this on a 12v system, it will require too much amperage. 24v system may work better so long as you’re within amperage limits of the ribbon connector. (Doubling up on wires can help here) Ribbon cable can be an IDC-style connector, which means it’s actually just a bunch of thin round-style wires next to each other. These are easier to terminate yourself, fit well into 0.1" headers (shrouded work best), and can be customized pretty easily.

FFC ribbon cables are typically copper traces like you’d find on a PCB sandwiched between polymer layers. Sometimes the ends are backed with a little piece of fiberglass board to make them rigid and easy to plug into things. They are not easily terminated by a DIYer and would probably require a PCB with a special connector to be matched up for them.

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(Anders Jackson) #6

@ThantiK it is current that you measure in Ampere, there are no such thing as amparage. Yes, it is called voltage that you measure in Volt, but that is another thing.

Half the voltage, and the current will be 2²=4 times higher for the same energy transfer if the resistance are the same.

P = UI can be written like this with Ohms law. P = I² R or P = U²/R. If you set Power equal and R equal, then you get the conclusion from above.
If you double the connections you get half the resistans, BUT you can easily get uneven distribution of the current, as the resistance is probably not the same. Then you might burn one wire and then the other by transfer to much energy in them. That why it is not recommended to have parallell wires. On wire will transfer energy between different strains in the wire, and avoid this problem.

(Mano Biletsky (Open MAKER)) #7

@Anders_Jackson Actually @ThantiK this correct. You can call it ‘power and current’ or ‘voltage and amperage’. Both are correct. But the ones of us that are schooled as electrical engineers usually use amperage over current.

(Peter Hertel) #10

The Mendel90 uses ribbon cable. Have worked flawlessly for me for several years now. Nophead has some calculations on why he chose it. I use an old floppy cable for mine.

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(Anders Jackson) #12

@Peter_Hertel good to hear from someone with experience.
What kind of current and voltage are we talking about there?

(Peter Hertel) #15

@Anders_Jackson Page 20 and 36+37 of the manual https://github.com/nophead/Mendel90/blob/master/dibond/manual/Mendel90_Dibond.pdf?raw=true explains some.
It’s 12v and I don’t recall exactly but isn’t the standard reprap setup from back then 8-10amps for ramps+motors+jhead/extruder and 15-20amps for the bed?
https://github.com/nophead/Mendel90/blob/master/dibond/manual/Mendel90_Dibond.pdf?raw=true

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(Anders Jackson) #16

@Peter_Hertel thanks for the link.
I guess there are a reason why it isn’t used anymore. :wink:
Running stepper motors on wires I think is a reasonable option, even it the wires are still a but under sized.
But really, running the heater is a bad idea, when there are proper ways of handling that, with cable chains. There are reasons why one should take electricity seriously, and not design on the lower limits. Undersized wires will get hot. Especially if the wires turn bad and resistance get higher, but the CURRENT still are high.

(ekaggrat singh kalsi) #17

i am using 26 guage ribbon cable on my printer with no problem. you can even use idc 28 guage cable. you just need to run the heater though multiple wires. 2-3 wires in a pair will work fine…

(Michael K Johnson) #18

If you know the maximum current, and you know the gauge of the wires in your ribbon cable, you can look up tables of current-carrying capacity, often called “ampacity” as a portmanteau of “amperage” and “capacity”. In those tables, you will typically find cross-sectional area. You can find the gauge with sufficient current-carrying capacity in free air with PVC insulation, look up its cross-sectional area, and use as many strands in your ribbon cable as have equal or higher cross-sectional area as the the sufficient gauge. Don’t forget to sum your currents for required ground gauge, otherwise all your work is useless. In ribbon cable, you might consider for signal lines (e.g. bltouch data lines, thermistor connections) having immediately adjacent lines bonded to ground on only one end as a bit of a shield, and definitely not running them immediately adjacent to stepper driver lines which will inject all sorts of noise. :slight_smile:

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(James Rivera) #19

I’m not an EE (though that was my original goal in college)—just a wannabe. But as stated above, Nophead used them in his Mendel90 reprap design. If you’ve ever read Nophead’s blog or any of his posts, then you know he is an EE and does thorough investigation before posting his thoughts and designs. (Aside: a personal hero of mine wrt reprap 3D printers for this very reason). Basically, if he used it on the Mendel90 then it should be fine. IIRC, whosawhatsis also used ribbon cables in his printer design (another smart reprap guy). Additionally, I find it odd that 2 wires of nearly identical lengths and thickness would be out of balance. If so, it should be negligible. Finally, can we stop being pedantic? Please? Okthxbye.

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(Michael K Johnson) #20

Heh, I had deleted from my response a request for reduced pedantry!

For summing currents, I was just trying to say that if, for example, you are running dual extruders and determine that you need two wires for the current drawn by one extruder, each will take two for positive, and they can share four for negative.

Your signal grounds should be separate from power grounds because the wires are resistors. This is normal design practice, and I forgot to mention it in my first reply.

(Rod Shampine) #21

Another good trick is to attach a cheap tape measure to it as a bend controller; this will keep your ribbon cable from getting kinked or failing at the ends.

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(Whosawhatsis) #22

Yes, the Bukito also uses ribbon cables. Almost everything on a typical 3D printer is within spec for a single line on a standard 28awg ribbon cable except the heaters (larger stepper motors are marginal). For those, parallel lines work.

Yes, it is possible for one 28awg wire to have a very slightly lower resistance than another, but it’s not a big effect, and remember that copper has a positive temperature coefficient of resistance, so if one wire is heating more because it is carrying more current, its resistance will increase, bringing it into a closer balance of resistance with the others. This makes the current carried by the multiple lines somewhat self-leveling, rather than a situation where you could get thermal runaway in one wire until it fails, causing a cascading failure in the parallel lines.

Nophead backed his ribbon cables with a thin plastic sheet to enforce a minimum bend radius (similar to a cable chain). I always liked this idea, and we experimented with it for the Bukito, but ultimately decided that it wasn’t a fit for our application. Nophead does NOT use IDC connectors on his, and instead individually solders the wires into D-sub connectors, which I always thought was a dumb idea.

Check the ratings of your wires and connectors (note that the current-carrying ability of ribbon cables is slightly different when you have multiple current-carrying lines adjacent on the cable, since they will both be heating the same bit of insulation). We determined that ours could safely handle 1A per line, and our heaters drew 3.33A @12V, so at least 4 lines were needed. I increased this to 5 for some additional safety margin, and further ganged the high side with a sixth one paired with the switched fan power lines (which did not need a full 1A). Even if a single wire did fail, it would still be well within spec, and a double failure in the same gang would probably still have been ok.

There are ribbon cables you can buy with higher current ratings. Though they are more rare, there are 26AWG cables with the same .05" spacing, compatible with standard IDC connectors. Those will carry more current per line, but at Deezmaker, we decided to go with the more common cables, both for cost reasons and because we wanted to design with the safety margins for it anyway, since we wanted to make it possible for users to create their own cables (we had ideas about selling the boards separately as upgrades and creating standards that never really came to fruition), and knew that if we did, someone would eventually try to use it with the cheapest, lowest-spec’d parts available, and we wanted that to be safe.

The best cables, of course, are silicone-insulated high-flex cables. Not only are they the best for repetitive motion applications, but the insulation can handle much higher temperatures as well. Cicoil sells IDC-terminated high-flex ribbon cables that are supposedly rated for a whopping 5A per line, though my research showed that none of the connector hardware could possibly be rated that high. Still, other than maybe a custom flat-flex cable, I’d say those are probably the best type of cables you could possibly use for moving components in a 3D printer.

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