Unpluggable Hotend

Hey guys,

My printer has just destroyed its hotend now I have to change the heater cartrige which is quite annoying. So i thought of putting a plug between everything which is connected from hotend to the board. Has anyone of you done that or thought of doing that too?

Which plugs would you use? I am thinking of a bigger one with 4 wires for the two hotends (which get about 3 amps) and a second plug for the thermistors, the endstop and the 4 fans (which get <0.7 amps) with thinner wires.

I'd love to hear some recommendations

Thanks in advance
Marius

The usual choice is Molex Microfit 3.0 series connectors. One disadvantage of these is that the pins are impossible to remove from the shells without a special tool.

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Large delta printer [miscsolutions.wordpress.com], E3D tool changer, Robotdigg SCARA printer, Crane Quad and Ormerod

Disclosure: I design Duet electronics and work on RepRapFirmware, [duet3d.com].

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dc42
The usual choice is Molex Microfit 3.0 series connectors. One disadvantage of these is that the pins are impossible to remove from the shells without a special tool.

Exactly what I had in my mind I just did not know how the plug from a graphics card is called.
With remove you mean disassembling the wires from the plug once they are connected?
Do you need a special tool to connect the wires to the plug too?

And isn't there a smaller solution for the fans endstops etc? They do not get high current and 14 pins would be quite large

Edited 1 time(s). Last edit at 10/23/2017 07:56AM by Schild0r.

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Schild0r

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dc42
The usual choice is Molex Microfit 3.0 series connectors. One disadvantage of these is that the pins are impossible to remove from the shells without a special tool.

Exactly what I had in my mind I just did not know how the plug from a graphics card is called.
With remove you mean disassembling the wires from the plug once they are connected?
Do you need a special tool to connect the wires to the plug too?

And isn't there a smaller solution for the fans endstops etc? They do not get high current and 14 pins would be quite large

Yes I mean disassembling the wires from the plug or socket once they are connected. To connect the pins to the wires, use a crimping tool.

For fans and endstop switches, Molex KK254 series are popular (and you can easily remove the pins from the shells), however AFAIK they are only available in cable-to-PCB versions, not cable-to-cable. You could also use JST 1.5 or 2mm connectors, but they are very fiddly to crimp.

Edited 1 time(s). Last edit at 10/23/2017 04:55PM by dc42.

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Large delta printer [miscsolutions.wordpress.com], E3D tool changer, Robotdigg SCARA printer, Crane Quad and Ormerod

Disclosure: I design Duet electronics and work on RepRapFirmware, [duet3d.com].

Thanks for the suggestions I will look which one fits best for me. I also heard of superseal plugs which a friend of me is using.
Maybe I will use industrial standard micro round connectors for the x endstop, the z probe and the two thermistors which would need 9 pins in total
And for the hotends and the fans the molex or superseal plugs which will need 5 pins (4 ground wires for the fans will be on a single pin)

I've got Toranado's.
[www.thingiverse.com]

The hot end is an insert:
[www.thingiverse.com]

I think that cabling and especially connectors to the extruder carriage are one of the hardest problems to solve in 3D printers. Multipin connectors that have at least a couple pins that can handle the hot-end heater current tend to be expensive, bulky, and difficult to separate when the time comes. I've been through at least 5 or 6 different types of connectors and cables in multiple printers and I have yet to find a method that I'm really happy with.

The closest I've come to extruder cable nirvana is a machine I built that uses a flex ribbon for the cable, but requires circuit boards at each end of the cable to terminate it in either header pins or screw terminals. It was a PITA to set all that up, but that cable will probably not fail in my lifetime.

I my latest printer, I took the path of least resistance and just used DuPont connectors for everything but the extruder heater. The heater wires are soldered to the cable. If I ever have to change the heater I'll have to cut the wires loose and maybe solder them again, or maybe use some Anderson Power Pole connectors.

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Ultra MegaMax Dominator 3D printer: [drmrehorst.blogspot.com]

For what its worth DB9 connectors can be found up to 5A per contact and the mixed varieties can go as high as 50A per contact.

I plan on using DB terminated CF884 cable on a future printer. It has perfectly sized bundles for a heater and stepper motor, plus three individually shielded pairs for temp/fans; and the entire thing is double shielded and flex rated.



For some reason the CF884 is about a third of the price of its surrounding part numbers (maybe its standard and the others are lower volume?). More expensive than loose hook-up wire, but very cheap as far as flex-rated cable goes.

I'd be happy with a DB9 or rj45(though the cables can be bulky whats the diam of one above?) for most/all other things and a seperate on for the hotend, XT60 or 90 somewhere on the cable so I can detach from ramps easy/quick, but ideally one in the mount like the tornado.

Edited 3 time(s). Last edit at 10/24/2017 09:48AM by MechaBits.

That CF884 looks interesting. Have you used it?

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Ultra MegaMax Dominator 3D printer: [drmrehorst.blogspot.com]

I've used other Chainflex cables but not 884 in particular. Flex-rated cables can be a bit of a PITA to terminate because there are so many layers of insulation and shielding to get through (and in most cases you want the drain and shield intact). You also have to remember that even though they are designed for bending, cables with a large number of conductors still need a lot of room. For example the min bend radius for continuous flexing of CF884 is 4".

On the other hand the cable is rated for five million strokes, can operate over a wide range of temperatures, and is both shielded and flame retardant. A single 9mm cable is also much nicer to route and look at than the usual mess.

E3D sell thermistors and heater cartridges with connectors... Quite handy actually, but as digital dentist said it is still not the perfect answer. I tried flex cable but I wasn't happy with having to fit a small pcb near the hotend to put the connectors on.

If we are talking about cabling nirvana though, the delta carriages by dc42 must come very close! All the electronics integrated into the carriage all with soldered on connectors.... Now if I could fit that into a corexy we would be onto a winner!

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prot0typ1cal
I've got Toranado's.
[www.thingiverse.com]

The hot end is an insert:
[www.thingiverse.com]

How are those toranados?

I'd say +1 for the smart effector in terms of dealing with all the wiring, which on my kossel Xl is now 2 cat5e network cables. 6 cores devoted to the hotend heater which is on 24v so 2A max and then the rest of the cores take care of thermistor, hotend fan, and print fans leaving 2 spare. These cables are omnipresent and fairly flexible. Make sure you use the 24 awg ones not 26, and that they are stranded not solid.

Something in the same spirit would be very useful for other styles of machine also.

I've recent been talking with someone on thingiverse who is designing a pcb integrating our piezo circuit and offering all the above functionality to make connection between controller and print head easy, but its quite early days yet.

[www.thingiverse.com]

Edited 1 time(s). Last edit at 11/04/2017 05:15PM by DjDemonD.

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Simon Khoury

Co-founder of [www.precisionpiezo.co.uk] Accurate, repeatable, versatile Z-Probes
Published:Inventions