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Standardised hot-end connector

Posted by frankvdh 
Standardised hot-end connector
March 17, 2018 07:23PM
I'm thinking about using different hot-ends and nozzles on my printer (Volcano vs E3DV6 vs Diamond), and thinking therefore about easy ways to disconnect and connect from the controller board. Has anyone gone done this route and want to share what they've done and the good points/bad points of their solution?

What I have is a pair of wires 12V/4A for the heater, 2 pairs 12V/0.1A for fans, 1 pair for the thermocouple. Anything I should add for future expansion? I might be able to reduce that by a couple of wires by combining the grounds of the heater & fans, but I suspect that's a bad idea. So an 8-pin socket and plug. Is an ordinary PCB header strip of 8 pins going to be suitable? Probably it would be a good idea for each component to be (dis)connected separately, so I'm thinking a short piece of Veroboard 8 strips wide, with 8 pins at one end, and 8 sockets at the other. Each pair of wires from the controller would be soldered to a pair of sockets, and each pair of wires to the hhot-end would be soldered to a pair of pins. The Veroboard could be mounted or clipped onto the effector.

So removing a hot-end would be a matter of unplugging the 4 pairs of wires, undoing the Bowden connector and cutting the filament, then detaching the rods from the magnets. The new hot-end could be swapped onto the effector, or each hot-end could have its own effector. Since removing the hot-end is much easier, its would also make it easier to change nozzles, and do any other hot-end maintenance.

Thoughts please!
Re: Standardised hot-end connector
March 17, 2018 08:24PM
Well, I haven't done this myself, but E3D's current generation cartridge temperature sensors and the new 'high-precision' heater cartridges both include disconnect points about 3 inches up the wires, so you'd only need a 4 pin connector for the fans with the V6/Volcano, one pair for the part-cooling fan and one always on pair for the heat-sink fan. The Diamond is a completely different beast entirely, I'd seriously not recommend installing it on a multi-head machine, it's already 3 heads in one anyway.
Re: Standardised hot-end connector
March 18, 2018 03:03AM
PCB header pins are only good up to about 2A, so no good for the hot end heater if you are using 12V power.

It's a good idea to separate the low voltage (e.g. temperature sensor, Z probe) and higher voltage (heaters and fans) so that you are less likely to mix them up.

On the Smart Effector we use a 6-pin Molex Microfit connector for the fans and heaters, and an 8-pin Molex KK for the low voltage connections. See [duet3d.dozuki.com]. This is sufficient to handle one heater, two fans, a 4-wire temperature sensor and a 4-wire Z probe.

Edited 2 time(s). Last edit at 03/18/2018 03:05AM by dc42.



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

Disclosure: I design Duet electronics and work on RepRapFirmware, [duet3d.com].
Re: Standardised hot-end connector
March 18, 2018 05:48AM
Quote
dc42
PCB header pins are only good up to about 2A, so no good for the hot end heater if you are using 12V power.

It's a good idea to separate the low voltage (e.g. temperature sensor, Z probe) and higher voltage (heaters and fans) so that you are less likely to mix them up.

On the Smart Effector we use a 6-pin Molex Microfit connector for the fans and heaters, and an 8-pin Molex KK for the low voltage connections. See [duet3d.dozuki.com]. This is sufficient to handle one heater, two fans, a 4-wire temperature sensor and a 4-wire Z probe.

And avoid ground loops. For ex. the - (ground) of the heater must be separate from the T° sensor ...


"A comical prototype doesn't mean a dumb idea is possible" (Thunderf00t)
Re: Standardised hot-end connector
March 22, 2018 08:54AM
Some sort of standard connector would be very useful. It's conceivable that a hotend could have a 4pin plug with two 4A and two (four) much smaller connectors for a thermistor (or pt sensor). But having a universal unit for a print head is much more difficult it will need spare unused pins for any number of possible configurations of 1-4 hotends, parts fan, hotend fan, sensors, servos etc.. Which makes for a large complex automotive type connector which would be far too bulky for a simple setup.

I think the possible route of having a daughter board on the head with power and a data bus connection back to the main controller could achieve a more suitable solution.

Edited 1 time(s). Last edit at 03/22/2018 08:54AM by DjDemonD.


Simon.

[www.precisionpiezo.co.uk] Accurate, repeatable, versatile z-probe plus piezo discs, endstop cables, pt100, 50w heaters. PT1000 cartridge sensors plug straight into duet boards and others.
Published:Inventions
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