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Connectors for hotend wires

Posted by StlLooking 
Connectors for hotend wires
May 15, 2019 09:11AM
Hi, I would like to change out my hotend heating element as it is old and not keeping up with the demand printing at higher temps.

All the wires to the head are bunched in a cable chain and do not want to strip out the wires and snake the new ones in. I'd like to cut the wires at the head-end and install connectors for a simple swap over.

It is a 12v, 40Watt element so around 3.5Amps. What connectors can I get from Amazon that will handle that DC current OK? Something not too huge, like the XT-60 things, a 6-Amp version of those would be nice.

Thanks

Edited 1 time(s). Last edit at 05/15/2019 09:13AM by StlLooking.
Re: Connectors for hotend wires
May 15, 2019 10:48AM
For that sort of application I use Molex Mini-fit connectors - good for 9A continuous in hotish environments
[www.mouser.co.uk]

Mike
Re: Connectors for hotend wires
May 15, 2019 11:43AM
Great, thank you.

Found them on Amazon and vendor ("Bretlux" or something close to that) seems to have a lot of Molex stuff. I will know where to look next time.
Re: Connectors for hotend wires
May 15, 2019 05:20PM
Quote
StlLooking
Great, thank you.

Found them on Amazon and vendor ("Bretlux" or something close to that) seems to have a lot of Molex stuff. I will know where to look next time.

Try to make sure they are official Molex connectors as I've heard a lot of bad things about the counterfeit ones that go around. The fake ones from Aliexpress tend to loosen after a while causing spark gaps and thus heating of the connectors eventually with the possibility of causing fire etc.

(To be honest, I myself use a lot of Chinese connectors so I'm advising you against doing what I do).

Edited 1 time(s). Last edit at 05/15/2019 05:21PM by Ohmarinus.


http://www.marinusdebeer.nl/
Re: Connectors for hotend wires
May 15, 2019 05:28PM
Molex micro-fit are good for 8.5A, and a bit smaller than the mini-fit range.

I've experimented with a couple of connector types, but haven't yet found anything that's cheap, easy, and good. A big issue with connectors here, especially on a delta, is strain relief. You need to ensure the wires don't flex relative to the connectors, or the wires will break at the crimps. A tidier, but more expensive, solution would be to put a bit of Veroboard on your effector/carriage, and connect from the controller to that, and from there to the heater/thermistor/fans.

I tried using a PC power supply extension cable for the hotend... cut the cable in half, and you have a male and female connector with 4 leads. Cheap, but poor quality, and didn't last, and in failing melted the connector. Don't do this.

FWIW, I've found it convenient when working on the hot-end if there are 2 separate 4-pin connectors. One has heater and thermocouple wires, i.e. the wires that are tied to the hot-end. The other is for the two fans, and can be a lower current rating... I use JST SM connectors for this, and they work well (and I can't connect things wrongly). Depending on how the controller board MOSFETs and the GND connections work, each connector could possibly be 3 pins, but it keeps thing simple if you keep all the circuits separate. You will need another connector for the Z probe if you have one.
Re: Connectors for hotend wires
May 15, 2019 05:37PM
Quote
frankvdh
Molex micro-fit are good for 8.5A, and a bit smaller than the mini-fit range.

I've experimented with a couple of connector types, but haven't yet found anything that's cheap, easy, and good. A big issue with connectors here, especially on a delta, is strain relief. You need to ensure the wires don't flex relative to the connectors, or the wires will break at the crimps. A tidier, but more expensive, solution would be to put a bit of Veroboard on your effector/carriage, and connect from the controller to that, and from there to the heater/thermistor/fans.

I always thought the solution to compensate for wire strain, was to bundle the cables together with the bowden tube with something like spiral tube, sometimes adding in just a piece of 1.75mm nylon filament or something similar.


http://www.marinusdebeer.nl/
Re: Connectors for hotend wires
May 15, 2019 08:15PM
Quote
Ohmarinus
Quote
frankvdh
Molex micro-fit are good for 8.5A, and a bit smaller than the mini-fit range.

I've experimented with a couple of connector types, but haven't yet found anything that's cheap, easy, and good. A big issue with connectors here, especially on a delta, is strain relief. You need to ensure the wires don't flex relative to the connectors, or the wires will break at the crimps. A tidier, but more expensive, solution would be to put a bit of Veroboard on your effector/carriage, and connect from the controller to that, and from there to the heater/thermistor/fans.

I always thought the solution to compensate for wire strain, was to bundle the cables together with the bowden tube with something like spiral tube, sometimes adding in just a piece of 1.75mm nylon filament or something similar.

Yeah, I do that, and it works well for continuous wires to the hot-end and fans. I have my connectors down near the hotend, and even though I bundled the wires above and below the connectors to the Bowden tube, I still got wires breaking at the crimps. I use spiral wrap to do the bundling, and I think it allows a bit of vertical motion of individual wires, which causes stress at the crimps.
Re: Connectors for hotend wires
May 16, 2019 03:25PM
When I did this I used XT-30s (the little brothers of the common RC XT-60 connector) for the heater cartridge and Dupont connectors for the thermistor.
Re: Connectors for hotend wires
May 16, 2019 05:47PM
Quote
StlLooking
Hi, I would like to change out my hotend heating element as it is old and not keeping up with the demand printing at higher temps.

All the wires to the head are bunched in a cable chain and do not want to strip out the wires and snake the new ones in. I'd like to cut the wires at the head-end and install connectors for a simple swap over.

It is a 12v, 40Watt element so around 3.5Amps. What connectors can I get from Amazon that will handle that DC current OK? Something not too huge, like the XT-60 things, a 6-Amp version of those would be nice.

Thanks

Because I don't trust the smaller connectors, and the crimps are often difficult to do, AND I know 3 or 4 Amps will flow, I just go the safe path. I use XT60 connectors. Yes, they are big and bulky. BUT they can handle 30 Amps from RC car and plane batteries to electric motors. I KNOW they will handle 4 Amps and they are easy to solder up and will NOT come apart. Best of all, they are cheap, 10 pairs for $16, shrink insulators included.

DLC


Kits: He3D K200 Kossel, Folgertech Kossel 2020 upgraded E3Dv6, Anet A8 upgraded E3Dv6, Tevo Tarantula enhanced parts and dual-head
Scratch: Large bed Cartesian, Linear slide Delta, Maker-Beam XL Micro Delta
Re: Connectors for hotend wires
May 17, 2019 05:18AM
I had never before found info on the XT30 and XT60 connectors but was so intrigued that I did a major search and found this [www.tme.eu]
Click on the PDF at the end of each description to get specification and dimensions.

I will go over to XT30 on my printers in the future. I had recommended Molex Mini-Fit as Micro-Fit were only rated to 4.7A in the very old datasheet I looked at.

Mike
Re: Connectors for hotend wires
May 17, 2019 01:27PM
Quote
leadinglights
I had never before found info on the XT30 and XT60 connectors but was so intrigued that I did a major search and found this [www.tme.eu]
Click on the PDF at the end of each description to get specification and dimensions.

I will go over to XT30 on my printers in the future. I had recommended Molex Mini-Fit as Micro-Fit were only rated to 4.7A in the very old datasheet I looked at.

Mike

Thanks for the link. I am going to check those out for future setups (I have a bunch on the XT60's now, if these are more petite, they would be better.

DLC


Kits: He3D K200 Kossel, Folgertech Kossel 2020 upgraded E3Dv6, Anet A8 upgraded E3Dv6, Tevo Tarantula enhanced parts and dual-head
Scratch: Large bed Cartesian, Linear slide Delta, Maker-Beam XL Micro Delta
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