All Metal Hot End jamming

I'm using an all metal hotend in my prusa i3, it has been working nicely for a few months, but now sometimes the extruder idler makes a tic sound and the extruder stops extruding, the filament gets jammed inside the hotend making it impossible to pull it out or push it further into the nozzle. I tried cleaning the nozzle and heat break using gas welding flame, but despite being cleaned twice, it still gets jammed. has anyone experienced the same? any ideas on what might be the cause? any help is appreciated,
thanks in advance

Which hot end was it exactly? Are you sure it did not have a PTFE sleeve in it?

Filament can get stuck in the cold break if you're printing with PLA and heat creeps up the cold cold break toward the cold end of the extruder. Check to make sure the fan on the cold end is operating OK and make sure you run the fan for a while after finishing a print, to allow the hot end to cool properly without heat creep.

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Damp some filament in Olive oil and run it through the hot end, then run a clean one. Be sure your fan is working an on all the time.

Had this exact same thing happen on one of the all metal hot ends we tested.
We never tried oil, but we always used a fan. Leaving it on after prints didn't help at all in our case.

The real reason for jamming in all metal hot ends with pla is due to the sharp heat break and retraction. At least I think so. With ABS its not such a problem simply due to the higher temperatures. At this point I think we need to take all we have learned and design a proper all metal hot end that can be used passively for any material.

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I would say the Prometheus hotend fits that bill perfectly.

I have to agree with Prometheus being an ideal high temp hotend, and possibly the best. The barrel is a one-piece polished design which eliminates joints that can cause binding, sticking, etc.

I have mine configured with a 2mm long transition zone and a nut on each side of the heater block and I get excellent results with a bowden setup and PLA. No need to using the oil trick and it works well the cheapest and premium priced PLA's. ABS is even easier. With minimal retraction and wipe settings, I have zero stringing.

Another advantage of the Prometheus is strength. I've see too many other high temp hotends with bent or broken heat breaks. The one-piece Prometheus is much stronger.

Came across this thread while researching some jamming issues on one of the new-fangled all metal hotends.

I honestly don't understand this constant cyclic need to reinvent the wheel over and over again.
Arcol.hu hotends have been extruding PLA, ABS and whatever else you want, without jams and without hotend fans for years.

The draft from the print fan is enough to keep them happy.

All the while being shorter and more compact, with less parts, than any of the newcomers.

Hello,

Genuine J-Head hot-ends have worked fine with PLA for years, as well. However, china has taken over the J-Head market and produce poor quailty knock-offs. So, you have to shop around for the few vendors that still sell the real thing.

Best Regards,

Brian

I do need a fan for my arcol hi v4 with abs. i starts printing fine, but constantly jammes without a fan after a few layers.,maybe i print too slow,,or the temperature of hotend or extruder is too high. or its my x carriage on a classic sells reprap. or the all metal extruder

with the fan i am totally fine

i dont have a fan directed to the print. this does not work with me for abs on glass.

Edited 1 time(s). Last edit at 04/19/2016 08:34AM by Nio.

I haven't tried it yet but I did buy some to try next time I rebuild my hot end - tungsten disulphide. It's a coating which apparently nothing ever sticks to including molten plastic. Quite toxic by all accounts but I'm not intending to eat it.

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Simon Khoury

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

This has been ruining my life. I just drilled a hole from the top through the throat and ran PTFE all the way down to the nozzle. Runs smooth as silk now. I am going to go back and troubleshoot this to get the all metal one working. Any luck for you?

I've had no jams with the tungsten disulphide. With all metal polishing seems to be very important, drilling is going to leave a very rough surface, there are lots of instuctable-type things out these about how to polish inside hot end throats.

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Simon Khoury

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

I run 1.75 filament of PLA in my 3 mm bowden printer, and works very well. Nothing as smooth and thermal insulator as air.
Not useful for 1.75 mm printers.