ALL Metal Hot Ends and Printing PLA

Curious how many of you have been able to run a all metal hot end and not have any issues with PLA filament jamming?

If you could please provide:
-Type of hot end
-Did it print without jamming for an extended period

Also if you care to share your opinion on why all metal hot ends tend to jam in the first place

I use an E3D V6 running 3mm filament, and haven't had problems. From what I've read the main issue with metal hot ends seems to be the inner surface finish of the heat break, and temperature. You need a cool heat break down as low as possible near the heater block. As PLA warms it turns soft and sticky. It will stick in the hot end if it's too warm and jam. Also the retraction seems to be an issue as well. You want retraction as low as possible. This may conflict with optimal retraction for print quality especially with Bowden setups that require large retraction moves to fight ooze. This is the same issue you are battling with polished internals and fans, the warm PLA is pulled into the cold part of the heat break and cools quickly due to the heat conductivity of the metal. This creates a plug that jams in the heat break. The shorter the retraction settings the less likely this will happen.

Hot ends with PTFE liners alleviate this issue since the PTFE is much smoother and PLA doesn't stick to it nearly as much even when warm.

Main tips for trouble free metal hot end printing seem to be

1. Well polished innards (This is a main difference between genuine hot ends and Chinese clones)

2. Good fan on the heat sink. You want the sharpest temperature transition possible. It can be hard to find a good fan that is small enough to fit the space around the hot end.

3. Dial down the retraction as low as possible.

4. If all else fails you can try wiping a very light coat of oil such as canola on the filament as it feeds. I don't think you need to continuously add oil. Just a bit as you start. This lubricates the cold area of the hot end so plugs are less likely to stick and jam.

I've thought about doing some experiments with oil seasoning like people do with cast iron skillets. Wipe a very thin coat of canola oil in the hot end, bake, repeat, till you get that nice non stick coating. Should be a fairly durable upgrade to your all metal hot end. But since I haven't had any issues I haven't taken the time yet.

E3D v6 here. I mostly run PLA, with the occasional ABS and PETG.

I have had jams, but it's always been my fault, e.g. junk stuck in the nozzle. Using decent PLA at reasonable speeds and temperatures, the hotend performs amazingly well.

Jams seem to be caused by either too much retraction, junk in the nozzle, or too high of printing speeds / pressures. If you want to print faster, use fatter layers, it should allow higher volume per second, and higher strength, without added chance of jamming.

B3 Innovations Pico --- no heated bed, so only print PLA --- had to season the hot end by lubing the foam filament filter w/ canola oil. Refresh it as seems necessary.

[www.eckertech.com]

I am use this, and have no jamming.

I have an E3d v6 with an all metal (nothing but good things to say) also run several MK8 direct drives with all metal thermal breaks. Some of this has been previously mentioned, however, I would like to comment on some things I’ve found in my testing. It seems that with a clone (China sourced or otherwise) the focus seems to be on the interior throat of the break not being well polished. Although I have seen this on occasion, something that seems more common in my experience is that the interior diameter is simply inconsistent from break to break. Given the nature of an all metal break and the tight tolerances we see this can become problematic especially when heat issues arise. The additional force needed to clear a dimensionally inaccurate throat and the nature of PLA when cooling is insufficient causes the filament to buckle above the reduction of the barrel.

The all metal break needs to be well cooled as previously mentioned, however, depending on your extruder set up—a MK8 for instance—the distance you thread the break into the heat sink can be critical.

Finally, bryanandaimee did a great job of covering the PTFE advantages and in short this can be summed up by saying that PTFE allows for more slop. The best thing I have done to print PLA in an all metal throat is to ensure the extruder driver is well tuned, this seems to prevent many of the jams I have seen with all metals… This is of course my experience but at one point I had all but given up on all metal thermal breaks and PLA, however, now I have a healthy mix of China sourced breaks and some higher quality ones running as well. I hope this helps. Best of luck.

I have coated the inside of one throat with tungsten disulphide which I bought on ebay. Its like a Teflon coating but much more slippery. No jams yet. Second the idea of polishing, can be done with wire wool and a drill.

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Simon Khoury

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

I don't think jamming is a hot-end only issue. If the extruder can't push very hard you're going to experience more jams than if it can push hard. I think things like hot-end internal surface finish are less important when you have a strong extruder. Geared extruders can usually push a lot harder than ungeared extruders, as long as you crank the pinchwheel pressure up.

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

I had alot off problems with my Clone R1 all metal hotend and PLA. But now i am using Raise3D printer with their all metal hotend and never had any problems. It is really amazing. They use titanium for the heatbreak part. [www.raise3d.com]

@DjDemonD - Can you describe how you coated the barrel with WS2? Is it still jam free? Did you have to re-coat? Also describe your polishing technique and if you still believe it was effective.

Hi I bought WS2 dissolved in alcohol from ebay. Dipped a microbrush (http://r.ebay.com/93W18G)
in it and spun it into the hot end throat with a drill.

Polishing done with some steel wool pulled into a long thin piece put through the throat and spun with a drill. Then some multistrand copper wire used in the same way.

Worked okay until I tried petg and it wouldn't feed it at all. So I switched to genuine e3d and had no problems since.
I am currently using a cloned volcano, and whilst I had the 0.4mm nozzle block once, I think due to some foreign object in/on the filament, its been performing quite well with no alteration except just being assembled properly.

Clones = 1/3 of the price but might work, might not, might need a lot of tinkering.
Genuine= works very well.

You pays your money etc...

Edited 1 time(s). Last edit at 08/22/2016 08:57AM by DjDemonD.

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Simon Khoury

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

One thing to note, it's not just the hot end that causes a jam either. I've experienced a few jams with an E3D lite6 hotend using a 0.3 nozzle, but in my case I think it was more the extruder wasn't strong enough to keep pushing the filament. Changed to a geared extruder setup and I've not had a jam since with any of the E3D hotends.

Yes I'd agree, but the jams I was getting were with a titan albeit driven with a 20mm nema 17 rather than the usual 40-48mm motor.

That or too many large retracts causing a plug of material to stick to the throat.

I was using a cloned v5 hotend.

Edited 1 time(s). Last edit at 08/22/2016 11:33AM by DjDemonD.

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Simon Khoury

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

Running 2 China clone E3D v6's, 1.75mm PLA no ptfe in the heatbreaks, so still all metal even though its a clone.

Only had a consistent jamming problem twice, once it ended up being a physical containment larger than my nozzle diameter the other was testing my new extruder I designed, All I had to do was up the voltage and tighten the tension-er, I have all kinds of torque, could allow me to power through what would jam other extruders

Edited 1 time(s). Last edit at 08/24/2016 09:31PM by DaGameFace.

I had a lot of trouble in the beginning with my e3dv5 clone with NO teflon. Things I did to solve it:
- First I used a 0.3mm nozzle on 3mm filament. This needs a lot of pressure - too much - and caused a lot of slippage in the hobbed hub. Changed to 0.4 mm nozzle now.
- There is a very loooong thread somewhere in a forum where they discussed the jamming of pla in all metal hotends. The conclusion was that the length where the nozzle is narrow is very important. This must be as short as possible. My nozzle narrow section was quite long (>1mm or so) and reduce this by drilling it out carefully so left with a 0.5mm narrow section.
- Last thing I did was to feed some sojaoil in the hotend to make a carbon not slip coating inside the nozzle. NOTE: I will never do this again - no jamming, but the oil caused a huge amount of adhesion issues on the glass bed. I had to print for a lot of hours on a gluestick covered bed till the oil was fully disappeared and plain glass was working again.

After this I could print without any issues with PLA. I am not certain what of the above did the trick. Just try them and see what helps.

I'm finishing up a 4 day print through a e3d v6 (0.4 mm nozzle) with PLA. I print for weeks straight with PLA, never a problem.

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n8bot
I'm finishing up a 4 day print through a e3d v6 (0.4 mm nozzle) with PLA. I print for weeks straight with PLA, never a problem.

Um, can i see some of the finished prints? cuz damn, that print time..

I just finished a second print of this: [imgur.com]

Awesome print.

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Simon Khoury

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

Thanks!

HA! nice photoshops, no way thats fdm, worth a laugh though..

on a serious note, DAMN, its like the layers dont even exist. Nice machine and nice tuning

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If you need some help, or don't understand what I just said, feel free to send me a PM anytime

Printer: Prusa i3, 2 E3D v6 Hotends, Arduino + RAMPS 1.4 with a Bypassed 5V Regulator, 400w Insignia ATX PSU, Custom Designed Bowden Extruders

Quote
DaGameFace
HA! nice photoshops, no way thats fdm, worth a laugh though..

on a serious note, DAMN, its like the layers dont even exist. Nice machine and nice tuning

Haha, thanks. There are layer defects that are quite obvious at points, which I'm trying to alleviate by designing an entirely new printer. This one isn't good enough for me (only half joking).

Most allmetal hotend problems are due to lack of cooling. Use powerful cooler 0.3-0.5A and no problem. Yes it's noisy.

The discussion about all metal hotends and pla in this and another thread got me wondering how far I could push mine. The things that are hard on the hot end are low extrusion rates (less cool filament is brought in to the hot end, so there is more time for heat to creep back up into the throat) and lots of retraction. The classic torture test is voronoi style models, so I found one on thingiverse and gave it a try. This is way out of my comfort zone (I normally print very simple functional parts in abs) and I really struggled with it. The overhangs, particularly at the bottom of the model, are obscene and I had a lot of trouble with the edges curling up. I eventually got a successful print with .08mm layers and a lot of cooling fan.



It's not a great print, but the extruder/hotend survived to the end, about 8 hours of non-stop retractions. This used 3mm pla at 180C, and a nema14 geared extruder with an all metal hotend loosely based on the e3d designs. Model link: [www.thingiverse.com]

Edited 1 time(s). Last edit at 09/24/2016 07:47PM by JamesK.

Oh thanks.
I will simply have to try that one.

Looks like a nice challenge yes. Good to see that you did get a result.

Lykle