Ceramic hotend...?

LHelge

If you're looking for exotic nozzle materials, the Olsson Ruby could be a good start before trying out ceramics.

fma

I'm using this exact product¹! It works well, but there is a lack of inertia, and temperature drops when you extrude fast (when purging, for example). But I do recommend it, it is very nice to have a compact hotend. It allowed me to have small tubes to blow air at the output of the nozzle:

https://www.logre.eu/wiki/Tête_à_FNU#Ventilation_de_la_pi.C3.A8ce

Note that I use a FNU (http://www.1730hotend.com/filament-nozzle-units/brass/1-75-mm.html) which will soon be replaced by the Zatsit version, which only has a threaded rod, allowing easy change of nozzle.

¹: I think this is also the one we can see on the Zatsit printer examples (https://www.kickstarter.com/projects/396334038/zatsit-the-awesome-delta-robot-and-3dprinter-with)

Pat

The ceramic ring is the heater, so i guess the time to reach the temp is at least the same or maybe even shorter.
Way less mass to heat.

gavatron3000

Furnaces use ceramics so they don't lose heat to the environment. With a hotend you want a high thermal conductivity to keep the tip temperature accurate. Hence why the blocks are usually aluminium or copper.

fma

Correction: I only use the ceramic heater, not the nozzle... I may try it, though, as I have to order from them.

fma

Looking closer, their nozzle does not seem to be in ceramic!

fma

BTW, there is also this product, part of the all-in-one hotend: http://www.hotends.fr/fr/home/63-corps-de-chauffe-ae.html

OBELIKS

@gavatron3000 They solved this by putting the thermistor in the nozzle.
For me it is an interesting design, so I am thinking to buy one, when I will switch to 24V

gavatron3000

@obeliks see how you go I'm interested to see your results

OBELIKS

I will post results, but it will take some time. I am not planning the switch in near future.

deckingman

I looked into these some while back. What you see is an annular (hollow cylinder) heater around an aluminium block. The ceramic part is just the insulation. The heating element is just nichrome wire wrapped around a ceramic core. So in that respect, it's much like a conventional cartridge heater but annular in shape. Oh , and the two wires are for the heater - you still need a thermistor (at least I haven't seen one with integrated thermistor).

dc42

@gavatron3000 said in Ceramic hotend...?:

I'd imagine it'd be not very good due to ceramics being insulators

Actually, there are some ceramics that are good thermal conductors. I know this because while I was doing my PhD I had to build some waveguide carbon dioxide lasers, and I needed a material that was a good thermal conductor and good electrical insulator. Beryllium oxide is one of the best, but highly toxic. Alumina is not as bad as you might think, it conducts heat about 30 times better than glass. For the lasers I settled on hexagonal boron nitride, which has a thermal conductivity about 600 times better than glass (more than aluminium) along the layers and 30 times better perpendicular to the layers.

My guess is that ceramic hot ends are made from either alumina or hexagonal boron nitride. Both are white. Alumina is hard, hexagonal boron nitride is soft like graphite.

fma

@obeliks said in Ceramic hotend...?:

@gavatron3000 They solved this by putting the thermistor in the nozzle.

I drilled my FNU to insert the thermistor as TriangleLabs does with there nozzle... That's maybe why I can see the temperature dropping when I extrude fast: when thermistor is in the heater block, you don't see fast variations.

OBELIKS

@fma That makes sense. Maybe that nozzle is a bit better since it is bigger than usual E3D

gavatron3000

Interesting! I had a general view on ceramics and didn't know that David. Ceramic wrapped heater I think would be good. I guess similar in a way to how e3d put a silicon sock onto the heater block.
Always good to keep an open mind

fma

@obeliks said in Ceramic hotend...?:

@fma That makes sense. Maybe that nozzle is a bit better since it is bigger than usual E3D

As soon as I receive the part from Zatsit, I try their nozzle.

themelle

@pat Looks similar to the hotend design M3D use in their Micro printer range.

warbunnies

Just to clear up any misunderstanding about how well these things heat. The ceramic hotends heat up much faster than e3d hotends. Usually pass 200 after 30 seconds with the deltaprintr one. Though I wouldnt suggest using their mini hotend. Originally they said they would be coming up with different nozzle sizes & 3 years later, nothing. emailed them last year and they pretended not to know anything about it & had no plans to do it. But it was a very very good hotend for the period of time i used it. The heater is so strong that it seems to react much faster to changes than the normal heating method.

I've been trying to find a good source of ceramic heaters myself and hopefully they will catch on. The fast heating/ cooling time is great for tool changing.

deckingman

@warbunnies said in Ceramic hotend...?:
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I've been trying to find a good source of ceramic heaters myself and hopefully they will catch on. The fast heating/ cooling time is great for tool changing.

Let me know if do find a source. I've been looking myself with not much luck.

warbunnies

@deckingman

I will let the world know! Good lord I want them to catch on. I'm probably gonna try making my own at some point. It is just nichrome & a non conductive, high heat material after all...

Alibaba seems to be the only place which kinda sucks cause i cannot buy bulk at the volume they want to make me custom parts.