Ceramic hotend...?
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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).
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@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.
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@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.
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@fma That makes sense. Maybe that nozzle is a bit better since it is bigger than usual E3D
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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 -
@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.
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@pat Looks similar to the hotend design M3D use in their Micro printer range.
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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.
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@warbunnies said in Ceramic hotend...?:
...........................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.
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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.
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@warbunnies said in Ceramic hotend...?:
@deckingman
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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.Yup. Been down that road too.
My only slight concern is that if one fails, it'll be a bit of a pain to replace compared to a "normal" drop in cartridge. For what I have in mind, disassembly for the purpose of replacing an annular heater could be problematic, unless I change the design - the jury is still out on that.......
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Okay ya that is a fair point. they are more delicate, proper wire constraint is a MUST. It could be offset by a good supplier. The heater itself isn't that expensive to make. Along with a good design of the metal parts. The nozzles need to be easier to remove & the temp sensor should be close to but not in the nozzle. Combine a decent design with that heater & you got a winning hotend.
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@warbunnies said in Ceramic hotend...?:
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.
Are your talking about M3D micro-extruder? I'm very tempted to buy one with the Pro nozzle...
https://store.printm3d.com/collections/parts/products/micro-extruder-core-assembly
https://store.printm3d.com/collections/parts/products/pro-4mm-nozzle-assembly -
Nope I'm talking about these: https://www.deltaprintr.com/product/mini-hotend/
they even have a damn picture labled "micro nozzles coming soon" bunch of lies.
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Ok, I see.
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How are these micro-hotends build, inside? Are they using PTFE? Are they made of 1 block from top to nozzle?
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they are a full metal. the ptfe stops up in the cold end. the nozzle & heatblock are separate. the ceramic heater encloses a metal core that threads into the heatbreak & the nozzle threads into the metal core.
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Thanks for your answer.
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Web skills MAY have nothing to do with product quality... but... very "high bling" web site... who's security certificate expired four days ago...
Sigh.