Just a weird idea.
Instead of aluminum, you could always do cement of some sort. At least that would be somewhat insulative. For plastic though, this likely isn’t the greatest of ideas.
Have you read through @Gary_Hodgson 's http://garyhodgson.com/reprap/2012/02/a-history-of-reprap-development/ ??
No, but I just started downloading it, so I might Skim over it later.
Having better insulation than aluminum around the heater cartridges would result in bad heat transfer to the filament. If necessary, the inside of the steel tube could be lined with an insulator of some sort. Perhaps a zirconia based ceramic or a refractory concrete/mortor. A person may be able to use tubes made from firebrick too.
Keep in mind that alot of hotends are nothing but some blocks of aluminum with holes drilled in them and a heater cartridge and thermistor inserted in them. I doubt this could do any worse than that.
My understanding is that you do want a hotend to be able to lose heat quickly enough for some applications, but want it to retain heat as well as possible for others.
I think if you’re going to start making multi material/complex heater blocks, it’s probably worth considering a nichrome coil around the melt zone rather than heater cartridges. I strongly suspect someone out there is already working on such a concept if it’s not already been discarded.
That’s all the stainless 40w heaters are. Precisely coiled nichrome wire wrapped around a ceramic core and stuffed into a stainles steel body. I’m thinking maybe of an arcol-style heater block. But with all these all-metal ends using that counter-tightening method, you can’t make it too thin height-wise.
The height before the cooling and mounting zones would be about 1 inch which is how long the heater cartridge is.
The beauty of using the heater cartridges is that you don’t need to get ceramics involved (besides what is in the heater cartridge itself).
@ThantiK yeah but what I was getting at is having that nichrome coil around the actual melt zone itself, I assume the bit at the centre of the coil is the hottest zone, ceramic is there in the cartridges as it can handle those temps right? Putting heater cartridge next to the melt zone doesn’t seem ideal if your going to start machining complex parts. I’ve not looked at the arcol blocks, will do so now. Out of depth with this stuff as I’ve not done much research, I assume that if it was easy or had a significant improving effect someone would have done it.
There is one project that I know with very little mass and driven by a heater cartridge. I do not know what the print quality is. They seem to with to make a business around the hotend.
“if your going to start machining complex parts”? Actually, this design would not require any machining of parts. That is why it is using tubing and heater cartridges and aluminum that would melt itself into place.
This is an interesting idea @NathanielStenzel , and one I’ve been keen to try for some time. though rather than making a whole new hotend, I’d look at simply replacing the heater block on either the prusa nozzle or the e3d nozzle, with a copper or brass one (the blocks themselves are very simple and you wouldn’t need much in the way of tools to make them). insulating that block as well with a suitable material would also be a good idea.
placing the printer in an airtight box and filling the box with either argon or CO2 would be the next step, and probably fairly easy to do as well. Argon and CO2 can both be purchased from a welding supplier.
@NathanielStenzel Sorry, misunderstood your concept.
So, next probably stupid question: Pretty much all heatblocks have the cartridges oriented perpendicular to the direction of filament flow to ensure the melt zone is as short as possible, because a short melt zone is what you want for accurate extrusion. Granted, at high extrusion rates, you might want to increase the melt zone somewhat if you can’t pump enough heat into a short zone to keep up with flowrate but the full length of a cartridge heater seems too long.
@Jonathan_se5a_Sorens Why the gas? Cooling I assume as oxidisation isn’t a problem (is it?). If it’s cooling, you won’t be printing ABS or Nylon.
Tim, those gases would be for printing aluminum if a person is brave enough. I think a pulsing electric arc may do too. I am not sure. That would be groundbreaking 3d printer stuff.
As for the height of this, the 1 inch height is shorter than the hot area of my current nozzle even if most of the heat may be in the lower half inch.
@NathanielStenzel Really? What nozzle is that? My E3D melt zone is 2-3mm I think.
It does not exist yet.