Advantages over traditional 6mm diameter heater cartridge:
Symmetrical heating of the hotend for uniform melting.
More compact than traditional 6mm heater cartridges.
No need for an aluminum heater block anymore.
No need for extra screws/assembly to mount it.
Lighter setup.
Heats up quickly - can reach 700C!
Less bulky heater cables and no need to bend them 90 degrees upwards.
No need to change an entire heater block/nozzle/heater cartridge if you want to switch to faster printing/bigger nozzle. All you need to do is change this heater and a nozzle. Much simpler, lower cost in parts to change printing speed/nozzle size.
We can get them at different Volts/Watts to suit all needs.
The ones in the picture are 5mm ID, so you would need a matching hotend. Various sizes are available, though the range of sizes varies.
How many would be interested in such a heater? We plan to have them available at http://deltaprintr.com soon.
Certainly I’d be interested in seeing how it performs. The thing I worry about is the contact between it and the area it’s heating. E3D was pretty smart in this designing their heater block so it wraps around the cartridge slightly, maximizing contact.
I would have to check what combinations we can get, but different watts are available. If anyone knows… what are the different “standard” diameters of heated nozzles/barrels? They’re usually threaded in all hotends, so might have to come up with a threaded cartridge, though this may increase the price. OR… could just increase the inside diameter so it goes over the threads and add some compound for heat transfer if it’s threaded? not the most ideal method.
@Shai_Schechter I have a thought: this heating element mounted on a cylindrical copper block. In this copper block a channel of 1.8mm and at both sides a M6 thread for the nozzle and heat barrier (barrier=with 4 mm bored screw M6). This is not a standard, but a good solution for a perfect Hotend.
I share @ThantiK 's concerns about thermal coupling. Without any clamping load to deform surface roughness/asperities into good solid/solid contact, you’ll just have an airgap and a few microscopic contact points. My measurements show a standard 40w heater cartridge runs ~100C hotter than the hot block during preheating already. So I worry about hot spots, both on the heater where contact is poor, and on the barrel at the main contact points. (One of the primary purposes of the standard hot block is to take the relatively small and hot heater contact area and spread it over a larger surface area at the barrel at a more moderate temperature.)
The other concern is controllability. Feedback algorithms like PID have fundamental limits for how high the gain can be for a certain measuring lag before they oscillate uncontrollably. High heater power and low hot end heat capacity means a very high process gain – a little power will cause a large temperature change. Combine that with the unavoidable 3-10 sensing lag we get with contact temp sensing devices, and it’s a recipe for unstable temp control. So you might have to dial back the max power to a small fraction of its capacity to get the hot end to behave.
All that said, I love these experiments, and really want to see it in action
@Step_Cia Never saw a M3D up close, so wouldn’t know.
@Ryan_Carlyle All valid points, but the tolerance on this is 0.05mm, which is very precise. But of course, we’ll do testing to confirm all this.
Another important thing I just realized… if you want to print faster/larger nozzle, all you need to do is change a single nozzle/heater instead of an entire heater block/heater cartridge/nozzle like an E3D. This way it’s less parts that need changing.
Perhaps it would be possible to temperature shrink the barrel when installing the heater. Alternatively a high thermal conductivity adhesive might be used.
I have an M3D but never really thought about the heater. I noticed it was pretty small. I should have paid more attention before I sent it to my son last week. I think it did a pretty good job of heating the nozzle quickly and maintained good temperatures.
@Ryan_Carlyle I see your point. I was actually researching CPUs and heatsinks the other day and how thermal paste affects it… air bubbles and all that stuff. So we’ll see how it performs. Maybe some silicon or thermal paste or other may be needed.
I’ve been using thermal paste on my E3dV6 heatbreak/heatsink interface and it works for a while, then it breaks down and has to be replaced. I never print hotter than 235C, unfortunately most thermal compounds are only good to about 170C rated temp. Some claim up to 300C; but, many don’t trust those claims and I have yet to try one rated that high.
Yeah, thermal paste is a difficult subject at these temps. Remember, in order for heat to flow from the heater to nozzle, the heater has to be quite a bit hotter than your actual printing temp… with a standard steel-jacket cartridge and hot block with set screw, I did a measurement a while back of ~2.5 degrees C temp delta per watt of heat flux. So at 40w (during preheating) the heater is 100C hotter than the hot block. (That drops to more like 40C while printing because there’s less heat flux, but it depends on your insulation and print speed and airflow.) Whatever thermal interface material you use probably has to be good to, say, >350C. At that point, you really want something more like a compliant solid metal layer than a grease/paste.
@Alan_Thomason What are you trying? I was kind of thinking aluminum foil.
Although, on further thought, a low-melting liquid metal like gallium could be awesome for this. A liquid metal interface would solve the thermal expansion and heat transfer issues. Shame it utterly destroys aluminum. And I think it would probably leak out over time.
@Ryan_Carlyle I think what could work great is high temperature silicone enclosed all around the heater. But that’s on the outside, so it wouldn’t necessarily solve the heat-transfer issue (if there is an evident one, might just be minor - have to test).
Any gap transfer issue can be solved with some kind of a high temp thermal transfer paste. I’ve heard of one guy that rewrote a faster PID loop for a heater because of the issue of managing a higher than usual power to thermal mass.
but it’s practically a no-brainer.