One way to protect your nozzle from getting dirty is to wrap it in a cover, sock, sleeve or boot and prevent all the hot nasty stuff sticking to it. E3D released their silicone sock for Vulcano nozzles but someone found a way to make a DIY version.
Ubermeisters used 3d printed model of the nozzle and made a mold around it and than used some high temperature silicone mixture to produce the final cover. All steps are photographed in detail.
Diamond hotend is a new attempt to make a hot end capable of mixing three colors from three filament inputs.
Key features from product page:
3 pcs inputs for 1.7 mm filament
Common 0.4 mm nozzle orifice
Smallest possible mixing chamber for minimal waste and fast color change
Cutout for standard 40W heater cartridge and leaded thermistor
3 pcs threaded mounting holes for state of the art E3D v6 HeatBreaks & HeatSinks
Combined mounting bracket and airguide for optimal cooling by a simgle fan
Optional pendant for attaching a 5015 blower fan for extrudate cooling
The key feature of The Diamond Hotend is the diamond shaped nozzle. We have designed the nozzle to have smallest possible mixing chamber, to make color shifts as fast as possible and to avoid unnecessary filament waste. To ensure rapid nozzle heat up we have constructed the nozzle as compact as possible.
Here is the KS campaign video:
Here is Diamond hot end printing in multiple colors on Prusa I3:
Standard extruders are heated by simple resistive heaters and you basically need to push enough 12 or 24 V DC electric current trough a resistor and simple MOSFET.
Induction heated extruders would have many advantages over them: faster heating up, no high temperature insulation is needed and less thermal mass. All of this could make induction heaters light and fast. Main disadvantage is the more complex electric circuits needed to power it and more complex control unit since it is using much higher voltage and hundreds of kHz AC.
Slow convergence to desired steady state temperature at extruder tip, (many seconds, up to several minutes) and
slow feedback loop for temperature control, (from 100's of ms to s)
Lack of fine-grain temperature control at extruder tip, in steady state, the entire metal nozzle is essentially soaked to, or near, the melting temperature.
Inconsistent feeder response due to varying liquid plastic volume near tip and
limits on filament and extruded plastic drop size
The extruder tip with inductive heating coil would be physically similar in appearance, but would have several distinct differences:
Rather than a metal nozzle, it would be made of a thermally insulating, nonconductive material such as glass or boron nitride.
The actual heated element would be buried inside the tip to make direct contact with the plastic
The power for heating is transferred through electromagnetic coupling of a driving coil to the heated element. The heated element, (and the molten plastic around it), are thermally isolated from the rest of the extruder.
By using inductive heating and passive, digital temperature sensing of the heating target at the nozzle tip, significant improvements can be made to the issues above, resulting in faster production of more isotropic/mechanically stronger plastic prototypes. Also, the above problems typically put a limit on useable filament size, something this system should be able to surpass.
Here is the comparison of resistive heated extruder vs. induction heated extruder:
Resistive compared to inductive heated extruder head, schematics made by aka47
RepRap builder SB made a post about his induction heated extruder, here is his work and schematics:
Induction heated extruder, you can clearly see the induction coils
The induction coil heats the sleeve made from mild steel (ferromagnetic) while the stainless steel is not heated directly because it is not ferromagnetic.
There are other people actively experimenting with this concept like Bulent, who made the extruder and posted a YT video of it working (his videos are not in English, but you will get some insight):
Here is a video showing more details, but again language is not English:
As someone noticed in the comments, it would be interesting to see the induction extuder based on filament with metal particles where induction heats the filament itself. Then you could reduce the mass even further.
Another thing to mention is a possibility that the induction coil will interfere with nearby electronics and maybe emit noisy radio waves. It could also interact with build platform or other parts causing heating or melting damage.
If you want to build a serious desktop induction heater for metal melting of larger pieces here is a link:
E3D just released their Volcano super high flow nozzle upgrade that will speed up your 3d printing by pushing more filament trough the hot end. Putting on a larger diameter nozzle and extruding more molten filament also improves strength since the more mass and more heat improve adhesion between the layers.
Shenzhen based Esun company sells the filament they developed that should clean your extruder and nozzle. Composition of this filament is unknown but it is probably similar to nylon. Nylon filament is used in a cleaning process where it is extruded at 200 C and then cooled to 135 C which hardens it and makes it attract and clean up all the particles that clog up the extruder. Like all similar cleaning methods, this one can also fail.
There is not much information or reviews available around, so if you know something more about this or have any practical experience with it let me know ...
You may even not know that your nozzle is partially clogged. Eric William made this excellent tutorial on how to fix partially clogged nozzle and improve 3d print quality.You will need acetone and some tools. But it looks simple to do.
German RepRap is selling new 1mm hot end nozzle which can cut in half the printing time. The trade-off is rougher surface finish and more visible layers. So, the target audience is someone who needs more speed and less detail. The ideal setup would be some kind of dual extruder with extra fine nozzle for details and larger diameter nozzle for infills. It's compatible with X400, the X400 CE and PRotos V2, but could probably adapted for other extruders.
Crown extruder with four nozzles is design idea of Cem Schnitzler inspired by microscope rotating lenses. It enables you to use different nozzle diameters for different purposes, ie.: very small nozzle for precision and large one for speed and rougher infills. It would be interesting to see it developed and tested.
Universal Mount: Laser-slotted and taped to fit the pico hot-end to various printers Light weight Aluminum for reduced moment of inertia and ease of modifications
Operating Temperature: Up to 300º Celsius (572ºF) Limited by the thermistor
