When you zoom in on a fractal you find it is made of more fractals. Perhaps that helped inspire the Harvard 3D printers that have various arrays of mixing nozzles. In the video below you can see some of the interesting things you can do with an array of mixing nozzles. The coolest, we think, is a little multi-legged robot that uses vacuum to ambulate across the bench. The paper, however, is behind a paywall.
There are really two ideas here. Mixing nozzles are nothing new. Usually, you use them to mimic a printer with two hot ends. That is, you print one material at a time and purge the old filament out when switching to the new filament. This is often simpler than using two heads because with a two head arrangement, both the heads have to be at the same height, you must know the precise offset between the heads, and you generally lose some print space since the right head can’t cross the left head and vice versa. Add more heads, and you multiply those problems. We’ve also seen mixing nozzles provide different colors.
On a fused deposition modeling (FDM) 3D printer, the nozzle size dictates how small a detail you can print. Put simply, you can’t print features smaller than your nozzle for the same reason you’d have trouble signing a check with a paint roller. If the detail is smaller than the diameter of your tool, you’re just going to obliterate it. Those who’ve been around the block a few times with their desktop 3D printer may have seen this come up in practice when their slicer refused to print lines which were thinner than the installed nozzle (0.4mm on the vast majority of printers).
As [René] sees it, the hotend is too close to the subject being printed when using nozzles finer than 0.4mm. Since you’re working on tiny objects, the radiant heat from the body of the hotend being only a few millimeters away is enough to deform what you’re working on. But using the long and tapered airbrush nozzle, the hotend is kept at a greater distance from the print. In addition, it gives more room for the part cooling fan to hit the print with cool air, which is another critical aspect of high-detail FDM printing.
Of course, you can’t just stick an airbrush nozzle on your E3D and call it a day. As you might expect, they are tiny. So [René] designed an adapter that will let you take widely available airbrush nozzles and thread them into an M6 threaded hotend. He’s now selling the adapters, and judging by the pictures he posted, we have to say he might be onto something.
With few exceptions, it seemed like every 3D printer at the first inaugural East Coast RepRap Festival (ERRF) was using a hotend built by E3D. There’s nothing inherently wrong with that; E3D makes solid open source products, and they deserve all the success they can get. But that being said, competition drives innovation, so we’re particularly interested anytime we see a new hotend that isn’t just an E3D V6 clone.
The Mosquito from Slice Enginerring is definitely no E3D clone. In fact, it doesn’t look much like any 3D printer hotend you’ve ever seen before. Tiny and spindly, the look of the hotend certainly invokes its namesake. But despite its fragile appearance, this hotend can ramp up to a monstrous 500 C, making it effectively a bolt-on upgrade for your existing machine that will allow you to print in exotic materials such as PEEK.
We spent a little time talking with Slice Engineering co-founder [Dan], and while there’s probably not much risk it’s going to dethrone E3D as the RepRap community’s favorite hotend, it might be worth considering if you’re thinking of putting together a high-performance printer.
3D printers can be hacked into a multitude of useful machines, simply by replacing the filament extruder with a new attachment such as a laser engraver or plotter.
However, [geggo] was fed up with re-wiring and mounting the printhead/tool every time he wanted to try something new, and set out to design a modular printhead system for next-level convenience. The result? A magnetic base-plate, allowing a 3D printer to become a laser engraver within a matter of seconds. This new base-plate mounts onto the existing ball bearings and provides a sturdy place for attachments to snap to – with room for two at once.
Using neodymium magnets to mount the printhead to the base-plate provides enough force to keep the attachment in place and compress 30 pogo pins, which make the electrical connections. These carry the lines which are common to all attachments (heater, thermistor and fan), as well as custom connections for certain attachments – for example the extruder stepper motors. A Flexible Flat Cable (FFC) is used to connect the pogo pin PCB to the main controller.
So far, the list of tools available for fitting includes an MK8 extruder, a E3D v6 hotend (for Bowden extrusion), a laser, a micrometer dial indicator, and a pen plotter (used for writing a batch of wedding invitations!). There was even some success milling wood.
The benefits of having a 3D printer with multiple extruders are numerous: you can print soluble support material for easy removal, print a combination of flexible and rigid filament, or simply print in different colors. Unfortunately, traditional multi-extruder setups have some serious drawbacks, even aside from the cost.
Usually, the extruders are all mounted next to each other on a single carriage. This increases the mass, which can cause print quality issues like shadowing. It also reduces the printable area, as each extruder needs to be able to reach the entire area. All of this means that the design becomes more and more impractical with each extruder you add, and that’s why it’s uncommon to see more than two extruders on a printer.
Over on Hackaday.io, [rolmie] has come up with a very practical (and affordable) solution to this problem. He has designed a tool changer that gives the printer the ability to switch out hot ends on the fly. The system is very similar to the tool changers we see on CNC machining centers: tools (the hotends) are stored on a rack, and a tool change in the G-code sends the carriage over to the rack to drop off the old hotend and pick up a new one.
The benefit of the design is that both the mass and volume of the carriage are kept to a minimum, while allowing you to use many different hot ends. Each hotend’s settings can be configured individually, and you can even use different models of hotend altogether (maybe one model works better for PLA, while another is better for ABS). The design is still in the prototyping stage and needs some refinement, but it’s a very promising proof of concept that seems like it could be implemented fairly easily into most 3D printer models.
3D printers are now cheaper than ever and Monoprice is at the absolute forefront of that trend. However, some of their printers struggle with flexible filaments, which is no fun if you’ve discovered you have a taste for the material properties of Ninjaflex and its ilk. Fear not, however — the community once again has a solution, in the form of a hot end adapter for the Monoprice Mini Delta.
The Mini Delta is a fantastic low-cost entry into 3D printing but its hot end has a break in the Bowden between the extruder and nozzle. This can lead to flexible filaments not being properly guided through the hot end and a general failure to print. This adapter allows the fitting of the popular E3D V6 hot end, and is similar to modifications out there for other Monoprice printers.
Overall, 3D printing has long benefited from the efforts of the community to bring both incremental improvements and major leaps forward to the technology. We look forward to seeing more hacks on the Monoprice range!
Since the beginning of time, or 2006, the ‘hot glue gun’ part of our CNC hot glue guns have had well-defined parts. The extruder is the bit that pushes plastic through a tube, and the hot end is where all the melty bits are. These are separate devices, even though a shorter path from the extruder to hotend is always better. From Wade’s gear extruder to a nozzle made from an acorn nut, having the hotend and extruder as separate devices has become the standard.
This week at the Midwest RepRap Festival, E3D unveiled the Titan Aero. It’s an extruder and hotend rolled into one that provides better control over the filament, gives every printer more build height, and reduces the mass of a 3D printer toolhead.
The Titan Aero, revealed on the E3D blog yesterday, is the next iteration of E3D’s entry into the extruder market. It’s a strange mashup of their very popular V6 hotend, with the heat break coupled tightly to the extruder body. A large fan provides the cooling, and E3D’s thermal simulations show this setup will work well.
The core component of the Aero extruder is a fancy and complex piece of milled aluminum. This is the heatsink for the extruder and provides the shortest path possible between the hobbed gear and the nozzle. This gives the Aero better control over the extrusion of molten plastic and makes this the perfect extruder and hotend setup for hard to print materials.
Combine the Aero with a smaller ‘pancake’ stepper motor, and you have a very small, very light hotend and extruder. This makes it perfect for the small printers we’re so fond of and for printers built for fast acceleration. I can easily see a few end effectors for Delta-style printers built around this extruder in the near future.
Also at the E3D booth were a few prototypes of nozzle socks. Late last year, E3D released silicone nozzle covers – we’re calling them nozzle socks – for their V6 hotend. These are small silicone covers designed to keep that carbonized crap off of your fancy, shiny hotend. It’s not something that’s necessary for a good print, but it does keep filament from sticking to your hotend, and you get the beautiful semantic satiation of saying the words nozzle socks.
E3D’s other hotend, the Volcano, a massive and powerful hotend designed to push a lot of plastic out fast, did not get its own nozzle sock at the time. Now, the prototypes are out, and the E3D guys expect them to be released, ‘in about a month’.