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.
While milling machines and other fancy industrial CNC have had tool changing for decades, and the subject has been pursued by the RepRap community for a few years now, it really hasn’t caught on. The question then is, what is tool changing on a 3D printer good for? The answer is multimaterial printing, and doing it in a way that doesn’t have the downsides of current methods of printing with multiple materials.
There are three current methods of printing in multiple materials. The first is putting two nozzles on the same extruder, but this has the downside of one nozzle interfering with the other. The second is pushing two different kinds of plastic through the same nozzle, such as in the E3D Cyclops, or Prusa’s multimaterial upgrade. This has the downside of cross-contamination, and you can’t print in materials that require different temperature profiles. The third method is simply using multiple carriages on the same machine, such as the lovely stuff from Autodesk or Project Escher. This last method is horrifically complex.
The answer the problem of multimaterial printing is hot-swapping toolheads, but to do this you need precision and repeatability. The folks at E3D have been working on this for years, and I remember seeing some experiments with electro-permanent magnets a few MRRFs ago, but now they finally have a solution. The answer is simply a cam that’s turned by a cheap hobby servo. This is kinematic coupling that allows the carriage to clamp onto a toolhead with 5 μm precision.
Right now, E3D’s experiments in toolchanging 3D printers have culminated in a single 3D printer featuring their toolchange carriage, four toolheads, some amazing linear rails, and a CoreXY configuration. The prints that are coming off of this printer are spectacular. There are four-color Benchies, and the drivetrain of a remote-controlled car with gears printed in Taulman plastic and a driveshaft printed in ABS. The car was a single print made with multiple hotends, demonstrating most of the problems of multimaterial printing disappear with the E3D swapping toolhead printer.
Hipster hardware! [Bunnie] found something interesting in Tokyo. It’s a LED matrix display, with a few PDIP chips glued onto the front. There are no through-holes or vias, and these PDIPs can’t be seen through on the back side of the board. Someone is gluing retro-looking chips onto boards so it looks cool. It’s the ‘gluing gears to everything therefore steampunk’ aesthetic. What does this mean for the future? Our tubes and boxes of 74-series chips will be ruined by a dumb kid with a hot glue gun when we’re dead.
Speaking of unimaginable problems in EDA suites and PCB design tools, here’s a Git-based visual version control thingy for Eagle. Cadlab.io is a version control system for Github and Eagle that offers visual diff of PCB layouts and schematics. Neat? Yes, especially if you have more than one person working on a board.
How about a 3D printed business card embosser? [Taekyeom] designed and printed a pair of 3D rollers, one of which is embossed with the ‘negative’ of a design, the other with the ‘positive’ of a design. When rolled against each other, these rollers mesh and putting a piece of paper through the pinky pinching machine embosses paper. Add a frame, a handle, and a few zip ties for belts, and you have a fully 3D printed paper embosser.
Aw, snap, 3D printers with automatic tool changing. This is a project from E3D that shows off magnetic (?) extruders and hot ends for 3D printers. You can change your hot end (and nozzle, and filament) in mid-print. What does this mean? Well, swapping filament is the most obvious use case, but the Prusa system might have this nailed down. What is more interesting is swapping hotends, allowing you to print in multiple temperatures (and different materials), and maybe even different nozzle sizes. This is coming to MRRF, the greatest 3D printing con on the planet. MRRF is happening in March 23-25th in beautiful scenic Goshen, Indiana.
It may seem like a paradox, but one of the most important things you have to do to a 3D printer’s hot end is to keep it cool. That seems funny, because the idea is to heat up plastic, but you really only want to heat it up just before it extrudes. If you heat it up too early, you’ll get jams. That’s why nearly all hot ends have some sort of fan cooling. However, lately we have seen announcements and crowd-funding campaigns that make it look like water cooling will be more popular than ever this year. Don’t want to buy a new hot end? [Dui ni shuo de dui] will show you how to easily convert an E3D-style hot end to water cooling with a quick reversible hack.
That popular style of hot end has a heat sink with circular fins. The mod puts two O-rings on the fins and uses them to seal a piece of silicone tubing. The tubing has holes for fittings and then it is nothing to pump water through the fittings and around the heat sink. The whole thing cost about $14 (exclusive of the hot end) and you could probably get by for less if you wanted to.
Over the years, E3D has made a name for themselves as a manufacturer of very high-quality hotends for 3D printers and other printer ephemera. One of their more successful products is the Titan Extruder, a compact extruder for 3D printers that is mostly injection-molded plastic. The front piece of the Titan is a block of molded polycarbonate, a plastic that simply shouldn’t fail in its normal application of holding a few gears and bearings together. However, a few months back, reports of cracked polycarbonate started streaming in. This shouldn’t have happened, and necessitated a deep dive into the failure analysis of these extruders. Lucky for us, E3D is very good at doing engineering teardowns. The results of the BearingGate investigation are out, and it’s a lesson we can all learn from.
The first evidence of a problem with the Titan extruders came from users who reported cracking in the polycarbonate case where the bearing sits. The first suspect was incorrectly manufactured polycarbonate, perhaps an extruder that wasn’t purged, or an incorrect resin formulation during manufacturing. A few whacks with a hammer of each production run ruled out that possibility, so suspicion turned to the bearing itself.
After a few tests with various bearings, the culprit was found: in some of the bearings, the lubricant mixed with the polycarbonate to create a plastic-degrading toxic mixture. These results were verified by simply putting a piece of polycarbonate and the lubricant in a plastic bag. This test resulted in some seriously messed up plastic. Only some of the bearings E3D used caused this problem, a lesson for everyone to keep track of your supply chain and keep records of what parts went into products when.
The short-term fix for this problem is to replace the bearing in the Titan with IGUS solid polymer bushings. These bushings don’t need lubricant, and therefore are incapable of killing the polycarbonate shell. There are downsides to this solution, namely that the bushings need to be manufactured, and cause a slight increase in friction reducing the capability of the ‘pancake’ steppers E3D is using with this extruder.
The long-term solution for this problem is to move back to proper bearings, but changing the formulation of the polycarbonate part to something more chemical resistant. E3D settled on a polymer called Tritan from Eastman, a plastic with similar mechanical properties, but one that is much more chemically resistant. This does require a bit more up-front work than machining out a few bearings, but once E3D gets their Tritan parts in production, they will be able to move back to proper bearings with the right lubrication.
While this isn’t a story of exploding smartphones or other disastrous engineering failures, it is a great example of how your entire supply chain goes into making a product, and how one small change can ruin an entire product. This is real engineering right here, and we’re glad E3D finally figured out what was going on with those broken Titan extruders.
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’.
People have been experimenting with 3D printed molds for fiberglass and carbon fiber for a while now, but these molds really aren’t much different from what you could produce with a normal CNC mill. 3D printing opens up a few more options for what you can build including parts that could never be made on any type of mill. The guys at E3D are experimenting with their new dissolvable filament to create incredible parts in carbon fiber.
For the last year, E3D has been playing around with their new soluble filament, Scaffold. This is the water-soluble support material we’ve all been waiting for: just throw it in a bucket of warm water and it disappears. The normal use case for this filament is as a support material, but for these experiments in composites, E3D are just printing whole objects, covering them in carbon fiber prepreg, vacuum bagging them, and allowing them to cure. Once the carbon fiber isn’t floppy and gooey, the support material is dissolved in water, leaving a perfect composite part.
E3D aren’t that experienced with composites, so they handed a bit of filament off to So3D for some additional experimentation. The most impressive part (in the title pic for this post) is a hollow twisted vase object. This would have required a six-part machined mold and would have cost thousands of dollars to fabricate. Additional experiments of embedding ABS parts inside the Scaffold mold were extremely successful.
As you would expect, there are limitations to this process. Since E3D are using a dissolvable mold, this is a one-time deal; you’re not going to be pulling multiple composite parts off a 3D printed mold like you would with a machined mold. Curing the parts in a very hot oven doesn’t work — Scaffold filament starts to sag around 60°C. Using prepreg is recommended over dry fabric and resin, but that seems to be due more to the skill of the person doing the layup rather than an issue with materials.
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