Have you ever wondered what’s actually going on inside the hotend of your 3D printer? It doesn’t seem like much of a mystery — the filament gets melty, it gets squeezed out by the pressure of the incoming unmelty filament, and lather, rinse, repeat. Or is there perhaps more to the story?
To find out, a team from the University of Stuttgart led by [Marc Kreutzbruck] took the unusual step of putting the business end of a 3D printer into a CT scanner, to get a detailed look at what’s actually going on in there. The test setup consisted of a Bondtech LGX extruder and an E3D V6 hot end mounted to a static frame. There was no need for X-Y-Z motion control during these experiments, but a load cell was added to measure extrusion force. The filament was a bit specialized — high-impact polystyrene (HIPS) mixed with a little bit of tungsten powder added (1% by volume) for better contrast to X-ray. The test system was small enough to be placed inside a micro CT scanner, which generated both 360-degree computed tomography images and 2D radiographs.
The observations made with this experimental setup were pretty eye-opening. The main take-home message is that higher filament speed translates to less contact area between the nozzle wall and the melt, thanks to an air gap between the solid filament and the metal of the nozzle. They also saw an increased tendency for the incoming filament to buckle at high extruder speeds, which matches up with practical experience. Also, filament speed is more determinative of print quality (as measured by extrusion force) than heater temperature is. Although both obviously play a role, they recommend that if higher print speed is needed, the best thing to optimize is hot end geometry, specifically an extended barrel to allow for sufficient melting time.
Earth-shattering stuff? Probably not, but it’s nice to see someone doing a systematic study on this, rather than relying on seat-of-the-pants observations. And the images are pretty cool too.
“The lathe is the only machine tool that can make copies of itself,” or so the saying goes. The reality is more like, “A skilled machinist can use a lathe to make many of the parts needed to assemble another lathe,” which is still saying quite a lot by is pretty far off the implication that lathes are self-replicating machines. But what about a 3D printer? Could a printer print a copy of itself?
Not really, but the Infini-Z 3D printer certainly has some interesting features that us further down the road to self-replication. As the name implies, [SunShine]’s new printer is an infinite Z-axis design that essentially extrudes its own legs, progressively jacking its X- and Y-axis gantry upward. Each leg is a quarter of an internally threaded tube that engages with pinion gears to raise and lower the gantry. When it comes time to grow the legs, the print head moves into each corner of the gantry and extrudes a new section onto the top of each existing leg. The threaded leg is ready to use in minutes to raise the gantry to the next print level.
When it comes to 3D printing clay, there are a lot of challenges to be met. An extruder capable of pushing clay is critical, and [davidsfeir] has an updated version suitable for an Ender 3 printer. This extruder is based on earlier designs aimed at delta printers, but making one compatible with an Ender 3 helps keep things accessible.
What’s special about a paste extruder that can push clay? For one thing, clay can’t be stored on a spool, so it gets fed into the extruder via a hose with the help of air pressure. From there, the clay is actually extruded with the help of an auger that takes care of pushing the clay down through the nozzle. The extruder also needs a way to deal with inevitable air bubbles, which it does by allowing air to escape out the narrow space at the top of the assembly while clay gets fed downward.
For a lot of us, soldering has become so ingrained that it’s muscle memory. We know exactly when the iron is hot enough, how long to leave the tip in contact with the joint to heat it up, and exactly where to dab in the solder to get it to flow. When you’re well-practiced it can be a beautiful thing, but for those who don’t do it frequently, soldering can be frustrating indeed.
The “Solder Sustainer” looks like it just might be aimed at solving that problem, as well as a few others. It comes to us from [RoboticWorx], and while it looks a little like the love child of a MIG welder and a tattoo machine, it’s got a lot going for it. The idea is to make soldering a one-handed task by combining the soldering iron and a solder wire feeder into one compact package. The solder feeder is very reminiscent of a filament extruder on a 3D printer, using a stepper to drive spring-loaded pinch wheels, which forces the solder down a curved 3D-printed tube that directs it toward the tip. The pancake stepper is driven by an ESP32, which also supports the touch sensor that lets you advance the solder. The whole thing can be powered off a USB-C power supply, or using the onboard USB charger that can be connected in line with the soldering iron supply.
The video below shows Solder Sustainer in use. Yes, we know — some of those joints look a little iffy. But that seems to have more to do with technique than with the automatic solder feed. And really, in situations where you’ve previously wished for a third hand while soldering, this would probably be just the thing.
The Solder Sustainer is an entry in the “Gearing Up” round of the 2023 Hackaday Prize. If you’ve got an idea for a tool, jig, fixture, or instrument that makes hacking easier, we want to know about it. But you’d better hurry — the round ends on August 8.
In the bright sunshine of a warm spring afternoon at Delft Maker Faire, were a row of 3D printers converted with paste extruders. They were the work of [Nedji Yusufova], and though while were being shown printing with biodegradable pastes made from waste materials, we were also interested in their potential to print using edible media.
We’ve seen quite a few syringe extruders and at least one food printer, so there’s nothing particularly new about this one. What it does give you is a relatively straightforward build and a ready integration with some mass market printers you might be familiar with. Perhaps the most interesting part of this project isn’t even the extruder itself but the materials, after all having a paste extruder gives you the opportunity to experiment with new recipes. We like it.
Ultimately, the goal of Hackaday is to shine a light on the incredible projects coming from the hardware hacking community. In the vast majority of cases, said projects end up being one-off creations — a clever solution that solved a specific problem for the creator, which may or may not be directly applicable to anyone else. But occasionally, perhaps one in every few thousand projects, we see an idea that’s compelling enough to become a commercial product.
Today, we’re happy to add the Cocoa Press to that list. Creator [Ellie Weinstein] has recently unveiled a commercialized version of the chocolate 3D printer she’s been working on for several years, and true to the maker spirit, it’s being offered as a DIY kit. You can currently put a $100 USD deposit on the final product, which is expected to ship before the end of the year. Assembly time is estimated to be around 10 hours and no previous experience with building 3D printers is required, though we’re sure it wouldn’t hurt.
Extrusion is a process for forming materials by forcing them through an opening, which can allow for complex shapes. Aluminum extrusion beams are what most of us are probably thinking of, but plenty of other things are made from extruded material like pipe, heat sinks, and even macaroni. Extrusion can also be used for modelling clay to create uniform sections of rounded clay as a starter material for producing other pottery, and [Justins Makery] has built a custom extruder to do just that.
The build starts with welding together a metal frame to hold the press, and uses a wooden wagon handle to drive the extruder. The handle can be moved up or down the frame to increase the range of motion thanks to a custom bearing and slots cut into the frame’s post. The piston mechanism itself is built out of aluminum plate with a cylinder loosely fitted to it to allow for easy cleaning, and the top of the piston uses a loose-fitting plastic cap cut out of an old cutting board.
With everything in pace, the extruder can make cylinders of clay of any desired thickness thanks to swappable dies. While it doesn’t produce the end result of the workshop directly, it definitely helps to provide the potter with clay of uniform dimensions used for building other pieces of pottery, much like how aluminum extrusions are used to build all kinds of other things as well.