Art of 3D printer in the middle of printing a Hackaday Jolly Wrencher logo

Is Now The Time For Volumetric 3D Printing?

Of all innovations adopted by the maker community within the past couple of decades, one stands among the rest on top for anything regarding manufacturing. It goes without saying here at Hackaday how many projects have been reliant on using the technology to turn their ideas into reality. 3D printing has been a maker community invention and, in return, has expanded this hacky community into something that anyone with an imagination can get into. It also goes without saying that the layer-based tech imposes limits on what we can actually create: think overhangs and layer adhesion. However, there’s a possibility that a recent offshoot of this scrappy community has the power to eliminate some of these faults.

Volumetric additive manufacturing (VAM) is a young technology that has a similar start to many new tech toys, including the original SLA of the first 3D printers. That is expensive and completely stuck in the laboratory… Fortunately, that’s not where 3D printing as a whole stayed, as the RepRap project managed to bring the obscure technology to the hobbyists’ main stage. An entire group of people formed and spent countless hours until the useless pieces of poorly extruded plastic could form parts impossible to make with anything else. A cool quirk of history is that it likes to repeat: examples spur recreation, and this appears to be happening with the technology found within VAM printing.

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Microdistillery For Microchemistry

Much like radio operators being encouraged to use the least possible amount of power to make a contact, chemists have a similar rule encouraging using the least amount of materials in experiments. Not only is this rooted in economics, but in safety as well; if something goes wrong it’s generally good if there’s not excess amounts of reactants. With modern techniques, though, it’s possible to bring experimental chemistry down to incredibly small scales, and [Marb’s lab] found that they needed a custom built still for these new, diminutive experiments.

The first step is to build the heating component of the still. This is provided with a few custom aluminum parts for the base and a pair of heaters originally meant for 3D printers, with the assembled unit wrapped in insulation. The heater accomodates a 25 mL round-bottom flask. Temperature control of the heating mantle is provided by a controller mounted to a DIN rail which receives power from a 24V power supply, and an additional temperature probe is added to measure the temperature of the distillate. A test run with water shows the small still quickly and efficiently evaporating the water up to a condenser.

Although building a still doesn’t have to be technically difficult, building something this small that’s effective and safe is a bit more challenging than a backyard moonshining operation. Scaling chemical reactions down can often be a challenge but is possible with the right mindset and equipment. We’ve seen miniaturization of many things that we might not have expected including hydrogen production, aluminum smelting, and even the construction of a microscope.

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Solid-State Batteries Take To The Sky

There always seem to be a handful of revolutionary technologies perpetually out of reach: fusion energy, quantum computers, and full self-driving cars are always in this list, and it seems like there’s also some battery technology which will finally let us fully decouple from fossil fuels in there as well. Although lithium batteries have allowed some ground-based electric transportation, the energy density is still not enough to enable full electrification, especially for things like aircraft. Solid state batteries may be on the verge of changing some of this, though, and a team has recently put them to work in a test aircraft to help make some headway with this novel battery chemistry.

The main contributing factor of these batteries’ improved energy densities is the ability to use a solid lithium anode, which has much higher energy density than the graphite-based anodes in modern liquid electrolyte batteries. Solid state batteries also have improved safety, since the solid electrolyte is generally not flammable and the battery itself is less prone to thermal runaway. The tests in this aircraft, a modified motorized glider, bear this out as well. With a standard lithium ion pack the team was able to harness 250 Wh/kg and with their new solid state battery they managed 410 Wh/kg, which let them fly the craft up to 24,000 feet (7,315 m) with the help of some wing-mounted solar panels.

Of course, a motorized glider is a long way away from battery-powered commercial flights, but tests like this are an important step on the way to de-carbonizing one of the more impactful industries on the planet, as well as hopefully making it less expensive to operate aircraft in the way EVs are generally much cheaper to operate than their internal combustion equivalents. But the limiting factor to adopting solid state batteries isn’t going to be implementation but rather the discovery of a cost effective way to manufacture them at scale. It’s the same reason we haven’t seen mass adoption of things like algae-based biodiesel or economic carbon capture yet.

Introducing Boron Buckyballs

A buckminsterfullerene, also known as a buckyball, is typically a fullerene consisting of sixty carbon atoms (C60) arranged in a way that resembles a football-like sphere. Extending this arrangement to other types of atoms has until now however proven as elusive as finding non-carbon-based lifeforms. In a paper by [Hyun Wook Choi] et al. and published in Chemical Science the discovery of boron buckyballs is detailed. There is also a soft-paywalled article in the Chemical & Engineering News magazine for a higher-level perspective.

The discovered boron-based buckyball ups the number of atoms to eighty, forming B80 (boron fullerite) with a slightly larger diameter than C60 at 0.85 nm versus 0.71 nm. Perhaps more interesting are the claims by the authors that boron fullerite may have more practical applications than its carbon-based cousin, mostly due to it being predicted to be a semiconductor with an 0.8 eV energy gap and better electron acceptance that provides interesting doping prospects.

Producing these boron structures used laser vaporization with a helium carrier gas that was seeded with argon to increase cooling efficiency. Inside this boron cluster the reported structures were then discovered and characterized as described in the paper.

Obviously, going from a fascinating laboratory discovery to bulk production won’t be easy, and the predicted properties of boron fullerite may turn out to be incomplete or have a dark side that we aren’t aware of. Regardless, they’re bound to be more useful at least than the carbon version that’s remained mostly a curiosity despite many years of research.

Be Your Own Oil Company With Desktop Fischer-Tropsch Process

Plastics, oil, petrol– the modern world is entirely dependent on hydrocarbons. The good sources are slowly running low and supply is increasingly complicated by geopolitical factors we really don’t want to get into, but hey! It’s just hydrogen and carbon, right like it says in the name. How hard could it be to roll your own at home. Well, if you’ve got a lab like [Marb]’s Lab on YouTube, it might just be doable, as he demonstrates in his latest video.

The Fischer-Tropsch reaction was discovered back in 1925 in Germany by a couple of gents named Fischer and Tropsch. In the unpleasantness that followed later, Germany made good use of their process on an industrial scale, since they had ample coal and no oil on hand. Coal-rich South Africa has also made us of it, particularly during the Apartheid-era trade restrictions. Every so often the idea of industrializing the process comes up in the USA, but there’s still enough oil there it doesn’t make sense economically.

Those nations all have something in common: they’re all coal-rich countries, and that makes sense because coal is easily converted to carbon monoxide and hydrogen– a combo known as syngas– and it just so happens that those are the feedstock for this reaction. The actual chemistry going on inside is quite complex, but conceptually it is pretty simple: hydrogen and carbon monoxide mix over a hot metal catalyst, and combine to form various hydrocarbons.

In [Marb]’s glassware-based demonstration, the catalyst is Cobalt (III) Oxide on silica gel– a lovely, cancer-causing substance that must be prepared for each use, as it lasts but 24 hours before further oxidization ruins it. That’s in spite of purging the system with argon– a necessary step if one does not wish to explode. The yield isn’t amazing, and [Marb] isn’t sure exactly what mix of hydrocarbons he has created– although they smell like gasoline and burn like the dickens, so mission accomplished.

This might seem like the furthest thing from green, but if you use solar power to run the process and something like woodgas– which is syngas by any other name– as a feed-stock, then you’ve got a carbon neutral energy storage medium.

Thanks to [Markus Bindhammer] for the tip!

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Battery Tester Outperforms Cheaper Options

Batteries are notoriously difficult pieces of technology to deal with reliably. They often need specific temperatures, charge rates, can’t tolerate physical shocks or damage, and can fail catastrophically if all of their finicky needs aren’t met. And, adding insult to injury, for many chemistries, the voltage does not correlate to state of charge in meaningful ways. Battery testers take many efforts to mitigate these challenges, but often miss the mark for those who need high fidelity in their measurements. For that reason, [LiamTronix] built their own.

The main problem with the cheaper battery testers, at least for [LiamTronix]’s use cases, is that he has plenty of batteries that are too large to practically test on the low-current devices, or which have internal battery management systems (BMS) which can’t connect to these testers. The first circuit he built to help solve these issues is based on a shunt resistor, which lets a smaller IC chip monitor a much larger current by looking at voltage drop across a resistor with a small resistance value. The Pi uses a Python script which monitors the current draw over the course of the test and outputs the result on a handy graph.

This circuit worked well enough for smaller batteries, but for his larger batteries like the 72V one he built for his electric tractor, these methods could draw far too much power to be safe. So from there he built a much more robust circuit which uses four MOSFETs as part of four constant current sources to sink and measure the current from the battery. A Pi Zero monitors the voltage and current from the battery, and also turns on some fans pointed at the MOSFETs’ heat sink to keep them from overheating. The system can be configured to work for different batteries and different current draw rates, making it much more capable than anything off the shelf.

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Virus-Based Thermoresponsive Separation Of Rare-Earth Elements

Although rare-earth elements (REEs) are not very rare, their recovery and purification is very cumbersome, with no significant concentrations that would help with mining. This does contribute to limiting their availability, but there might be more efficient ways to recover these REEs. One such method involves the use of a bacteriophage that has been genetically modified to bind to specific REEs and release them based on thermal conditions.

The primary research article in Nano Letters is sadly paywalled, but the supporting information PDF gives some details. We can also look at the preceding article (full PDF) by [Inseok Chae] et al. in Nano Letters from 2024, in which they cover the binding part using a lanthanide-binding peptide (LBP) that was adapted from Methylobacterium extorquens.

With the new research an elastin-like peptide (ELP) was added that has thermoresponsive responsive properties, allowing the triggering of coacervation after the phages have had some time in the aqueous REE containing solution. The resulting slurry makes it fairly easy to separate the phages from the collected REE ions, with the phages ready for another cycle afterwards. Creating more of these modified phages is also straightforward, with the papers showing the infecting of E. coli to multiply the phages.

Whether the recovery rate and ability to scale makes it an economically feasible method of REE recovery remains to be seen, but it’s definitely another fascinating use of existing biology for new purposes.