The famous particle accelerator has gone silent, but its next chapter could usher in a new era of particle physics.

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.

History

Hold up for a second. While we have covered VAM here before at Hackaday, it’s not exactly the most well-known tech or the easiest to understand. So what is it? Starting from the beginning and simplest forms, VAM is similar to the more  common SLA printing. Using a light source and light sensitive resin, both of these methods can create entire physical objects by solidifying or curing specific areas of a vat or vial of resin. SLA will often use something like a laser and layer by layer “draw” the model until the entire geometry is finished. A quirk of most of many photosensitive resins is that they need to overcome a threshold before they can start curing. This allows VAM to do something a bit different. The earliest methods of VAM used intercepting lasers which allowed selective curing only where these beams were intercepted. One singular spot at a time would be able to overcome the threshold required for printing, allowing you to build up most geometries.

This works, but for more complicated models there’s more effective methods. One type has been covered here before called Xolography, still using intercepting beams, however with differing wavelengths which allows for more finite control. This is effective, but the resin is complex, requiring two-wavelength-photon-sensitive photoinitiators. Introduce the current standard in VAM printing, computed axial lithography (CAL). This method finds itself using existing methods found in traditional tomography, such as CT scanners. CAL methods are basically reverse tomography, where a model is used to create projections to be projected in printing. These projections allow dose control in each “voxel” of resin from changing the projection as the volume of resin is rotated. When ideal, this means that the entire model is printed at once. No layers needed for printing, and printing in minutes rather than hours.

Open-Sourced

Cool, but why should you care about this tech? Because you could start using it now! Just like the RepRap project before it, VAM has OpenCAL. OpenCAL was started by the same lab that originally created the axial version of the technology. UC Berkeley released the first OpenCAL around 2019 which was… well a start.

Functionally practical for only big budget research, it was far too expensive and complicated for any hobbyist with a 9-5 to realistically touch. Last year saw a new model presented at Open Sauce which used a consumer projector and common hobbyist electronics. While this was an improvement, there are three barriers to VAM printing; the hardware, software, and chemical resins make it a challenge for any individual alone. A newer version of the hardware was quickly put together for this summer. This helps with the hardware element, but there’s two new aspects being released alongside OpenCAL V2 for other unsolved problems.

 

Software: Tomo

For a little while now there have been various software packages available for allowing easier use of whatever VAM printer you might have, however these had various problems. From being undocumented to being complicated for anyone without comfort in command line , something different would be needed. A standalone application would certainly work, and low and behold that’s exactly what’s being tried here, called Tomo. Tomo allows you to use an OpenCAL printer with little thought or expertise, or ideally any other type of VAM printer.

Chemistry: Formlabs Resin

Material science is always a particular challenge for the open source community. Unlike software, you can’t distribute unlimited copies of your perfect mix of photosensitive resin without special chemical clearances and certainly not for free. Some of the first 3D printers from RepRap would use a nylon weed wacker line in place of the standard PLA of today. Unfortunately there’s less flexibility in the fine tuned resin found in VAM. This resin has to have a nonlinear photo-reaction for selective curing, be fairly transparent to the reactive wavelength, and be very viscous to prevent resin movement during printing. Formlabs, which makes resin printers and resins, has gotten into the act. Through talks between the OpenCAL team and Formlabs, an agreement for production of this special resin is being worked out, allowing for far cheaper material.

Hardware: OpenCAL

Of course this leaves the printer itself. OpenCAL is designed for a variety of different sized printing volumes, projectors, or anything else you might have in mind. Expect printing anything from this printer to finish in the span of minutes. While it can do the same small prints found in the older model of OpenCAL, experiments involving larger form factors have been attempted. But if you want more details make sure to check out the documentation here or join their Discord channel!

Future of VAM Printing

So how far can this technology really go? Could it pass traditional methods of 3D printing? Well, it’s certainly faster than traditional printing, however, there’s still plenty of trouble when trying it out. How do you remove partially cured resin off your print? How do you actually tell when the print is done? These are problems that are being fixed right now by the community, and maybe you can be the one to fix something holding it back. It’s fair to say that the community that has propped this technology up to where it currently stands is who is going to decide where it goes.

The 19th century was an absolutely electrifying era, including in a literal sense. Although the phenomenon of electricity had been known by that time for centuries, actually making it do useful work was a much taller order. Aside from big, coal-powered generators, there also was a need for a more compact electrochemical solution, such as in the form of a wet or dry cell. One of the first major commercial successes here came in the form of the Leclanché cell, such as the genuine version that [Big Clive] found in an old UK building’s attic and has now revived.

Invented in 1866 by French scientist Georges Leclanché, the Leclanché cell features an ammonium chloride electrolyte solution, carbon cathode and zinc anode. There’s also a manganese dioxide depolarizer for preventing hydrogen build-up. Here water is the solvent for the ammonium chloride (also known as sal ammoniac).

The version that [Clive] got his grubby mitts on features a glass container, an already partially consumed zinc electrode and a slightly cracked porous ceramic tub that contains the carbon electrode and the manganese dioxide. After placing the components inside the specially shaped glass jar and filling it with an electrolyte mixture of one part ammonium chloride and four parts water by weight, the cell starts generating its approximate 1.4 VDC.

This type of wet cell was very popular, being essentially ‘rechargeable’ by topping up the water and replacing the zinc electrode consumable. They did suffer from a voltage drop-off during use due to increasing internal resistance, something that got improved upon with the zinc-carbon dry cell. Itself effectively an evolution of the Leclanché wet cell.

From there zinc-carbon dry cells got replaced with alkalines, which itself got mostly replaced by NiMH and Li-ion cells. Despite more than a hundred years between the electrochemical cell that [Clive] featured in his video and today’s batteries, it’s clear that this wet cell was quite literally just the Victorian-era equivalent of an alkaline AA cell.

NASA’s Perseverance rover has spent five years traversing Jezero Crater looking for the chemical leftovers of whatever processes were at work on Mars billions of years ago. The rover has found organic carbon, but it has mostly been inside rocks that had to be drilled or abraded to expose it. But now, at an outcrop on the edge of an ancient river channel named Neretva Vallis, Perseverance detected complex macromolecular carbon sitting right on the rock’s surface.

“To our knowledge, that’s the shallowest detection of organic matter on Martian surface to date,” said Ashley E. Murphy, a researcher at the Planetary Institute in Tucson, Arizona, and lead author of the study of the rock, which was found at a site called Bright Angel. On Earth, this much macromolecular carbon usually suggests a biological origin. But to learn what this Bright Angel carbon is and where it came from, we might need to bring samples back to Earth.

Carbon on the rocks

The detection of Bright Angel carbon came from SHERLOC (Scanning Habitable Environments with Raman and Luminescence for Organics and Chemicals), a UV Raman spectrometer fitted on Perseverance’s robotic arm. SHERLOC fires a deep-ultraviolet laser at a target and reads the light that bounces back at shifted energies, a signal that enables scientists to identify specific molecular bonds.

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© NASA/JPL-Caltech

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.