Last time we looked in on Injekto — a homemade plastic injection machine — it was at version 1.0. A recent video from the team that you can see below shows version 2 which is much improved and can work with 3D printed molds. Injection molding takes a lot of pressure and the machine certainly looks stout with lots of machined aluminum.
If you want to skip the build process, you can skip up to around the 9-minute mark. That’s where they show a machined mold and a 3D printed mold being used with the machine.
Canadian researchers at Concordia University want to change how you do 3D printing. Instead of using light or thermal mechanisms, they propose using ultrasound-activated sonochemical reactions. Sounds wild? You can see a video about it below, or read the paper in Nature.
The idea is that sound causes bubbles of cavitation. This requires a focused ultrasonic beam which means you can actually print through items that are transparent to ultrasonic energy. Wherever the cavitation bubbles form, liquid polymer turns solid.
For anyone looking to buy a 3D printer at home, the first major decision that needs to be made is whether to get a resin printer or a filament printer. Resin has the benefits of finer detail, but filament printers are typically able to produce stronger prints. Within those two main camps are various different types and sizes to choose from, but thanks to some researchers at Switzerland’s École polytechnique fédérale de Lausanne (EPFL) there’s a new type of resin printer on the horizon that can produce prints nearly instantaneously.
The method works similarly to existing resin printers by shining a specific light pattern on the resin in order to harden it. The main difference is that the resin is initially placed in a cylinder and spun at a high speed, and the light is shined on the resin at different angles with very precise intensities and timings in order to harden the resin in specific areas. This high-speed method allows the printer to produce prints in record-breaking time. The only current downside, besides the high price for the prototype printer, is that it’s currently limited to small prints.
With the ability to scale in the future and the trend of most new technologies to come down in price after they have been on the market for some amount of time, it would be groundbreaking to be able to produce prints with this type of speed if printers like these can be scalable. Especially if they end up matching the size and scale of homemade printers like this resin printer.
Montana, rightfully nicknamed the big sky country, is a beautiful state with abundant wide open landscapes, mountains, and wildlife. It’s a fantastic place to visit or live, but if you happen to reside in the city of Butte, that amazing Montana landscape is marred by the remnants of an enormous open pit mine. Not only is it an eyesore, but the water that has filled the pit is deadly to any bird that lands there. As a result, a group of people have taken to some ingenious methods to deter birds from landing in the man-made toxic lake for too long.
When they first started, the only tool they had available was a rifle. Scaring birds this way is not the most effective way for all species, though, so lately they have been turning to other tools. One of which is a custom boat built on a foam bodyboard which uses a plethora of 3D printed parts and sensors to allow the operator to remotely pilot the boat on the toxic lake. The team also has a drone to scare birds away, plus an array of other tools like high-powered lasers, propane cannons, and various scopes in order to put together the most effective response to help save wildlife.
While this strategy runs the gamut of the tools most commonly featured here, from 3D printers to drones to lasers, the only thing that’s missing is some automation like we have seen with other drone boat builds we’ve featured in the past. It takes quite a bit of time to continually scare birds off this lake, even through the winter, so every bit of help the team can get could go even further.
When it comes to 3D printing using fused deposition modeling (FDM) technology, there are two main groups of printers: Cartesian and CoreXY, with the latter being the domain of those who wish to get the fastest prints possible, courtesy of the much more nimble tool head configuration. Having less mass in the X/Y carriage assembly means that it can also move faster, which leads to CoreXY FDM enthusiasts to experiment with carbon fiber and a recent video by [PrimeSenator] in which an X-beam milled out of aluminium tube stock that weighs even less than a comparable carbon fiber tube is demonstrated.
As the CoreXY FDM printer only moves in the Z-direction relative to the printing surface, the X/Y axes are directly controlled by belts and actuators. This means that the faster and more precise you can move the extruder head along the linear rails, the faster you can (theoretically) print. Ditching the heavier carbon fiber for these milled aluminium structures on a Voron Design CoreXY printer should mean less kinetic inertia, with the initial demonstrations showing positive results.
The interesting thing about this ‘speed printing’ community is that not only the raw printing speeds, but also that in theory CoreXY FDM printers are superior in terms of precision (resolution) and efficiency (e.g. build volume). All of which makes these printers worthy of a look next time one is shopping for an FDM-style printer.
Everybody knows the trick to holding a candle flame to a balloon without it bursting — that of adding a little water before the air to absorb the heat from the relatively cool flame. So [Integza], in his quest to 3D print a jet engine wondered if the same principle could applied to a 3D printed combustion chamber. First things first, the little puddle of water was replaced with a pumped flow, from an external reservoir, giving the thin plastic inner surface at least a vague chance of survival. Whilst this whole plan might seem pretty bonkers (although we admit, not so much if you’ve seen any of other videos in the channel lately) the idea has some merit. Liquid cooling the combustion jacket is used in a great many rocket engine designs, we note, the German WWII V2 rocket used this idea with great success, along with many others. After all, some materials will only soften and become structurally weak if they get hot enough in any spot, so if it is sufficiently conductive, then the excess heat can be removed from the outer surface and keep the surface temperature within sensible bounds. Since resin is a thermoset plastic, and will burn, rather than melt, this behaviour will be different, but not necessarily better for this application.
The combustion chamber itself didn’t burn
The issue we can see, is balancing the thermal conductivity of the resin wall, with the rate of cooling from the water flow, whilst making it thick enough to withstand the pressure of combustion, and any shock components. Quite a complicated task if you ask us. Is resin the right material for the job? Probably not, but it’s fun finding out anyway! In the end [Integza] managed to come up with a design, that with the help of a metal injector separator plate, survived long enough to maintain some sort of combustion, until the plate overheated and burned the resin around its support. Better luck next time!
We’re all familiar with FDM 3D printing, and some of the more well-heeled or adventurous among us may even have taken a faltering step into the world of SLA printers. But for most of us there’s a step further in 3D printing that remains beyond our reach. SLS, or Selective Laser Sintering, creates prints from powder by melting it layer by layer using a laser, and has the advantage of opening up more useful materials than the polymer stock of the other methods. It’s not entirely unreachable though, as [Kenneth Hawthorn] shows us by using a laser cutter to produce SLS prints from powdered glass.
He evolved the technique of repeated fast passes with the laser to gradually melt more glass together as opposed to slower passes. He achieved a resolution as low as 0.1 mm, though he found a better glass color when the laser was less tightly focused. It raises the concern that glass powder is abrasive and thus a threat to any mechanism, thus he’s being extremely careful with the fan settings.
This may not be quite in the league of an SLS printer costing thousands of dollars, but it’s a technique that bears more investigation and could no doubt be refined for more custom fused glass creations. He tells us he was inspired by a previous Hackaday post about sintering sand, and of course we’d like to remind readers of a 3D printer that did the same job with the power of the sun.
