Using light to 3D print liquid resins is hardly a new idea. But researchers at the University of Texas at Austin want to double down on the idea. Specifically, they use a resin with different physical properties when cured using different wavelengths of light.
Natural constructions like bone and cartilage inspired the researchers. With violet light, the resin cures into a rubbery material. However, ultraviolet light produces a rigid cured material. Many of their test prints are bio-analogs, unsurprisingly.
If you’re looking for a long journey into the wonderful world of instrument hacking, [Arty Farty Guitars] is six parts into a seven part series onhacking an existing guitar into a guitar-hurdy-gurdy-hybrid,and it is “a trip” as the youths once said. The first video is embedded below.
The Hurdy-Gurdy is a wheeled instrument from medieval europe, which you may have heard of, given the existence of the laser-cut nerdy-gurdy, the electronicmidi-gurdy we covered here, and the digi-gurdy whichseems to be a hybrid of the two. In case you haven’t seen one before, the general format is for a hurdy-gurdy is this : a wheel rubs against the strings, causing them to vibrate via sliding friction, providing a sound not entirely unlike an upset violin. A keyboard on the neck of the instrument provides both fretting and press the strings onto the wheel to create sound.
[Arty Farty Guitars] is a guitar guy, so he didn’t like the part with about the keyboard. He wanted to have a Hurdy Gurdy with a guitar fretboard. It turns out that that is a lot easier said than done, even when starting with an existing guitar instead of from scratch, and [Arty Farty Guitar] takes us through all of the challenges, failures and injuries incurred along the way.
Probably the most interesting piece of the puzzle is the the cranking/keying assembly that allows one hand to control cranking the wheel AND act as keyboard for pressing strings into the wheel. It’s key to the whole build, as combining those functions on the lower hand leaves the other hand free to use the guitar fretboard half of the instrument. That controller gets its day invideo five of the series. It might inspire some to start thinking about chorded computer inputs– scrolling and typing?
If you watch up to the sixth video, you learn that that the guitar’s fretting action is ultimately incompatible with pressing strings against the wheel at the precise, constant tension needed for good sound. To salvage the project he had to switch from a bowing action with a TPU-surfaced wheel to a sort of plectrum wheel, creating an instrument similar to thethousand-pick guitar we saw last year.
Even though [Arty Farty Guitars] isn’t sure this hybrid instrument can really be called a Hurdy Gurdy anymore, now that it isn’t using a bowing action, we can’t help but admire the hacking spirit that set him on this journey. We look forward to the promised concert in the upcoming 7th video, once he figures out how to play this thing nicely.
We love 3D printing. We’ll print brackets, brackets for brackets, and brackets to hold other brackets in place. Perhaps even a guilty-pleasure Benchy. But 3D printed shoes? That’s where we start to have questions.
Every few months, someone announces a new line of 3D-printed footwear. Do you really want your next pair of sneakers to come out of a nozzle? Most of the shoes are either limited editions or fail to become very popular.
First World Problem
You might be thinking, “Really? Is this a problem that 3D printing is uniquely situated to solve?” You might assume that this is just some funny designs on some of the 3D model download sites. But no. Adidas, Nike, and Puma have shoes that are at least partially 3D printed. We have to ask why.
We are pretty happy with our shoes just the way that they are. But we will admit, if you insist on getting a perfect fitting shoe, maybe having a scan of your foot and a custom or semi-custom shoe printed is a good idea. Zellerfield lets you scan your feet with your phone, for example. [Stefan] at CNC Kitchen had a look at those in a recent video. The company is also in many partnerships, so when you hear that Hugo Boss, Mallet London, and Sean Watherspoon have a 3D-printed shoe, it might actually be their design from Zellerfield.
Commercial 3D printers keep getting faster and faster, but we can confidently say that none of them is nearly as fast as [Jan]’s Minuteman printer, so named for its goal of eventually printing a 3DBenchy in less than a minute. The Minuteman uses an air bearing as its print bed, feeds four streams of filament into one printhead for faster extrusion, and in [Jan]’s latest video, printed a Benchy in just over two minutes at much higher quality than previous two-minute Benchies.
[Jan] found that the biggest speed bottleneck was in cooling a layer quickly enough that it would solidify before the printer laid down the next layer. He was able to get his layer speed down to about 0.6-0.4 seconds per layer, but had trouble going beyond that. He was able to improve the quality of his prints, however, by varying the nozzle temperature throughout the print. For this he used [Salim BELAYEL]’s postprocessing script, which increases hotend temperature when volumetric flow rate is high, and decreases it when flow rate is low. This keeps the plastic coming out of the nozzle at an approximately constant temperature. With this, [Jan] could print quite good sub-four and sub-thee minute Benchies, with almost no print degradation from the five-minute version. [Jan] predicts that this will become a standard feature of slicers, and we have to agree that this could help even less speed-obsessed printers.
Now onto less generally-applicable optimizations: [Jan] still needed stronger cooling to get faster prints, so he designed a circular duct that directed a plane of compressed air horizontally toward the nozzle, in the manner of an air knife. This wasn’t quite enough, so he precooled his compressed air with dry ice. This made it both colder and denser, both of which made it a better coolant. The thermal gradient this produced in the print bed seemed to cause it to warp, making bed adhesion inconsistent. However, it did increase build quality, and [Jan]’s confident that he’s made the best two-minute Benchy yet.
If you’re curious about Minuteman’s motion system, we’ve previously looked at how that was built. Of course, it’s also possible to speed up prints by simply adding more extruders.
[Ryan] of [Fat Lip Collective] has been on a streak of using 3D printing for his car mod projects. From spark plug adapters to exhaust pipes to dash panels, his CAD skills and additive manufacturing tech have played a number of roles in his process.
Most recently, [Ryan] has embarked on a mission to equip an ’80s-era Toyota KE70 Corolla with a turbo engine. The main question there being how to fit the engine back into the car once he’s inserted a salvaged turbo into the exhaust line.
There is a non-trivial amount of stuff that needs to be packed in with the rest of the engine and finding a working configuration that doesn’t get in the way of anything else requires some trial and error. Furthermore, the alignment of the many twisting and turning pieces of schedule 40 pipe that will direct gasses where they need to go needs to be pretty precise.
Juggling all of this would be tedious, time consuming, and error prone if it were not for [Ryan’s] mighty 3D printer. He printed a set of the different elbows and reducers modeled on the schedule 40 pipe that he would likely be using. He added degree markers for easy reference later and flat sections at the ends of each piece so they could be bolted to each other. With this kit of parts in hand, he was able to mock up different arrangements, re-configuring them as he considered the position of other nearby components.
You could use a little pocket-sized Pez dispenser if you’re a humble, reserved person. Or, you could follow the example of [Backhaul Studios], and build a dangerously powerful blaster that shoots Pez fast enough to shatter them into pieces. Just don’t aim it at your own mouth.
As the video explains, Pez is really the perfect candy for this application. It’s compact, hard, and already designed to be dispensed via a magazine. It’s thus not a big stretch to set it up to be fired out of a pistol-like blaster. The build is of the flywheel type, where a pair of counter-rotating wheels fling the candy out at great speed. The wheels themselves are spun up to high speed with a pair of small brushless motors, running off hobby speed controllers and lithium-ion batteries. A simple trigger mechanism dispenses the rectangular candies into the wheel mechanism, sending them flying out of the blaster at will. It’s all 3D-printed, designed specifically for the purpose of high-speed candy delivery.
The video goes into great detail on the design, from the development of the TPU treads on the flywheels and other details that helped improve the effectiveness of the design. The final build shoots Pez fast enough that they practically detonate upon hitting a surface.
Since the earliest days of affordable, home 3D printers, the technology behind them has been continuously improving. From lowering costs, improving print quality, increasing size and detail, and diversifying the types of materials, it’s possible to get just about anything from a 3D printer today with a minimum of cost. Some of the things that printers can do now might even be surprising, like this upgrade that makes [Startup Chuck]’s 3D printer capable of printing realistic-sounding cowbells out of plastic.
The key to these metal-like prints is a filament called PPS-CF which is a carbon fiber-reinforced polyphenylene sulfide, or PPS. PPS-CF has a number of advantages over other plastics including high temperature tolerance and high dimensional stability, meaning its less likely to warp or deform even in harsh environments. But like anything with amazing upsides, there are some caveats to using this material. Not only does the carbon fiber require more durable extruder nozzles but PPS-CF also needs an extremely hot print head to extrude properly in addition to needing a heated bed. In [Startup Chuck]’s specific case he modified his print head to handle temperatures of 500°C and his print bed to around 100°C. This took a good bit of work just to supply it with enough energy to get to these temperatures and caused some other problems as well, like the magnet on the printer bed demagnetizing above around 75°C.
To get to a working cowbell took more than just printer upgrades, though. He had to go through a number of calibrations and test prints to dial in not only the ideal temperature settings of the printer but the best thicknesses for the cowbell itself so it would have that distinct metallic ring. But cowbells aren’t the only reason someone might want to print with carbon-reinforced materials. They have plenty of uses for automotive, chemical processing, high voltage, and aerospace applications and are attainable for home 3D printers. Just make sure to take some basic safety precautions first.
