The toroidal propeller's details in the CAD software. (Credit: rctestflight))

Testing Futuristic Propeller Designs With A 3D Printer And A Solar-Powered Boat

July 2, 2023 by Maya Posch 21 Comments

The toroidal boat propeller pair installed. (Credit: rctestflight)

As boring as propeller designs may seem to the average person, occasionally there’s a bit of a dust-up in the media about a ‘new’ design that promises at least a few percent improvement in performance, decreased noise profile, or any combination of such claims. Naturally, if you’re [Daniel Riley] of RCTestFlight, then you have to 3D print a few of them, and make a video covering a handful. Most famous of these is probably the toroidal propeller that made waves a while ago, mostly in the field of flying drones, but commercial toroidal boat props exist too.

Test results of the different boat propeller designs. (Credit: rctestflight)

Interestingly, the 2-blade FDM-printed propeller ended up performing the best, while the bi-blade design (with two sets of blades positioned one after the other) performed worse — but better than the toroidal design. Here the last two designs were professionally printed in nylon, rather than printed at home in a standard FDM printer with all of the surface sanding and treatment required. Even so, the surface treatment did not seem to noticeably affect the results in further testing.

Hints at the root cause of the problem came from the bubble tests. In a bubble test, air is blown in front of the spinning propeller to visualize the flow of the water. This revealed some stalling on the bi-blade and the toroidal design too, which would explain some of the performance loss. Going back between the CAD model and the design in the patent by Sharrow Marine didn’t provide any obvious hints.

Considering that this latter company claims a performance uplift over regular boat propellers, the next steps for [Daniel] would appear to involve some careful navigating between fluid dynamic modeling and claims made in glossy marketing material to figure out exactly how close someone at home with a 3D printer and some spare time can get to those claimed numbers.

(Heading image: The toroidal propeller’s details in the CAD software. (Credit: rctestflight) )

Continue reading “Testing Futuristic Propeller Designs With A 3D Printer And A Solar-Powered Boat” →

Ventbot fans with 3D printed brackets and control circuit board with ESP32 breakout and multicolored 3D printed cases

Ventbots Are Fans Of HVAC And Home Automation

June 24, 2023 by Michael Shaub 21 Comments

[WJCarpenter] had a common HVAC problem; not all the rooms got to a comfortable temperature when the heater was working to warm up their home. As often happens with HVAC systems, the rooms farthest from the heat source and/or with less insulation needed a boost of heat in the winter and cooling in the summer too. While [WJCarpenter] is a self-reported software person, not a hardware person, you will enjoy going along on the journey to build some very capable vent boosters that require a mix of each.

There’s a great build log on hackaday.io here, but for those who need more of a proper set of instructions, there’s a step-by-step guide that should allow even a beginner hardware hacker to complete the project over on Instructables. There you’ll find everything you need to build ESPHome controlled, 3D printed, PC fan powered vent boosters. While they can be integrated into Home Assistant, we were interested to learn that ESPHome allows these to run stand-alone too, each using its own temperature and pressure sensor.

The many iterations of hardware and software show, resulting in thoughtful touches like a startup sequence that checks for several compatible temperature sensors and a board layout that accommodates different capacitor lead spacings. Along the way, [WJCarpenter] also graphed the noise level of different fans running at multiple speeds and the pressure sensor readings against the temperatures to see if they could be used as more reliable triggers for the fans. (spoiler, they weren’t) There are a bunch of other tips to find along the way, so we highly recommend going through all that [WJCarpenter] has shared if you want to build your own or just want some tips on how to convert a one-off project to something that a wider audience can adapt to their own needs.

See a video after the break that doesn’t show the whole project but includes footage of the start-up sequence that tests each fan’s tachometer and the customizable ramp-up and ramp-down settings. Continue reading “Ventbots Are Fans Of HVAC And Home Automation” →

Open Source And Giving Back

June 24, 2023 by Elliot Williams 41 Comments

3D printing YouTuber [Thomas Sanladerer] made a fairly contentious claim in a video about the state of open source hardware and software: namely that it’s not viable “anymore”. You can watch his video for more nuance, but the basic claim is that there are so many firms who are reaping the benefits of open designs and code that the people who are actually doing the work can’t afford to make a living anymore.

[Thomas] then goes on to mention a few companies that are patenting their 3DP innovations, and presumably doing well by it, and he then claims that patenting is probably the right way forward from a business standpoint.

The irony that he says this with a Voron 3D printer sitting behind him was not lost on us. The Voron is, after all, a very successful open-source 3D printer design. It’s just rock solid, has lots of innovative touches, and an extensive bill of materials. They don’t sell anything, but instead rely on donations from their large community to keep afloat and keep designing.

At the same time, a whole bunch of companies are offering Voron kits – all of the parts that you’d have to source yourself otherwise. While not mass-market, these kit sales presumably also help keep some of the 3D printer enthusiast stores that sell them afloat. Which is all to say: the Voron community is thriving, and a number of folks are earning their livings off of it. And it’s completely open.

When [Thomas] complains that some players in the 3DP business landscape aren’t giving back to the open-source community effort, he’s actually calling out a few large-scale Chinese manufacturers making mass-market machines. These companies aren’t interested in pushing the state of the art forward anyway, rather just selling what they’ve got. And sure, there are a million Creality Enders for every Voron 2 out there. And yes, they reap the benefits of open designs and code. But they’re competing in an entirely different market from the real innovators, and I’m not sure that’s a bad thing.

Let us know what you think. (And if you’re reading this in the newsletter format, head on over to Hackaday on Saturday morning to leave us your comments.)

Hinged Parts For The 8th Grade Set

June 16, 2023 by Al Williams 8 Comments

I recently agreed to run a 3D printing camp for 8th graders. If you’ve never shared your knowledge with kids, you should. It is a great experience. However, it isn’t without its challenges. One thing I’ve learned: don’t show the kids things that you don’t want them to try to print.

I learned this, of course, the hard way. I have several “flexy”3D prints. You know the kind. Flexy dinosaurs, cats, hedgehogs, and the like. They all have several segments and a little hinge so the segments wobble. The problem is the kids wanted to print their own creations with flexy hinges.

I’ve built a few print-in-place hinges, but not using Tinkercad, the software of choice for the camp. While I was sure it was possible, it seemed daunting to get the class to learn how to do it. Luckily, there’s an easy way to add hinges like this to a Tinkercad design. There was only one problem.

Continue reading “Hinged Parts For The 8th Grade Set” →

Microsculptures 3D Printed With Advanced Macromolecular “Inks”

June 5, 2023 by Lewin Day 3 Comments

When we think about 3D printing, our mind often jumps to hot nozzles squirting out molten plastic. Other popular techniques include flashing bright light into resin, or using lasers to fuse together metal powders. All these techniques are great at producing parts with complicated geometries at desktop scales.

However, it’s also possible to 3D print at altogether microscopic scales. Researchers in Germany have now developed advanced macromolecular “inks” that can be used to create microscopic 3D sculptures with finer control than ever before.

Continue reading “Microsculptures 3D Printed With Advanced Macromolecular “Inks”” →

3D Printing Safety (According To The UL)

June 4, 2023 by Al Williams 17 Comments

If you want to start a heated discussion in 3D printing circles, ask people about the requirements to print safely. Is ABS safe to print without ventilation? Can you drink out of a PLA cup? How nasty is that photo resin if you spill it on yourself? If you are at home, it’s more or less up to you. But if you are building a shared hackerspace, a corporate workstation, or a classroom, these questions might come up, and now, the UL has your answer. The UL200B document is aimed at 3D printers in “institutions of higher education,” but we imagine what’s good for the university is good for us, too.

The 45-page document isn’t an easy read. It does cover both “material extrusion” and “vat photopolymerization” technology. In fact, they identify seven “most common” processes ranging from powder bed fusion, energy deposition, and more. The work results from a UL task force with participants from Harvard, Princeton, and Carnegie-Mellon. We were surprised there didn’t seem to be any industry representation, but maybe that was on purpose.

With extrusion printing — what we’d call FDM — the focus seems to be on ultra-fine particles and volatile organic compounds (VOCs). However, the level of VOCs rose up to six times with resin printers when compared to FDM. Filters helped with ABS, nylon, and ASA, and polycarbonate/ABS. The paper does acknowledge that PLA is probably safer, although it is quick to point out that PLA with additives may not be as safe as plain PLA. If you want a quick summary, check out Table 2, starting on page 23.

The rest of the document is about creating a safety plan for all the printers that might be on a college campus — that might not be as interesting. However, you’ll want to skip forward to the appendix section. It has some data about relevant industrial standards and other data.

This is a great step in analyzing the risks of 3D printing. Of course, laser printers and copiers also spew micro-particles, and we seem to have survived those for a number of decades. Still, more data is good — you should be informed to make decisions about your health and safety. We didn’t see much in the document that covered food safety, something we’ve talked about before. If you want to monitor your VOC exposure, we got you.

3D Printing Bores Without Support

May 28, 2023 by Danie Conradie 14 Comments

If you’ve done even a small amount of 3D printing, you probably ran into the challenge of printing a small hole on top of a larger hole. The conventional solution is just to add support, but in the video after the break, [Angus] of Maker’s Muse demonstrates an alternative solution you can implement in CAD, without having to do manual post-processing.

This is a common problem when you have a countersink feature for a bolt head or captured nut on the bottom of the part. [Angus] first demonstrates some other techniques, including printing the bore over empty space, adding a sacrificial bridge, and making the overhang 45°. Each of these work but have some trade-offs. The proposed solution is what [Angus] calls sequential overhangs. It involves bridging the sides of the open space in steps to create supporting edges onto which the bore perimeter can print. It starts with 2 or 3 bridging layers to create a rectangle the same width as the bore, and then a second set of bridges at 90° to turn the opening into a square. For smaller holes this should create enough of a support to start the bore perimeter, but for larger holes three sets of bridges at 60° offsets might be needed.

[Angus] does not claim to have invented the technique but states he borrowed the idea from parts printed by Prusa Research for their popular line of 3D printers. One of the comments on the [Maker’s Muse] video referenced a 2014 blog post by [nophead] showing the same approach. Regardless of the idea’s lineage, it’s a great addition to anyone’s 3D printing design toolbox.
Continue reading “3D Printing Bores Without Support” →