Compact 3D Printed Hovercraft Is Loungeroom Floor Fun

December 26, 2019 by Lewin Day 7 Comments

Hovercraft come in all shapes and sizes. and while they’ve largely disappeared as a major commercial transit option, they remain popular in the hearts and minds of makers everywhere. [RCLifeOn’s] latest project concerns a compact, indoor-sized hovercraft piloted via FPV, and it looks to be brilliant fun.

The build consists of a 3D printed chassis, with a skirt cut out of a garbage bag and held on with press-fit clamps. Twin ducted fans are employed, one for propulsion, the other for levitation. A 5GHz FPV camera is nestled on top of the rear fan housing to provide a video feed for the pilot.

The craft was somewhat uncontrollable in initial testing. Tweaks to the weight distribution and the addition of a bigger rudder helped tame the rig. [RCLifeOn] also demonstrates a unique way of balancing damaged fan assemblies in the field; it’s a technique we’ll keep in the back of our mind for future use.

The trick to a good hovercraft build is light weight, big control surfaces, and a good skirt. You can even go off-book and use the Coanda effect, if you’re so inclined. Video after the break.

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Custom Control Panels With Photogrammetry

December 26, 2019 by Tom Nardi 22 Comments

One of the best applications for desktop 3D printing is the creation of one-off bespoke components. Most of the time a halfway decent pair of calipers and some patience is all it takes to model up whatever part you’re after, but occasionally things get complex enough that you might need a little help. If you ever find yourself in such a situation, salvation might be just a few marker scribbles away.

As [Mangy_Dog] explains in a recent video, he wanted to model a control panel for a laser cutter he’s been working on, but thought the shapes involved were a bit more than he wanted to figure out manually. So he decided to give photogrammetry a try. For the uninitiated, this process involves taking as many high-resolution images as possible of a given object from multiple angles, and letting the computer stitch that into a three dimensional model. He reasoned that if he had a 3D model of the laser’s existing front panel, it would be easy enough to 3D print some replacement parts for it.

That would be a neat enough trick on its own, but what we especially liked about this video was the tip that [Mangy_Dog] passed along about increasing visual complexity to improve the final results. Basically, the software is looking for identifiable surface details to piece together, so you can make things a bit easier for it by taking a few different colored markers and drawing all over the surface like a toddler. It might look crazy, but all those lines give the software some anchor points that help it sort out the nuances of the shape.

Unfortunately the markers ended up being a little more permanent than [Mangy_Dog] had hoped, and he eventually had to use acetone to get the stains off. Certainly something to keep in mind. But in the end, the 3D model generated was accurate enough that (after a bit of scaling) he was able to design a new panel that pops right on as if it was a factory component.

Hackaday readers may recall that when we last heard from [Mangy_Dog] he was putting the finishing touches on his incredible “Playdog Blackbone” handheld gaming system, which itself is a triumph of mating 3D printed components with existing hardware.

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Finishing FDM Prints With SLS Resin

December 25, 2019 by Al Williams 17 Comments

[Thomas Sanladerer] has a filament-based 3D printer and a resin one. Can the two types of raw material combine to make something better? [Thomas] did some experiments using some magnets to suspend the parts and a hot air soldering gun to heat things up.

The trick turns out to be cutting the resin with alcohol. Of course, you also need to use a UV light for curing.

The parts looked pretty good, although he did get different results depending on a few factors. To see how it would work on a practical part, he took a very large printed alien egg. The problem is, the egg won’t fit in the curing station. A few minutes with a heat sink, a drill press, and an LED module was all it took to build a handheld UV curing light.

The good news is you don’t need a resin printer to take advantage of the process — just the resin. He also points out that if you had parts which needed to maintain their dimensions because they mate with something else, you could easily mask the part to keep the resin away from those areas.

If this video (and the results it shows) has you interested, then you’ll love the in-depth account that [Donald Papp] wrote up last year about his own attempts to smooth 3D printed parts with UV resin.

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Super Easy Small Robot Wheels

December 19, 2019 by Donald Papp 17 Comments

Anyone who has delved into DIY wheels knows that they are a trickier than it may seem, especially if the wheels aren’t just for show and need to provide things like decent traction and durability. 3D printers have helped a lot, but they’re not a cure-all.

Check out how [Robert K.] makes wheels from segments of automotive silicone hose, which are constructed with fibers embedded within them for durability and structure. Not only are these hoses easily sourced, but the silicone makes a great wheel surface and the hoses themselves are highly durable. He uses a 3D printed jig to cut a slice of hose that press-fits perfectly onto a 3D printed hub. [Robert] finds that a 28 mm hose pulled over a 35 mm diameter wheel is a perfect fit.

These wheels are for a Beetleweight class combat robot, which are limited to three pounds (1.36 kg) or less. You can see some video of [Robert]’s previous Beetleweight robot named ‘Bourbon’, and we have featured what goes into the even-smaller Antweight class (one pound or less) in the past.

Annealing 3D Prints: A Scientific Approach

December 18, 2019 by Al Williams 28 Comments

We’ve all been taught the scientific method: Form a hypothesis, do some experiments, gather some data, and prove or disprove the hypothesis. But we don’t always do it. We will tweak our 3D prints a little bit and think we see an improvement (or not) and draw some conclusions without a lot of data. Not [Josef Prusa], though. His team printed 856 different parts from four different materials to generate data about how parts behaved when annealed. There’s a video to watch, below.

Annealing is the process of heating a part to cause its structure to reorganize. Of course, heated plastic has an annoying habit of deforming. However, it can also make the parts firmer and with less inner tension. Printed parts tend to have an amorphous molecular structure. That is to say, they have no organization at all. The temperature where the plastic becomes soft and able to reorganize is the glass transition temperature.

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Giant 3D Printer For Giant Projects

December 18, 2019 by Danie Conradie 21 Comments

Established FDM 3D printers designs generally lead themselves well to being scaled up, as long as you keep frame stiffness, alignment and movement in mind. [Ivan Miranda] needed a big printer for his big projects (videos below), so he built his own i3 style printer with a 800 mm × 500 mm usable print bed and about 500 mm vertical print height.

The frame of the new machine is built using 20×20 and 20×40 aluminium V-slot extrusions with some square tubing for reinforcement. To move all the weight, all 3 axes are driven by double NEMA17 steppers, via a DUET3D board with an expansion board for the extra motors. The extruder is the new E3D Hemera with a 0.8 mm nozzle. The print bed is a mirror, on top of the aluminium plate, headed by a large silicone heat pad. The first bed version used a smaller heat pad directly on the back of the mirror, but it heated up unevenly and the mirror ended up cracking. Look out for the ingeniously lightweight and simple cable management to the extruder. When all was said and done he printed a 800 mm long size 66 wrench as a test piece with zero warp, which is pretty good even for PLA. This project is also a perfect example of the power of 3D printing for rapid iterative development, as lot of the printed fittings went through multiple versions.

Although [Ivan] received most of the components for free, a printer like this is still within reach of the rest of us. We look forward to a lot of big prints by [Ivan] in his signature red, like a massive nerf gun and the ridable tank he is currently working on. Continue reading “Giant 3D Printer For Giant Projects” →

Humongous 3D Printer Produces Boat And Challenges

December 17, 2019 by Danie Conradie 27 Comments

We’ve seen some pretty big polymer 3D printers, but nothing quite as big as the University of Maine’s 3D printer with a 22,000 ft³ (623 m³) build volume. It holds the Guinness World Record for the largest polymer 3D printer, and with that size comes some interesting challenges and advantages.

You might have already seen the video of it printing an entire patrol boat hull in a single piece, and would have noticed how it printed at a 45° angle. Due to the sheer weight and thermal mass of the print bead, it cannot bridge more than an inch, since it’ll just sag. A 45° overhang angle is about all it can manage, but since the layers can be tilted at that angle, it ends up being able to print horizontal roofs with no support. A 10 mm nozzle is used and the extruded line ends up being 12.5 mm in diameter with a 5 mm layer height. The boat mentioned above was printed with carbon ABS, but it can reportedly use almost any thermoplastic. It looks like the extruder is a screw extruder from an injection moulding machine, and is likely fed with pellets, which is a lot more practical than filament at this scale. Check out the video below by [Paul Bussiere] who works in the Advanced Structures & Composites Center at the University. He also does a very interesting interview with his boss, [James M. Anderson].

The 45° layer angle is very similar to how some infinite build volume 3D printers work. For something more within the reach of the average hacker, check out the tool changing Jubilee.
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