Fifty Shades Of Brown: 3D Printing With Sugar

November 25, 2021 by Dave Rowntree 20 Comments

[Norbert Heinz] has been busy for the 2021 Hackaday Prize entry, working on the design of a direct granule extruder for 3D printing with waste materials, or materials that are not provided in the form of a filament. Sugar is pretty common in most households, so since that’s already available in granular form, [Norbert] gave 3D printing with granulated sugar a try. (Video, embedded below.)

[Editor’s note: He earned fifth place for this one! Well, not the sugar in particular, but the overall great work on granular extruders.]

Success was somewhat variable, as the gloopy material is notoriously fickle to work with, but the setup did produce some structures that stayed in one piece, at least for a while. Initially [Norbert] tried it real slow, effectively printing with the liquified sweet stuff, by dragging a molten blob of it around on the end of the extruder nozzle. Whilst this did work, the resulting print resolution did leave something to be desired. The next thing tried was increased print speed. This produced clearer prints, as the sugar did not have time to caramelise, or form a noticeable blob, but as soon as the bed started to cool, it caused it to crack badly.

Going slow seemed to be the way forward, as more time to cool may have reduced the stresses in the structure due to the increased cooling time. But anyway, the way we see it, is it’s fun trying, and if it fails, you can just eat it, so long as you disregard all that food safety stuff anyway.

[Norbert] documents the granule extruder journey on the project Hackaday.io page, so it should be straightforward enough to duplicate this is you were so inclined.

We’ve covered a few sugary hacks before; Need a renewable bed adhesive? out of glue stick? try sugar as a bed adhesive! Printing in gloopy, sloppy materials is nothing new at all, we covered it nearly ten years ago.

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E-MonoWheel

November 24, 2021 by Matthew Carlson 16 Comments

Generally, monowheels are that wacky, wildly futuristic transport that we lump in the same category as hoverbikes and jetpacks: strange, currently impractical, but very cool. Not content with waiting for the distant future, [Sam Barker] made his own electric monowheel. (Video, embedded below.)

The hardest part of any monowheel is that the outside rim needs to stand enormous abuse. It supports the weight of the vehicle and provides most of the structural integrity, but also is the means of propulsion. [Sam]’s first thought was to use a trampoline frame as it is a round and reasonably sturdy tube steel. He 3D printed the rollers that connected the subframe to the trampoline frame. Flat bar stock was used to make the angles inside the subframe and straight tube steel connected the inner frame into a trapezoid. The trampoline frame was welded together and on the first test spin, it broke apart from the stress. It simply wasn’t strong enough.

Not to be dissuaded, he found a company that bends steel into custom shapes. He stole the e-bike kit from another bike he had converted earlier, and the wheel was turning. Some handles and foot-pedal later, it was time for a proper test drive. Overall, the result is pretty impressive and the double-takes [Sam] gets while riding down streets in town are wonderful. If you’re looking to scratch the monowheel itch, check out this wooden monowheel.

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Significantly Improved Egg Timer Makes Pictionary Better

November 23, 2021 by Lewin Day 24 Comments

The traditional sand timer, known colloquially as an egg timer, served its purpose well over the centuries since its development. However, [MakerPaul] realised it had some significant flaws that were ruining Pictionary, and set out to fix the problem.

If you’re not looking directly at an egg timer, it’s easy to miss the moment when the timer runs out. Resetting the timer before it runs out also requires waiting for the sand to filter to one side. Clearly the world needs a better mousetrap.

The tipping timer from [MakerPaul] solves both those issues. In this design, sand flows down into an offset area, which tips the device over when reaching a certain time limit. Additionally, turning the device upside down and then rotating it instantly reloads the sand, meaning the timer can be reused immediately.

[MakerPaul] first came up with the idea about 20 years ago, refining it during the recent lockdowns. The design files are freely available for anyone that wishes to build one. [MakerPaul] isn’t commercializing the idea, but mentions that it would be great if anyone using it makes a donation to the Mind mental health charity.

Most timers we feature are electronic and digital, but it’s easy to appreciate the elegance of what [MakerPaul] has achieved here. As a bonus, he documented the entire project and its application in under 90 seconds. How good is that? Video after the break.

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Ender 3 Meets MIG Welder To Make A Metal Benchy — Kind Of

November 23, 2021 by Dan Maloney 20 Comments

When you can buy a 3D printer at Aldi, you pretty much know that 3D printing has been reduced to practice. At least for the plastic version of 3D printing; metal printing is another thing entirely. It’s easy to squeeze out a little molten plastic in a controlled fashion, but things get a little more — energetic — when you try to do the same with metal.

At least that’s what [Lucas] has been experiencing with his attempts to build a metal 3D printer over on his Cranktown City YouTube channel. Granted, he set himself up for a challenge from the get-go by seeking to stick a MIG welder onto an Ender 3, a platform that in no way was ready for the abuse it was about to endure. Part 1 of the video series below shows the first attempt, which ended badly for both the printer and for the prints.

But that first prototype, melted parts notwithstanding, gave [Lucas] enough to go on for the improvements of version 2, including a better build plate, heat shielding for the printer’s tender bits, and a legit MIG welder wire feeder. [Lucas] also built current control in, with a clever non-destructive interface to the welder controls. These improvements were enough to attempt a Benchy print, which started out pretty decent but got a bit droopy toward the end.

As imperfect as it is, the Benchy is a vast improvement over the formless blobs from version 1, and the printer holds quite a bit of promise for the future. One thing you can’t accuse [Lucas] of is giving up on a project too easily; after all, he built a laser cutter from scratch, including the laser tube.

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DIY High Flow 3D Printing Nozzle

November 23, 2021 by Al Williams 50 Comments

Sometimes advances happen when someone realizes that a common sense approach isn’t the optimal one. Take radio. Success in radio requires bigger antennas and more power, right? But cell phones exist because someone realized you could cram more people on a frequency if you use less power and smaller antennas to limit the range of each base station. With FDM 3D printing, smaller nozzles were all the rage for a while because they offer the possibility of finer detail. However, these days if you want fine detail you should be using resin-based printers and larger nozzles offer faster print times and stronger parts. The Volcano hotend started this trend but there are other options now. [Stefan] over at CNC Kitchen decided to make his own high flow nozzle and he claims it is better than other options.

Don’t get too carried away with the DIY part. As you can see in the video below, he starts with a standard nozzle, so it is really a nozzle conversion or hack. The problem with high flow isn’t the hole in the nozzle. It is melting the plastic fast enough. The faster the plastic moves through the nozzle, the less time there is for it to melt.

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Polymer Discovery Gives 3D-printed Sand Super Strength

November 21, 2021 by Dave Rowntree 29 Comments

Research activity into 3D printing never seems to end, with an almost constant stream of new techniques and improvements upon old ones hitting the news practically daily. This time, the focus is on a technique we’ve not covered so much, namely binder jetting additive manufacturing (BJAM for short, catchy huh?) Specifically the team from Oak Ridge National Laboratory, who have been exploring the use of so-called hyperbranched Polyethyleneimine (PEI) as a binder for jetting onto plain old foundry silica sand (nature, free access.)

The PEI binder was mixed with a 75:25 mix of water and 1-propanol (not to be mixed up with 2-propanol aka isopropanol) to get the correct viscosity for jetting with a piezoelectric print head and the correct surface tension to allow adequate powder bed penetration, giving optimal binding efficiency. The team reported a two-fold increase in strength over previous jetting techniques, however, the real news is what they did next; by infusing the printed part (known as the green part) with common old ethyl cyanoacrylate (ECA, or super glue to us) the structural strength of the print increased a further eight times due to the reaction between the binder and the ECA infiltrate.

To further bestow the virtues of the PEI binder/ECA mix, it turns out to be water-soluble, at least for a couple of days, so can be used to make complex form washout tooling — internal supports that can be washed away. After a few days, the curing process is complete, resulting in a structure that is reportedly stronger than concrete. Reinforce this with carbon fiber, and boy do you have a tough building material!

Not bad for some pretty common materials and a simple printing process.

We covered a similar binder jetting process for using sawdust a little while ago, and a neat way of printing with metal powder by carrying it in a stream of argon and cooking it with a laser, but there is an opening for a DIY effort to get in on the binder jetting game.

Thanks [Victor] for the tip!

Cheap Big Servo For Robot Arm

November 19, 2021 by Lewin Day 10 Comments

[Skyentific] is looking to push the hobbyist robotics state of the art. Motors and their gears, the actuators, are typically the most expensive part. For his build, he realised he needed big servos capable of delivering plenty of torque. Thus, he set about creating a 3D-printed design to get the job done on a budget. (Video, embedded below.)

Stepper motors are the order of the day here, chosen for their low cost compared to brushless solutions, particularly when taking control hardware into account. In this design, the stepper motor drives a sun gear as part of a bigger planetary gearbox with a high gear ratio. Cross-roller bearings are used to allow the servo to effectively handle both radial and axial loads. The servo as a whole is designed to fit neatly into the joints of the robot arm itself, and has external mounting points provisioned as such.

It’s a neat servo that somewhat apes those used on full-sized industrial designs, at least in the sense of being an integrated part of the joints of a robot arm. It also comes in at a relatively-cheap $32 based on the materials used by [Skyentific].

We’ve seen some related work from [Skyentific] before, too – like this interesting cable-driven joint. Video after the break.

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