A chocolate coating machine works in the round to enrobe mint Oreos.

Chocolate-Coating Machine Mk. 2: The Merry-Go-Round

November 28, 2024 by Kristina Panos 16 Comments

This holiday season, [Chaz] wanted to continue his family’s tradition of enrobing a little bit of everything in dark chocolate, and built an improved, rotating chocolate-coating machine.

You may remember last year’s offering, aka the conveyor belt version. Although that one worked, too much chocolate was ultimately lost to the surface of the kitchen table. [Chaz] once again started with a standard chocolate fountain and bought a round wire rack that fits the circumference of the bowl at the bottom. He snipped a hole in the center large enough to accommodate the business part of the fountain and printed a collar with holes that he cleverly zip-tied to the rack.

[Chaz] also printed a large gear to go around the bowl, a small gear to attach to a six RPM motor, a motor mount for the bowl, and an air blade attachment for a portable Ryobi fan. The air blade worked quite well, doing the double duty of distributing the chocolate and thinning out the coating. Plus, it gives things a neat rumpled look on the top.

Want to make some special chocolates this year, but don’t want to build an enrober? Get yourself a diffraction grating and make some rainbow goodies with melted chocolate.

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Dispense 60 Bolts In 2.3 Seconds

March 21, 2023 by Michael Shaub 26 Comments

We’ve covered a number of projects that assist makers who need to fill orders for their small businesses, or kitting. [Helmke] has sorted thousands of pieces of hardware that they include with 3D printed parts sold online. They have been developing an alternative, a modular system for sorting and packaging specific quantities of parts.

After the break, check out the latest video from their small but growing channel for a very clear walk-through of the counting system they’ve been iterating on. The 2nd video in the series explores solenoids, Geneva drives, and ultimately a sprocket to dispense a variable number of bolts from the sorting machine. The approach gives consistent results, easily to vary quantities, and is fast! These videos are also rich with lots of small details you might want to explore on your own like magnetic part feeding, discussions of different sensors for detecting and counting parts, 3D printed gear box designs, and we love the use of stackable crates for project enclosures.

We hope to see more videos from [Helmke] in the series as the project matures for deeper dives into the existing mechanisms and new features they develop next. Hungry for more? We’ve brought you everything from cutting and stripping wire, to SMD tape, to resistors, to laser-cut parts. Continue reading “Dispense 60 Bolts In 2.3 Seconds” →

Radial Vector Reducer Rotates At Really Relaxed Velocity

December 5, 2022 by Ryan Flowers 15 Comments

When [Michael Rechtin] learned about Radial Vector Reducers, the underlying research math made his head spin, albeit very slowly. Realizing that it’s essentially a cycloidal drive meshed with a planetary gear set, he got to work in CAD and, in seemingly no time, had a design to test. You can see the full results of his experiment in the video below the break. Or head on out to Thingiverse to download the model directly.

[Michael] explains that while there are elements of a cycloidal drive, itself a wonderfully clever gear reduction mechanism, the radial vector reducer actually has more bearing surfaces, and should be more durable as a result. Two cycloidal disks are driven by a planetary gear reduction for an even greater reduction, but they don’t even spin, they just cycle in a way that drives the outer shell, setting them further apart from standard cycloidal drives.

How would this 3D printed contraption hold up? To test this, [Michael] built a test jig with a NEMA 23 stepper providing the torque, and an absurd monster truck/front loader wheel — also printed — to provide traction in the grass and leaves of his back yard. He let it drive around its tether for nearly two weeks before disassembling it to check for wear. How’d it look? You’ll have to check the video to find out.

If you aren’t familiar with cycloidal drives, check out this fantastic explanation we featured. As for planetary drives, what better way to demonstrate it than by an ornamental planetary gear clock!

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Magnetic Gearbox Can Go Fast But Not Hard

September 2, 2022 by Danie Conradie 13 Comments

3D printed gearboxes are great for experimental designs, but due to roughness and inaccuracies in the printed surfaces, they can wear quickly and be rather noisy. As a possible alternative, [Resetman] is experimenting with magnetic 3D printed gearboxes that work without physical contact between the rotating wheels, and can also be “geared” for different ratios in some interesting ways.

Naturally, two closely spaced wheels with magnets will interact with each other, with the ratio defined by the number of magnets on each wheel. A much less obvious implementation is a second-order radial flux coaxial magnetic gearbox. It works similar to a normal planetary gearbox, with an outer and inner wheel containing magnets, and an intermediate ring known as a flux modulator, containing equally spaced pieces of ferromagnetic steel metal. In [Resetman] demonstration, the flux modulator is just a 3D printed ring screws around its circumference.

The most obvious disadvantage is of course severely limited torque transfer. [Resetman] could easily accelerate the sun wheel to 12,000 RPM if the flux modulator is accelerated slowly, but any sudden changes in speed would cause it to lose synchronization. Of course, you can consider this a torque-limiting feature for certain use cases. With a bit of testing, he determined the torque limit at a 1:4 ratio was a meager 0.05 Nm. This could be increased by some optimization, for example rearranging the magnets to form Halbach arrays, and reducing the air gaps between the components.

Magnetic gearboxes are nothing new, we’ve featured another demonstrator before, and even did an “Ask Hackaday” on the subject. What would you use these for? Let us know below.

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Stackable 3D-Printed Gearbox For Brushless Motor

July 24, 2022 by Danie Conradie 11 Comments

Affordable brushless motors are great for a variety of motion applications, but often require a gearbox to tame their speed. [Michael Rechtin] decided to try his hand at designing a stackable planetary gearbox for a brushless motor that allows him to add or remove stages to change the gear ratio.

The gearbox is designed around a cheap, 5010 size, 360 KV, sensorless motor from Amazon. Each stage consists of a 1:4 planetary gear set that can be connected to another stage, or to an output hub. This means the output speed reduces by a factor of four for each added stage. Thanks to the high-pressure angle, straight-cut teeth, and fairly loose clearances, the gearbox is quite noisy.

To measure torque, [Michael] mounted the motor-gearbox combo to a piece of aluminum extrusion, and added a 100 mm moment arm to apply force to a load cell. The first test actually broke the moment arm, so a reinforced version was designed and printed. The motor was able to exert approximately 9.5 Nm through the gearbox. This number might not be accurate, since sensorless motors like this one can not provide a smooth output force at low speeds. As [Michael] suggests, adding a sensor and encoder would allow for better testing and low speed applications. Check it out in the video after the break.

We’ve featured a number of [Michael]’s projects before, including a bag tracking corn hole board, and a 3D printed linear actuator. Continue reading “Stackable 3D-Printed Gearbox For Brushless Motor” →

Can A Drone Push A Bike?

June 19, 2022 by Matthew Carlson 20 Comments

It sounds like a rhetorical question that a Midwestern engineer might ask, something on the order of ‘can you fix this bad PCB spin?’ [Tom Stanton] sets out to answer the title question and ends up building a working e-bike with a drone motor.

You might be thinking, a motor is a motor; what’s the big deal? But a drone motor and a regular e-bike motor are made for very different purposes. Drone motors spin at 30,000 RPM, and an e-bike hub motor typically does around 200-300 RPM while being much larger. Additionally, a drone motor goes in short spurts with a large fan blowing right on it, and an e-bike motor can run almost continuously.

The first step was to use gears and pulleys to reduce the RPM on the motor to provide more torque. A little bit of CAD and 3D printing later, [Tom] had a setup ready to try. However, the motor quickly burned out. With a slightly bigger motor and more gear reduction, version 2 performed remarkably well. After the race between a proper e-bike and the drone bike, the coils were almost melted.

If you’re thinking about making your bike electric, we have some advice. We’ll throw in a second piece of advice for free: use a larger motor than the drone motor, even though it technically works. Video after the break.

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3D-Printed Gear Press Can Squash Stuff, Kinda

June 16, 2022 by Lewin Day 2 Comments

A press is a useful thing to have, whether you like destroying stuff or you simply want to properly install some bearings. [Retsetman] decided to build one from scratch, eschewing the typical hydraulic method for a geared design instead.

The benefit of going with a gear press design is that [Retsetman] was able to 3D print the required gears himself. The design uses a series of herringbone gears to step down the output of two brushed DC motors. This is then turned into linear motion via a rack and pinion setup. Naturally, the strength of the gears and rack is key to the performance of the press. As you might expect, a fair few of the printed gears suffered failures during the development process.

The final press is demonstrated by smooshing various objects, in true YouTube style. It’s not really able to destroy stuff like a proper hydraulic press, but it can kind of crush a can and amusingly squash a teddy bear. If you’re really keen on making a gear press, though, you’re probably best served by going with a metal geartrain. Video after the break.

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