Internals of 3D printed “print and fold” robot. [Image source: MIT CSAIL]Robot design traditionally separates the body geometry from the mechanics of the gait, but they both have a profound effect upon one another. What if you could play with both at once, and crank out useful prototypes cheaply using just about any old 3D printer? That’s where Interactive Robogami comes in. It’s a tool from MIT’s Computer Science and Artificial Intelligence Laboratory (CSAIL) that aims to let people design, simulate, and then build simple robots with a “3D print, then fold” approach. The idea behind the system is partly to take advantage of the rapid prototyping afforded by 3D printers, but mainly it’s to change how the design work is done.
To make a robot, the body geometry and limb design are all done and simulated in the Robogami tool, where different combinations can have a wild effect on locomotion. Once a design is chosen, the end result is a 3D printable flat pack which is then assembled into the final form with a power supply, Arduino, and servo motors.
A white paper is available online and a demonstration video is embedded below. It’s debatable whether these devices on their own qualify as “robots” since they have no sensors, but as a tool to quickly prototype robot body geometries and gaits it’s an excitingly clever idea.
A team of students in Antwerp, Belgium are responsible for Project Aslan, which is exploring the feasibility of using 3D printed robotic arms for assisting with and translating sign language. The idea came from the fact that sign language translators are few and far between, and it’s a task that robots may be able to help with. In addition to translation, robots may be able to assist with teaching sign language as well.
The project set out to use 3D printing and other technology to explore whether low-cost robotic signing could be of any use. So far the team has an arm that can convert text into finger spelling and counting. It’s an interesting use for a robotic arm; signing is an application for which range of motion is important, but there is no real need to carry or move any payloads whatsoever.
Closeup of hand actuators and design. Click to enlarge.
A single articulated hand is a good proof of concept, and these early results show some promise and potential but there is still a long ways to go. Sign language involves more than just hands. It is performed using both hands, arms and shoulders, and incorporates motions and facial expressions. Also, the majority of sign language is not finger spelling (reserved primarily for proper names or specific nouns) but a robot hand that is able to finger spell is an important first step to everything else.
Future directions for the project include adding a second arm, adding expressiveness, and exploring the use of cameras for the teaching of new signs. The ability to teach different signs is important, because any project that aims to act as a translator or facilitator needs the ability to learn and update. There is a lot of diversity in sign languages across the world. For people unfamiliar with signing, it may come as a surprise that — for example — not only is American Sign Language (ASL) related to French sign language, but both are entirely different from British Sign Language (BSL). A video of the project is embedded below.
Here’s some interesting work shared by [Ben Kromhout] and [Lukas Lambrichts] on making flexible 3D prints, but not by using flexible filament. After seeing a project where a sheet of plywood was rendered pliable by cutting a pattern out of it – essentially turning the material into a giant kerf bend – they got interested in whether one could 3D print such a thing directly.
The original project used plywood and a laser cutter and went through many iterations before settling on a rectangular spiral pattern. The results were striking, but the details regarding why the chosen pattern was best were unclear. [Ben] and [Lukas] were interested not just in whether a 3D printer could be used to get a similar result, but also wanted to find out what factors separated success from failure when doing so.
After converting the original project’s rectangular spiral pattern into a 3D model, a quick proof-of-concept showed that three things influenced the flexibility of the end result: the scale of the pattern, the size of the open spaces, and the thickness of the print itself. Early results indicated that the size of the open spaces between the solid elements of the pattern was one of the most important factors; the larger the spacing the better the flexibility. A smaller and denser pattern also helps flexibility, but when 3D printing there is a limit to how small features can be made. If the scale of the pattern is reduced too much, open spaces tend to bridge which is counter-productive.
Kerf bending with laser-cut materials gets some clever results, and it’s interesting to see evidence that the method could cross over to 3D printing, at least in concept.
It is amazing how makers can accomplish so much when they put their mind to something. [Marcus Wu] has uploaded a mesmerizing video on how to build a 3D printed Curta Mechanical Calculator. After nine iterations of design, [Marcus] presents a polished design that not only works but looks like a master piece.
For the uninitiated, the Curta is a mechanical calculator designed around the time of World War II. It is still often seen used in time-speed-distance (TSD) rallies to aid in the computation of times to checkpoints, distances off-course and so on. Many of these rallies don’t allow electronic calculators, so the Curta is perfect. The complex inner workings of the contraption were a key feature and point of interest among enthusiasts and the device itself is a highly popular collectible.
As for the 3D printed design, the attention to detail is impeccable. The current version has around 80 parts that need to 3D printed and a requires a few other screws and springs. Some parts like the reversing lever and selector knobs have been painted and digits added to complete the visual detail. The assembly took [Marcus Wu] around 40 minutes to complete and is one of the most satisfying builds we have ever seen.
What is even more amazing is that [Markus Wu], who is a software engineer by profession has shared all the files including the original design files free of cost on Thingiverse. A blog with written instructions is also available along with details of the iterations and original builds. We already did a post on a previous version so check it out for a little more background info.
How strong can you make a 3D-printed gearbox. Would you believe strong enough to lift an anvil? [Gear Down For What?] likes testing the limits of 3D printed gearboxes. Honestly, we’re amazed.
3D printing has revolutionized DIY fabrication. But one problem normally associated with 3D printed parts is they can be quite weak unless designed and printed carefully.
Using a whole roll of filament, minus a few grams, [Gear Down For What?] printed out a big planetary gear box with a ratio of 160:1 and added some ball bearings and using a drill as a crank. Setting it up on a hoist, he started testing what it could lift. First it lifted a 70 lb truck tire and then another without any issues. It then went on to lift a 120 lb anvil. So then the truck tires were added back on, lifting a combined weight of 260 lb without the gearbox breaking a sweat.
This is pretty amazing! There have been things like functional 3D-printed car jacks made in the past, however 3D-printed gear teeth are notoriously easily broken unless designed properly. We wonder what it would take to bring this gearbox to the breaking point. If you have a spare roll of filament and some ball bearings, why not give it go yourself? STL files can be found here on Thingiverse.
[James Bruton] built an electric skateboard out of oversized LEGO bricks he printed himself, and equipped the board with an excellent re-creation of a classic motor.
He began by downloading brick, gear, and pulley designs from Thingiverse and printing them up five times their normal size, taking 600 hours. The deck consists of 8M Technic bricks lengthwise and 4M bricks crosswise, with plates covering top. There’s even a monster 5×6 plate that’s clearly courtesy of a parametric brick design because you won’t find that configuration among LEGO’s official parts.
The coolest part of the project is probably [James]’ re-creation of an old school LEGO motor. He sized up a 6216M Technic motor originally rated for 4.5V swapping in a 1.5 kW, 24V motor controlled by a 120A ESC and powered pair of Turnigy 5000mAh LiPos wired in series.
[James] had to design his own casing in Blender because couldn’t find a file for the original LEGO part—pro tip for the future, LDraw has the 6216 design and it can be dropped into Blender.
Another nice touch are the wheels, with hubs based off upsized 40-tooth Technic gears with Ninjaflex tires that weigh half-a-kilo each and took 32 hours apiece to print.
The essence of a spot welder is nothing more than a microwave oven transformer rewound to produce low voltage and high current instead of vice-versa. Some people control the pulse-length during the weld with nothing more than their bare hands, while others feel that it’s better implemented with a 555 timer circuit. [Jim]’s version uses a NodeMCU board, which is desperately overkill, but it was on his desk at the time. His comments in GitHub about coding in Lua are all too familiar — how do arrays work again?
Using the fancier microcontroller means that he can do fancy things, like double-pulse welding and so on. He’s not even touching the WiFi features, but whatever. The OLED and rotary encoder system are sweet, but the star of the show here is the 3D printed case, complete with soft parts where [Jim]’s hand rests when he’s using the welder. It looks like he could have bought this thing. Continue reading “Beautiful DIY Spot Welder Reminds Us We Love 3D Printing”→
A team of students in Antwerp, Belgium are responsible for 
