3D Printing With A Drone Swarm?

October 18, 2022 by Dave Rowntree 14 Comments

Even in technical disciplines such as engineering, there is much we can still learn from nature. After all, the endless experimentation and trials of life give rise to some of the most elegant solutions to problems. With that in mind, a large team of researchers took inspiration from the humble (if rather annoying) wasp, specifically its nest-building skills. The idea was to explore 3D printing of structures without the constraints of a framed machine, by mounting an extruder onto a drone.

As you might expect, one of the most obvious issues with this attempt is the tendency of the drone’s to drift around slightly. The solution the team came up with was to mount the effector onto a delta bot carrier hanging from the bottom of the drone, allowing it to compensate for its measured movement and cancel out the majority of the positional error.

The printing method relies upon the use of two kinds of drone. The first done operates as a scanner, measuring the print surface and any printing already completed. The second drone then approaches and lays down a single layer, before they swap places and repeat until the structure is complete.

Multiple drones can print simultaneously, by flying in formation. Prints were demonstrated using a custom cement-like material, as well as what appeared to be expanding foam, which was impressive feat to say the least.

The goal is to enable the printing of large, complex shaped structures, on any surface, using a swarm of drones, each depositing whatever material is required. It’s a bit like a swarm of wasps building a nest, into whatever little nook they come across, but on the wing.

We’ve been promised 3D printed buildings for some time now, and while we’re not sure this research is going to bring us any closer to living in an extruded house, we’re suckers for a good drone swarm here at Hackaday.

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3D-Printed Laser Scanning Confocal Microscope Measures Microns

April 26, 2021 by Dan Maloney 15 Comments

When one thinks about microscopy, it seems to be mostly qualitative. Looking at a slide teeming with bacteria or protozoans is less about making measurements and more about recognizing features and describing their appearance. Not all microscopes are created equal, though, with some being far more optimized for making fine measurements of the microscopic realm.

This 3D-printed confocal laser scanning microscope is a good example of an instrument for measuring really small stuff. As [Zachary Tong] points out, confocal scanning microscopy uses a clever optical setup to collect light from a single, well-defined point within a sample; rather than getting an image of all the points within a two-dimensional focal plane, the scanning function moves the focal point around through the sample in three dimensions, capturing spatial data to go along with the optical information.

The stage of [Zach]’s microscope is based on OpenFlexure’s Delta Stage, an open-source, 3D-printed delta-bot motion control platform that’s capable of positioning samples with sub-micron precision. Above the stage are the deceptively simple optics, with a laser diode light source, an objective lens, and a photodiode detector behind a pinhole. The detector feeds a homebrew trans-impedance amplifier that captures data at millions of points as the sample is moved through a small three-dimensional space. All that data gets crunched to find the Z-axis position corresponding to the maximum intensity at each point.

It takes a while to gather all this data — up to several days for even a small sample — but it works pretty well. [Zach] already has some ideas for reducing noise and speeding up the scan time; perhaps a stage based on DVD parts like this one would be faster than the delta stage. We look forward to seeing his improvements.

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Cable Bots, Arise! Domination Of The Universe Is At Hand

October 20, 2017 by John Baichtal 30 Comments

Most CNC robots people see involve belts and rails, gantries, lead screws, linear bearings, and so forth. Those components need a rigid chassis to support them and to keep them from wobbling during fabrication and adding imperfections to the design. As a result, the scale is necessarily small — hobbyist bots max out at cabinet-sized, for the most part. Their rigid axes are often laid out at Cartesian right angles.

One of the exceptions to this common configuration is the delta robot. Deltas might be the flashiest of CNC robots, moving the end effector on three arms that move to position it anywhere in the build envelope. A lot of these robots are super fast and precise when charged with carrying a light load, and they get put to work as pick-and-place machines and that sort of thing. It doesn’t hurt that delta bots are also parallel manipulators, which means that the motors work together to move the end effector, with one motor pulling while the matching motor pulls.

But while Cartesian CNC bots are sturdy workhorses, and deltas are fly-weight racehorces, neither can really cut it when you want to go gigantic. In terms of simplicity and scale, nothing beats cable bots.

Cable Bots

Cable bots use wires or strings pulled by reel-mounted motors, with dimensions limited only by the room to mount the motors and the tensile strength of the cables used. When the strings are tensioned you can get a surprising degree of accuracy. Why not? Are they not computer-controlled motors? As long as your kinematic chain accounts for the end effector’s movement in one direction by unwinding another cable (for instance) you can very accurately control the end effector over a very wide scale.

The following are some fun cable bots that have caught my eye.

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Monster Mindstorms Delta Bot Delicately Picks Candy

July 24, 2017 by John Baichtal 6 Comments

A group of embedded developers from Sioux Embedded Systems in Eindhoven, the Netherlands, wanted to get experience working on Microsoft .Net. To make it fun they made it their project to produce a LEGO train with visitors at LEGO World, the official LEGO convention in the Netherlands. The team developed an application in C# to fully automate the train, with Mindstorms NXT and EV3 bricks as well as LEGO Power Functions motors controlling everything.

The train project carries a simple premise: the visitor chooses one of four colors, and the train goes and picks up a piece of simulated candy with the matching color. Called Sioux.net on Track, the project has produced a new train every year since 2012 with improvement goals in place to add features with every version. Ironically, the least interesting part of the setup is the actual train and track. The team’s creativity comes to the fore in two areas of the project: the method by which the candy color is selected, and the assembly that dispenses the correct color into the train car.

Team member [Hans Odenthal] has built candy-grabbers for various years’ trains. He learned about the ABB FlexPicker and this year decided to build a delta robot for the layout. It consists of huge girders constructed from 5×9 and 5×11 Technic beam frames held together with more Technic beams and hundreds of connector pegs. The three arms each move on a pair of turntables which are geared down to provide as much torque as possible — the fake candy pieces are light, but the arms themselves weigh a lot. [Hans] ended up revamping the gearboxes to up the ratio from 1:5 to 1:25.

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Pixar Style Robots Are Treasure Trove Of Building Tricks

June 28, 2017 by Steven Dufresne 25 Comments

[Alonso Martinez] is an artist working on virtual characters at Pixar so it’s no wonder that his real life robots, Mira and Gertie, have personalities that make them seem like they jumped straight out of a Pixar movie. But what we really like are the tricks he’s used inside to bring them to life that are sure to get reused for the same or other things.

Mira's head rotation mechanism — Mira’s head rotation mechanism

For example, Mira’s head can rotate in yaw, pitch and roll. To figure out how to make it do that he recalled having a joystick called the Microsoft Sidewinder Pro that had force feedback. That meant it might have had motors in line with the motions, much like what he wanted. To see how it worked, he bought one on eBay, took it apart, and improved on it to come up with his own design. But besides making use of the design in joysticks and heads, we can imagine it used to make robot eyeballs rotate in their sockets too. And as a side note, he’s running the robot off a Raspberry Pi, but notice the clever, space-saving way he’s mounted the whole mechanism to the Pi’s four mounting holes.

What also piqued our interest are the two tiny servos used in the head mechanism, two HD-DSM44 digital servos. These are even smaller than Tower Pro SG90s and with the added advantage of being metal geared.

Gertie's delta jumping legs — Gertie’s delta jumping legs

To make the eyes blink he had to overcome the fact the head was a thin-walled sphere sliding over the body, and the eyes had to fit in the thin wall without contacting the body. His solution was to make them out of OLED screens with acrylic hemispheres for the protruding eyeballs. The circuit boards talk to the screens through ribbon cables that are around 32 connections per inch, which made for some careful soldering. And to further create a thin profile he even sanded the solder points flat.

His other robot, the yellow and green Gertie, jumps to move around and its internal mechanism is also a joy to examine. To swivel and hop, it uses much the same design as a delta 3D printer, with three legs that can move the upper body in any direction, and compress like a spring before leaping. We like how his method for determining the appropriate thickness of 3D printed PLA parts such that they wouldn’t break was simply trial an error, taking advantage of the rapid prototyping possible with 3D printers. He did cheat on one main part of each leg though, and that was to go with RC car tie rods for the lower half of each leg — but we won’t tell on him if you won’t.

And that’s only a small sample of the neat tips and tricks you’ll find in the video below (they start looking inside the robots at 7:35).

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A Crash Sensor For Delta 3D Printers

July 30, 2016 by Moritz Walter 4 Comments

It doesn’t happen that often, but this is the last time that [Lucas] comes back from hours of unattended 3D printing to find a large portion of plastic spaghetti mess and a partly disassembled Kossel. The crash sensor he designed will now safely halt the printer if it detects that something went wrong during the print.

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Enormous Delta-bot 3D Designed To Print An Entire House

September 27, 2015 by Dan Maloney 43 Comments

[Massimo Moretti] has a big idea – to build housing on the cheap from locally sourced materials for a burgeoning world population. He also has a background in 3D printing, and he’s brought the two concepts together by building a 12 meter tall delta-bot that can print a house from clay.

The printer, dubbed Big Delta for obvious reasons, was unveiled in a sort of Burning Man festival last weekend in Massa Lombarda, Italy, near the headquarters of [Moretti]’s WASProject. From the Italian-language video after the break, we can see that Big Delta moves an extruder for locally sourced clay over a print area of about 20 square meters. A video that was previously posted on WASProject’s web site showed the printer in action with clay during the festival, but it appears to have been taken down by the copyright holder. Still, another video of a smaller version of Big Delta shows that clay can be extruded into durable structures, so scaling up to full-sized dwellings should be feasible with the 4 meter delta’s big brother.

Clay extrusion is not the only medium for 3D printed houses, so we’ll reserve judgment on Big Delta until we’ve seen it print a livable structure. If it does, the possibilities are endless – imagine adding another axis to the Big Delta by having it wheel itself around a site to print an entire village.

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