Microscopic Metal 3D Printing With Gels

December 7, 2022 by Al Williams 3 Comments

Everyone wants to 3D print with metals, but it is a difficult task. You need high temperatures and metals with high thermal conductivity make the problem even worse. Researchers at Caltech have a way of printing tiny metal structures. The trick? They don’t print metals at all. Instead, they 3D print a hydrogel and then use it as a scaffold to form metallic structures. You can read the full paper, if you are interested in the details.

Hydrogels are insoluble in water and made from flexible polymer chains. If you’ve ever handled a soft contact lens, that’s a hydrogel. Like resin printing, UV light triggers chemical reactions in the hydrogels, causing them to harden in the desired pattern.

What about the metal? They infuse the hydrogel with a metallic salt dissolved in water. This saturates the hydrogel. Burning in a furnace causes the hydrogel to burn away but leaves the metal. The furnace also causes the structure to shrink, so this is a good method for very tiny pieces. The team has made prints with feature sizes around 40 microns.

By altering the metal salts, you can work with different metals or even mix different metals. The team has produced parts using copper, nickel, silver, and several alloys.

Printing small structures is a big research goal with many different approaches. We’ve even seen a tiny welder.

DNA Computers Are In The Lab Now

March 30, 2019 by Al Williams 18 Comments

Although it isn’t very real-world practical, researchers at Cal Tech have produced a DNA-based programmable computer. Spectrum reports that the system executes programs using a set of instructions written in DNA using six bits. Like any programmable computer, this one can execute many programs, but so far they have run 21 different programs.

Using DNA for computation isn’t new — your body does it all the time. But, in general, DNA computers were akin to some logic gates that would do one set of things, not a general-purpose reprogrammable computer.

DNA has two parts composed of four different chemicals — you can think of each part as a ladder cut vertically down the middle with each “rung” being one of the four chemicals. Each part will try to pair up with a part that has a complementary set of rungs. The researchers created DNA strands to act like logic gates that have two inputs and two outputs. They combine five of these gates to create a layer with six inputs and six outputs. A program contains a stack of these six-bit layers.

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High Tech Drone Scarecrows Can Make Airports Safer

August 9, 2018 by Al Williams 8 Comments

If you pay attention to airplane news — or you watched the film Sully — you know planes have problems with birds. Sully was about US Airways flight 1549 which struck a flock of geese and ditched in the Hudson river. Engineers at Caltech say that was the inspiration for them to develop a control algorithm that enables a single drone scarecrow to herd flocks of birds away from airports.

Airports have tried a lot of things to discourage birds ranging from trained falcons to manually-piloted drones. Apparently, herding birds is harder than you would think. If you fly the drone too far from a flock, it will ignore the threat. If you get too close, the flock will scatter making it both threaten a larger area and harder to control.

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Detoured: Caltech’s Hackerspace

April 23, 2018 by Brian Benchoff 1 Comment

Over the last few months, the folks over at the SupplyFrame Design Lab, home to Hackaday meetups, the Hackaday Superconference, and far, far too many interesting tools, have been spending their time visiting workshops and hackerspaces to see how they tick. Staff Designer of the Design Lab, [Majenta Strongheart], recently took a trip down the road to Caltech to check out their hackerspace. Actually, it’s a rapid prototyping lab, but a rose by any other name…

The prototyping lab at Caltech exists for a few reasons. The first, and most important, are the graduate students. This is a research facility, after all, and with research comes the need to make stuff. Whether that’s parts for biomechanical fixtures, seismology experiments, or parts for a radio telescope, there’s always going to be a need to make mechanical parts. The rapid prototyping lab is also available to undergraduates. Many of the courses at Caltech allow students to build robots. For example, when the DesignLab staff was filming, the students in Mechanical Engineering 72 were taking part in Tank Wars, a robot competition. Here, students built little rovers built to climb over obstacles and traverse terrain.

As far as tech goes, this is a real shop. There are vintage knee mills, manual lathes, but also fancy CNC lathes, Tormach mills, and laser cutters galore. The amount of tooling in this lab has slowly accumulated over decades, and it shows. Right next to the bright white Tormach, you’ll find drill presses that are just that shade of industrial green. It’s a wonderful space, and we’re happy the faculty and students at Caltech allowed us to take a look.

You can check out the video below.

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CalTech’s Manipulator-arm Equipped Robot

May 30, 2012 by Mike Szczys 3 Comments

[Justin] wrote in to tell us about the rover which his CalTech team has entered in NASA’s Exploration Robo-Ops Competition. Their time to shine is later this week, but you can see some of the test footage after the break.

The operator pictured above is using a controller which is a scale model of the manipulator arm, with two cameras giving feedback. One of those monitors shows a feed from the arm itself, providing a view of the gripper. The other feed is a wide shot of the working area from the body of the robot. The arm has six degrees of freedom actuated by servo motors. The controller is a replica of the arm laser cut from acrylic. At each joint there’s a potentiometer whose value is used to establish the position of the frame.

At first we thought that this would be more fatiguing and less convenient than using a gaming controller. But as we look at the dexterity of the arm it becomes obvious that joysticks and buttons would just make things more difficult.

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Hackaday Links: April 7, 2012

April 7, 2012 by Brian Benchoff 8 Comments

Need some gears? Got a timing belt?

[filespace] sent in a neat build he stumbled upon: making gears with plywood and a timing belt. Just cut out a plywood disk and glue on a section of timing belt. There’s some math involved in getting all the teeth evenly placed around the perimeter, but nothing too bad. Also useful for wheels, we think.

We’re on a chess kick now.

Huge chess sets are cool, right up until you try to figure out where to store the pieces when they’re not being used. [Jayefuu] came up with a neat solution to this problem. His pieces are cut out of coroplast (that corrugated plastic stuff political campaign signs are made of), making it relatively inexpensive and just as fun as normal giant chess pieces on a tile floor.

<INSERT MARGINALLY RELEVANT PORTAL QUOTE HERE>

[Randy]’s son is in the cub scouts. Being the awesome father he is, [Randy] helped out with this year’s pinewood derby build. It’s a car shaped like a portal gun with the obligatory color-changing LED. The car won the ‘Can’t get more awesome’ award, but wheel misalignment kicked it out of the competition during qualifying rounds. Sad, that. Still awesome, though.

These people are giving you tools for free

Caltech professor [Yaser Abu-Mostafa] is teaching a Machine Learning class this semester. You can take this class as well, even if the second lecture started last Thursday.

Turning an Arduino into a speech synthesizer

[AlanFromJapan] sent in this product page for an Arduino-powered speech synthesizer. We’re probably looking at a relabeled ATmega328 with custom firmware here; to use it, you replace the micro in your Arduino Uno with this chip. The chip goes for about $10 USD here, so we’ll give it a week until someone has this proprietary firmware up on the Internet. There are English morphemes that aren’t in Japanese, so you can’t just ‘type in English’ and have it work. Here’s a video.