3D Printed Battery Forms

What’s the worst thing that can happen when you are trying to show off a project? Dead batteries might not be the absolute worst thing, but it is pretty close to the top of the list. [KermMartian] has this problem every year at World Maker Faire with demos based around calculators. At first, he tried wedging power supply wires into the calculator using dead batteries to hold the wires in place. However, it didn’t take much wear and tear before the wires would pull out.

The solution? A 3D printed battery form that accepts metal hardware that can connect to the external power supply. The AAA-sized plastic batteries insert into the calculator’s battery compartment and the small machine screws and washers form the connection points.

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3D Printed Kinetic Art

Artificial muscles and soft robotics don’t get the respect they deserve, but [mikey77] is doing some very interesting work with artificial muscles that can be made on just about any 3D printer.

Like other artificial muscles and soft robotic actuators we’ve seen – like this walking sea slug and this eerie tentacle – [mikey77]’s muscles are powered by air. Instead of the usual casting method, he’s printing these muscles from Ninjaflex, a flexible plastic that is compatible with most 3D printers.

As they come off the printer, these 3D printed pneumatic muscles leak, and that means [mikey77] has to seal them. For that, he created a sealant out of Loctite fabric glue thinned with MEK. The addition of MEK dissolves the outer layer of Ninjaflex, allowing the glue to bond very, very well to the printed muscle.

So far, [mikey77] has created a pneumatic flower that blooms when air is added. He’s also created a muscle that can lift more than four pounds of weight with the help of a 3D printed skeleton. It’s a great way to experiment with flexible robots and pneumatic muscles, and we can’t wait to see what weird creatures can be created with these actuators.

Thanks [Lloyd] for sending this one in.

CubeSat Challenge Winners Show Interesting Design Approaches

The winners are in for the GrabCad CubeSat Challenge, which asked designers to rethink the way that CubeSats are built. These tiny 10 cm square satellites are the hot thing in orbit, and the competition was looking for new ways to build and pack more into this tiny space. The winners offered some fascinating new approaches to building CubeSats, and some excellent design lessons that anyone can use.

The winner was FoldSat, by [Paolo Minetola]. His excellent design is a 3D printed folding case for a satellite that is built from just two 3D printed parts. The case can be snapped together and offers multiple ways to mount electronic components and sensors inside. [Paolo] estimates that it could save 40% time and 30% materials from existing CubeSat casings, which means more space inside and more time to build. It is an excellent example of how 3D printing can make things cheaper, easier and better, all at the same time.

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Learn 3D Modeling in Your Browser

If you have a 3D printer, it is a good bet you’ve at least seen or heard of Tinkercad. There’s pros and cons to doing your design in a Web browser, but Tinkercad is very easy to use and great for making simple objects. However, there are other 3D object designers you can use in your browser, too. Tinkercad is just the one that everyone seems to know about.

I won’t talk much about Tinkercad, but if you haven’t tried it, it is well worth a look. It has a simple system of drawing things and holes. When you merge holes with things you can make lots of shapes. The alignment tools are good, and since Autodesk acquired them (part of its 123d app suite), it isn’t likely they will go under any time soon (which, as you may remember, almost happened).

If you are designing some great new secret invention you may shy away from cloud-based design programs. But if you are printing out key chains with your coworker’s cat’s name on it, do you really care? Most of these cloud-based programs will work from any computer so you can quickly do a design in a coffee shop and then go home and print it.

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3D Objects From a Laser Cutter

Actors want to be singers and singers want to be actors. The hacker equivalent to this might be that 3D printers want to be laser cutters or CNC machines and laser cutters want to be 3D printers. When [Kurt] and [Lawrence] discovered their tech shop acquired a 120 Watt Epilog Fusion laser cutter, they started thinking if they could coax it into cutting out 3D shapes. That question led them to several experiments that were ultimately successful.

The idea was to cut away material, rotate the work piece, and cut some more in a similar way to how some laser cutters handle engraving cylindrical objects. Unlike 3D printing which is additive, this process is subtractive like a traditional machining process. The developers used wood as the base material. They wanted to use acrylic, but found that the cut away pieces tended to stick, so they continued using wood. However, the wood tends to char as it is cut.

In the end, they not only had to build special jigs and electronics, they also had to port some third party control software to solve some issues with the Epilog Fusion cutter’s built in software. The final refinement was to use the laser’s raster mode to draw surface detail on the part.

The results were better than you’d expect, and fairly distinctive looking. We’ve covered a similar process that made small chess pieces out of acrylic using two passes. This seems like a natural extension of the same idea. Of course, there are very complicated industrial machines that laser cut in three dimensions (see the video below), but they are not in the same category as the typical desktop cutter.

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Custom Threaded Inserts for 3D Printing

There’s a variety of ways to add threaded holes to 3D printed objects. You can tap a hole, but the plastic isn’t always strong enough. Nut traps work, but aren’t very attractive and can be difficult to get exactly the right size. If you try to enclose them, you have to add a manual step to your printing process, too. You can buy threaded inserts (see video below) but that means some other piece of hardware to have to stock in your shop.

[PeterM13] had a different idea: Cut a piece of threaded stock, put nuts on the end and heat it up to let the nuts reform the plastic. This way the nut traps wind up the perfect size by definition. He used two nuts aligned and secured with thread locker. Then he used a hot air gun to only heat the metal (so as to reduce the chance of deforming the actual part). Once it was hot (about 15 seconds) he pulled the nuts into the open hole, where it melted the plastic which grips the nuts once cooled again.

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You Own Your MRI Brainscan; Do Something Interesting With It

The most complicated and fascinating gadget you will ever own is your brain. Why not pay tribute to this wonder by creating a 3D scale model that you can print yourself? If you have had a full-head MRI scan, it is simple to take this data and create a 3D model that you can print out on any 3D printer. Here’s how to print your brain.

To begin, you are going to need an MRI scan. Unfortunately, the low-field MRI that [Peter Jansen] is working on won’t quite cut it (yet): you’ll have to get the pros to do it. The type of scan also matters, because we want a scan that focusses in on the brain itself, not the bits around it. What type you get depends on what your doctor wants to know, as the radiologist can run a lot of different scans and analysis of the data to show different types of tissue. After looking through the scans that I got, I settled on one that was labelled eB1000i(BRAIN) With and Without Contrast. To a radiologist, that information means a lot, telling you what type of scan it is, and that it was done with a contrast agent, a metal dye that is injected to make water-rich tissues (like my brain) more visible. The number refers to something called the diffusion weighting, which helps the doctor look for swelling that can indicate things like strokes, tumors, etc. There’s a good guide to some of the jargon here.

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