Holman Is Your Phone’s Best Friend

June 18, 2017 by Al Williams 12 Comments

Let’s get something straight right up front: this isn’t much of an electronics project. But it is a very artistic 3D printing project that contains some electronics. [Sjowett] used an off-the-shelf class D amplifier with BlueTooth input to create a simple BlueTooth speaker with a subwoofer. As you can see from the pictures, woofer is exactly the term to use, too.

The clever mechanical design uses 3D printing and common metric PVC pipe. That’s a great technique and resulted in a very clean and professional-looking build. If you don’t have easy access to metric pipe, you could print the pipes, but it will take longer and might not look quite as good.

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Annealing Plastic For Stronger Prints

June 17, 2017 by Brian Benchoff 24 Comments

Much fuss has been made over the strength of 3D printed parts. These parts are obviously stronger in one direction than another, and post processing can increase that strength. What we’re lacking is real data. Luckily, [Justin Lam] has just the thing for us: he’s tested annealed printed plastics, and the results are encouraging.

The current research of annealing 3D printed parts is a lot like metallurgy. If you put a printed part under low heat — below the plastic’s glass transition temperature — larger crystals of plastic are formed. This research is direct from the Society of Plastics Engineers, and we’re assuming they know more about material science than your average joe. These findings measured the crystallinity of a sample in relation to both heat and time, and the results were promising. Plastic parts annealed at a lower temperature can attain the same crystallinity, and therefore the same strength, if they’re annealed for a longer time. The solution is simple: low and slow is the best way to do this, which sounds a lot like sous vide.

A while back, [Justin] built a sous vide controller for the latest cooking fad. The idea behind a sous vide controller is to heat food in a water bath at a lower temperature, but for a longer time. The result here is the most tender steaks you’ll ever have, and also stronger 3D printed parts. In his test, [Justin] printed several rectangular samples of PLA, set the temperature to 70°C, and walked away for a few hours. The samples annealed in the water bath were either cooled quickly or slowly. The test protocol also included measuring the strength in relation to layer height. The test jig consisted of a bathroom scale, a drill press, and a slot head screwdriver bit.

Although the test protocol is slightly questionable, the results are clear: annealing works, but only if the part is printed at a low layer height. However, parts with larger layer heights had a higher maximum stress. Is this helpful for the home prototyper? That depends. The consensus seems to be that if you’re at the mechanical limits of a 3D printed part, you might want to think about more traditional manufacturing. That’s just common sense, but there’s always room to push the envelope of 3D printing.

Biped Bob Walks And Dances

June 14, 2017 by Al Williams 5 Comments

If you have a few servo motors, an Arduino, and a Bluetooth module, you could make Biped Bob as a weekend project. [B. Aswinth Raj] used a 3D printer, but he also points out that you could have the parts printed by a service or just cut them out of cardboard. They aren’t that complex.

Each of Bob’s legs has two servo motors: one for the hip and one for the ankle. Of course, the real work is in the software, and the post breaks it down piece-by-piece. In addition to the Arduino code, there’s an Android app written using Processing. You can build it yourself, or download the APK. The robot connects to the phone via BlueTooth and provides a simple user interface to do a few different walking gaits and dances. You can see a few videos of Biped Bob in action, below.

This wouldn’t be a bad starter project for a young person or anyone getting started with robotics, especially if you have a 3D printer. However, it is fairly limited since there are no sensors. Then again, that could be version two, if you were feeling adventurous.

We have mixed feelings about the BlueTooth control. BlueTooth modules are cheap and readily available, but so are ESP8266s. It probably would not be very difficult to put Bob on WiFi and let him serve his own control page to any web browser.

If Bob meets Jimmy, he may find himself envious. However, Jimmy would be a little more challenging to build. We’ve actually seen quite a few walking ‘bots over the years. Continue reading “Biped Bob Walks And Dances” →

PrusaControl: The Beginner’s Slicer

June 12, 2017 by Brian Benchoff 29 Comments

There are two main applications for managing 3D prints and G-Code generation. Cura is a fantastic application that is seeing a lot of development from the heavy hitters in the industry. Initially developed by Ultimaker, Lulzbot has their own edition of Cura, It’s the default software packaged with thousands of different printers. Slic3r, as well, has seen a lot of development over the years and some interesting hacks. Do you want to print non-planar surfaces? Slic3r can do that. Slic3r and Cura are two sides of the CAM part of the 3D printing coin, although Cura is decidedly the prettier side.

The ability to combine the extensibility of Slic3r with the user interface of Cura has been on our wish list for a while now. It’s finally time. [Josef Prusa] has released PrusaControl, a 3D printing CAM solution that combines the best of Slic3r into a fantastic, great looking package. What are the benefits? What’s it like? Check that out below.

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3D Printed Radiation Patterns

June 11, 2017 by Michael Uttmark 19 Comments

Radiation patterns for antennas can be utterly confusing, especially when presented in two dimensions, as they usually are. Fear not, [Hunter] has your back with 3D printed and color-coded radiation patterns.

In the field of antenna design, radiation patterns denote the relationship between the relative strength of radio waves emitted from antennas and the position of a receiver/transmitter in 3D space. In practice, probes can be used to transmit/receive from documented locations around an antenna while recording signal intensity, allowing researchers and engineers to determine the characteristics of arcane antennas. These measurements are normally expressed as two-dimensional slices of three-dimensional planes. Naturally, this sometimes (often) complex geometry is difficult for all but the most spatially inclined to mentally conceptualize with only the assistance of a 2D drawing. With computers came 3D models, but [Hunter] wasn’t satisfied with a model on a screen: they wanted something they could hold in their hands.

To that end, [Hunter] simulated several different antenna structures, cleaned up the models for 3D printing, and 3D printed them in color sandstone, and the end result is beautiful. By printing in colored sandstone through Shapeways, [Hunter] now has roughly walnut-sized color-coded radiation patterns they can hold in their hand. To save others the work, [Hunter] has posted his designs on Shapeways at Ye Olde Engineering Shoppe. So far, he has a horn antenna, dipole, inset fed patch antenna and a higher order mode of a patch antenna, all of which are under 15.00USD. Don’t see the antenna radiation pattern of your dreams? Fret not, [Hunter] is looking for requests, so post your ideas down in the comments!

Further, beyond the immediate cool factor, we can see many legitimate uses for [Hunter’s] models, especially in education. With more and more research promoting structural rather than procedural learning, [Hunter’s] designs could easily become a pedagogical mainstay of antenna theory classes in the future. [Hunter] is not the only one making the invisible visible, [Charles] is mapping WiFi signals in three dimensions.

Video after the break.

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Hackaday Prize Entry: Printing Bones

June 8, 2017 by Brian Benchoff 23 Comments

You would be forgiven to think that 3D printing is only about rolls of filament and tubs of resin. The fact is, there are many more 3D printing technologies out there. Everything from powders to paper can be used to manufacture a 3D model. [Jure]’s Hackaday Prize entry is meant to explore those weirder 3D manufacturing techniques. This is a printer that lays down binder over a reservoir of powder, slowly building up objects made out of minerals.

The key question with a powder printer is exactly what material this printer will use. For this project, [Jure] is planning on printing with hydroxyapatite, a mineral that makes up about 70% of bones by weight. Printing bones — yes, they do that — is quite expensive and has diverse applications.

The design of this printer is about what you would expect. It’s a Cartesian design with a roller to distribute powder, a piston to drop the part down into the frame, and an industrial inkjet printhead designed for wide format printers. It’s a fantastic piece of work and one of the better powder printers we’ve seen, and we can’t wait to see what [Jure] is able to produce with this.

Mini Delta 3D Printer In Action At The Monoprice Booth

June 8, 2017 by Mike Szczys 12 Comments

When I was at Bay Area Maker Faire a few weekends ago I stopped by the Monoprice booth to chat with [Chris Apland], their head of 3D Printing. Earlier in the week, the company had just announced preorders for their new $169 delta-style 3D printer called the MP Mini Delta.

[Brian Benchoff] covered that launch and I don’t have a lot of details about the machine itself to add. I saw it in action, printing tiny waving cat models. The stock printer can use ABS or PLA and has a build volume of 110mm in diameter and 120mm tall and these preorder units (being sold through Indegogo) will begin shipping in August.

What was of interest is to hear the shipping estimates the Monoprice team is throwing around. Chris told me that their conservative estimate is that 20,000 of these printers will ship through this preorder, but he is optimistic that by the end of the fourth quarter they’ll be closer to 100,000 units. That is incredible.

Calibration cat printed at 45mm

Part of the promise here is the out of the box functionality; [Chris] mentioned having a printed cat in your hands within 5 minutes. If it can actually do that without the need for setup and calibration that’s impressive. But I know that even seasoned printing veterans are interested in seeing how fast they can run this tiny delta and still turn out quality prints.

You’ll find the video interview after the break.

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