Printing Liquid Concrete

February 24, 2020 by Sharon Lin 9 Comments

In the world of additive manufacturing, there’s always need materials being added to the list of potential filaments to use for printing objects. A method of rapid liquid printing of concrete designed by [Anatoly Berezkin] of Stoneflower 3D makes it possible to print a large variety of shapes from concrete while avoiding the negative effects of fast dehydration. The technique is based on an approach to printing polyurethanes, developed by MIT in 2017. This technique requires physically drawing a 3D object within a gel suspension using a chemical curing process. The gel allows gravity to not affect the printing process, as well as helping out with the curinng. Berezkin, an engineer and hobbyist working out of his garage, has published other work including print heads, ceramic printing, and micro printing sets.

One might be skeptical of whether the weight of the material could cause potential collapse during the printing process, or whether it is simply unrealistic to print objects given the time needed for the concrete to dry. Their demo shows the process being done in household items – bowls and tupperware – combining affordable items such as clay, concrete, and sand for the matrix and mortar. The viscous clay is strong enough to act as a good scaffold for keeping the concrete structure in place as it is being printed. As their video demonstrates, at least for simply objects, the process seems relatively fast.

RLPC doesn’t require toxic chemicals or proprietary components such as gels and suspensions. Its immersion of the final printed object in a humid environment is also superior to the standard process of liquid deposition for hardening concrete. Moreover, the process simply requires clay or retarded mortar for the matrix and mortar paste for turning into concrete. It’s advertised as eco-friendly, but just the simplicity of the materials needed for the matrix and mortar make this a promising technique.

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Multiple 3D Printers, And One Pi To Rule Them All

February 24, 2020 by Tom Nardi 17 Comments

If you’ve got a desktop 3D printer, there’s an excellent chance you’ve heard of OctoPrint. This web front-end, usually running on a Raspberry Pi, allows you to monitor and control the printer over the network from any device that has a browser. But what if you’ve got two printers? Or 20? The logistics of each printer getting its own Pi can get uncomfortable in a hurry, which is why [Jay Doscher] has been working on a way to simplify things.

Leveraging the boosted processing power of the Raspberry Pi 4 and some good old fashioned Linux trickery, [Jay] is now controlling multiple printers from a single device. The trick is to run multiple instances of the OctoPrint backend and assign them to virtual network interfaces so they don’t interfere with each other. This takes some custom systemd unit files to get up and running on Raspbian, which he’s been kind enough to include them in the write-up.

But getting multiple copies of OctoPrint running on the Pi is only half the battle. There still needs to be a way to sort out which printer is which. Under normal circumstances, the printers would be assigned random virtual serial ports when the Pi booted. To prevent any confusion, [Jay] explains how you can use custom udev rules to make sure that each printer gets its own unique device node. Even if you aren’t trying to wrangle multiple 3D printers, this is a useful trick should you find yourself struggling to keep track of your USB gadgets.

If you’re wondering why [Jay] needs to have so many 3D printers going at the same time, we hear they’ve been keeping rather busy running off parts for commissioned copies of his popular projects. Something to consider the next time you’re wondering if there’s a way to make a happy buck out of this little hobby of ours, folks.

3D Printed Breadboard Helper Makes Wiring Neater And Easier

February 23, 2020 by Al Williams 25 Comments

Breadboards make it simple to prototype and test circuits. If you use flexible wires with pins to make connections, it usually results in a rat’s nest. For many of us, using solid wire makes a rat’s nest, too. However, the very neat among us will cut solid wire to just the right length and strip just the right amount of wire and lay the wires very flat and neat along the board. [Moononournation] did a 3D print that makes the latter method much easier. You can find his Breadboard Wire Helper on Thingiverse and see a video, below.

The idea is simple: start with a piece of wire stripped on one side, then count out the number of holes it needs to traverse and push the stripped end through the hole. Trim the wire to fit. To complete the other side, lay the wire flat along the tool to the edge. Now you can see where to strip that side of the wire. After you remove the insulation, you can bend the wire down and cut the wire to fit. Now you have a perfect size and shape wire to place in the actual breadboard.

Granted, this isn’t that hard to do with the existing breadboard if it isn’t too packed. You could even use a spare breadboard. But it is a little easier to trim the wire to the right size with this jig. If you don’t want to 3D print it, you could probably pull the tape off the back of a cheap board and remove the springs to get a similar effect.

So while this little tool probably won’t change your life, it might make it a little easier. What other tools do you use when breadboarding? Let everyone know in the comments.

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3D Printable Nameplates From Your Web Browser

February 22, 2020 by Tom Nardi 33 Comments

It’s an unwritten rule that all proper pieces of shop equipment need a nameplate. Otherwise, how are you going to know what name to use when you curse it under your breath? In the old days these would have been made out of something fancy such as brass, but for the modern hacker that doesn’t stand on tradition, you can now easily outfit all your gear with custom 3D printed nameplates using this online tool.

Granted, it wouldn’t be very difficult to throw one of these together in whatever CAD package you happen to have access to. But with the tool [Tobias Weber] has developed, you don’t have to. Simply pick the font, the shape of the border, and fill in a few variables to fine tune things such as padding and base thickness.

Finally, enter your text and marvel at the real-time 3D preview that’s rendered thanks to the magic of modern web technologies. In seconds, you’ll have an STL file that’s ready for the warm liquid goo phase.

The huge collection of fonts are a particularly nice touch, ranging from delicate scripts to military style stencils. Depending on your CAD software, getting arbitrary fonts imported and extruded into a three dimensional shape can be tricky for new players. If we do have one complaint though, it’s that there doesn’t seem to be a clear indicator of how big the nameplate is going to be when exported. First time around, it spit out an STL that would have been 300 mm long if we hadn’t scaled it down in the slicer.

This project is very reminiscent of another web-based tool we featured recently. That one allowed you to make 3D printed QR codes which would whatever entomb in plastic whatever data your cold hacker heart desired.

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How To Slice Lightweight Aircraft Parts For 3D Printing

February 21, 2020 by Lewin Day 5 Comments

Historically, remote control aircraft were produced much like their early full-sized counterparts. Wooden structures were covered with adhesives and taut fabric membranes. Other techniques later came to the fore, with builders looking to foam and other materials. Of course, these days 3D printers are all the rage, so perhaps one can simply print out a whole plane? As [sahevaantaneja] discovered, it’s not that easy!

One of the foremost problems is the process of slicing. This is where 3D geometry is transformed into the G-code which defines the path taken by the 3D printer during production of a component. Slicer software is generally optimised for working with mostly-solid objects, and some tweaks can be required when working with thin-walled designs.

These challenges come to bear with an aircraft design, which, by necessity must be lightweight. [sahevaantaneja] does a great job of explaining the journey of discovery in which their design was optimised to work with conventional slicers. This allowed the various components to be printed without errors, while retaining their strength to survive in flight.

The design was successful in test flights – a great reward after much experimentation. We’ve seen other 3D printed designs take flight, too. Video after the break.

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LEGO Microtonal Guitar: Building Blocks Of Music Theory

February 20, 2020 by Kristina Panos 8 Comments

Is there anything LEGO can’t do, aside from turning to a soft gelatin when a human steps on one? The incredible range of piece sizes that make them such versatile building blocks extends their utility far beyond the playroom floor, as [Tolgahan Çoĝulu] demonstrates with his LEGO microtonal guitar.

His LEGO what now? If you’re in the western world, microtones simply refer to those that fall between the 12 semitones-per-octave shackles of the western scale. Microtones are smaller than semitones, so they can bring a richer flavor to music, as evidenced in eastern cultures. In the past, [Tolgahan] has made microtonal guitars with fixed and adjustable frets using standard fret wire. After his young son copied his design in LEGO, he decided to bring it to life.

[Tolgahan] and a friend designed and printed a compatible base plate fingerboard and glued it in place on an old classical guitar. Then he and his son spent hours digging through their hoard to look for 1x1s and other 1x pieces to build up the fingerboard.

Here’s where it gets really interesting — they printed a ton of special 1×1 pieces to build up the moveable frets. Since they’re 1x1s, they can also be used to teach music simply by moving them around to the notes of the scale or song being taught, no matter the hemisphere it comes from. Pluck your way past the break to watch the story play out and hear this LEGO guitar for yourself.

If [Tolgahan] and his son had used machine learning to sort their LEGO, it probably wouldn’t have taken so long to find all those 1x1s.

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3D Print Your 3D Scanner

February 19, 2020 by Al Williams 15 Comments

[QLRO] wanted a 3D scanner, but didn’t like any of the existing designs. Some were too complex. Some were simple but required you to do things by hand. That led to him designing his own that he calls AAScan. You can see the thing operating in the video below.

In general, you can move the camera around the object or you can move the object around while the camera stays fixed. This design chooses the latter. You’ll need a stepper motor with a driver board and an Arduino to make the turntable rotate. You also need a computer running Python and Meshroom. The phone also has to run Python and [QLRO] used QPython on an Android device.

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