If 3D Printer, Then Custom Aluminum Extrusion Brackets

December 16, 2017 by Donald Papp 63 Comments

Aluminum extrusions are a boon for mechanical assemblies, but they require a stock of brackets and other hardware to be kept on hand. [mightynozzle] has decided to make things a little easier for prototyping and low-stress assemblies by creating a collection of 3D printable brackets for aluminum extrusions. 3D printing your own bracket hardware means faster prototyping, and if the assemblies don’t need the extra strength and rigidity of metal brackets you can just stick with the 3D printed versions.

The files are on Thingiverse, and include STL files of common brackets as well as an OpenSCAD script for customizing. Not familiar with OpenSCAD? No problem, we have a quick primer with examples.

This project showcases two things well. The first is that while brackets are not particularly expensive or hard to obtain, it can still be worth 3D printing them to reduce the overall amount of hardware one needs to keep on hand to make prototyping faster. The other is that 3D printing can shine when it comes to the creation of things like brackets: a few dimes’ worth of plastic can be turned into precise yet geometrically simple objects that would be a pain to make by other means. It certainly beats sitting on one’s hands waiting for parts to be delivered.

Hangprinter Build Videos

December 16, 2017 by Al Williams 22 Comments

We figure with the rise in 3D printing, it is time for a new Finagle’s law: Any part you want to print won’t fit on your print bed. There was a time when a 100 mm x 100 mm bed was common for entry-level printers. These days, more printers have beds around (200 mm)². A hangprinter’s work area can be larger. Much larger. [Thomas Sanladerer] is building one, and has a series of videos about the build. You can see the first one below, but there are several posted, including about 11 hours of recordings of live sessions of the build.

If you haven’t heard of a hangprinter, it is essentially a 3D print head that — well — hangs from cables and can turn an entire room into a 3D printer. When we looked at the original, it was printing a five-foot tall model of the tower of Babel.

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Better 3D Printing Through Holography

December 16, 2017 by Al Williams 22 Comments

When most of us think about 3D printing, we usually think about a machine that melts plastic filament and extrudes it through a nozzle. But we all know that there are other technologies out there that range from cutting and laminating paper, to printing with molten metal or glass. Many of those are out of range for the common hacker. Probably the second most common method uses photo resin and some light source to build the layers in the resin. Researchers at Lawrence Livermore National Laboratory (LLNL) and several universities are experimenting with a new technique that exposes photo resin using three lasers, printing an entire object at one time. You can see a cube formed using the technique in the video below.

In all fairness, the process really isn’t holography but LLNL refers to it as “hologram-like.” In fact, it appears the lasers project more like an oblique projection (you know, like in drafting) which is considerably simpler. Simple enough, that we can’t help but wonder if the hacker community couldn’t develop machines based on this principle. The key would be arranging for the resin to only cure where laser light overlaps.

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Brute Forcing Passwords With A 3D Printer

December 15, 2017 by Adam Fabio 17 Comments

Many of us use a 4 digit pin code to lock our phones. [David Randolph] over at Hak5 has come up a simple way to use a 3D printer to brute force these passwords. Just about every 3D printer out there speaks the same language, G-code. The same language used in CAD and CNC machines for decades.

[David] placed a numeric keypad on the bed of his printer. He then mapped out the height and positions of each key. Once he knew the absolute positions of the keys, it was easy to tell the printer to move to a key, then press and release. He even created a G-code file which would press every one of the 10,000 4 key pin combinations.

A file this large was a bit unwieldy though, so [David] also created a python script which will do the same thing — outputting the G-code and coordinates to brute force any 4 pin keypad. While a printer is quite a bit slower than Hak5’s own USB Rubber Ducky device (which acts as an automated keyboard), it will successfully brute force a password. Although most phones these days do limit the number of password attempts a user gets.

[David] admits this is probably useless in a clandestine/hacking application, but the video is still a great introduction to G-code and using 3D printers for non-printing functions.

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Thermistors And 3D Printing

December 15, 2017 by Al Williams 24 Comments

I always find it interesting that 3D printers — at least the kind most of us have — are mostly open-loop devices. You tell the head to move four millimeters in the X direction and you assume that the stepper motors will make it so. Because of the mechanics, you can calculate that four millimeters is so many steps and direct the motor to take them. If something prevents that amount of travel you get a failed print. But there is one part of the printer that is part of a closed loop. It is very tiny, very important, but you don’t hear a whole lot about it. The thermistor.

The hot end and the heated bed will both have a temperature sensor that the firmware uses to keep temperatures at least in the ballpark. Depending on the controller it might just do on-and-off “bang-bang” control or it might do something as sophisticated as PID control. But either way, you set the desired temperature and the controller uses feedback from the thermistor to try to keep it there.

If you print with high-temperature materials you might have a thermocouple in your hot end, but most machines use a thermistor. These are usually good to about 300 °C. What got me thinking about this was the installation of an E3D V6 clone hot end into my oldest printer which had a five-year-old hot end in it. I had accumulated a variety of clone parts and had no idea what kind of thermistor was in the heat block I was using.

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How Mini Can A Mini Lamp Be?

December 12, 2017 by Jenny List 4 Comments

If there is one constant in the world of making things at the bench, it is that there is never enough light. With halogen lamps, LEDs, fluorescent tubes, and more, there will still be moments when the odd tiny part slips from view in the gloom.

It’s fair to say that [OddDavis]’ articulated mini lamp will not provide all the solutions to your inadequate lighting woes, as its lighting element is a rather humble example of a white LED and not the retina-searing chip you might expect. The lamp is, after all, an entry in our coin cell challenge, so it hardly has a huge power source to depend upon.

What makes this lamp build neat is its 3D-printed articulated chassis. It won’t replace your treasured Anglepoise just yet, but it might make an acceptable alternative to that cheap IKEA desk lamp. With the coin cell LED you’d be hard pressed to use it for much more than reading even with its aluminium foil reflector, but given a more substantial lighting element it could also become a handy work light.

If 3D printed articulated lamps are your thing, take a look at this rather more sophisticated example.

A Remote Controlled Air-Plane

December 11, 2017 by Brian Benchoff 37 Comments

The Air Hogs Sky Shark was a free-flying model airplane powered by compressed air. When it was released in the late ’90s, it was a fairly innovative toy featuring a strikingly novel compressed air engine made entirely out of injection molded plastic. Sales of these model planes took off, and landed on the neighbor’s roof, never to be seen again.

A few weeks ago, [Tom Stanton] revisited this novel little air-powered motor by creating his own 3D printed copy. Yes, it worked, and yes, it’s a very impressive 3D print. That build was just on a workbench, though, and to really test this air motor out, [Tom] used it to propel a remote-controlled plane through the air.

The motor used for this experiment is slightly modified from [Tom]’s original air-powered motor. The original motor used a standard 3-blade quadcopter prop, but the flightworthy build is using a much larger prop that swings a lot more air. This, with the addition of a new spring in the motor and a much larger air tank constructed out of plastic bottles results in a motor that’s not very heavy but can still swing a prop for tens of seconds. It’s not much, but it’s something.

The airframe for this experiment was constructed using [Tom]’s 3D printed wing ribs, a carbon fiber boom for the tail, and only rudder and elevator controls. After figuring out some CG issues — the motor doesn’t weigh much, and planes usually have big batteries in the nose — the plane flew remarkably well, albeit for a short amount of time.

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