Add Slots and Tabs to Your Boxes in FreeCAD

FreeCAD is a fairly sophisticated, open-source, parametric 3D modeler. The open-source part means that you can bend it to your will. [Alexandre] is working on a module that lets him easily add tabs, finger joints, and t-slots to models (YouTube link, embedded down under).

Right now the plugin is still experimental, but it looks usable. In the video demo, [Alexandre] builds up a simple box, and then adds all manner of physical connective pieces to it. You’ll note that the tabs look like they’re pieces added on to the main face — that’s because they are! He then exports the outlines to SVG and erases the lines that separate the tabs from the sides, and hands these files off to his laser cutter. Voilà! A perfect tab-and-t-slot box, with only a little bit of hand-work. ([Alexandre] mentions that it’s all still very experimental and that you should check out your design before sending it to the laser.)

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Hackaday Prize Entry: Robotic Prosthetic Leg Is Open Source And 3D-Printable

We’ve been 3D-printing parts for self-replicating machines before, but we’ve been working on the wrong machines. Software and robotics engineer [David Sanchez Falero] is about to set it right with his Hackaday Prize entry, a 3D-printable, open source, robotic prosthetic leg for humans.

[David] could not find a suitable, 3D-printable and customizable prosthetic leg out there, and given the high price of commercial ones he started his own prosthesis project named Drakkar. The “bones” of his design are made of M8 steel threaded rods, which help to keep the cost low, but are also highly available all over the world. The knee is actively bent by a DC-motor and, according to the source code, a potentiometer reads back the position of the knee to a PID loop.

drako_footWhile working on his first prototype, [David] quickly found that replicating the shape and complex mechanics of a human foot would be too fragile when replicated from 3D-printed parts. Instead, he looked at how goat hooves managed to adapt to uneven terrain with only two larger toes. All results and learnings then went into a second version, which now also adapts to the user’s height. The design, which has been done entirely in FreeCAD, indeed looks promising and might one day compete with the high-priced commercial prosthesis.

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KiCad Script Hack for Better Mechanical CAD Export

Open source EDA software KiCad has been gaining a lot of traction recently. CERN has been devoting resources to introduce many new advanced features such as differential pair tracks, push and shove routing and this plenty more scheduled in the pipeline. One important requirement of EDA packages is a seamless interface with mechanical CAD packages by exporting 3D models in industry common formats. This improves collaboration and allows further engineering designs such as enclosures and panels to be produced.

KiCad has had a 3D viewer available for quite a long time. But it uses the VRML mesh format (.wrl files) and there are compatibility issues which prevent it from rendering certain versions of VRML files. Moreover, the VRML mesh export is not particularly useful since it cannot be easily manipulated in mechanical CAD software. Recent versions of KiCad now offer IDFv3 format export – the Intermediate Data Format, a mechanical data exchange specification for the design and analysis of printed wiring assemblies. Taking advantage of this new feature, [Maurice] created KiCad StepUp – an export script that allows collaborative exchange between KiCad and FreeCAD.

A FreeCAD macro and a corresponding configuration file are added to the KiCad project folder. You start with .STEP files for all the components used in the KiCad design. The next step is to convert and save all .STEP files as .WRL format using FreeCAD. On the KiCad side, you use the .WRL files as usual. When you want to export the board, use the IDFv3 option in KiCad. When [Maurice]’s StepUp script is run (outside of KiCad) it replaces all instances of .WRL files with the equivalent .STEP versions and imports the board as well as the components in to FreeCAD as .STEP models. The result is a board and its populated components which can be manipulated as regular 3D objects.

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Automatically Designing 3D Printers From E-Waste

No one wants to design consumer electronics that last longer than a few years. This trend is an ecological disaster, with millions of tons of computers, printers, fax machines and cell phones ending up in landfills. In these landfills, all the lead and chemicals used to extract minuscule amounts of gold plating leech into the environment. Turning it all around is monumental, but reusing some of this waste can help make a difference.

[Masterperson] and [Maaphoo] have been working on a way to turn those tons of e-waste into something useful. They’ve come up with a framework for turning e-waste into 3D printers. With a clever application of Python and FreeCAD Macros, this project can generate a model of a 3D printer using motors, shafts, and bearings taken from discarded 2D printers.

Right now a printer can be configured by adding the parts you have on hand to a configuration file, running a Python macro in FreeCAD, and waiting until the macro generates the parts to build a cartesian bot. This macro also spits out the files for the parts that need to be printed, and can interface with Plater to optimize the placement of these printed parts on an existing printer.

It’s a very cool project, but it’s not done yet: the team is looking for help to refine the printer designs and possibly growing more designs than a simple cartesian bot. Anything that is explicitly designed to pick the meat off of 2D printers is a great idea, and turning those into real 3D printers is the cherry on top.

A Calculator with Free Software and Open Hardware

We’re fond of open source things here. Whether it’s 3D printers, circuit modeling software, or a global network of satellite base stations, the more open it is the more it improves the world around us. [Pierre Parent] and [Ael Gain] have certainly taken these values to heart with their open handheld graphing calculator.

While the duo isn’t giving away the calculators themselves, they are releasing all of the hardware designs so that anyone can build this calculator. It’s based on a imx233 processor because this chip (and most everything else about this calculator) is easy to source and easy to use. That, and there is a lot of documentation on it that is in the public domain. All of the designs, including the circuit board and CAD files for the case, are available to anyone who is curious, or wants to build their own.

The software on the calculator (and the software that was used to design the calculator) is all free software too. The calculator runs Linux (of course) and a free TI simulator environment in the hopes of easing the transition of anyone who grew up using TI’s graphing calculators. The project is still in a prototype phase, but it looks very promising. Even though the calculator can already run Pokemon, maybe one day it will even be able to run Super Smash Bros as well!

3D Printering: Making A Thing In FreeCAD, Part II


It’s time once again for another installment of a Making A Thing tutorial, where I design the same part, over and over again, in multiple 3D design software packages.

Last week we took a look at FreeCAD, a free, open source parametric modeller. It’s an amazingly powerful tool, and not it’s finally time to complete our model of a strange object ripped from the pages of an 80-year-old drafting textbook.

Here’s some links to previous Making A Thing tutorials, doe:

Read on for the second part of our FreeCAD tutorial

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3D Printering: Making A Thing In FreeCAD, Part I


I’ve been writing these tutorials on making an object in popular 3D modeling programs for a while now, and each week I’ve put out a call for what software I should do next. There is one constant in all those comment threads: FreeCAD. I don’t know if these suggestions reflect the popularity or difficulty of FreeCAD nevermind, it’s totally the difficulty.

FreeCAD is an amazing tool that, if used correctly, can be used to make just about any part, and do it in a manufacturing context. If you need a bauble that’s three times the size of the original, FreeCAD’s parametric modeling makes it easy to scale it up. If you’re designing a thumbscrew and want the head larger while keeping the threads the same, FreeCAD is for you. Basically, you can think of this as a graphical extension of the Thingiverse Customizer. Very powerful, very cool, and unlike a lot of CAD packages out there, free.

Our in-house, overpaid SEO expert (he’s really just a monkey someone trained to use a bullwhip) demands I link to the previous ‘Making a Thing’ tutorials:

The tutorial for FreeCAD continues below.

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