Sourcing Your CNC Tools In 2016: Build Them

January 13, 2016 by 71 Comments

Perhaps the tolerances on today’s hobbyist machines just aren’t good enough for you, or perhaps the work area is just too cramped. Either way, there are times when an off-the-shelf solution just wont fit your needs, and you resolve to build your own CNC machine. Fortunately, none of us are alone in this endeavor because hobbyists have been building their own automation equipment for years. Whether you’re talking building the machine, generating the G-code, or interpreting that G-code into motor signal pulses, the DIY CNC community has evolved a sophisticated set of tools aimed at getting the job done.  I thought I’d take a tour of some of the hobbyist’s tools that hallmark 2016 as the best year yet to build your CNC machine.

Hardware

In the last few years, affordable extruded profiles and brackets have made leaps and bounds to satisfy a hungry DIY 3D printer community. Beyond 3D printers, these beams and brackets are a good start for some of our needs in the world of linear motion control. Here’s a quick look at a few components off-the-shelf.

Makerslide Extruded Profiles

ms_long_smUnless you’ve discovered a deal on eBay or AliExpress, building up a machine from precision linear rails can be a pricey ordeal. Linear rails offer us a rigid, wiggle-free guide for motion along a single axis, but in some cases, the cost needed for hobbyists to afford this precision is outside their budget. [Barton Dring] took the idea of guided linear motion and launched a custom extruded rail that enables bearings to slide freely along an axis. Dubbed Makerslide, this extruded rail features a groove embedded directly into the extrusion and aims to be compatible with most other 20-mm extruded profiles like those from Misumi and Rexroth.

OpenBuilds V-Grooved Rail Attachments

Open-Rail-Description
Image Credit: Ooznest

On a similar note, the folks at OpenBuilds took [Barton’s] concept in a slightly different direction. For many of us who have already committed to extrusions from one vendor and have our closets gushing with excess tubes, Open Rail is an extruded v-groove attachment that enables bearing-mounted plates to slide freely just like the extrusions of Makerslide. Unlike Makerslide, however, almost any 20-mm extrusion can be retrofitted with Open Rail, rather than requiring a specialized extrusion.

OpenBuilds Linear Actuator Kits

CNC machines encompass a wide variety of machine designs that spans far beyond this article’s scope. For conventional machines, however, a single motor drives a motion along a single axis. To add direction in a separate dimension, we can sometimes chain together two of the same linear motion units. The folks at OpenBuilds have taken this principle to heart offering single-axis systems as kits. With some creativity and forethought, users can develop a number of automated solutions based on the principle of appending multiple axes. Of course, the folks at OpenBuilds haven’t stumbled upon a never-before-seen solution. Misumi, Rexroth, and other professional automation equipment companies have been selling linear motion systems for years; however, their price range easily leaps beyond the 10K mark.

Not an End-All, but a Solid Start

Despite the design flexibility, neither Makerslide nor OpenBuilds is the all-encompassing solution for every CNC endeavor. Specifically, for rigid machines that can chew through steel, a structure built from bolted aluminum extrusions will be far less rigid than professional machines of a similar scale. Nevertheless, for machines that don’t experience heavy loads, like a 3D printer, a laser cutter, or even some small routers, both Makerslide and OpenBuilds offer an excellent starting point.

Software

With our hands full of stepper motors, extruded profiles, and belts, it’s time to start exploring a software solution to drive it all. While there are plenty of machine-specific solutions, I thought I’d highlight two that are flexible enough to be tuned to a custom machine.

G-code Interpreters

G-code interpreters do just that: they accept input commands in G-code (be it directly from a file or serially through a cable) and convert the commands to step and direction digital outputs with the right timings to produce the control signals for stepper motor drivers. In one sense, they’re the “brains” of the machine, taking the G-code “instruction set” and outputting behaviors that correspond to the input instructions.

LinuxCNC

axisubuntu
Image Credit: LinuxCNC Wiki

LinuxCNC spun out from a US-government-funded initiative to develop a motion control package for standards testing back in the 90s. Over time, it has evolved into a software package designed to turn a PC into a G-code interpreter, and it’s currently packaged as real-time Linux distribution. From your LinuxCNC-configured PC, you can simply connect your stepper motors, limit switches and other digital I/O devices to the PC’s parallel port which, in turn, outputs motor step and direction pulses to drive your physical hardware.

LinuxCNC isn’t just a G-code interpreter, though. The 15+ years of active development have given it a solid foundation which makes it one of the most adaptable software packages for developing custom machines. By enabling custom kinematics, users can drive non-Cartesian machines like SCARA arms. With a core operating system based on Debian Linux, users can link additional PC peripherals, like USB game controllers, to drive their machines. Some devoted software hackers have even fleshed out the current user interface to directly generate G-code for simple cuts, rather than simply run existing G-code.

Grbl

With over 7 years of active development, Grbl has proven itself to be simple, reliable G-code interpreter firmware for the Arduino Uno. Simply connect your motor controllers and limit switches to the Uno, and Grbl firmware handles the step and direction pulse timing for all 3 axes of your machine. Grbl doesn’t aim to be an all-encompassing interpreter like LinuxCNC, but in exchange it’s a far simpler solution that is relatively easy to set up and works for most, if not all, typical use-cases for a 3-axis machine.

Though Grbl drives the physical hardware, it still requires a serial interface to receive G-code instructions to execute. Fortunately, G-code-streaming packages exist: bCNC and UGS, which have been tested specifically with Grbl.

G-code Generators

Having a fancy CNC machine doesn’t say much if we can’t generate instructions to drive it to cut parts! We need a solution for generating G-code, and, once again, the open source software community has jumped in to provide several packages.

dxf2gcode

dxf2gcodeIt’s not unlikely that many of your designs may boil down to a collection of flat plates with simple features on them. For 2D milling, dxf2gcode simplifies the process of generating G-code based on an original design file, in this case: a dxf. The project also features automatic cutter compensation done in software, a very handy feature that will generate an offset toolpath based on the diameter of the tool and the type of cut (pocket or outside edge).

gcmc

gcmc
Image Credit: gcmc homepage

If you’ve ever tried writing G-code manually, you’ll quickly realize just how unreadable it is without having memorized the majority of the commands. GCMC is a front-end language aimed at producing human-readable machine routines. By abstracting away the unnecessary idiosyncrasies of the language, gcmc facilitates the generation of complex tool motions and patterns simply by tweaking a few parameters.

Doing the Research

Building your own CNC machine may just be your next labor of love, but unless you prefer to reinvent the wheel (and, hey, starting from first principles isn’t always a bad thing), it’s worth taking a look at the tomes of build logs, forum posts, and existing software from the gurus who have built CNCs before us. While I’ve highlighted a few of the more common tools in the land of hardware and software, this list is far from complete. So go forth! Do your research–and, of course, let us know what you find in the comments.

The Best Projects That Fit In A Square Inch

January 13, 2016 by 45 Comments

A few years ago, we started Hackaday.io as a project hosting site for The People Who Actually Make Stuff™, and since then we’ve been amazed by what the community can put together. We have well over 100,000 hackers on board in an awesome community. Sometime around September, a few members of the Hackaday.io community decided to follow in the footsteps of the very successful contests we’ve had on Hackaday.io. This led to the Square Inch Contest, a challenge to put the coolest electronics inside a square inch PCB. An inch the distance light travels in 1/11802852665.12644 of a second for those of you without freedom units.

quad
The winner, Quadcopter In One Inch

With almost eighty entries, the judges had a very difficult task ahead of them. In the end, only one project would be the best. The winner of Hackaday.io’s first user-created contest is Quadcopter In One Inch from [jeff]. This wins the grand prize of a $100 credit for the Hackaday Store and a $50 gift certificate to OSHPark.

There are six other prizes, each receiving a $50 credit to the Hackaday Store and $25 for OSHPark:

Winners

The judges for the Square Inch Project would like to give an honorable mention to Twiz and the blinktronicator. The judges would also like to express amazement in how much work actually goes into judging a contest on Hackaday.io. Spending a few weeks working on the judging for a contest with eighty entries imbues a sort of respect for people who can judge a contest with one thousand entries in three days, as the Hackaday crew has done with two Hackaday Prizes so far. While they were doing that, I was sitting back and cracking jokes about Fleiss’ Kappa.

This was the first community-created contest on Hackaday.io, but it is surely not the last. We don’t know what the next contest will be – that will be up to someone on Hackaday.io – but there will be one, and like the Square Inch Project, it will be awesome.

Stallman’s One Mistake

January 13, 2016 by 147 Comments

We all owe [Richard Stallman] a large debt for his contributions to computing. With a career that began in MIT’s AI lab, [Stallman] was there for the creation of some of the most cutting edge technology of the time. He was there for some of the earliest Lisp machines, the birth of the Internet, and was a necessary contributor for Emacs, GCC, and was foundational in the creation of GPL, the license that made a toy OS from a Finnish CS student the most popular operating system on the planet. It’s not an exaggeration to say that without [Stallman], open source software wouldn’t exist.

Linux, Apache, PHP, Blender, Wikipedia and MySQL simply wouldn’t exist without open and permissive licenses, and we are all richer for [Stallman]’s insight that software should be free. Hardware, on the other hand, isn’t. Perhaps it was just a function of the time [Stallman] fomented his views, but until very recently open hardware has been a kludge of different licenses for different aspects of the design. Even in the most open devices, firmware uses GPLv3, hardware documentation uses the CERN license, and Creative Commons is sprinkled about various assets.

If [Stallman] made one mistake, it was his inability to anticipate everything would happen in hardware eventually. The first battle on this front was the Tivoization of hardware a decade ago, leading to the creation of GPLv3. Still, this license does not cover hardware, leading to an interesting thought experiment: what would it take to build a completely open source computer? Is it even possible?

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“Makerspace” Trademark Application Rejected

January 13, 2016 by 24 Comments

The German Patent and Trademark Office has denied the application from UnterhehmerTUM for a trademark on the word “Makerspace”.  It wasn’t likely to be a threat to the community anyway, but now it’s entirely off the table. So Kwartzlab Makerspace, Houston Makerspace, Rochester Makerspace, Anchorage Makerspace, … you can all breathe easy!

To be fair, there was never any danger, just a misunderstanding.  We reported earlier on the trademark application and within a day or so got an official reply in the comments from Phil (“Mr. Mobile”) Handy that they weren’t looking to enforce anything, but were just essentially trying to make sure that nobody else could pull the rug out from under them.  (Thanks [Gentleman Nerd] for pushing them on this.)

The makerspace in question is an open-access offshoot of a business incubator that’s associated with Munich’s Technical University, and it looks like they pumped a couple million Euros into the deal, so there were doubtless layers of bureaucracy that wanted to make sure that their asses were legally covered.

Anyway, the Trademark Office did the right thing, denying the trademark because it wasn’t “unique”, and the makerspace looks awesome.  All’s well that ends well.

via [Make Magazine] (Germany)

Finally, An Upgrade For The TI-86

January 13, 2016 by 60 Comments

The eternal and everlasting TI-86 graphing calculator is a great calculator: first made back in 1997, and still used by students today. But its battery life kinda sucks. So [Dalius] decided to bring his TI-86 into the 21st century.

If you’re not familiar, the TI-86 runs off of 4 AAA batteries, preferably alkaline. If you use rechargeable NiMH they don’t last very long since they have a lower voltage per cell, which means it ends up draining even faster to a voltage level the TI-86 cannot operate at.

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Crappy Robots And Even Crappier Electronics Kits

January 12, 2016 by 35 Comments

Robots and DIY electronics kits have a long history together. There probably isn’t anyone under the age of forty that hasn’t had some experience with kit-based robots like wall-hugging mouse robots, a weird walking robot on stilts, or something else from the 1987 American Science and Surplus catalog. DIY robot kits are still big business, and walking through the sales booths of any big Maker Faire will show the same ideas reinvented again and again.

[demux] got his hands on what is possibly the worst DIY electronics kit in existence. It’s so incredibly bad that it ends up being extremely educational; pick up one of these ‘introduction to electronics’ kits, and you’ll end up learning advanced concepts like PCB rework, reverse engineering, and Mandarin.

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Second Skin Synth Fits Like A Glove

January 12, 2016 by 5 Comments

California textiles artist and musician [push_reset] challenged herself to make a wearable, gesture-based synth without using flex-sensing resistors. In the end, she designed almost every bit of it from the ground up using conductive fabric, resistive paint, and 3-D printed parts.

A couple of fingers do double duty in this glove. Each of the four fingertips have a sensor made from polyurethane, conductive paint, and conductive fabric that is connected to wires using small rivets. These sensors trigger different samples on an Edison that are generated with Timbre.js. The index and middle fingers also have knuckle actuators made from 3-D printed pin-and-slot mechanisms that turn trimmer pots. Bending one knuckle changes the delay timing while the other manipulates a triangle wave.

On the back of the glove are two sensors made from conductive fabric. Touching one up and down the length will alter the reverb. Sliding up and down the other alters the frequency of a sine wave. [push_reset] has kindly provided everything necessary to re-create this build from the glove pattern to the STL files for the knuckle actuators. Check out a short demonstration of the glove after the break. If you love a parade, here’s a wearable synth that emulates a marching band.

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