Turning and Burning with a CNC Pyrography Machine

With CNC machines, generally the more axes the better. Three-axis machines with a vertical quill over a rectangular workspace are de rigueur, and adding an axis or two can really step up the flexibility of a machine. But can only two axes be of any use? Sure can, as witnessed by this two-axis CNC wood burning machine.

As [tuckershannon] tells the tale, this was a newbie build aided by the local hackerspace. Axis one is a rotary table of laser-cut wood gears powered by a stepper. Axis two is just a stepper and lead screw sitting on a couple of blocks of wood. A Raspberry Pi under the hood controls the motors and cycles the pyrography pen on and off as it scans across a piece of wood on the rotary table, burning a spiral pattern that makes for some interesting art. Hats off to [tuckershannon] for figuring out the math needed to adapt to the changing speed of the pen over the wood as the diameter gets bigger.

We love this build, can’t help but wonder if some clever gearing could eliminate the need for the second stepper. And perhaps an upgrade from the standard resistive wood burner to an arc lighter pyrography pen would improve resolution. Still, it’s hard to argue with results, and this is a great hack.

[via r/raspberrypi]

Thanks to [Liz] for the tip!

CNC Mill out of a Building Set

I have some aluminum building-set parts on hand and just got a second rotary tool, so I thought I’d try my hand at making a light-duty CNC mill—maybe carve up some cheap pine or make circuit boards. This post explores some of the early decisions I’m facing as I begin the project.

Of primary importance is the basic format of the mill’s chassis. Gantry configuration or put everything in a box of girders? How will the axes move–belts or racks? How will the Z-axis work, the assembly that lowers the tool onto the material? Finally, once the chassis is complete, or perhaps beforehand, I’ll need to figure out how I intend to control the thing.

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A Poor-Man’s Laser CNC Engraver

What do you get when you mix the disappointment that sometimes accompanies cheap Chinese electronics with the childhood fascination of torturing insects with a magnifying glass on a sunny day? You get a solar-powered CNC etcher, that’s what.

We all remember the days of focussing the sun on a hapless insect, or perhaps less sadistically on a green plastic army man or just a hunk of dry wood. The wonder that accompanied that intense white spot instantly charring the wood and releasing wisps of smoke stayed with you forever, as seemingly did the green spots in your vision. [drum303] remembered those days and used them to assuage his buyer’s remorse when the laser module on his brand new CNC engraver crapped out after the first 10 minutes. A cheap magnifying glass mounted to the laser holder and a sunny day, and he don’t need no stinkin’ lasers! The speed needs to be set to a super slow — 100mm per minute — and there’s the problem of tracking the sun, but the results are far finer than any of our childhood solar-artistic attempts ever were.

Do we have the makings of a possible performance art piece here? A large outdoor gantry with a big Fresnel lens that could etch a design onto a large piece of plywood would be a pretty boss beachside attraction. Of course, you’d need a simple solar tracker to keep things in focus.

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Overhead Trolley Helps Clear the Air over CNC Router

[Frank Howarth] has a shop most woodworkers would kill for, stuffed with enough tools to equip multiple hackspaces — four radial-arm saws alone! But while the CNC router in the middle of the shop, large enough to work on an entire sheet of plywood, is a gem of a machine, it was proving to be a dusty nightmare. [Frank]’s solution was as unique as his workspace — this swiveling overhead dust extraction system.

The two-part video below shows how he dealt with the dual problems of collection and removal. The former was a fairly simple brush-bristle shroud of the type we’ve featured before. The latter was a challenge in that the size of the router’s bed — currently 8′ but soon to be extended to 12′ — and the diameter of the hoses needed to move enough air made a fixed overhead feed impractical. [Frank]’s solution is an overhead trolley to support the hoses more or less vertically over the router while letting the duct swivel as the gantry moves around the work surface. There were a few pitfalls along the way, like hoses that shorten and stiffen when air flows through them, but in the end the system works great.

Chances are your shop is smaller than [Frank]’s, but you still need to control the dust. This dust collector for a more modest CNC router might help, as would this DIY cyclonic chip separator.

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Robot Draws Using Robust CNC

While initially developed for use in large factory processes, computer numeric control (CNC) machines have slowly made their way out of the factory and into the hands of virtually anyone who wants one. The versatility that these machines have in automating and manipulating a wide range of tools while at the same time maintaining a high degree of accuracy and repeatability is invaluable in any setting. As an illustration of how accessible CNC has become, [Arnab]’s drawing robot uses widely available tools and a CNC implementation virtually anyone could build on their own.

Based on an Arudino UNO and a special CNC-oriented shield, the drawing robot is able to execute G code for its artistic creations. The robot is capable of drawing on most flat surfaces, and can use almost any writing implement that will fit on the arm, from pencils to pens to brushes. Since the software and hardware are both open source, this makes for an ideal platform on which to build any other CNC machines as well.

In fact, CNC is used extensively in almost everything now, and are so common that it’s not unheard of to see things like 3D printers converted to CNC machines or CNC machines turned into 3D printers. The standards used are very well-known and adopted, so there’s almost no reason not to have a CNC machine of some sort lying around in a shop or hackerspace. There are even some art-based machines like this one that go much further beyond CNC itself, too.

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CNC Machine Boasts Big Bed, Impressive Power from Off-the-Shelf Parts

A lot of homebrew CNC machines end up being glorified plotters with a router attached that are good for little more than milling soft materials like wood and plastic. So if you have a burning need to mill harder materials like aluminum and mild steel quickly and quietly, set your sights higher and build a large bed CNC machine with off-the-shelf components.

With a budget of 2000 €, [SörenS7] was not as constrained as a lot of the lower end CNC builds we’ve seen, which almost always rely on 3D-printed parts or even materials sourced from the trash can. And while we certainly applaud every CNC build, this one shows that affordable and easily sourced mechatronics can result in a bolt-up build of considerable capability. [SörenS7]’s BOM for this machine is 100% catalog shopping, from the aluminum extrusion bed and gantry to the linear bearings and recirculating-ball lead screws. The working area is a generous 900 x 400 x 120mm, the steppers are beefy NEMA23s, and the spindle is a 3-kW VFD unit for plenty of power. The video below shows the machine’s impressive performance dry cutting aluminum.

All told, [SörenS7] came in 500 € under budget, which is a tempting price point for a machine this big and capable.

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Converting Parallel Port CNCs To USB

If you’re looking for a small, benchtop CNC machine for PCBs and light milling the ubiquitous Sherline CNC machine is a good choice. There’s a problem with it, though: normally, the Sherline CNC controller runs off the parallel port. While some of us still have a Windows 98 battlestation sitting around, [David] doesn’t. Instead, he built a USB dongle and wrote the software to turn this mini CNC into something usable with a modern computer.

First up, the hardware. The core of this build is the rt-stepper dongle based around the PIC18F2455 microcontroller. With a bare minimum of parts, this chip converts USB into a parallel port for real-time control. It’s fast — at least as fast as the parallel port in the ancient laptops we have sitting around and plugs right into the CNC controller box for the Sherline.

The software is where this really shines. the application used to control this dongle is a hack of the EMC/LinuxCNC project written in nice, portable Python. This application generates the step pulses, but the timing is maintained by the dongle; no real-time kernel needed.

There are a lot of choices out there for a desktop CNC machine made for routing copper clad board, wood, brass, and aluminum. The Othermill is great, and Inventables X-Carve and Carvey are more than up for the task. Still, for something small and relatively cheap, the Sherline is well-regarded, and with this little dongle you can actually use it with a modern computer. Check out the demo video below.

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