Laser-Etching Photos On To Eggs

August 28, 2020 by Lewin Day 15 Comments

CNC machines are every maker’s dream. Capable of churning out accurate parts from CAD designs with a minimum of manual labor, they’re a great tool to have in the workshop. Alternatively, you can use them for more entertaining pursuits. [Leo]’s project is one of the latter – etching greyscale photos on to eggs.

The first thing you’ll need is an egg-compatible CNC machine. The Eggbot is a popular option, else a fourth-axis on an existing machine can also do the job as in [Leo]’s case. Coupling the egg is a delicate task, for which some rubber paper rollers are salvaged from an old printer and put to work. Then, a laser needs to be fitted to the CNC head, and the egg depth mapped with a probe to ensure the entire etching is in focus. Then it’s simply a matter of loading up an image, and turning the greyscale data into the relevant G-code to burn it onto the egg.

Using eggs coated in black ink, the results [Leo] achieves are impressive. The eggs would make an amusing Easter gift, or serve as a great cheap way to teach students about CNC techniques. Obviously, eye protection is a must, and be sure to mount your laser securely to avoid any unintentional exposures. Video after the break.

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Mini CNC Mill Goes Horizontal To Reuse CD Drives

August 25, 2020 by Dan Maloney 22 Comments

Here at Hackaday, we pride ourselves on bringing you the freshest of hacks, preferably as soon as we find out about them. Thanks to the sheer volume of cool hacks out there, though, we do miss one occasionally, like this e-waste horizontal CNC mill that we just found out about.

Aptly called the “CDCNC” thanks to its reliance on cast-off CD drive mechanisms for its running gear, [Paul McClay]’s creation is a great case study on what you can do without buying almost any new parts. It’s also an object lesson in not getting caught in standard design paradigms. Where most CNC mills mount the spindle vertically, [Paul] tilted the whole thing 90 degrees so the spindle lies on its side. Moving it back and forth on a pair of CD drive mechanisms is far easier than fighting gravity for control, and as a bonus the X- and Y-axes have minimal loading too. The video below shows the mill in action, and it’s easy to see how the horizontal arrangement really helps make this junk bin build into something special.

We think [Paul] did a great job of thinking around the problem with this build, and we’re glad he took the time to tip us off. Apparently it was the upcoming CNC on the Desktop Hack Chat that moved him to let us know about this build. Here’s hoping he drops by for the chat and shares his experience with us.

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The Mother(board) Of All CNC Controllers

July 17, 2020 by Dan Maloney 38 Comments

If you’re building a CNC machine from scratch, the number of decisions you have to make is nearly boundless. Metal or wood construction? Welded or bolted? Timing belts or lead screws? And even once the mechanical bits are sorted, you still face a universe of choices in terms of control electronics. That’s where something like this modular CNC controller could really prove to be a game-changer.

The idea behind [Barton Dring]’s latest creation started with his port of GRBL to the ESP32. In fact, the current controller bears a strong family resemblance to his version 1.0 dev board, with a few conspicuous and intriguing additions. First, everything is modular — the main PCB is basically a motherboard with little more than a 5-volt power supply and some housekeeping electronics, plus a lot of headers. There’s support for up to six channels of steppers, either directly on the board with Pololu-style modules or as external drivers using pluggable screw terminal blocks. There’s also room for five IO modules; the current collection of modules includes a four-channel switch input, a relay output, an RS-485 module and a 0-10-V interface for talking to a variable frequency drive (VFD) spindle controllers, and buffered 5-V output module. The best part is that the IO module spec is completely open, so designing custom modules should be a snap.

The video below gives a quick tour of the controller. We’re really impressed with the thought that went into this, and we’ll venture a guess that having something like this available is going to kickstart a lot of stalled CNC machine projects. We can think of one shop that finally lost its last excuse for making the move.

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Interactive CNC Foam Cutter Churns Out Abstract Art

July 11, 2020 by Adil Malik 3 Comments

Foam is certainly an indispensable raw material for various craft and construction projects. Any serious sculptor however, inevitably grows tired of grinding through a foam block using a simple preheated utensil. The next step up, is to assemble a simple but thoroughly effective hot wire cutting contraption, formed out of a thin guitar wire held taut on a “C” shaped mounting frame. Finally, the addition of some electronics to regulate the power delivery makes this simple tool useful for most settings.

[Freddie] has taken this basic idea a step further, by building a complete multi-axis CNC foam cutter intended as an interactive exhibit on computational art. The CNC has the traditional three Cartesian axes but the platform hosting the foam piece can also rotate, introducing an additional degree of freedom. As this is indented to be controlled by attendees, there is no G-code in the mix, rather the inputs of an Xbox controller are applied directly to the work piece.

What is very interesting is how the resulting tool path is visualised and displayed. [Freddie] explains that while the user input tool path could be generated and displayed as equivalent G-code, it does not capture and convey the inherent organic nature of the finished pieces. The solution [Freddie] came up with is to display the toolpath much like a series of musical notes!

We would have loved to have a go at this machine in person, but seeing that isn’t possible in the current circumstances, you can either build a simpler machine we featured earlier or [Freddie] could perhaps fire up a camera and let us control it via the interweb, with a live video feed ofcourse!

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Making PCBs The Easy Way

July 10, 2020 by Bryan Cockfield 50 Comments

Building a PCB at home can be fraught. If you’re etching, there are chemicals and the nuances of toner transfer. If you’re milling, getting the surface height just right, and not breaking those pointy little v-cutters is always a challenge. [Robin] has tips for both of these cases, and solves a lot of the common hassles by using a milling machine.

Whether he’s scraping away etch resist or entire copper isolation lines, [Robin] uses a non-spinning scratching tool instead of a v-bit: they’re more robust and cut every bit as well. He’s got tips for using FlatCam and KiCAD to make scratched-out traces. His registration system allows him to get double-sided boards with a minimum of hassle. And as a bonus, he’s doing some experimentation with embedding SMT parts inside the boards as well. Be sure that you check out his whole guide, or just watch the video embedded below.

We’re pretty sure you’ll pick up a trick or two, and maybe you’ll be convinced to bite the bullet and invest in a nice mill. If you’d like a more traditional take on PCB milling, try out our own [Adil Malik]’s guide.

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Turning A Waterjet Cutter Into A Wood Lathe, For No Reason

July 9, 2020 by Dan Maloney 30 Comments

On the shortlist of dream tools for most metalworkers is a waterjet cutter, a CNC tool that uses insanely high-pressure water mixed with abrasive grit to blast sheet metal into intricate shapes. On exactly nobody’s list is this attachment that turns a waterjet cutter into a lathe, and with good reason, as we’ll see.

This one comes to us by way of the Waterjet Channel, because of course there’s a channel dedicated to waterjet cutting. The idea is a riff on fixtures that allow a waterjet cutter (or a plasma cutter) to be used on tubes and other round stock. This fixture was thrown together from scrap and uses an electric drill to rotate a wood blank between centers on the bed of the waterjet, with the goal of carving a baseball bat by rotating the blank while the waterjet carves out the profile.

The first attempt, using an entirely inappropriate but easily cut blank of cedar, wasn’t great. The force of the water hitting the wood was enough to stall the drill; the remedy was to hog out as much material as possible from the blank before spinning up for the finish cut. That worked well enough to commit to an ash bat blank, which was much harder to cut but still worked well enough to make a decent bat.

Of course it makes zero sense to use a machine tool costing multiple hundreds of thousands of dollars to machine baseball bats, but it was a fun exercise. And it only shows how far we’ve come with lathes since the 18th-century frontier’s foot-powered version of the Queen of the Machine Shop.

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Milling Dies And Injection Moulding Some Acrylic Lenses

July 7, 2020 by Adil Malik 18 Comments

[Zach] over at his channel Breaking Taps has put up an extraordinary account on manufacturing some homemade acrylic lenses. In the end, not only does he produce some beautiful concave lenses, he also covers the complete manufacturing process, from milling the aluminium die used for injection moulding to tweaking the parameters associated with injecting the actual acrylic, he even goes over the limitations of optics produced in this fashion.

What caught our eye in particular, was how [Zach] used the finished product to practically demonstrate photoelasticity originating from the stress induced by the moulding process. You might be familiar with describing the optical properties of a material by a single number, i.e its permittivity. But what happens if in addition to altering speed, the material also alters the polarisation and direction of light depending on the stress distribution within the material? Whilst a quantitative answer gets a bit complicated you can check out [Zach’s] additional videos to visualise the answer in a pretty and colourful way, without resorting to fancy computer simulations! If however, you really want to persist with the simulation route, check out our article on stress analysis in a totally different setting using Finite Element Analysis.

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