[Christian] wrote and sells some CAM/CNC controller software. We’re kinda sticklers for open source, and this software doesn’t seem to be, so “meh”. But what we do like is the Easter egg that comes included: the paths to mill out the base for a clock, and then the codes to move steel ball-bearings around to display the time.
Of course we’d like to see more info (more, MORE, MOAR!) but it looks easy enough to recreate. We could see redesigning this with marbles and a vacuum system, for instance. The seats for the ball bearings don’t even need to be milled out spheres. You could do this part with a drill press. Who’s going to rebuild this for their 3D printer? You just have to make sure that the machine is fast enough to move the balls around within one minute.
[Oscar] wonders why hobby projects ignore all the powerful brushless motors available for far less than the equivalent stepper motors, especially with advanced techniques available to overcome their deficiencies. He decided it must be because there is simply not a good, cheap, open source motor controller out there to drive them precisely. So, he made one.
Stepper motors are good for what they do, open-loop positioning along a grid, but as far as industrial motors go they’re really not the best technology available. Steppers win on the cost curve for being uncomplicated to manufacture and easy to control, but when it comes to higher-end automation it’s servo control all the way. The motors are more powerful and the closed-loop control can be more precise, but they require more control logic. [Oscar]’s board is designed to fill in this gap and take full advantage of this motor control technology.
The board can do some pretty impressive things for something with a price goal under $50 US dollars. It supports two motors at 24 volts with up to 150 amps peak current. It can take an encoder input for full closed loop control. It supports battery regeneration for braking. You can even augment a more modest power supply to allow for the occasional 1 KW peak movement with the addition of a lithium battery. You can see the board showing off some of its features in the video after the break.
At first glance, [Frank Howarth]’s turned bamboo Death Star seems like a straight woodworking project. No Arduino controlled lights, no Raspberry Pi for audio clips of an X-wing attack or escaping TIE fighter. In other words: where’s the hack?
It’s a freaking bamboo Death Star!
If that’s not enough for you, check out the pattern on the surface of the finished model. That’s not painted on – those are the layers of the laminated bamboo lumber used to create the rings [Frank] used to form the structure. After lots of turning, sanding and polishing, the characteristic vascular bundles of the bamboo create light and dark panels for a convincing effect of the Death Star’s surface detail. And although we like the natural finish, we can imagine a darker stain might have really made the details pop and made for an effect closer to the original.
Still not hackish enough? Then feast your eyes on [Frank]’s shop. It’s a cavernous space with high ceilings, tons of natural light, and seemingly every woodworking machine known to man. While the lathe and tablesaw do a lot of the work for this build, the drool-worthy CNC router sees important duty in the creation of the multiple jigs needed for the build, and for making the cutout for the superlaser, in what must have been a tense moment.
Bamboo is an incredible material, whether for fun builds like this or for more structural uses, like a bamboo bike. All this bamboo goodness puts us in the mood to call on [Gerrit Coetzee] for a new installment on his “Materials You Should Know” series.
[Martin Raynsford] wrote a program that converts a black-and-white 2D image to G-code so that his laser printer could then etch the image. Not satisfied with just that, he used his laser printer to make a scanner that consists of a stand for his webcam and a tray below it for positioning the paper just right. The result was something he took to a recent Maker Faire where many kids drew pictures on paper which his system then scanned and laser etched.
[Martin’s] program, written in C#, does the work of taking the image from the webcam using OpenGL and scanning it line by line looking for pixels that surpass a contrast threshold. For each suitable pixel the program then produces G-code that moves the laser to the corresponding coordinate and burns a hole. Looking at the source code (downloadable from his webpage) it’s clear from commented-out code that he did plenty of experimenting, including varying the laser burn time based on the pixel’s brightness.
While it’s a lot of fun writing this code as [Martin] did, after the break we talk about some off-the-shelf ways of accomplishing the same thing.
Epoxy granite is an overlooked material when it comes to making home CNC builds. As far as time and money goes, when you add in all the equipment it comes out cheaper than an aluminum casting set-up. Epoxy granite has mechanical properties better than cast iron, increased dimensional stability, better vibration damping, and looks awesome when done right. Also, you can cast precision surfaces and threaded holes into your design, which is pretty cool.
In these two videos by [Jørgen Hegner] we get to watch him and a friend make a matching set of precision CNC machines. It’s built in a similar style to other nice builds we’ve featured. This way of making it needs a bigger footprint than a gantry mill and can’t be built as large. However, it solves a lot of mechanical issues and squaring with the gantry design while not being as difficult to get right as a box or knee mill.
After casting they machined the material embedded in the granite to mount the ways. The ways are linear bearings and ball screws. Expensive, but as the footage shows, very accurate. The rest of the machine is assembled and tuned. Then it gets installed in a home made 80/20 enclosure. We really like the LCD panel that’s incorporated into the front shield of the machine. They really went all out with the CNC control panel. It looks like they can do anything from jog the axis to monitor and control the water cooling for the spindle.
It appears that all the precision work is put to good use as there are some shots at the end of video two of a beautiful clock CNC’d on this machine. Videos after the break.
When we create a printed circuit board, the chances are these days that we’ll export it through our CAD package’s CAM tool, and send the resulting files to an inexpensive PCB fabrication house. A marvel of the modern age, bringing together computerised manufacturing, the Internet, and globalised trade to do something that would have been impossible only a few years ago without significant expenditure.
Those files we send off to China or wherever our boards are produced are called Gerber files. It’s a word that has become part of the currency of our art, “I’ll send them the Gerbers” trips off the tongue without our considering the word’s origin.
This morning we’re indebted to [drudrudru] for sending us a link to an EDN article that lifts the lid on who Gerber files are named for. [H. Joseph Gerber] was a prolific inventor whose work laid the ground for the CNC machines that provide us as hackers and makers with so many of the tools we take for granted. Just think: without his work we might not have our CNC routers, 3D printers, vinyl cutters and much more, and as for PCBs, we’d still be fiddling about with crêpe paper tape and acetate.
An Austrian Holocaust survivor who escaped to the USA in 1940, [Gerber] began his business with an elastic variable scale for performing numerical conversions that he patented while still an engineering student. The story goes that he used the elastic cord from his pyjamas to create the prototype. This was followed by an ever-more-sophisticated range of drafting, plotting, and digitizing tools, which led naturally into the then-emerging CNC field. It is probably safe to say that in the succeeding decades there has not been an area of manufacturing that has not been touched by his work.
So take a look at the article, read [Gerber]’s company history page, his Wikipedia page, raise a toast to the memory of a great engineer, and never, ever, spell “Gerber file” with a lower-case G.
Last November, after [HomoFaciens]’ garbage-can CNC build, we laid down the gauntlet – build a working CNC from cardboard and paperclips. And now, not only does OP deliver with a working CNC plotter, he also plans to develop it into a self-replicating machine.
To be honest, we made the challenge with tongue firmly planted in cheek. After all, how could corrugated cardboard ever make a sufficiently stiff structure for the frame of a CNC machine? [HomoFaciens] worked around this by using the much less compliant chipboard – probably closest to what we’d call matboard here in the States. His templates for the machine are extremely well thought-out; the main frame is a torsion box design, and the ways and slides are intricate affairs. Non-cardboard parts include threaded rod for the lead screws, servos modified for continuous rotation, an Arduino, and the aforementioned paperclips, which find use in the user interface, limit switches, and in the extremely clever encoders for each axis. The video below shows highlights of the build and the results.
True, the machine can only move a pen about, and the precision is nothing to brag about. But it works, and it’s perfectly capable of teaching all the basics of CNC builds to a beginner, which is a key design goal. And it’s well-positioned to move to the next level and become a machine that can replicate itself. We’ll be watching this one very closely.