The Complete Beginner’s Guide To Building A CNC Machine

December 5, 2018 by Dan Maloney 18 Comments

Despite appearances, [This Old Tony]’s latest series has little to do with CNC-ifying an Etch A Sketch. Although he certainly achieves that, more or less, automating the classic toy is just the hook for a thorough lesson in CNC machine building starting with the basics.

Fair warning: we said basics, and we mean it. [Old Tony]’s intended audience is those who haven’t made the leap into a CNC build yet and need the big picture. Part one concentrates on the hardware involved – the steppers, drivers, and controller. He starts with one of those all-in-one eBay packages, although he did upgrade the motion controller to a Mach4 compatible board; still, the lessons should apply to most hardware.

By the end of part one, the Etch A Sketch is connected to two of the steppers and everything is wired up and ready to go for part two, the first part of which is all about inputs and outputs. Again, this is basic stuff, like how relays work and why you might need to use them. But that’s the kind of stuff that can baffle beginners and turn them off to the hobby, so kudos to [Old Tony] for the overview. The bulk of the second part is about configuring Mach4 Hobby, with a ton of detail and some great tips and tricks for getting a machine ready to break some end mills.

For someone looking to get into a CNC build, [Old Tony]’s hard-won CNC experience really fills in the gaps left by other tutorials. And it looks like a third part, dealing with making all this into something more than an automated Etch A Sketch, is in the works. We’re looking forward to that.

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Replace Legacy CNC PCs With A Gerbil

December 4, 2018 by Bryan Cockfield 48 Comments

There are lots of laser cutters and other CNC machines available for a decent price online, but the major hurdle to getting these machines running won’t be the price or the parts. It’s usually the controller PC, which might be running Windows XP or NT if you’re lucky, but some of them are still using IBM XT computers from the ’80s. Even if the hardware in these machines is working, it might be impossible to get the software, and even then it will be dated and lacking features of modern computers. Enter the Super Gerbil.

[Paul] was able to find a laser cutter with one of these obsolete controllers, but figured there was a better way to getting it running again. As the name suggests, it uses GRBL, a G-Code parser and CNC controller software package that was originally made to run on an 8-bit AVR microcontroller, but [Paul] designed the Super Gerbil to run on a 32 bit ARM platform. He also added Z-axis control to it, so it now sports more degrees of freedom than the original software.

By way of a proof of concept, once he was finished building the Super Gerbil he ordered a CNC machine from China with an obsolete controller and was able to get it running within a day. As an added bonus, he made everything open so there are no license fees or cloud storage requirements if you want to use his controller. [Paul] also has a Kickstarter page for this project as well. Hopefully controllers haven’t been the only thing stopping you from getting a CNC machine for your lab, though, but if they have you now have a great solution for a 3040 or 3020 CNC machine’s controller, or any other CNC machine you might want to have. Continue reading “Replace Legacy CNC PCs With A Gerbil” →

Spring-Loaded Bed For K40 Laser Acts As An Auto-Focus

December 2, 2018 by Donald Papp 12 Comments

Laser engraving and cutting has something in common with focusing the sun’s rays with a magnifying glass: good focus is critical to results. If materials of varying thicknesses are used, focus needs to be re-set every time the material changes, and manual focusing quickly becomes a chore. [Scorch Works] has a clever solution to avoid constant re-focusing that doesn’t involve sensors or motors of any sort. The result is a self-adjusting bed that compensates for material height changes, ensuring that the top surface of the material is always a fixed distance from the laser’s head.

The way [Scorch Works] has done this is to make two spring-loaded clamps from angle aluminum and a few pieces of hardware. When a sheet of material is placed into the machine, the edges get tucked underneath the aluminum “lips” while being pushed upward from beneath. By fixing the height of the top layer of angle aluminum, any sheet stock always ends up the same distance from the laser head regardless of the material’s thickness.

[Scorch Works] shows the assembly in action in the video embedded below, along with a few different ways to accommodate different materials and special cases, so be sure to check it out.

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CNC Machine Most Satisfyingly Mills Double-Sided PCBs

December 2, 2018 by Dan Maloney 50 Comments

We know that by this point in the development of CNC technology, nothing should amaze us. We’ve seen CNC machines perform feats of precision that shouldn’t be possible, whether it be milling a complex jet engine turbine blade or just squirting out hot plastic. But you’ve just got to watch this PCB milling CNC machine go through its paces!

The machine is from an outfit called WEGSTR, based in the Czech Republic. While it appears to be optimized for PCB milling and drilling, the company also shows it milling metals, wood, plastic, and even glass. The first video below shows the machine milling 0.1 mm traces in FR4; the scale of the operation only becomes apparent when a gigantic toothbrush enters the frame to clear away a little swarf. As if that weren’t enough, the machine then cuts traces on the other side of the board; vias created by filling drilled holes with copper rivets and peening them over with a mandrel and a few light hammer taps connect the two sides.

Prefer your boards with solder resist and silkscreening? Not a problem, at least judging by the second video, which shows a finished board getting coated with UV-cure resist and then having the machine mill away just the resist on the solder pads. We’re not sure how they deal with variations in board thickness or warping, but they sure have it dialed in. Regardless of how they optimized the process, it’s a pleasure to watch.

At about $2,600, these are not cheap machines, but they may make sense for someone needing high-quality boards with rapid turnaround. And who’s to say a DIY machine couldn’t do as good a job? We’ve seen plenty of them before, and covered the pros and cons of etching versus milling too.

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Already Impressive CNC Router Gets An Extra Axis

November 25, 2018 by Dan Maloney 6 Comments

The type of CNC machine within the financial reach of most DIYers is generally a three-axis affair, with a modest work envelope and a spindle that never quite seems powerful enough. That’s not to say that we don’t covet such a machine for our own shop of course, but comparing small machines with the “big boy” five-axis tools might leave the home-gamer feeling a tad inadequate.

Luckily, there’s a fix that won’t necessarily break the bank: adding a fourth axis to your CNC router. [This Old Tony] tore into his CNC router – a build we’ve featured before and greatly admire – to add a machine spindle that lets him work with the machine much as if it was a CNC lathe. The first video below covers the mechanical part of the build, which involves welding and machining a sturdy assembly to hold a spindle connecting a four-jaw chuck to a Lexium MDrive, a stepper motor with integrated driver and feedback that makes it act more like a servo. [Old Tony] covered integrating the drive into Mach4 in a previous video.

The assembled machine spindle is a beefy looking affair that can smoothly ramp up to 3000 rpm and has decent enough holding torque to allow it to act as an indexing head in addition to a lathe. The second video below shows some tests turning aluminum and steel; we were surprised by how aggressive the cuts can be before stalling the spindle.

No, it’s not a Tormach or Haas or even a Pocket NC, but it’s a great addition to an already capable machine, and we’re looking forward to what [Old Tony] cranks out with it.

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Mug-O-Matic Plots On Coffee Mugs

November 25, 2018 by Al Williams 12 Comments

There is something fascinating about watching an autonomous machine. An automatic car wash, a soda vending machine that picks up the product behind a window, a plotter, or a robot like a CNC or 3D printer are all interesting to watch. Although [EngineerDog] bills Mug-O-Matic as a tiny CNC, we think it is more of a plotter for coffee mugs. It’s still fun to watch though, as you can see in the video below.

The design has about 60 printed parts and uses a Sharpie at the business end. It accepts gcode and can even emblazon your favorite mug with our own Jolly Wrencher, so you know we like it.

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CNC Embroidery Machine Punches Out Designs A Stitch At A Time

November 17, 2018 by Dan Maloney 19 Comments

It’s doubtful that the early pioneers of CNC would have been able to imagine the range of the applications the technology would be used for. Once limited to cutting metal, CNC machines can now lance through materials using lasers and high-pressure jets of water, squirt molten plastic to build up 3D objects, and apparently even use needle and thread to create embroidered designs.

It may not seem like a typical CNC application, but [James Kolme]’s CNC embroidery machine sure looks familiar. Sitting in front of one of the prettiest sewing machines we’ve ever seen is a fairly typical X-Y gantry system. The stepper-controlled gantry moves an embroidery hoop under the needle of the sewing machine, which is actually the Z-axis of the machine. With the material properly positioned, a NEMA 23 stepper attached to the sewing machine through a sprocket and drive chain makes a stitch, slowly building up a design. Translating an embroidery pattern to G-code is done through Inkstitch, and extension to Inkscape. [James]’ write-up is great, and the video below shows it in action.

We’ve seen a CNC embroidery machine or two before, but our conspicuously non-embroidered hat is off to [James] on this one for its build quality and documentation. And the embroidered Jolly Wrencher doesn’t hurt either.

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