Make An Impression At The Bar With A CNC Coaster Plotter

If you’re anything like us, your success with the opposite sex at the bar wasn’t much to brag about. But imagine if you had only had this compact CNC polar plotter and could have whipped up a few custom coasters for your intended’s drink. Yeah, that definitely would have helped.

Or not, but at least it would have been fun to play with. This is actually an improved version of [bdring]’s original “Polar Coaster”. Version 2 is really just a more compact and robust version of the original. The new one has a custom controller for the steppers and pen-lift servo, and everything is mounted neatly to the main PCB. Where the original used a timing belt to drive the platter, the new one uses 3D-printed helical gears, and the steppers have been replaced by slimmer motors. It even has an SD card and smartphone UI, and the coasters look pretty good.

There’s no video of the new one, but you can see its predecessor in action below and imagine the possibilities. Snap a picture and have a line art rendition of someone plotted while you’re waiting for drinks? Just remember not to take any laser engraved wooden nickels.

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Achieving Zen The Arduino Way

The purpose of a Zen garden, those stylized landscapes created by painstakingly placing rocks and raking gravel into perfect patterns, is the doing of the thing. Making sure every line is perfectly formed is no mean feat, and the concentration required to master it is the point of the whole thing. But who has time for that? Why not just build a robot to create the perfect Zen garden in miniature?

That was what [Tim Callinan] and his classmates did for a semester project, and the “ZenXY” sand plotter was the result. There isn’t a build log for the device per se, although the video below makes it plain how they went about this. The sand table itself is a plywood box whose bottom is layered with fine white sand and contains a single steel ball. Below the table is an X-Y gantry carrying a powerful magnet. A gShield riding on top of an Uno turns G code into slow, stately movement of the ball through the sand. The patterns are remarkably intricate, and while it might not be the same as mastering the body control needed to rake gravel with precision, watching the ball push the sand around is pretty Zen all by itself

This isn’t the first time we’ve seen someone try to automate a traditional Japanese practice. This tea ceremony robot comes to mind, and this nicely crafted sand table is very similar to the ZenXY.

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Manual 3D Digitizer Works A Bit Like 3-Dimensional Measuring Tape

Digitizing an object usually means firing up a CAD program and keeping the calipers handy, or using a 3D scanner to create a point cloud representing an object’s surfaces. [Dzl] took an entirely different approach with his DIY manual 3D digitizer, a laser-cut and 3D printed assembly that uses rotary encoders to create a turntable with an articulated “probe arm” attached.

Each joint of the arm is also an encoder, and by reading the encoder values and applying a bit of trigonometry, the relative position of the arm’s tip can be known at all times. Manually moving the tip of the arm from point to point on an object therefore creates measurements of that object. [Dzl] successfully created a prototype to test the idea, and the project files are available on GitHub.

We remember the earlier version of this project and it’s great to see how it’s been updated with improvements like the addition of a turntable with an encoder. DIY 3D digitizing takes all kinds of approaches, and one example was this unit that used four Raspberry Pi Zeros and four cameras to generate high quality 3D scans.

Advent Calendar – ‘Tis The CNSeason

CNC machines are powerful tools when used correctly, but it’s often necessary to test a new machine before getting into serious production work. This advent calendar is a great festive project that was designed to put a CNC through its paces.

The calendar is made primarily from wood. This is an excellent choice for test machining projects, as it is softer and less likely to cause tool or machine damage when compared to steel or aluminum. The calendar base was first milled out using end mills, while a 30-degree V-bit was used to engrave the days of the week. Brass brazing rod was then used to create hangers for the calendar tags.

Thanks to the clever use of chalkboard paint and removable tags, the calendar can be reconfigured to work for any given year and month combination — just in case you wish to have an advent calendar year round. Overall, it’s a good low-intensity machining project that would also be a fun craft project for kids.

As it’s that time of year, you might like this blinky advent calendar, too. Video after the break.

[Thanks to Michael for the tip!]

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The Complete Beginner’s Guide To Building A CNC Machine

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

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”

CNC Machine Most Satisfyingly Mills Double-Sided PCBs

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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