Omni Wheels Move This CNC Plotter

March 12, 2019 by Dan Maloney 12 Comments

We’ve always had a soft spot for omni wheels and the bots that move around somewhat bumpily on them. Likewise, CNC pen plotters are always a welcome sight in our tip line. But a CNC plotter using omni wheels is new, and the results are surprisingly good.

Built from the bottom of a spring-form baking pan, [lingib]’s plotter is simplicity itself. Four steppers turn the omni wheels while a hobby servo raises and lowers the pen. The controller is an Uno with a Bluetooth module for smartphone control. Translating wheel rotations into X- and Y-axis motions was not exactly trivial, and the video below shows the results. Lines are a bit wobbly, and it’s clear that the plotter isn’t hitting the coordinates very precisely. But given the somewhat compliant nature of the omni wheels, we’re surprised [lingib] got results as good as these, and we applaud the effort.

[lingib] reports the most expensive part of this $100 build was the omni wheels themselves. We suppose laser-cut MDF omni wheels could reduce the price, or even Mecanum wheels from bent metal and wood. We’re not sure either will help with the precision, though.

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Painting With Light And A Little G-Code

March 11, 2019 by Dan Maloney 9 Comments

Most photographs are made in the fraction of a second that the camera’s shutter is gathering reflected light from the scene. But there’s fun to be had by leaving the shutter open and directing light into the camera. Called light painting, it can be as simple as a camera on a tripod in a dark room and a penlight spelling out dirty words – not like we’d know – or as complicated as this CNC dot-matrix light printer.

The first idea that [Jeremy S. Cook] had for this build didn’t go so well. He fitted an LED to the gantry of his 3D-printer, intending to send it G-code representing bitmaps. The idea would be to set it up in a dark place, open the shutter, and let the machine build up the image by rastering through the X- and Y- axes while blinking the LED on and off at the right time. But since the gantry only moves in one axis, he abandoned the printer in favor of his CNC router. He printed a collar to fit the dust collector shroud we previously featured, added a battery-powered LED, and affixed a pushbutton switch to the let the Z-axis turn on the light. It took some tweaking such as adding a translucent PLA diffuser, to get decent images, but in the end it worked. We like the soft look of the floating voxels, which were really helped by the later addition of a Nano and a Neopixel. Check out the build in the video below.

One thing we’d suggest is better reflection control. [Jeremy] used a black platen as a background, but it wasn’t quite enough. We suggest going none more black next time.

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Creating Lenses On Cheap CNC Machines

March 8, 2019 by Brian Benchoff 48 Comments

There are a lot of CNC machines sitting around in basements and garages, but we haven’t seen anything like this. It’s making lenses using a standard CNC machine and a lot of elbow grease.

The process of making a lens with a CNC machine begins by surfacing a waste board and taping an 8mm sheet of cast acrylic down with double-stick tape. The lens is then cut out with an 8mm endmill, removed from the stock material, and wet sanded to remove the tool marks. Wet sanding begins at 400 grit and progresses to 2000 grit, after which the lens is polished with a polishing compound meant for high-gloss car finishes. This was done by hand, but in this instance there’s no shame in using a real buffing wheel.

Several other lenses are demonstrated, including a cylindrical convex lens, but these are only planoconvex lenses, or lenses that are flat on one side. Biconvex lenses can be constructed by gluing two planoconvex lenses back to back, which is done with an acrylic glue, in this case Acrifix adhesive. The result is remarkable: with a lot — and we mean a lot — of sanding and polishing, you can make an acrylic lens on a cheap hobby CNC machine. The trick is just a very small stepover on your CNC path.

There are a few more videos planned in this series, including one on using Fusion 360 on defining the shape of the lens to have the right focal length. We can’t wait to see that.

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CNC Your Own PCB With This Tutorial

March 3, 2019 by Al Williams 26 Comments

It is getting so easy to order a finished printed circuit board that it is tough to justify building your own. But sometimes you really need a board right now. Or maybe you need a lot of fast iterations so you can’t wait for the postal service. [Thomas Sanladerer] shows how he makes PCBs with a CNC machine and has a lot of good advice in the video below.

He starts with Eagle, although, you could use any creation package. He shows what parameters he changes to make sure the traces don’t get eaten away and how to do the CAM job to get the files required to make the boards. If you don’t use Eagle, you’ll need to infer how to do similar changes and get the same kind of output.

We’ve only heard a few people pronounce Gerber (as in Gerber file) with a soft G sound, but we still knew what he meant. We have the same problem with GIF files. However, once you have Gebers, you can join the video’s workflow about 5 minutes in.

At that point, he uses FlatCAM to convert the Gerbers to a single G-code file that integrates the paths and drill files. There were a few tricks he used to make sure all the tracks are picked up. Other tricks include leveling a spoil board by just milling it down and mounting different size bits. He also has ideas on aligning the Z axis.

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Polar Platform Spins Out Intricate String Art Portraits

February 23, 2019 by Dan Maloney 14 Comments

We have semi-fond memories of string art from our grade school art class days. We recall liking the part where we all banged nails into a board, but that bit with wrapping the thread around the nails got a bit tedious. This CNC string art machine elevates the art form far above the grammar school level without all the tedium.

Inspired by a string art maker we recently feature, [Bart Dring] decided to tackle the problem without using an industrial robot to dispense the thread. Using design elements from his recent coaster-creating polar plotter, he built a large, rotating platform flanked by a thread handling mechanism. The platform rotates the circular “canvas” for the portrait, ringed with closely spaced nails, following G-code generated offline. A combination of in and out motion of the arm and slight rotation of the platform wraps the thread around each nail, while rotating the platform pays the thread out to the next nail. Angled nails cause the thread to find its own level naturally, so no Z-axis is needed. The video below shows a brief glimpse of an additional tool that seems to coax the threads down, too. Mercifully, [Bart] included a second fixture to drill the hundreds of angled holes needed; the nails appear to be inserted manually, but we can think of a few fixes for that.

We really like this machine, both in terms of [Bart]’s usual high build-quality standards and for the unique art it creates. He mentions several upgrades before he releases the build files, but we think it’s pretty amazing as is.

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Honda Key Fob Turned CNC Work Of Art

February 19, 2019 by Tom Nardi 16 Comments

Now that nearly every car on the road comes with an electronic key fob, people are desperate to find ways to repair these indispensable little gadgets without coughing up potentially hundreds of dollars at the dealership. There’s a whole market for replacement shells which you can transplant your (hopefully) still functional electronics into, but if you’re going to go through the trouble of putting the electronics into a new case, why not make it special?

That’s what [Michicanery] was thinking when he decided to build his own custom key fob. The end result is an utterly magnificent feat of engineering that’s sure to be a conversation for the life of the vehicle, if not beyond. Made of wood and aluminum cut on his OpenBuilds Lead CNC 1010, this build just might inspire you to “accidentally” drop your existing fob from a great height. Oh no, what a shame.

[Michicanery] starts by disassembling his original fob, which is the type that has a key integrated directly into the device. This meant his replacement would need a bit more thought put into it than a separate stand-alone fob, but at least it wasn’t one of the ones where you have to stick the whole thing into the dashboard. To make sure the build was strong enough to survive a lifetime of being turned in the ignition and generally fiddled with, he cut the central frame and buttons out of 1/4″ thick aluminum.

The top and bottom of the fob were then cut from Chechen wood and then chamfered on a table router so it felt a bit better in the hand. He applied oil to the pieces to bring out the natural color and grain of the wood, but not before engraving his own logo onto the back of the case for that extra touch of personalization. Not that we think [Michicanery] is going to have trouble identifying his keys from this point on.

Like the incredible watch cases we’ve seen recently, this is a perfect example of an everyday object getting a new lease on life as a bespoke creation thanks to a custom built enclosure. Granted we’re not sure Honda key fobs have quite the heirloom potential of a good watch, but we’d still prefer it over the black plastic original.

[via /r/DIY]

CNC Tellurion Lets You See The Earth And Moon Dance

February 16, 2019 by Dan Maloney 11 Comments

Kids – they’re such a treasure. One minute you’re having a nice chat, the next minutes they’re testing your knowledge of the natural world with a question like, “Why can we see the Moon during the day?” And before you know it, you’re building a CNC Earth-Moon orbital model.

We’ve got to applaud [sniderj]’s commitment to answering his grandson’s innocent question. What could perhaps have been demonstrated adequately with a couple of balls and a flashlight instead became an intricate tellurion that can be easily driven to show the relative position of the Earth and Moon at any date; kudos for anticipating the inevitable, “Where was the moon when I was born, Grampa?” question. The mechanism is based on the guts of a defunct 3D-printer, with the X-, Y-, and Z-axis steppers now controlling the Earth’s rotation and tilt and the Moon’s orbit respectively, with the former extruder drive controlling the tilt of the Moon’s orbital plane. A complex planetary gear train with herringbone gears, as well as a crossed-shaft helical gear set, were 3D-printed from PLA. The Earth model is a simple globe and the Moon is a ping-pong ball; [sniderj] is thinking about replacing the Moon with a 3D-printed bump-map model, a move which we strongly endorse. The video below shows the tellurion going through a couple of hundred years of the saros at warp speed.

There’s just something about machines that show the music of the spheres, whether they be ancient or more modern. And this one would be a great entry into our 3D-Printed Gears, Pulleys, and Cams contest too.

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