CNC Router Frame Repurposed For Colorful String Art Bot

December 11, 2020 by Dan Maloney 12 Comments

Pandemic lockdowns have been brutal, but they’ve had the side-effect of spurring creativity and undertaking projects that are involved enough and complex enough to keep from going stir crazy. This CNC string art robot is a great example of what’s possible with a little imagination and a lot of time. (Video, embedded below.)

According to [knezuld11], the robot creates its art through mathematical algorithms via a Python program that translates them into nail positions and string paths. The modified CNC router frame, constructed of laser-cut plywood, has two interchangeable tool heads. The first places the nails, which are held in a small hopper. After being picked up by a servo-controlled magnetic arm and held vertically, a gear-driven ram pushes each nail into a board at just the right coordinates. After changing to a different tool, the robot is able to pick up one of nine different thread dispensers. A laser sensor verifies the thread nozzle position, and the thread starts its long journey around the nails. It’s a little mesmerizing to watch, and the art looks great, with a vibe that brings us right back to the 70s. Groovy, man.

This reminds us a little of a recent [Barton Dring] project that makes art from overlapping strings. That one was pretty cool for what it accomplished with just one thread color, while this one really brings color to the party. Take your pick, place your nails, and get stringing.

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DIY Camera Motion Rig Is Mostly 3D Printed

November 24, 2020 by Lewin Day 7 Comments

These days, Youtube is more competitive than ever. Creators put out videos of wildly expensive, complex projects with equally pricy camera gear. [Do It Whenever?] wanted to join the arms race, building his own camera rig for smooth, swooping shots.

The rig consists of a series of 3D printed axes all joined together into a 6-axis motion rig. Additionally, actuators attached to the lens of the camera allow zoom and focus to be be controlled programmatically too. An Arduino runs the show, interpreting G-code and running the various axes, with a Raspberry Pi acting as a gateway to allow the rig to be commanded from PCs or smartphones.

Currently, control is largely manual, by entering G-code commands to move the rig in various ways. The rig can also have its motors temporarily disengaged by a button, allowing the camera to be aimed by hand, before holding the position. In this way, it acts as a highly versatile tripod. Future plans involve more automation if suitable open-source software can be found.

It’s an impressive rig, even if it hasn’t quite found the perfect software to fully exploit its capabilities yet. We’ve seen similar builds before, too. Video after the break.

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Cutting Balsa Wood With Air (Oh, And A Laser)

November 15, 2020 by Al Williams 34 Comments

[DIY3DTech] likes using his Ortur laser cutter for balsa wood and decided to add an air assist system to it. Some people told him it wasn’t worth the trouble, so in the video below, he compares the results of cutting both with and without the air assist.

The air assist helped clear the cut parts and reduced charring in the wood. The air system clears residue and fumes that can reduce the effectiveness of the laser. It can also reduce the risk of the workpiece catching on fire.

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Rotary Plotter Draws On Bottles

November 11, 2020 by Lewin Day 10 Comments

A pen plotter is often the first experience many ambitious makers have of the world of Computer Numerical Control, or CNC. While they typically operate on flat stock, with the right build, they can be designed to draw on curved surfaces, too – as [tuenhidiy] demonstrates with this rotary bottle plotter.

The plotter uses shafts salvaged from an old printer to act as the rollers for the bottle to be drawn upon, turned by a pair of stepper motors. X and Z axes are created out of two CD drive mechanisms – a popular way to build two linear axes on the cheap. The hardware is controlled by GRBL, running on an Arduino Uno kitted out with a CNC shield to handle the necessary I/O.

The build is somewhat limited to by the short range of its X axis, which prevents the plotter from easily drawing on a full-size bottle label or can. However, this could easily be fixed with some upgrades and extra steppers if so desired. As a home build, it’s a great way to learn about the CNC techniques required to work with curved surfaces effectively. Video after the break.

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Teensy Controller For Powerful CNCs

November 11, 2020 by Adam Zeloof 42 Comments

It seems like every year, it gets a bit easier to build your own CNC. From the Enhanced Machine Controller (EMC) project of the early 1990s to Arduinos running Grbl in the late 2000s, the open source community has moved ahead in leaps and bounds. Grbl is at its core firmware that interprets G-code and commands stepper motors, usually to move a tool head in such a way as to make something. Tons of systems have been built around it, including early Makerbot printers.

Its also spawned a plethora of other projects (the Grbl GitHib repo has 2,400 forks!), including a 32-bit flavor called grblHAL. This version is at the heart of a fantastic CNC controller board developed by [Phill Barrett]. Ditching the Arduino for a more powerful Teensy 4.1, [Phil]’s controller supports full five-axis control, variable frequency drive spindles, dust extractor control, and flood and mist coolant control. It can run at blazing stepping rates of up to 160 kHz (standard Grbl on an Arduino hits 30 kHz) and can be assembled with either a USB or Ethernet interface.

There’s no shortage of interesting Grbl-based machines out there — including a revamped Atari plotter and a three-axis rotary CNC (shameless plug for the author’s own project) but it’s always exciting to see new hardware developed that will undoubtedly find its way into the next generation of a family of projects. We can’t wait to see what comes next!

Five-Axis Pumpkin Carving

October 29, 2020 by Danie Conradie 21 Comments

The day of carved pumpkins is near, and instead of doing manually like a mere mortal, [Shane] of [Stuff Made Here] built a five-axis CNC machine to take over carving duties. (Video, embedded below.)

[Shane] initially intended to modify his barber robot, but ended up with a complete redesign, reusing only the electronics and the large ring bearing in the base. The swiveling spindle is a rotating gantry with two sets of aluminum extrusions for vertical and horizontal motion. The gantry isn’t very rigid, but it’s good enough for pumpkin carving. Software is the most challenging part of the endeavor due to the complexity of five-axis motion and mapping 2D images onto a roughly spherical surface. Cartographers have dealt with this for a long time, so [Shane] turned to Mercator projection to solve the problem. We’re also relieved to hear that we aren’t the only ones who sometimes struggle with equation-heavy Wikipedia pages.

Since there are no perfectly spherical pumpkins, [Shane] wrote a script to probe the surface of the pumpkin with a microswitch before cutting, appropriately named “TSA.exe”. The machine is capable of carving both profiles and variable depth lithophanes, mostly of [Shane]’s long-suffering wife. She seriously deserves an award for holding onto her sense of humor.

With projects like explosive baseball bats and CNC basketball hoop, the [Stuff Made Here] YouTube Channel is worth keeping an eye on.

Simple Induction Heater Helps With Homebrew Shrink-Fitting

October 26, 2020 by Dan Maloney 14 Comments

Machinists have a lot of neat shop tricks, but one especially interesting one is shrink-fitting tools. Shrink-fitting achieves an interference fit between tool and holder by creating a temperature difference between the two before assembly. Once everything returns to temperature, the two parts may as well be welded together.

The easiest way to shrink-fit machine tooling is with induction heating, and commercial rigs exist for doing the job. But [Roetz 4.0] decided to build his own shrink-fitting heater, and the results are pretty impressive. The induction heater itself is very simple — a 48 volt, 20 amp power supply, an off-the-shelf zero-voltage switching (ZVS) driver, and a heavy copper coil. When the coil is powered up, any metal within is quickly and evenly heated by virtue of the strong magnetic flux in the coil.

To use the shrinker, [Roetz 4.0] starts with a scrupulously clean tool holder, bored slightly undersized for the desired tool. Inside the coil, the steel tool holder quickly heats to a lovely deep brown color, meaning it has gotten up to the requisite 250-300°C. The tool is quickly dropped into the now-expanded bore, which quickly shrinks back around it. The advantage of this method over a collet or a chuck is clear in the video below: practically zero runout, and the tool is easily released after another run through the heater.

You say you’ve got no need for shrink-fitting tools? How about stuck bolts? Induction heaters work great there too.

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