DIY CNC Router Uses Chains The Right Way

November 19, 2019 by Lewin Day 28 Comments

There are a million and one ways to build your own CNC router, depending on your tastes, budget, and application, your design choices will differ accordingly. [Steve Tyng] was well aware of this when undertaking his project, and built the machine that made sense for him.

[Steve’s] build has a strong focus on keeping costs down, and that’s reflected in the hardware used. Wanting a large work area of 30″ x 60″, off-the-shelf linear rails in 6 foot lengths were prohibitively expensive. Instead, 1″ angle iron was sourced from the local garden centre, and used in conjunction with steel v-bearings. It’s a lot cheaper, and good enough for the application at hand, so why not? Other smart choices abound, such as using an IKEA cabinet as the base, and a fanless computer to run the show to avoid death by dust.

When it came time to build the axes, there was plenty of roller chain on hand. Chain is usually passed up for options such as timing belts or ballscrews in the CNC community, as it tends to stretch over time and offers poor accuracy. However, [Steve] took stock of the drawbacks of the method, and made efforts to overcome these weak points in the design. The Y and X axes were specially designed to keep the chain supported along its length. This helped avoid the problem of long drooping chains and poor tension.

While it’s not an industrial-strength build with world-beating accuracy, it’s a solid CNC machine that can carve out large workpieces without issue. Over the years, we’ve seen plenty of DIY CNCs, built with everything from PVC pipe to welded steel. Video after the break.

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Core XY Explained

November 12, 2019 by Al Williams 28 Comments

If you are building a CNC machine, a 3D printer, or even a plotter, you have a need for motion in both the X and Y directions. There are many ways to accomplish this, for example, some printers move the tool in the X direction and the bed in the Y direction while others move the entire X carriage in the Y direction and yet more use a delta mechanism. However, one of the oldest means of doing this is the Core XY method. It is interesting because both motors remain stationary and the business end moves entirely on belts or cords. This is similar to the H-Bot technique, but with some differences. [Michael Laws] has a video (see below) that explains how two stationary motors can move a tool anywhere in an XY region.

The idea behind Core XY goes back to at least old drafting tables. You can think of it as an object held by two ends of the same belt. As one end of the belt gets shorter the other end gets longer. The belts are arranged so that motion of one motor causes the tool to move at a 45 degree angle. That means you have to move both motors to go in a straight line.

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High-Precision Air Bearing CNC Lathe And Grinder

October 31, 2019 by Maya Posch 27 Comments

You know you’re in for a treat when you are told that a lathe which can reach a resolution of one micrometer (1×10⁻⁶, a millionth of a meter, or 0.00004″ for people who love zeros) is ‘not hard to build’. This is one of the opening statements in this video by [Dan Gelbart], as he walks the viewer through the details of a custom CNC lathe which he built. (Video embedded below.)

As it’s a combined CNC lathe and grinder, it uses custom software he had developed specifically for the machine. Much of the high precision of the machine is courtesy of air bearings. All but two of the air bearings were made by [Dan], with the two surplus air bearings he used coming from machines used in the semiconductor industry.

The bed of the machine is formed out of off-the-shelf reference granite, to which the other parts are epoxied, providing a stable base with well-defined dimensions. Though perhaps a few light years beyond most DIY lathe efforts, [Dan]’s videos nevertheless provide a treasure trove of tips and information for lathe builders and users alike. Certainly worth a look.

Thanks [Drew] for the tip in the comments.
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Retro Hardware Plots Again Thanks To Grbl And ESP32

October 24, 2019 by Dan Maloney 11 Comments

When it comes to building a new CNC machine, you’ve got a wide world of controller boards to choose from. Whether you’re building a 3D-printer or a CNC plasma cutter, chances are good you’ll find a controller that fits your needs and your budget. Not so much, though, when you want to add CNC to a pen plotter from the early days of the PC revolution.

[Barton Dring] just posted the last installment of a five-part series in which he documented putting an Atari 1020 plotter under CNC control. The plotter was a peripheral for the Atari line of 6502 machines from the late 1970s; the guts of the little roll-fed, ballpoint-pen plotter appeared in Commodore, Tandy, and TI versions as well. [Bart]’s goal was to not add or modify anything to the mechanically simple device apart from the controller. That was easier said than done, given the unipolar stepper motors controlling the pen position and paper roll, and the fact that the pen lift mechanism uses a solenoid. Support for those had to be added to his Grbl_ESP32 firmware, as did dealing with the lack of homing switches in the plotter, and adapting the Grbl tool change command to the pen color change mechanism, which rotates the pen holder by bumping it into the right-hand carriage stop. The stock controller was replaced by a custom PCB that fits perfectly within the case, with plenty of room to spare. The video below shows it plotting out a vexillogically relevant sample.

From custom coasters to wooden nickels to complex string art, [Bart] has really put Grbl through the wringer. We really like this retro-redo, though, and fully support his stated desire to convert more old hardware to Grbl_ESP32.

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Larger-Than-Life Game Of Operation Is The Future Of Healthcare

September 21, 2019 by Mike Szczys 13 Comments

It’s hard to beat the warm memories of Hasbro’s Operation, a game that boils down the fine art of surgery to removing farcically named plastic bones and organs. Just in case you can’t conjure up the memory, the game board looks just like this huge version of it, but normally sits flat on the table and is no larger than… well, a board game. Players take turns using a tethered tweezer to remove butterflies from your stomach without touching the metal sides of the incision area. If the tweezers touch the metal, a buzzer goes off and the player loses a turn.

Of course, we now live in the future and robots do our difficult surgeries while the talented doctor looks on from a video console. So, [Ben] and [Jonathan] built themselves an oversized upright version of the game that includes a CNC-wielding surgery robot.

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Delightfully, the controls are designed like a coin-op arcade machine and the three-axis CNC machine they’ve built is a new take on the claw machine. It has a gantry that moves left and right, a head that moves up and down along that gantry rail, and an actuator that moves in to snatch those pesky organs. Limit switches cut the power to the motors if the axis moves too far.

Pieces are foam and hang from a coat-hanger hook

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In true robosurgery fashion, there’s a webcam that goes along for the ride to give the surgeon a close-up look. Just stay away from those edges! There’s a button on the tip of the actuator that sets off the alarm if you miss the hole and hit the surface of the board, thereby ending your turn. Each organ is made of foam, faced with a piece of sheet metal, and hung from a hook made of coat hanger wire. That sheet metal allows the gripper to use an electromagnet to pick each piece up.

The project is called Sergio and you can see it demonstrated in the video below. We first met these hackers last fall at Maker Faire New York when they were showing off a giant Connect Four game where you play against the computer. It’s nice to hear they’ll be exhibiting Sergio at Philadelphia Maker Faire two weeks from now.

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Hackaday Podcast 036: Camera Rig Makes CNC Jealous, Become Your Own Time Transmitter, Pi HiFi With 80s Vibe, DJ Xiaomi

September 20, 2019 by Mike Szczys 5 Comments

Hackaday Editors Elliot Williams and Mike Szczys work their way through a fantastic week of hacks. From a rideable tank tread to spoofing radio time servers and from tune-playing vacuum cleaners to an epic camera motion control system, there’s a lot to get caught up on. Plus, Elliot describes frequency counting while Mike’s head spins, and we geek out on satellite optics, transistor-based Pong, and Jonathan Bennett’s weekly security articles.

Take a look at the links below if you want to follow along, and as always tell us what you think about this episode in the comments!

Take a look at the links below if you want to follow along, and as always, tell us what you think about this episode in the comments!

Direct download (60 MB or so.)

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A Masterpiece, But Our Maestro Is A CNC Machine

September 13, 2019 by Jenny List 12 Comments

Sometimes we manage to miss projects when they first appear, only to have the joy of discovering them a while later. So it is with [John Opsahl]’s Project Convert To Paint, a CNC painting ‘bot that takes a bitmap image and paints it on canvas as a fine artist would, with a real brush, and paints.

It was first created for the 2017 robotart.org competition, and takes the form of a fairly standard CNC gantry machine. It departs from the norm in its chuck however, as it has what is described as a universal artist chuck, capable of holding a variety of artistic implements. The images are converted from bitmap to vector format, and thence to gcode with the help of a bit of custom Python code.

He’s at pains to say that simply because an image can be converted to a paintable format does not mean that it will produce a good picture. But some of the results are rather impressive, delivering anything from a pointilist effect to a broader brush stroke. We can see that with a bit of experience in the processing it would be possible to create a veritable gallery of masterpieces.

We may have missed this one the first time, but we did catch another drawbot from the same competition.