Complex Wood Joints, Thanks To New Software’s Interactive Features

October 23, 2020 by Donald Papp 23 Comments

Artfully-crafted wooden joints that fit together like puzzle pieces and need neither glue nor nails is fascinating stuff, but to call the process of designing and manufacturing them by hand “time-consuming” would be an understatement. To change that, a research team from the University of Tokyo presented Tsugite, a software system for interactively designing and fabricating complex wooden joints. It’s named after the Japanese word for joinery, and aims to make the design and manufacture of glue and fastener-free joints much easier than it otherwise would be.

Three-way joint that requires no glue or fasteners.

~~It looks like the software is so far only a research project and not something that can be downloaded~~ The software is available on GitHub and the approach it takes is interesting. This downloadable PDF explains how the software deals with the problem of how to make such a task interactive and practical.

The clever bit is that the software not only provides design assistance for the joints themselves in a WYSIWYG (what you see is what you get) interface, but also generates real-time feedback based on using a three-axis CNC tool as the manufacturing method. This means that the system understands the constraints that come from the fabrication method, and incorporates that into design feedback.

The two main limitations of using a three-axis CNC are that the cutting tool can only approach the material from above, and that standard milling bits cannot create sharp inner corners; they will have a rounded fillet the same radius as the cutting bit. Design can be done manually, or by selecting joints from a pre-defined gallery. Once the design is complete, the system generates the toolpaths for manufacture.

Currently, Tsugite is limited to single joints meant for frame structures, but there’s no reason it couldn’t expand beyond that scope. A video to accompany the paper is embedded below, it’s short and concise and shows the software in action, so be sure to give it a look.

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Teaching An Old Lathe New Tricks With A Programmable Power Feed

October 4, 2020 by Adam Zeloof 17 Comments

Ask anybody whose spent time standing in front of a mill or lathe and they’ll tell you that some operations can get tedious. When you need to turn down a stainless rod by 1/4″ in 0.030″ increments, you get a lot of time to reflect on why you didn’t just buy the right size stock as you crank the wheel back and forth. That’s where the lead screw comes in — most lathes have a gear-driven lead screw that can be used to actuate the z-axis ( the one which travels parallel to the axis of rotation). It’s no CNC, but this type of gearing makes life easier and it’s been around for a long time.

[Tony Goacher] took this idea a few steps further when he created the Leadscrew Buddy. He coupled a beautiful 1949 Myford lathe with an Arduino, a stepper motor, and a handful of buttons to add some really useful capabilities to the antique machine. By decoupling the lead screw from the lathe’s gearbox and actuating it via a stepper motor, he achieved a much more granular variable feed speed.

If that’s not enough, [Tony] used a rotary encoder to display the cutting tool’s position on a home-built Digital Readout (DRO). The pièce de résistance is a “goto” command. Once [Tony] sets a home position, he can command the z-axis to travel to a set point at a given speed. Not only does this make turning easier, but it makes the process more repeatable and yields a smoother finish on the part.

These features may not seem so alien to those used to working with modern CNC lathes, but to the vast majority of us garage machinists, [Tony]’s implementation is an exciting look at how we can step up our turning game. It also fits nicely within the spectrum of lathe projects we’ve seen here at Hackaday- from the ultra low-tech to the ludicrously-precise.

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Watch A Fast Sand Plotter Plow Patterns At Speed

September 22, 2020 by Donald Papp 21 Comments

[Mark]’s sand table wisely has a glass top.

Most of us have probably seen a video of a sand drawing table at work, in which a steel ball — magnetically-coupled to a gantry under a layer of sand — lazily draws geometric patterns with utter precision and zen-like calmness. That’s all well and good, but [Mark Rehorst] thinks it can also be interesting to crank up the speed and watch the ball plow through sand just as physics intended. There’s a deeper reason [Mark] is working at this, however. Faster drawing leads to less crisp results, but by how much, exactly? To answer this, [Mark] simply ran his table (which is named The Spice Must Flow) at both fast and slow speeds and documented the results.

These two images show the difference between running the table at 100 mm/s versus 500 mm/s. The slower speed is noticeably crisper, but on the other hand the faster speed completed the pattern in about a fifth of the time. [Mark] says that as the ball aggressively accelerates to reach target speeds, more sand is thrown around over existing lines, which leads to a loss of detail.

Crisper detail, or a faster draw? Which is “better” depends on many things, but it’s pretty clear that [Mark]’s cat finds the fast version more exciting. You can see [Mark]’s table at high speed and the cat’s reaction in the video, embedded below.

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Cyberplotter Uses Multiple Tools To Great Success

September 17, 2020 by Lewin Day 14 Comments

The CNC bug is a familiar ailment in these parts. Often, patients present with persistent obsession with computer controlled machinery, most commonly after initial contact with gateway hardware such as 3D printers or basic plotters. Once diagnosed, there is no cure – simply the desire to build, and build again. [Adam Haile] knows this all too well, and built the Cyberplotter in service to the affliction.

The Cyberplotter is the culmination of [Adam]’s CNC wishlist – a two-axis build with a seriously large build area, and the capability to mount a whole bunch of different tools for different jobs. With a work area of up to 800mm x 750mm depending on what’s mounted, it can produce some seriously big output. With a Smoothieboard 5X running the show, [Adam] does all kinds of neat hacks to make the system play with different gadgets on the business end. There’s a laser for engraving, and a top-notch pen plotter featuring a high-quality linear rail for precise movement. But the fun doesn’t stop there – [Adam] goes so far as mounting a Z-axis, camera, and even a Sharpie-based airbrush which we’d never even contemplated before.

It’s not [Adam]’s first build, and past experience shines through here – armed with prior knowledge, the build does many things well without compromising on outright capability. You may find [Adam]’s name familiar – we’ve featured his Engravinator on these pages before. Video after the break.

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A Backlit Calendar For All Eternity

September 8, 2020 by Moritz v. Sivers 7 Comments

The advantage of the irregularities in the Gregorian calendar combined with the seven-day week is that they provide a constant source of yearly revenue for the paper calendar industry. Long before sustainability became a trending topic, people invented reusable, perpetual calendars, but the non-digital versions of these are sometimes complicated tables that are hard to interpret. [andrei.erdei] created an automated perpetual calendar that is mostly hardware but uses some digital tricks to overcome these problems.

The calendar consists of sandwiched panels of smoked acrylic which are backlit by some strips of WS2812Bs. Although the panels could have been processed with a laser cutter, [andrei.erdei] used a CNC which gave him the possibility to mill some grooves in the back panel to hold the LED strips. The stencil for the numbers was simply printed out on paper and the background made opaque by printing several times over the same piece of paper. The electronics consist of an ESP8266 which takes the date from an NTP server and lights up the corresponding LEDs in different colors for weekdays and weekends.

The classic version of this type of perpetual calendar uses a sliding frame but we have also seen completely different versions based on moving gears.

Video after the break.

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Easy Focus Stacking With Your CNC Machine

September 7, 2020 by Lewin Day 15 Comments

Macro photography is the art of taking photos of things very close up, and ideally at great detail. Unfortunately cameras have poor depth of field at close ranges, so to get around this, many use focus stacking techniques. This involves taking many photos at different focal lengths and digitally compositing them together. To help achieve this, [gtoal] realized that garden variety CNC machines would be perfect for the job.

To focus stack effectively, it’s desirable to move the camera in very small increments of sub-mm precision, in order to get different parts of the subject in focus. For this, a CNC machine excels, as it’s designed to move tool heads in very tiny, precise movements.

To achieve a bargain focus stacking rig, [gtoal] used a Dremel tool mount for cutting discs. It’s repurposed here, used as an easy way to fit a Raspberry Pi camera to a CNC tool head through its mounting holes. From there, it’s a simple manner of stepping the CNC a tiny amount at a time on the Z-axis, while taking photos with the Raspberry Pi along the way. [gtoal] notes that it would be simple for an experienced CNC user to whip up a program to automate the entire process.

We’ve seen other budget focus stacking rigs before, and even a busted 3D printer that was turned into an automated scanning microscope. If you’ve got your own tricks for top notch macro photography, drop us a note in the tipline!

Laser-Etching Photos On To Eggs

August 28, 2020 by Lewin Day 15 Comments

CNC machines are every maker’s dream. Capable of churning out accurate parts from CAD designs with a minimum of manual labor, they’re a great tool to have in the workshop. Alternatively, you can use them for more entertaining pursuits. [Leo]’s project is one of the latter – etching greyscale photos on to eggs.

The first thing you’ll need is an egg-compatible CNC machine. The Eggbot is a popular option, else a fourth-axis on an existing machine can also do the job as in [Leo]’s case. Coupling the egg is a delicate task, for which some rubber paper rollers are salvaged from an old printer and put to work. Then, a laser needs to be fitted to the CNC head, and the egg depth mapped with a probe to ensure the entire etching is in focus. Then it’s simply a matter of loading up an image, and turning the greyscale data into the relevant G-code to burn it onto the egg.

Using eggs coated in black ink, the results [Leo] achieves are impressive. The eggs would make an amusing Easter gift, or serve as a great cheap way to teach students about CNC techniques. Obviously, eye protection is a must, and be sure to mount your laser securely to avoid any unintentional exposures. Video after the break.

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