Split Flap Display Tells Us The Word

March 2, 2022 by Bryan Cockfield 12 Comments

LED and LCD displays are a technological marvel. They’ve brought the price of televisions and monitors down to unheard-of levels since the days of CRTs, but this upside arguably comes with an aesthetic cost. When everything is covered in bland computer screens, the world tends to look a lot more monotonous. Not so several decades ago when there were many sharply contrasting ways of displaying information. One example of this different time comes to us by way of this split-flap display that [Erich] has been recreating.

Split-flap displays work by printing letters or numbers on a series of flaps that are attached to a spindle with a stepper motor. Each step of the motor turns the display by one character. They can be noisy and do require a large amount of maintenance compared to modern displays, but have some advantages as well. [Erich]’s version is built out of new acrylic and MDF, and uses an Arduino as the control board. A 3D printer and CNC machine keep the tolerances tight enough for the display to work smoothly and also enable him to expand the display as needed since each character display is fairly modular.

Right now, [Erich]’s display has 20 characters on two different rows and definitely brings us back to the bygone era where displays of this style would have been prominent in airports and train stations. This display uses a lot of the basics from another split flap display that we featured a few years ago but has some improvements. And, if you’d prefer restorations of old displays rather than modern incarnations, we have you covered there as well.

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AR Display Shows CNC Lathe Operations In Real Time

February 16, 2022 by Dave Rowntree 16 Comments

[Kent VanderVelden] has come up with an interesting AR system to assist operators who are monitoring CNC lathes. (video, embedded, below) The idea is to first produce a ‘frozen’ video stream of the workpiece. This was achieved by placing a high-speed camera above the lathe, and triggering an image capture, synchronized to the rotational position of the workpiece. A high-speed rotary encoder, attached to the tailstock via a belt drive, feeds the current position into an Altera Terasic DE-Nano FPGA eval board. This is then compared to the position from another encoder, doing duty as an angular set point control. The resulting signal is used as the camera trigger to generate a video stream of just the frames where the angle is as selected by the operator, thus giving the impression of a frozen position. The video stream is sent over to a client device based on a Raspberry Pi 4 with a UPS hat, allowing it to be portable.

High speed rotary encoder driven via a belt

This video stream is overlaid with details of the current machine position, as well as the LinuxCNC G-code being executed and a graphical representation of the operation being performed by the machine. This combined video is then fed to a Vufine VUF-110 wearable, which is minimally invasive, allowing the operator to clearly see the machine of interest. As [Kent] suggests, there are many possible usage scenarios for such a setup, including remote monitoring of multiple operating machines by a single operator.

We’ve seen a few neat machine hacks over the years, here’s a nice project adding a programmable power feed to an old lathe, and since wood lathes are often missing out some DRO love, here’s a nice way to tell them that you care.

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Tiny CNC Cuts The Metal

January 28, 2022 by Al Williams 21 Comments

We’re no strangers to [Ivan]’s work and this time he’s building a relatively small CNC machine using extrusion, 3D printed parts, and a Makita router. The plans are available at a small cost, but just watching the accelerated build is fascinating.

You might think you could just attach something to an existing 3D printer frame that cuts like a Dremel tool. You can do that, but for most purposes, you need something stiffer than most desktop printers. You can see how solid this build is with multiple extrusions forming the base and very rigid axes.

Judging from the video, the machine made short work of some aluminum plate. Of course, some of that is in the choice of tool, but it appears the machine is stable enough to hold the workpiece and the tool stable to allow this sort of service. [Ivan] says the machine cost him about 600 Euro ($670 USD) and you need a printer that can create parts as large as 180 x 180 mm.

There are quite a few similar mostly 3D printed machines on Thingiverse, including some that have been through multiple versions. If you have an old 3D printer sitting around for parts, you may have nearly everything you need if you add some printed parts, presumably from your new printer.

We’ve seen plenty of CNC builds if you want to pick and choose your own design. Depending on your expectations, it doesn’t have to be an expensive project.

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Bringing The Power Of EDM To The Home Shop

January 20, 2022 by Dan Maloney 17 Comments

When you see something made from metal that seems like it would be impossible to manufacture, chances are good it was made with some variety of electrical discharge machining. EDM is the method of choice for hard-to-machine metals, high aspect ratio hole drilling, and precise surface finishes that let mating parts slip together with almost zero clearance. The trouble is, EDM is a bit fussy, and as a result hasn’t made many inroads to the home shop.

[Action BOX] aims to change that with a DIY wire EDM machine. In wire EDM, a fine brass wire is used as an electrode to slowly erode metal in a dielectric bath. The wire is consumable, and has to constantly move from a supply spool through the workpiece and onto a takeup spool. Most of the build shown in the video below is concerned with the wire-handling mechanism, which is prototyped from 3D-printed parts and a heck of a lot of rollers and bearings. Maintaining the proper tension on the wire is critical, so a servo-controlled brake is fitted to the drivetrain, which itself is powered by a closed-loop stepper. Tension is measured by a pair of strain gauges and Arduinos, which control the position of the shaft brake servo and the speed of the motor on the takeup spool.

Unfortunately, in testing this setup proved to live up to EDM’s fussy reputation. The brass wire kept breaking as soon as cutting started, and [Action BOX] never made any actual cuts. There’s certainly promise, though, and we’re looking forward to developments. For more on EDM theory, check out [Ben Krasnow]’s look at EDM hole-drilling.

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Electronic Lead Screws – Not Just For Threading Anymore

January 18, 2022 by Dan Maloney 6 Comments

An electronic leadscrew is an increasingly popular project for small and mid-sized lathes. They do away with the need to swap gears in and out to achieve the proper ratio between spindle speed and tool carriage translation, and that makes threading a snap. But well-designed electronic leadscrews, like this one from [Hobby Machinist], offer so much more than just easy threading.

The first thing that struck us about this build was the polished, professional look of it. The enclosure for the Nucleo-64 dev board sports a nice TFT display and an IP65-rated keyboard, as well as a beefy-looking jog wheel. The spindle speed is monitored by a 600 pulses-per-revolution optical encoder, and the lathe’s leadscrew is powered by a closed-loop NEMA 24 stepper. This combination allows for the basic threading operations, but the addition of a powered cross slide opens up a ton more functionality. Internal and external tapers are a few keypresses away, as are boring and turning and radius operations, both on the right and on the left. The video below shows radius-cutting operations combined to turn a sphere.

From [Hobby Machinist]’s to-do list, it looks like filleting and grooving will be added someday, as will a G-code parser and controller to make this into a bolt-on CNC controller. Inspiration for the build is said to have come in part from [Clough42]’s electronic leadscrew project from a few years back. Continue reading “Electronic Lead Screws – Not Just For Threading Anymore” →

This Little Minecraft Mine Cart Of Mine

January 10, 2022 by Matthew Carlson 8 Comments

[Joel] of Joel Creates loves trains and Minecraft. So what better way to combine them than to make a real-life electric mine cart and ride it around?

At first glance, it seems pretty straightforward. Four wheels, each with a flange, mounted to a box with a motor. In practice, it was a little more complex than that. Just finding a spot of track to even ride on is tricky. Most “abandoned” tracks that you might see around your city often aren’t all that abandoned. Luckily for [Joel], he remembered an amusement park in the area that he went to as a kid, which he remembered having a decent amount of track. Additionally, the rails were smaller and closer to the scale of a real Minecraft track where one block is 1 meter. After calling up the owner and receiving permission, Joel began to build his cart.

First attempts to procure actual train wheels were foiled by cost and lead times, and simply CNCing a set of wheels was too expensive from a time and materials point of view. [Joel]’s first thought was about making an assembly out of two wheels to grip the rail, much like a roller coaster. However, there were dozens of switch points on the track at the park and several road crossings, both things that wouldn’t work with that sort of setup. Stumbling upon a bit of hacker inspiration, [Joel] turned to brake drums, which happen to be reasonably close to the correct size. They also have the superb quality of being relatively cheap and available. Almost all the parts were CNCed out of aluminum, plywood, or foam.

Given that the theme of the build was doing things to scale, [Joel] was mindful of the top speed of a minecart in the game, which is 8 meters per second or roughly 25 miles per hour, so he set that as his goal to hit. A beefy motor from an online warehouse and a lithium-ion pack allowed him to hit that easily; it was just a matter of doing so safely.

If you need even more Minecraft vehicles in your life, perhaps an RC boat might do the trick? Video after the break.

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A Simple Touch Probe Made With Basic Tools

January 5, 2022 by Dave Rowntree 14 Comments

Six points of contact detect any displacement.

LinuxCNC contributor and machining enthusiast [Andy Pugh] is certainly not afraid to try making specialised tools to see how well they work out, and this time he’s been busy making a touch probe (video, embedded below) for checking the accuracy of machining operations and general measuring applications.

These things are not cheap, since they are essentially ‘just’ a switch with a long probe, But, as with anything specialised and machined with tight tolerances, you can understand why they cost what they do.

After inspecting and spending some time reverse-engineering such a unit, [Andy] then proceeded to grab some PEEK bar he had lying around and chuck it into the lathe (get it?). He notes Delrin would be more cost effective for those wishing to reproduce this, but as long as you have the ability to machine it and it’s non-conductive, there are many other options you could try.

Using no special tools other than a collet block (like this one) all the angled holes and slots were made with ease, with the help of a specially 3D-printed mount for the vise. A nice, simple approach, we think!

[Andy] tested the repeatability of the probe, mounted over his CNC-converted Holbrook lathe, reporting a value of 1 um, which seems rather good. Centering of the probe tip within the probe body was off a bit, as you’d expect for something made practically by hand, but that is less of a problem as it would seem, as it results in a fixed offset that can be compensated for in software. Perhaps the next version will have some adjustability to dial that out manually?

The whole assembly is formed from two plastic parts, a handful of ground-finished hardened steel pins, and a big spring. The only part remotely special is an off-the-shelf probe tip. During the electrical hookup, you may notice the use of a self-fluxing verowire pen, which was something this scribe didn’t know existed and has already placed an order for!

The reference 3D model for the design is shared from [Andy]’s Autodesk Drive for your viewing pleasure.

Of course, this isn’t the first DIY touch probe we’ve seen, here’s one for example, and over on Hackaday.IO, here’s an attempt to make one using a piezoelectric transducer.

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