3D Printed Forge For Recycling

March 27, 2022 by Matthew Carlson 30 Comments

If you own a CNC and have kept tabs on metal prices these past few years (honestly months), you might shed a small tear as you watch chips fly off your work and into the trash. With a sigh, these flecks and pieces are consigned to be the cost of machining a part. Thankfully, the fine folks at [ActionBox] have been working on a 3d printed plaster forge for recycling their metal scraps.

The team ordered some graphite crucibles of a few sizes from a large online bookstore and started 3D printing some molds for crucible holders. They started with a smaller version to try the method. While the walls were too thin in that initial version, the approach was proven. With slightly thicker walls, the medium-sized version worked much better. The goal of the forge was to smelt copper as they had a lot of thick copper wire lying around. Armed with several propane torches, they started melting aluminum and brass, which worked reasonably well. However, the melting point of copper continued to elude them (1984°F or 1085°C). To counter this, the [ActionBox] team bought some new torches that provided significantly higher BTU output, while still fitting the holes in the mold. This did the trick!

The mold to accommodate the large crucible was massive and printed in four sections. The team did melt copper successfully and had four ingots to show off. We want to stress how dangerous molten copper and other metals are, particularly regarding things you might not realize have moisture soaked up inside. Proper PPE is essential to use these things without getting hurt. [ActionBox] has some helpful pointers in that area, but they admit they are relatively new to forging and casting themselves. Perhaps version two can incorporate a flip lid for added safety.

Video after the break.
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Label Your SMD Tapes With An Inkjet Printer

March 25, 2022 by Jenny List 15 Comments

If you’ve ever had to use SMD components on tape outside the realm of the automated assembly machines for which they were designed, you’ll know that one tape looks very like another and it can be very annoying to keep track of which is which. We can’t help admiring [Yvo de Haas’] inkjet printer for SMD tapes then, which efficiently prints whatever identifying marks you need on the back of your tapes.

The printer uses the venerable HP45 inkjet cartridge, and teams it with a 3D printed mechanism and [Yvo]’s self-designed driver board. A worm gear motor and a sprocket take care of advancing the tape through the mechanism past the printhead, and there is a well-assembled piece of software to drive it all. With extremely comprehensive build instructions it should be within the reach of anyone who handles component tape, and from our experience of hand-labeling tape for kits we can see that it could be a Godsend. Take a look at it in action in the video below.

So far the tape-handling machinery we’ve seen has mostly been for cutting sections rather than labeling. We can see that this printer paired with a tape cutter should be essential equipment for anyone starting a kit business.

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Quick Hacks: Using Staples When Recapping Motherboards

March 22, 2022 by Dave Rowntree 23 Comments

[Marcio Teixeira] needed to recap an old Apple Macintosh motherboard, and came across a simple hack to use common paper staples as a temporary heat shield (video, embedded below) during hot air rework. The problem with hot air rework is minimizing collateral damage; you’re wielding air at a temperature hot enough to melt solder, and it can be take quite a lot of experience to figure out how best to protect the more delicate parts from being damaged. Larger items take longer to heat due to their thermal mass but smaller parts can be very quickly damaged from excess heat, whilst trying to remove a nearby target.

The sharp edges of plastic connectors are particularly prone, and good protection is paramount. Sticky tapes made from polyimide (Kapton), PET, as well as metallic options (aluminium tape is useful) are often used to temporarily mask off areas in danger of getting such collateral overheat. But they can cause other problems. Kapton tape, whilst great at withstanding the heat, tends to distort and buckle up a little when under the blast of the rework pencil. Not to mention that some brands of tape leave a nasty sticky transfer residue all over the board when exposed to heat, which needs additional cleanup.

Maybe a box or two of staples might be worth adding to one’s bag of tricks, after all more options is always good. If you’re less interesting in hacking with a hot air work station and much more in hacking a hot air rework station, here you go, and whilst we’re on reworking duff computers, here’s what happens when a Hackaday writer tries his hand at fixing his son’s Xbox.

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Tune Your Dish Antenna Like A Pro

March 22, 2022 by Elliot Williams 10 Comments

It’s a problem we all have at one time or another: your five-meter radio astronomy dish gets out of calibration and you don’t have a ridiculously expensive microwave holography rig on hand to diagnose it. OK, maybe this isn’t your problem, but when [Joe Martin]’s parabolic antenna got out of whack, he set out to diagnose and repair it, and then wrote up how he did it. You can download the PDF from his radio astronomy articles collection.

At the heart of the measurement rig is a laser rangefinder connected to a Porcupine Labs interface that passes the data on to a Pi 4. This is placed on the end of a two-degree-of-freedom servo gimbal that scans over the surface of the dish, measuring its shape. After measuring and math, [Joe] found out that it’s a little bit long here and short there, he attached two cables with turnbuckles to the front of the dish and pulled it back into shape — the sort of thing that you should probably only do if you’ve got a measurement rig already set up.

The Fluke rangefinder and Porcupine labs interface combo is pretty sweet, but it comes with a fairly hefty price tag. (Nothing compared to a professional dish measurement rig, we presume.) We’ve seen a few attempt at hacking into el-cheapo laser rangefinders, but other than [iliasam]’s heroic effort where he ended up writing his own firmware, it doesn’t seem like there are any successes. A shame, because applications like [Joe]’s prove that there’s a need for one. Let us know if there’s anything we missed?

Thanks [Ethan] for the tip!

Home Made Scanning Electron Microscope Shows Some Potential

March 21, 2022 by Dave Rowntree 7 Comments

Scanning electron microscopes are one of those niche instruments that most of us don’t really need all the time, but would still love to have access to once in a while. Although we’ve covered a few attempts at home-builds before, many have faltered, except this project over on Hackday.IO by user Vini’s Lab, which appears to be still under active development. The principle of the SEM is pretty simple; a specially prepared sample is bombarded with a focussed beam of electrons, that is steered in a raster pattern. A signal is acquired, using one of a number of techniques, such as secondary electrons (SE) back-scattered electrons (BSE) or simply the transmitted current into the sample. This signal can then be used to form an image of the sample or gather other properties.

The project is clearly in the early stages, as the author says, it’s a very costly thing to build, but already some of the machined parts are ready for assembly. Work has started on the drive electronics for the condenser stigmator. This part of the instrument takes the central part of the rapidly diverging raw electron beam that makes it through the anode, and with a couple of sets of octopole coil sets, and an aperture or two, selects only the central portion of the beam, as well as correcting for any astigmatism in the beam. By adjusting the relative currents through each of the coils, a quadrupole magnetic field is created, which counteracts the beam asymmetry.

Scanning control and signal acquisition are handled by a single dedicated card, which utilises the PIO function of a Raspberry Pi Pico module. The Pico can drive the scanning operation, and with an external FTDI USB3.0 device, send four synchronised channels of acquired sample data back to the host computer. Using PCIe connectors and mating edge connectors on the cards, gives a robust and cost effective physical connection. As can be seen from the project page, a lot of mechanical design is complete, and machining has started, so this is a project to keep an eye on in the coming months, and possibly years!

We have seen a few SEM hacks, here’s a teensy powered SEM hack from [Ben Krasnow] and here’s another attempt. For such a conceptually simple device, with such immense usefulness, its does seem a bit remiss that there aren’t more such projects out there.

Tech In Plain Sight: Tough As Nails

March 15, 2022 by Al Williams 17 Comments

When you think of machines you see around you every day, you probably think about your car, computer, or household appliances. However, the world is full of simple machines. One simple machine in particular, the inclined plane, shows up a lot. For example, think of the humble nail. If you are a woodworker or even a homeowner you probably have bags of them. They certainly are all around you if you are indoors and maybe even if you are outdoors right now. Nails have been the fastener of choice for a very long time and they are a form of a wedge which is a type of inclined plane.

What else can you say about nails? Turns out, there is a lot to know. Like other fasteners, there are nails for very specific purposes. There are even nails with two heads and — no kidding — nails with two points. Exactly what kind of nail you need depends on what you are doing and what’s important to you.

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Short Circuit Tracer For A Buck

March 10, 2022 by Al Williams 22 Comments

Almost every meter you find today will have a continuity tester. Connect the probes and it will beep if there is a short and won’t if there isn’t. But where is the short? That’s another problem when trying to measure a component that is connected to many other components. [Learn Electronics Repair] wanted to have a tool to find shorts on a board and wanted to build a tester that uses 4-wire resistance measurement to isolate the device under test without having to do surgery on the circuit. His $1 build appears in the video below.

The first part of the video talks about the theory behind resistance measurement with two and four wires. Let shows several diagrams, but he mentions that at one point he shows an incorrect schematic (at 12:03) instead of the early correct one (at 10:35) and mentions it, but if you are skimming the video, you might get confused.

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