Printed It: Print-in-Place PCB Gripper

July 15, 2020 by Tom Nardi 10 Comments

The goal of Printed It is to showcase creations that truly embrace the possibilities offered by desktop 3D printing. The most obvious examples are designs that can be printed quickly and cheaply enough that they’re a valid alternative to commercially available products. But as previous entries into the series have shown, there are also technical considerations. Is it simply a duplicate of something that could be produced via traditional means, or does the design really benefit from the unique nature of 3D printing?

A perfect example is the Print-in-Place PCB Holder/Gripper created by SunShine. This design is able to hold onto PCBs (or really, whatever you wish) without any additional components. Just pull it off the bed, and put it to work. While having to add a rubber band or generic spring would hardly be an inconvenience, there’s always something to be said for a design that’s truly 100% printable.

The secret is the dual flat spiral springs integrated into the device’s jaws. While most of the common thermoplastics used in desktop 3D printing are relatively stiff, the springs have been designed in such a way that they can be printed in standard PLA. The backside of the jaws have teeth that mesh together, so the energy of the springs is combined to provide a clamping force. Serrations have been added to the jaws to catch the edge of the PCB and help stabilize it.

Visually, it’s certainly striking. The design largely eschews right angles, giving it an almost biological appearance. Many have compared it to the head of a mantis, or perhaps some piece of alien technology.

There’s no question that the design leverages the strengths of 3D printing either; there’s no other way to produce its intricate interlocking components, especially without the use of any sort of fasteners. In short, this design is an ideal candidate for Printed It. But there’s still one question to answer: does it actually work?

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Build An Everlasting Continuity Tester

July 13, 2020 by Kristina Panos 34 Comments

When you need a continuity tester at the bench, what do you reach for? Probably your multimeter, right? It may surprise you to know that the continuity tester in the meter isn’t all that sensitive, even if it’s the yellow expensive kind. [Leo]’s will beep even if there is 50Ω of resistance in the line.

Disgusted by modern commercial testers, [Leo] set out to make the ideal continuity tester in the spirit of old school tools that do one thing and do it really well. It had to be simple to use, always ready to go, and capable of measuring continuity at 5Ω or less resistance (video, embedded below).

There’s no power switch or even labels, because it doesn’t need any. Just put the probes where you want ’em, and it either beeps and lights the LED or it doesn’t. It looks simple, but inside that blast-resistant enclosure are lots of cool features that certainly make it seem like the ideal tester to us.

Our favorite has to be the transient blocking unit that works like a little circuit breaker. They’re used to protect circuits from lighting and electrostatic discharge by way of depletion-mode MOSFETs and switches to protected mode in under a microsecond. Watch [Leo] build this workbench necessity and then abuse test it with mains power after the break.

Making your own tools, however simple or complex is a great experience. If you want to up your speedy prototyping game, [Leo]’s got you covered there with a special scratching tool for hand-scribing copper PCBs. Continue reading “Build An Everlasting Continuity Tester” →

Printed TS100 Case Beats The Heat With A Bearing

July 12, 2020 by Tom Nardi 55 Comments

As we’ve said many times in the past, the creation of custom cases and enclosures is one of the best and most obvious applications for desktop 3D printing. When armed with even an entry-level printer, your projects will never again have to suffer through the indignity of getting hot glued into a nondescript plastic box. But if you’re printing with basic PLA, you need to be careful that nothing gets too hot inside.

Which was a problem when [Oleg Vint] started work on this 3D printed case for the popular TS100 soldering iron. But with the addition of a standard 608 bearing, the case provides a safe spot for the iron to cool off before it gets buttoned back up for storage. Of course, you can also use the flip-out perch to hold the iron while you’re working.

The bearing stand that served as inspiration for the case.

As [Oleg] explains on the Thingiverse page for the case, he actually blended a few existing projects together to arrive at the final design. Specifically, the idea of using the 608 bearing came from a printable TS100 stand originally designed in 2017 by [MightyNozzle]. Released under Creative Commons, [Oleg] was able to mash the bearing stand together with elements from several other printable TS100 cases to come up with his unique combined solution.

In a physical sense, this project is a great example of the sort of bespoke creations that are made possible by desktop 3D printing. But it’s also a testament to the incredible community that’s sprung up around this technology. While the logistics of it still could use some work, seeing hackers and makers swap and combine their designs like this is extremely inspiring.

[Thanks Arturo182]

Tablet Oscilloscope Claims 100 MHz, But Is It?

July 9, 2020 by Al Williams 35 Comments

[LearnElectronics] grabbed a FNIRSI tablet oscilloscope from a vendor from China. The device has a seven-inch touchscreen and claims to be a two-channel 100 MHz scope. But is it? Watch the video below and you’ll see.

Spoiler alert: [LearnElectronics] was skeptical of the 100 MHz claim and it looks like it is more like a 30 MHz analog bandwidth. Despite that, it does seem like a pretty capable 30 MHz scope in a very handy form factor and a very cheap price: as little as $120 or so, depending on where you shop.

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Turning A Waterjet Cutter Into A Wood Lathe, For No Reason

July 9, 2020 by Dan Maloney 30 Comments

On the shortlist of dream tools for most metalworkers is a waterjet cutter, a CNC tool that uses insanely high-pressure water mixed with abrasive grit to blast sheet metal into intricate shapes. On exactly nobody’s list is this attachment that turns a waterjet cutter into a lathe, and with good reason, as we’ll see.

This one comes to us by way of the Waterjet Channel, because of course there’s a channel dedicated to waterjet cutting. The idea is a riff on fixtures that allow a waterjet cutter (or a plasma cutter) to be used on tubes and other round stock. This fixture was thrown together from scrap and uses an electric drill to rotate a wood blank between centers on the bed of the waterjet, with the goal of carving a baseball bat by rotating the blank while the waterjet carves out the profile.

The first attempt, using an entirely inappropriate but easily cut blank of cedar, wasn’t great. The force of the water hitting the wood was enough to stall the drill; the remedy was to hog out as much material as possible from the blank before spinning up for the finish cut. That worked well enough to commit to an ash bat blank, which was much harder to cut but still worked well enough to make a decent bat.

Of course it makes zero sense to use a machine tool costing multiple hundreds of thousands of dollars to machine baseball bats, but it was a fun exercise. And it only shows how far we’ve come with lathes since the 18th-century frontier’s foot-powered version of the Queen of the Machine Shop.

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The Simplest TS100 Upgrade Leads Down A Cable Testing Rabbit Hole

July 9, 2020 by Jenny List 55 Comments

By now, I must have had my Miniware TS100 soldering iron for nearly three years. It redefined what could be expected from the decent end of the budget soldering iron spectrum when it came on the market, and it’s still the one to beat even after those years. Small, lightweight, powerful, and hackable, it has even spawned direct imitations.

If the TS100 has a fault, it comes not from the iron itself but from its cable. A high-grade iron will have an extra-flexible PVC or silicone cable, but the TS100 does not have a cable of its own. Instead it relies on whatever cable comes on its power supply, which is frequently a laptop unit built with portable computing rather than soldering in mind. So to use it is to be constantly battling against its noticable lack of flexibility, a minor worry but one that I find irksome. I determined to find a solution, making a DC extension cable more flexible than that on my power supply. Continue reading “The Simplest TS100 Upgrade Leads Down A Cable Testing Rabbit Hole” →

Open-Source Grinder Makes Compression Screws For Plastic Extruders Easy

July 9, 2020 by Dan Maloney 13 Comments

In a world that’s literally awash in plastic waste, it seems a pity to have to buy fresh rolls of plastic filament to feed our 3D-printers, only to have them generate yet more plastic waste. Breaking that vicious cycle requires melding plastic recycling with additive manufacturing, and that takes some clever tooling with parts that aren’t easy to come by, like the compression screws that power plastics extruders.

This open-source compression screw grinder aims to make small-scale plastic recyclers easier to build. Coming from the lab of [Joshua Pearce] at the Michigan Technological University in collaboration with [Jacob Franz], the device is sort of a combination of a small lathe and a grinder. A piece of round steel stock is held by a chuck with the free end supported by bearings in a tailstock. On the bed of the machine is an X-Y carriage made of 3D-printed parts and pieces of electrical conduit. The carriage moves down the length of the bed as the stock rotates thanks to a pulley and a threaded rod, carrying a cordless angle grinder with a thick grinding wheel. A template attached to the front apron controls how deep the grinder cuts as it tracks along the rod; different templates allow the screw profile to be easily customized. The video below shows the machine in action and the complicated screw profiles it’s capable of producing.

We’ve seen lots of homebrew plastic extruders before, most of which use repurposed auger-type drill bits as compression screws. Those lack the variable geometry of a proper compression screw, so [Joshua] and [Jacob] making all the design documents for this machine available should be a boon to recycling experimenters.

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