Mining And Refining: Tungsten

April 2, 2024 by Dan Maloney 16 Comments

Our metallurgical history is a little bit like a game of Rock, Paper, Scissors, only without the paper; we’re always looking for something hard enough to cut whatever the current hardest metal is. We started with copper, the first metal to be mined and refined. But then we needed something to cut copper, so we ended up with alloys like bronze, which demanded harder metals like iron, and eventually this arms race of cutting led us to steel, the king of metals.

But even a king needs someone to keep him in check, and while steel can be used to make tools hard enough to cut itself, there’s something even better for the job: tungsten, or more specifically tungsten carbide. We produced almost 120,000 tonnes of tungsten in 2022, much of which was directed to the manufacture of tungsten carbide tooling. Tungsten has the highest melting point known, 3,422 °C, and is an extremely dense, hard, and tough metal. Its properties make it an indispensible industrial metal, and it’s next up in our “Mining and Refining” series.

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Getting A Close-Up View Of Chip Formation With An SEM

June 1, 2023 by Dan Maloney 16 Comments

When all you’ve got is a hammer, everything looks like a nail. And when you’ve got a scanning electron microscope, everything must look like a sample that would be really, really interesting to see enlarged in all its 3D glory. And this is what [Zachary Tong] delivers with this up close and personal look at the chip formation process.

We’ve got to hand it to [Zach] with this one, because it seems like this was one of those projects that just fought back the whole time. Granted, the idea of cutting metal inside the vacuum chamber of an SEM seems like quite an undertaking right up front. To accomplish this, [Zach] needed to build a custom tool to advance a cutting edge into a piece of stock by tiny increments. His starting point was a simple off-the-shelf linear stage, which needed a lot of prep work before going into the SEM vacuum chamber. The stage’s micrometer advances a carbide insert into a small piece of aluminum 50 microns at a time, raising a tiny sliver of aluminum while it slowly plows a tiny groove into the workpiece.

Getting the multiple shots required to make a decent animation with this rig was no mean feat. [Zach]’s SEM sample chamber doesn’t have any electrical connections, so each of the 159 frames required a painstaking process of advancing the tool, pulling down a vacuum in the chamber, and taking a picture. With each frame taking at least five minutes, this was clearly a labor of love. The results are worth it, though; stitched together, the electron micrographs show the chip formation process in amazing detail. The aluminum oxide layer on the top of the workpiece is clearly visible, as are the different zones of cutting action. The grain of the metal is also clearly visible, and the “gumminess” of the chip is readily apparent too.

For as much work as this was, it seems like [Zach] had things a bit easier than [Ben Krasnow] did when he tried something similar with a much less capable SEM.

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Pretty Fly For A DIY Guy

January 5, 2017 by Dan Maloney 12 Comments

Milling machines can be pretty intimidating beasts to work with, what with the power to cut metal and all. Mount a fly cutter in the mill and it seems like the risk factor goes up exponentially. The off-balance cutting edge whirling around seemingly out of control, the long cutting strokes, the huge chips and the smoke – it can be scary stuff. Don’t worry, though – you’ll feel more in control with a shop-built fly cutter rather than a commercial tool.

Proving once again that the main reason to have a home machine shop is to make tools for the home machine shop, [This Old Tony] takes us through all the details of the build in the three-part video journey after the break. It’s only three parts because his mill released the Magic Smoke during filming – turned out to be a bad contactor coil – and because his legion of adoring fans begged for more information after the build was finished. But they’re short videos, and well worth watching if you want to pick up some neat tips, like how to face large stock at an angle, and how to deal with recovering that angle after the spindle dies mid-cut. The addendum has a lot of great tips on calculating the proper speed for a fly cutter, too, and alternatives to the fly cutter for facing large surfaces, like using a boring head.

[ThisOldTony] does make things other than tooling in his shop, but you’ll have to go to his channel to find them, because we haven’t covered too many of those projects here. We did cover his impressive CNC machine build, though. All [Tony]’s stuff is worth watching – plenty to learn.

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Ringing In The New Year With An Arduino And Calcium Carbide

December 30, 2012 by Brian Benchoff 23 Comments

carbide

It’s the first we’ve heard of it, but a New Year’s Eve tradition in The Netherlands called Carbidschieten sounds like it’s just up our alley. Basically, a small chunk of calcium carbide and a little bit of water is placed in a metal milk churn. The carbide decomposes into acetylene and a flame is held up to a small hole in the milk churn. The resulting explosion sends the lid of the milk churn across a field and much fun is had by all.

[Edwin Eefting], [Johan Postema], [Elger Postema] are exploding 1000 liters of acetylene this New Years and needed a safe way to detonate their celebration. They came up with an electronic ignition system based on an Arduino that probably makes just as much noise as the explosion itself.

The build is basically an Arduino with a few relays. When a pair of buttons are pressed for longer than a second, the Arduino goes into countdown mode with the requisite alarms and ringing bells. When it’s time to fire the carbide cannon, a power supply is turned on that heats up a glow plug, igniting the acetylene. It’s a great build, and adds an adequate amount of safety for an event involving exploding 1000 liters of acetylene.

You can check out the videos of the countdown timer after the break, or check out the Facebook group here.

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