3D Printed Machine Shows How Braiding Is Done

If there’s something more fascinating than watching cleverly engineered industrial machines do their work, we don’t know what it could be. And at the top of that list has to be the machines that do braiding. You’ve probably seen them, with spools of thread or wire dancing under and around each other in an endless ballet that somehow manages to weave a perfect braid. It’s kind of magical.

For those who haven’t seen such a thing, now’s your chance, with this twelve-spool braiding machine. The building methods that [Fraens] used — mainly 3D printing and laser-cut acrylic — make the workings on this machine plain, even to those of us who never learned to manually braid even three strands. It’s far easier to understand by watching the video below than by trying to describe it, but basically, each vertical supply spool runs along a continuous track around a central point by a series of six meshed gears, passing under each other as they progress around the carousel and forming the braid.

There are a ton of details that go into making this work. Chief among them is the thread tensioning mechanism, which is a lever arm and spring-loaded axle that lives at the very center of each spool. The gears that form the inside-outside tracks are quite clever too, as are the worm-gear-driven takeup reel and output tensioner. We also appreciated the gate used to load the spool carriers into the track.

We can recall a couple of braiding machines before, including this one made entirely from Lego Technics.

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Make Your Desoldering Easier By Minding Your Own Bismuth

Any video that starts with a phase diagram has instantly earned our attention. Admittedly, we have a pretty low bar for that kind of stuff, but eye candy aside, [Robin Debreuil]’s quick outline of his technique for desoldering with the help of bismuth is worth watching.

Aside from its use in those pink gloopy solutions one takes for an upset stomach, bismuth has a lot of commercial applications. For the purposes of desoldering, though, its tendency to lower the melting point of tin and tin alloys like solder is what makes it a valuable addition to the toolkit. [Robin] starts with a demonstration of just how far a little bismuth depresses the melting point of tin solder — to about 135°. That allows plenty of time to work, and freeing leads from pads becomes a snap. He demonstrates this with some large QFP chips, which practically jump off the board. He also demonstrates a neat technique for cleaning the bismuth-tin mix off the leads, using a length of desoldering braid clamped at an angle to the vertical with some helping-hands clips. The braid wicks the bismuth-tin mix away from the leads along one side of the chip, while gravity pulls it down the braid to pool safely on the bench. Pretty slick.

Lest leaded solder fans fret, [Robin] ensures us this works well for lead-tin solder too. You won’t have to worry about breaking the bank, either; bismuth is pretty cheap and easily sourced. And as a bonus, it’s pretty non-toxic, at least as far as heavy metals go. But alas — it apparently doesn’t machine very well.

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