Hackaday Links: October 25, 2020

Siglent has been making pretty big inroads into the mid-range test equipment market, with the manufacturers instruments popping up on benches all over the place. Saulius Lukse, of Kurokesu fame, found himself in possession of a Siglent SPD3303X programmable power supply, which looks like a really nice unit, at least from the hardware side. The software it came with didn’t exactly light his fire, though, so Saulius came up with a Python library to control the power supply. The library lets him control pretty much every aspect of the power supply over its Ethernet port. There are still a few functions that don’t quite work, and he’s only tested it with his specific power supply so far, but chances are pretty good that there’s at least some crossover in the command sets for other Siglent instruments. We’re keen to see others pick this up and run with it.

From the “everyone needs a hobby” department, we found this ultra-detailed miniature of an IBM 1401 mainframe system to be completely enthralling. We may have written this up at an earlier point in its development, but it now appears that the model maker, 6502b, is done with the whole set, so it bears another look. The level of detail is eye-popping — the smallest features of every piece of equipment, from the operator’s console to the line printer, is reproduced . Even the three-ring binders with system documentation are there. And don’t get us started about those tape drives, or the wee chair in period-correct Harvest Gold.

Speaking of diversions, have you ever wondered how many people are in space right now? Or how many humans have had the privilege to hitch a ride upstairs? There’s a database for that: the Astronauts Database over on Supercluster. It lists pretty much everything — human and non-human — that has been intentionally launched into space, starting with Yuri Gagarin in 1961 and up to the newest member of the club, Sergey Kud-Sverchkov, who took off got the ISS just last week from his hometown of Baikonur. Everyone and everything is there, including “some tardigrades” that crashed into the Moon. They even included this guy, which makes us wonder why they didn’t include the infamous manhole cover.

And finally, for the machinists out there, if you’ve ever wondered what chatter looks like, wonder no more. Breaking Taps has done an interesting slow-motion analysis of endmill chatter, and the results are a bit unexpected. The footage is really cool — watching the four-flute endmill peel mild steel off and fling the tiny curlicues aside is very satisfying. The value of the high-speed shots is evident when he induces chatter; the spindle, workpiece, vise, and just about everything starts oscillating, resulting in a poor-quality cut and eventually, when pushed beyond its limits, the dramatic end of the endmill’s life. Interesting stuff — reminds us a bit of Ben Krasnow’s up close and personal look at chip formation in his electron microscope.

Fighting Machine Tool Chatter With A 555 Timer

Vibration is a fact of life in almost every machining operation. Whether you’re milling, drilling, turning, or grinding, vibration can result in chatter that can ruin a part. Fighting chatter has generally been a matter of adding more mass to the machine, but if you’re clever about things, chatter reduction can be accomplished electronically, too. (YouTube, embedded below.)

When you know a little something about resonance, machine vibration and chatter start to make sense. [AvE] spends quite a bit of time explaining and demonstrating resonance in the video — fair warning about his usual salty shop language. His goal with the demo is to show that chatter comes from continued excitation of a flexible beam, which in this case is a piece of stock in the lathe chuck with no tailstock support. The idea is that by rapidly varying the speed of the lathe slightly, the system never spends very long at the resonant frequency. His method relies on a variable-frequency drive (VFD) with programmable IO pins. A simple 555 timer board drives a relay to toggle the IO pins on and off, cycling the VFD up and down by a couple of hertz. The resulting 100 RPM change in spindle speed as the timer cycles reduces the amount of time spent at the resonant frequency. The results don’t look too bad — not perfect, but a definite improvement.

It’s an interesting technique to keep in mind, and a big step up from the usual technique of more mass.

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