[Ian Charnas] has taken a short break from building things that might injure himself, by building something that could injure somebody else instead. (Video, embedded below) Well, hopefully not anyway. After working with YouTuber [Tyler Csatari] on a few ideas, [Tyler] was insistent on getting some power-assisted jumping shoes, so [Ian] set to work mounting some compressed-air powered pistons to a pair of walking shoes. With a large backpack housing the 200 PSI air cylinder, control valves and timers. The whole affair looks solidly constructed, if a little ungainly, but does seem to work surprisingly well.
After some initial calculations of how much force each piston could exert before risking leg injury, he found that whilst it did work, to an extent, the pressure required was beyond the capability of the compressor they had on hand. After a shopping trip, a bigger compressor was located, but that still needed a modification to get anywhere near its maximum 200 psi rating. The thing is, that modification was to bypass the regulator and the safety valve, and this is definitely something you don’t want to be making a habit of. Compressed air systems like this can hold quite a bit of an explosion potential if pushed beyond reasonable limits, and care needs to be taken to keep things within safe bounds.
Cost-wise, [Ian] does mention a figure of around $3,000 USD making it a bit of a pricey project, but hey a YouTuber’s paying the bill, so it must just be a drop in the ocean for them?
While there are many in the 3D-printing community who loudly and proudly proclaim never to have stooped to printing a 3DBenchy, there are far more who have turned a new printer loose on the venerable test model, just to see what it can do. But Benchy is getting a little long in the tooth, and with 3D-printers getting better and better, perhaps a better benchmarking model is in order.
Knocking Benchy off its perch is the idea behind this print-in-place engine benchmark, at least according to [SunShine]. And we have to say that he’s come up with an impressive model. It’s a cutaway of a three-cylinder reciprocating engine, complete with crankshaft, connecting rods, pistons, and engine block. It’s designed to print all in one go, with only a little cleanup needed after printing before the model is ready to go. The print-in-place aspect seems to be the main test of a printer — if you can get this engine to actually spin, you’re probably set up pretty well. [SunShine] shares a few tips to get your printer dialed in, and shows a few examples of what can happen when things go wrong. In addition to the complexities of the print-in-place mechanism, the model has a few Easter eggs to really challenge your printer, like the tiny oil channel running the length of the crankshaft.
Whether this model supplants Benchy is up for debate, but even if it doesn’t, it’s still a cool design that would be fun to play with. Either way, as [SunShine] points out, you’ll need a really flat bed to print this one; luckily, he recently came up with a compliant mechanism dial indicator to help with that job.
These pistons are printed from high-purity aluminium alloy powder that was developed by German auto parts manufacturer Mahle. Porsche is having these produced by Mahle in partnership with industrial machine maker Trumpf using the laser metal fusion (LMF) process. It’s a lot like selective laser sintering (SLS), but with metal powder instead of plastic.
The machine dusts the print bed with a layer of powder, and then a laser melts the powder according to the CAD file, hardening it into shape. This process repeats one layer at a time, and supports are zapped together wherever necessary. When the print job is finished, the pistons are machined into their shiny final form and thoroughly tested, just like their cast metal cousins have been for decades. Continue reading “Porsche’s Printed Pistons Are Powerful And Precise”→
We all have our new and interesting challenges in lockdown life. If you’ve had to relocate to ride it out, the chances are good that even your challenges have challenges. Lockdown left [Kanoah]’s sister in the lurch when it came to feeding her recently-adopted pet rat, so he came up with a temporary solution to ensure that the rat never misses a meal.
Most of the automated pet feeders we see around here use an auger to move the food. That’s all fine and good, but if you just need to move a singular mass, the screw seems like overkill. [Kanoah]’s feeder is more akin to a pellet-pushing piston. It runs on a Metro Mini, but an Arduino Nano or anything with enough I/O pins would work just fine. The microcontroller starts counting the hours as soon as it has power, and delivers pellets four times a day with a servo-driven piston arm. [Kanoah] has all the files up on Thingiverse if you need a similar solution.
There many ways of solving the problem of dry pet food delivery. Wet food is a completely different animal, but as it turns out, not impossible to automate.
The build starts by disassembling the compressor, which contains three double-sided pistons. The housing is drilled with ports to allow gas to flow into and out of the cylinders, as well as to transfer from one side of the piston to the other. Acrylic end plates are fitted to the assembly. One end acts as an intake manifold, delivering air and fuel to the cylinders. The other side acts as the cylinder head, mounting the sparkplugs. Everything is then connected with acrylic tubing and a small square section of acrylic is turned into a carburetor to supply the air-fuel mix. Ignition is handled by coils triggered by the movement of the flywheel.
After an initial failure due to the acrylic manifold cracking, a stronger part is fabricated, and the engine bursts into life. The acrylic end caps give a great view of the combustion process in action. We’d love to see the a dyno graph on how much power and torque the unit puts out, or to see it hooked up to a bicycle or cart.
You see a lot of pneumatic actuators in industrial automation, and for good reason. They’re simple, powerful, reliable, and above all, cheap. Online sources and fluid-power suppliers carry a bewildering range of actuators, so why would anyone bother to make their own pneumatic cylinders? Because while the commercial stuff is cheap, it’s not PVC and plywood cheap.
Granted, that’s not the only reason [Izzy Swan] gives for his DIY single-acting cylinder. For him it’s more about having the flexibility to make exactly what he needs in terms of size and shape. And given how ridiculously easy these cylinders are, you can make a ton of them for pennies. The cylinder itself is common Schedule 40 PVC pipe with plywood endcaps, all held together with threaded rod. [Izzy] cut the endcaps with a CNC router, but a band saw or jig saw would do as well. The piston is a plywood plug mounted to a long bolt; [Izzy] gambled a little by cutting the groove for the O-ring with a table saw, but no fingers were lost. The cylinder uses a cheap bungee as a return spring, but an internal compression spring would work too,. Adding a second air inlet to make the cylinder double-acting would be possible as well. The video below shows the cylinder in action as a jig clamp.
True, the valves are the most expensive part of a pneumatic system, but if nothing else, being able to say you made your own cylinders is a win. And maybe you’ll get the fluid-power bug and want to work up to DIY hydraulics.
[Rulof Maker] is a master at making things from salvaged parts, and being an Italian lover of espresso coffee, this time he’s made an espresso machine. The parts in question are a piston and cylinder from an old motorbike, believe it or not, and parts from an IKEA lamp.
Why the piston and cylinder? For those not familiar with espresso machines, they work by forcing pressurized, almost boiling water through ground coffee. He therefore puts the water in the piston cylinder, and levers the piston down onto it, forcing the water out the bottom of the cylinder and through the waiting coffee grounds. Parts from the IKEA lamp form a base for the waiting cup to sit on.
Of course, he takes great care to clean out any burnt oil and gas before starting. We also like how he centers a lever arm on a U-shaped bolt using two springs. Clever. But see the master in action for yourself in the video below.