#video by #Ivan-Miranda on his #mechanical marble clock, this time adding a 20-stop geneva wheel
on 02024-11-14#video about #3D-printing a whole #flying drone, “even the motors”, using 3 kg of filament, but evidently they’re wound with regular copper wire and using steel cartridge ball bearings and steel nuts and bolts and, originally, a steel 8mm shaft and collar, which he replaced with (brass?) heat-stake inserts and a precision-ground steel shoulder bolt. The motor’s magnetic core is, however, 3D-printed using “magnetic PLA”. He’s also using (rare-earth?) permanent magnets. The dovetailed arms (evidently designed using #topology-optimization, and vastly overspecced) are held on with a very interesting plastic twistlock design. He measures the thrust as ≈3kg of weight (≈30N) using a US$8 load cell from Amazon, but the motor took 2½ seconds to spin up to full thrust rather than the 800ms for a much smaller comparable-thrust off-the shelf all-metal type. By #Michael-Rechtin. #mechanical #manufacturing
on 02024-06-25#video #toread on the cheapest MIG welder in the world. #mechanical #manufacturing
on 02024-06-25#video #toread about #3D-printing #mechanical parts with 25% glass filled filament
on 02024-06-25#video on how to design #flexures for #3D-printing. Unfortunately it’s pretty much just the same Snijlab living hinges and BYU CMR #mechanical things everyone makes, though BubsBuilds designed a flexure fractal vise. Recommends using nylon for FDM because it’s less vulnerable to fatigue than PLA, or PETG if nylon is too hard to print. Also make sure your slicer doesn’t position layer seams in the flexure blades, or change the number of perimeters there. Also you can adjust flexibility by changing the number of perimeters, i.e., “wall loops”. He also points out that short blades are more demanding and that you should use fillets.
on 02024-06-24#video about an “atmosphere powered battery” (like the Atmos clock, I thought, but it looks like he’s just using vacuum as a constant-force spring). The only interesting part about this is installing rubber syringe gaskets and transparent plexiglas tubes on a chassis made by #3D-printing. He ended up having to sandwich the syringe gasket between 3-D printed parts (with screws I guess) to keep it from popping off. Okay, maybe using cut timing belts as cables for power transfer is cool too. But basically I think this is dumb. Then he has a kind of cringey plug for PCBWay’s CNC services. Unfortunately the desktop-sized “battery” has an energy capacity of only 628 joules at about 10 watts, with what he said was 73% efficiency. My math: 1 atmosphere times 500mm (est.) per cylinder times circlearea(half 36mm) gives 412 joules. So maybe his cylinders are a little taller than I thought but basically it’s what you’d expect. #mechanical #energy
on 02024-06-24#video by #Retsetman about "pericyclic" #mechanical transmission, which looks like a strain-wave gear without the strain, instead nutating because the barrel-shaped gear can spin freely on a part of the shaft that’s ground (well, 3-D printed in this case) with its axis at a 4° angle to the shaft’s own axis of rotation. Four moving parts to get 409.5:1 reduction, or six to correct for vibration. It’s apparently too inefficient to be backdrivable at least in its plastic incarnation. The 409.5:1 version is differential: each rotation, the nutating gear rotates the output shaft one 8.37° step forward, while rotating backwards one 9.23° step with respect to the fixed gear, which I guess means they’re 43 and 39 teeth respectively. It seems to have a lot of backlash or something though. The video contains erroneous statements about spur #gears. With the gear profile he’s chosen (some kind of involute-like tooth profile, which may be responsible for the backlash), he gets a slip-clutch effect which he considers a defect but which is a great advantage in some situations.
on 02024-06-24#video #toread about five-stroke #mechanical engines
on 02024-06-24#video #mechanical #clickbait high-precision speed-reducer uses rope. This is a variant of the Jacob’s ladder rolling flexure pivot, with the variant that one of the rollers is a tiny capstan and therefore the angular velocity of the actuated joint is much lower than that of the capstan itself. Cable drive means limited range of motion, but you get a lightweight joint with no backlash and hopefully little wear. #flexures
on 02024-05-31#Skyentific #video of “virtual sphere rolling joint” #mechanical robot arm
on 02024-05-26#manufacturing a slingshot #mechanical design to reach 84 joules #video
on 02024-05-13Matt Chasen’s Hexa Lift #eVTOL 18-propeller 195-kg single-person #flying machine, actually flying. The batteries clip directly onto the motors. #mechanical #video
on 02024-05-11Another #compressed-earth block #construction #mechanical machine #video, this one on “Verde Equipamentos” in Minas Gerais, with chamfers on 8 of the 12 cuboid edges and with hollow circular interlocking studs. No tongue and groove. This one is powered by muscle power with a toggle mechanism.
on 02024-05-09previous #video on #compressed-earth block #mechanical machine from Zhenting Machine, similar to #Blocco-Mattone machine. Ideally 10–15% portland, 30% clay. The AECT machine cost US$60k so they bought this US$5500 machine from Alibaba, “Eco Brava Burning Free Interlock” from “Shandong Weida Construction Machinery Co. Ltd.”.
on 02024-05-09another #video on a #mechanical machine from Zhenting Machine in China costing several thousand dollars for interlocking #compressed-earth blocks for #construction. It measures the soil into the compression chamber, makes two bricks at a time, leaves hollow spaces in the bricks, and uses a hydraulic press for the compression the ejection, which is through an openable mold top like the #Blocco-Mattone machine. Although the compression work is done by a motor, the rest of the machine’s action is manual; the operator must run through a sequence of actions to make two bricks, taking about a minute — but preparing dirt is the bottleneck. The vertical and some horizontal corners of the bricks are chamfered, as are the interlocking studs, which are hollow. The horizontal corners on the ends of the brick are the ones which aren’t chamfered, an odd omission. They bought the 110VAC-powered model. (30 amps!!) Brick dimensions 300mm × 150mm × 115mm. 1½–2 buckets of dirt makes 6 bricks.
on 02024-05-09#video on a #mechanical machine called “Blocco Mattone”, designed by Professor Roberto Mattone, RIP, which produces #compressed-earth blocks with a Lego #construction-set appearance, but for real #construction. Two rounded studs with a lot of draft (10mm tall, 38.7mm radius at top, 39.8mm radius at base) are on top of each brick, fitting into much deeper hollows in the bottom, and there’s a tongue at one end (15mm long, 40mm wide at tip, 56mm wide at base, due to the generous draft angle) and a corresponding groove at the other. There are no chamfers on the faces of the brick. The main rectangular body of the brick is 280mm × 140mm × 95mm. The stud centers are 71.5mm from the ends of the main rectangular body, and I don’t know how that’s supposed to work, since the studs in a course of bricks ought to be equidistant; maybe the hollows are larger to allow some slop. Organic material and gravel must be removed by “sieving” (riddling, I suppose; a window screen is shown being used). 6–12% portland cement. The brick press is muscle-powered; it uses a “floating mold” which can move upwards against the fixed die along with the soil within it as the movable die is pressed into it from below. A cam mechanism gradually increases the mechanical advantage toward the end of the stroke so that from 300N input force it can produce 80kN (which works out to, surprisingly, only 2MPa). By pivoting the whole mechanism onto a different cam follower, a second cam ejects the block from the top of the mold. He demonstrates a three-point bending test for fully cured blocks. I’m not a big fan of the expensive precision cylindrical movement joint used by this design, especially in an environment with sand. But I really like the idea of the interlocking blocks.
on 02024-05-09#compressed-earth block #construction #video using #mechanical hydraulic cylinders to apply 1800 “pounds per square inch” (12MPa). Discusses screening (riddling?), mixing the soil with a farm-tractor-mounted rototiller, mixing in 10% portland cement, discovering you don’t have enough clay (he recommends 40% clay), making sure there’s no organics, etc. This machine (make, model, and pricing not specified) doesn’t seem to make chamfers or interlocking features.
on 02024-05-09#video on muscle-powered #mechanical cement-stabilized compressed soil brick #construction machine by Makiga Engineering Services of #Kenya, designed to make interlocking blocks that are stable even without mortar (though, I’d think, a bit fragile), at a rate of about one per minute with four workers. Costs 122 thousand shillings. The outside of the bricks do have beveled (chamfers) corners, but their interlocking features lack not just chamfers but even draft. #compressed-earth
on 02024-05-09#video #toread about #mechanical spherical parallel manipulator
on 02024-05-08#video #mechanical hammer reinvented, but badly. The "Hammerfist" is more like driving a nail with brass knuckles, 366-gram brass knuckles which transmit the impact directly into your hand. Apparently it’s easier for kids though.
on 02024-05-08another #video on #machining a #mechanical Frisbee launcher for disc golf
on 02024-05-02#StuffMadeHere #video on #machining a #mechanical 90 “miles per hour” Frisbee launcher for disc golf.
on 02024-05-02#video on #machining #mechanical worm gears on a lathe with a homemade gear hob
on 02024-05-02#3D-printing #mechanical worm gears (though for some reason single-throated) and running them with no load and with or without grease. They melt at 8000 rpm when run without grease, but survive at least ten minutes at 12000 rpm with an unspecified grease. Printing the worms on a 45° angle with some support material works better than horizontal or vertical. #video
on 02024-05-02#video of casting #mechanical lathe beds from scrap iron in holes in the dirt with lots of cores, then machining them on a planer, in Pakistan. The planer seems to have been retrofitted with brazed carbide tooling.
on 02024-04-29#video #toread about #mechanical threaded inserts for #3D-printing
on 02024-04-28#video #toread about #mechanical motors in hobby robotics
on 02024-04-28#video about improved #mechanical servomotors for hobby robotics. He’s using an SPI magnetic encoder with on-chip sensors to read the motor position, controlled with an #STM32 G0 interfaced via I²C, programmed in Rust, which controls an LV8548 H-bridge driver chip, which can handle 12V 2A output. #microcontrollers #electronics #hardware
on 02024-04-28#Harrison-Low #video about a #mechanical linear actuator design for a juggling robot, capable of a full 263mm stroke in 100ms. He’s mostly using carbon-fiber reinforced plastic tubes, with six 6001RS cartridge bearings for rollers (one too many for #exact-constraint), held in place by a piece made by #3D-printing, with interchangeable spacers to adjust the fit in 100μm units to the imprecisely-sized tubes. He’s doing the actual actuation with a kevlar-kite-string cable drive, with the cables actually run through teflon Bowden tubes so the motors don’t have to add mass to the actuator joints; the motor pulley has two V grooves for the two ends of the cable. This seems like a good way to do robotic #mechanisms in general. This replaces his first hydraulic design made out of syringes and a second iteration using a ballscrew which was too slow and (I assume) also super expensive. He has an AS5048 magnetic encoder for positional measurement, coupled to the actual moving parts with a constant-force spring, whose rotation is what it measures, but so far he’s just using encoders on the motors themselves (which I guess are brushless since he’s using #ODrive; in fact, the motors are ODrive-branded, model D6374-150KV). He says ODrive's current sensing “completely removes” the need for limit switches. His attempts to clamp the three frame tubes with a flexure from the inside failed, but I don’t know why he doesn’t clamp them with a flexure on the outside, instead relying on hammering them in. He uses a thin wire with a hook bent on the end as fish tape to pull the kevlar string through the teflon Bowden tubes, but doesn’t always need it because of how stiff the kevlar string is. On one occasion the kevlar string was able to friction on the 3-D printed plastic and just cut right through it, presumably from heat (a big advantage for kevlar over UHMWPE, except when you want to cut it; presumably kevlar will creep less for the same reason). #robotics
on 02024-04-28#video about #mechanical #gears sliding; #math says that if you take a parametric curve γ(s) and add a parameter t for its motion over time γ(s,t) the Jacobian of that function will have determinant zero at its envelope (where movement through time is the same as a movement along the surface), and from that this video derives a closed-form parametric representation of that envelope curve, which is the mating gear.
on 02024-04-28#CC machining plans for a #mechanical micrometer popularly (but probably falsely) believed to have been made by James Watt
on 02024-04-28#bigclive sex toy teardown, clitoral suction stimulator (“Nooky” brand from Poundland). It’s built around an unidentified 8-pin microcontroller and an outboard MOSFET (“A2SHB”) to PWM the motor, which pushes a rubber suction cup up and down with a crank. The microcontroller is powered at 3.6V with an E36F boost converter shunt controller running a diode, capacitor, and inductor, all of which are surface-mount, and then there’s an LC filter to low-pass filter the micro’s power. #mechanical #hardware
on 02024-04-14#VICE homemade guns of #Taiwan #video includes Tsai Ing-Wen’s 02016 apology to the indigenous Taiwanese peoples and Tama Talum Suqluman’s prosecution. Indigenous hunters have an exception to the general #gun-control prohibition in Taiwan, as long as they make the guns themselves. Much footage of colorful Taiwanese clothing. “It was in the 80s that the government told us to hand in the guns for safekeeping, and we never got them back.” They’re using nail-gun powder cartridges to drive ball bearings. Covers Tsai’s pardon of Talum. #mechanical #politics #history
on 02024-04-06another carbide-tipped sawblade turned into an electric auger for digging I guess. He slits it with an angle grinder cutoff wheel, clamps it in a vise, softens it with a rooftop-tar-melting gas torch, and twists it into a helix with a wrench, then quenches it in water. Then he stick-welds it to a steel pipe, in which he nests a smaller steel pipe which he stick-welds in place, and then stick-welds the whole assembly onto a galvanized steel rod he had lying around, with about 100mm of extra steel rod sticking out the bottom, which he laboriously angle-grinds down to a rounded point. Then he grinds a cutting edge onto the leading edge of the auger, then touches it up with a file. Then he chucks it up in his Makita and digs a hole in the garden. #mechanical #manufacturing #video
on 02024-04-06why Wankel rotary engines bankrupt motorcycle manufacturers #mechanical #mechanisms #video. Very nice footage from “@Warped Perception” of a running Wankel engine, then a guy riding a 27hp Hercules W2000 from 01974 West Germany and posing sexily with it on the autumn leaves. Hmm, is it true that the Nazis fired Felix Wankel for being too militant and then he became SS? Yes, yes it is. 8½:1 compression ratio, which I guess is inherent to the geometry. And the Hercules mixed oil into the fuel like a two-stroke. Oh, and apparently insurance companies classified it has having three times the 294cc displacement it actually did, 882cc, presumably because it fires three times as often. That was the first Wankel motorcycle, but then Norton bought the assets and also went bankrupt. Suzuki didn’t go bankrupt but abandoned their Wankel cycle after 12 months, he says. Van Veen went bankrupt.
on 02024-04-04CNC-cutting a precision DIY cycloidal gearbox from steel. He bought dowel pins for the rollers. And had to start over. #mechanical #video #toread
on 02024-04-04#mechanical chainless string-drive #bicycles #video
on 02024-04-03driveshafts #mechanical #video by #New-Mind; how driveshafts, universal joints (pot, Cardan, double Cardan, ball-and-trunnion, Tracta, Rzeppa, tripod, Bendix Weiss, and Thompson types), slip-yokes with splined shafts, and differential #mechanisms found their way into automobiles in #history. Lots of low-value filler footage with a somewhat inept voiceover.
on 02024-04-03#Proper-Printing #3D-printing gel of UV-curable resin, as if with FDM, maybe filled with silica fume to thicken it. He was able to do vase-mode printing but not bridging. #manufacturing #mechanical #video
on 02024-04-03#Clickspring on #manufacturing carbon steel hairsprings for #mechanical watches #video
on 02024-04-03“incredibly cool” "freevalve" #Koenigsegg #internal-combustion #mechanical design; uses solenoids and position-sensor feedback to control pneumatically-actuated poppet valves, but has taken many years to come to market. #video
on 02024-04-03rotary #internal-combustion #mechanical engine valves rather than poppet type. It’s a very nice idea, but it doesn’t seal as well, so it’s not used much, though there is a racecar in New Zealand by Ralph Watson called the BSA Racer or BSA Special. Vaztec in the USA is trying to commercialize a rotary-valve design. #video #mechanisms
on 02024-04-03some kind of weird #mechanical car contraption by Tom Stanton; he’s using an E-Z Spin motor (#lasersaber style, reed-switch commutator with a permanent-magnet rotor) to charge up a cap which then spins the motor. Then he runs it off a Peltier thermoelectric generator.
on 02024-04-03new #internal-combustion #mechanical engine design "Astron Omega 1" has a publicity video full of spelling errors
on 02023-09-19#bicycle cantilever brake #mechanical workings
on 02022-05-21Marcel Thomas’s #flexures page #mechanical
on 02022-02-11Jonathan Brigham Hopkins’s FACT thesis from 02007 #flexures #PDF #mechanical
on 02022-02-11This is the Disney Research paper that transforms rigid linkages into flexure-based linkages: A Computational Design Tool for Compliant Mechanisms, by Vittorio Megaro, Jonas Zehnder, Moritz Bächer, Stelian Coros, Markus Gross, and Bernhard Thomaszewski, 02017 #PDF #flexures #mechanical #mechanisms
on 02022-02-11notes and #calculator on #mechanical Belleville springs (though Engineers Edge apparently requires you to sign up to use their calculators now)
on 02022-02-10Marcel Adam Craig Thomas’s 02014 master’s thesis, “Design of non-serial, non-parallel flexural transmissions as applied to a micro-machined MEMS tuning fork gyroscope” #mechanical #flexures #ebook
on 02022-02-10"Fractal Vise" patent number 1,059,545 from 01913, clamps 32 points on a body. #mechanical
on 02021-12-07"ReChain" is #mechadense’s #reprap design for a proposed class of #mechanical frame systems for #3D-printing, robots and structures that totally abjures the use of frictional fasteners and “naïve use of clips”, instead using only tension to get stiffness.
on 02021-11-10#paper on #mechanical properties of #seacrete #materials as a possible replacement for #concrete, describing it as “electrolytically precipitated calcium carbonate”
on 02021-09-06#mechanical models, the Kinematic Models for Design Digital Library, formerly at Cornell, based on the Reuleaux Collection of Mechanisms and Machines
on 02020-11-11the Zenith Defy Lab ZO 342 #mechanical wristwatch’s oscillator uses silicon #flexures that oscillate at 15Hz, designed by Guy Sémon. They are cut with deep reactive ion etching.
on 02017-10-01Michal Zalewski’s page about #mechanical #cycloidal drives, including one he resin-cast, and his Grasshopper scripts
on 02016-12-21#mechanical #video playlist showing lots of renders, including many of thang010146’s.
on 02016-12-21#video of how to repair a #mechanical #cycloidal drive, unfortunately with horrible elevator music
on 02016-12-21#video of M. Oskar van Deventer’s “Extreme Reduction” gear #mechanical #hardware, which gears the input motion down by about 11.3 million to 1 by way of a differential between two sets of what he calls “grinder gears”, which are themselves differential #cycloidal drives made of about three moving parts. The mechanism is quite compact. Later he made a billion-to-one version.
on 02016-12-21CMU’s #mechanical engineering curriculum; there are only 21 courses! “Fundamentals of Mechanical Engineering”, calculus (1, 2, 3D), differential equations, numerical methods, physics (1 “for engineering students” and 2), thermodynamics I, statics, dynamics, fluid mechanics (a very basic introduction), heat transfer, stress analysis, thermal fluids, dynamic systems & controls, mechanical systems experimentation, intro to CAD, machine shop, design (1 and 2). Their four-year program in their undergraduate catalog isn’t exactly the same (it omits physics 2 and includes “Interpretation and Argument” and some bullshit courses like “experiential learning”), but close. #education
on 02016-11-24#mechanical #FEA of solids and fluids II, MIT #OCW 2.094
on 02016-10-11#mechanical #FEA of solids and fluids, MIT #OCW 2.092
on 02016-10-11#pdf #paper on #mechanical #flexure #metamaterials
on 02016-10-04#pdf #paper on “Multiple-Material #Topology-Optimization of Compliant Mechanisms (#mechanical #flexures) Created Via PolyJet #3D-Printing”. It says that multiple materials has the potential to eliminate the need for thin, weak sections. (PolyJet is a process that selectively deposits either of two liquid resin monomers and polymerizes them with UV. One of the resins is an elastomer.) Their results do not seem to justify that level of enthusiasm, as they still contain thin, weak sections, and they don’t seem to have measured the output force. #manufacturing
on 02016-09-22a third Wiki page about quantitative analogies between #mechanical (in this case #hydraulic) systems and electrical systems.
on 02016-07-21more about quantitative analogies between #mechanical (and #acoustic) and electrical systems.
on 02016-07-21Quantitative analogies between #mechanical systems (especially including #acoustic systems) and electrical systems.
on 02016-07-21a short #essay on the kinds of errors software people make when they start doing #mechanical engineering.
on 02016-05-27A #Mechanical Design Cookbook. “a collection of notes on how to make miscellaneous components of your machine. These notes have been written by various professors and TAs over many years at Cambridge University and MIT.”
on 02016-01-14on the difficulties of #mechanical sliding linear motion and how to avoid them.
on 02016-01-14A very simple and robust electro-#mechanical absolute position sensor.
on 02015-11-30Development of the Electrostatic Clutch: “A brief historical review of the electrostatic clutch operating on the #Johnsen-Rahbek effect is presented. #Mechanical design of a clutch, special lubrication, and the fabrication of electronically conductive clutch facing material are described. A high-speed, high torque-to-inertia ratio test model with bi-directional shaft control is described. With the clutch operating at 2500 rpm on 30 milliamperes at 150 volts, torques over 80 inch-pounds are available. The most useful single property of the electrostatic clutch is its fast response time. It can actuate levers, interposers, print hammers, optical gates, etc., in fractions of a millisecond; it can accelerate shafts to high rpm’s with moderate loads in a few milliseconds from extremely low input control energy.” Fitch 1957. Note that 30mA×150V is 4.5W, while 80 inch-pounds × 2500 rpm is 2400 W, an amplification factor of >500.
on 02015-11-26a collection of 220 19th-century #mechanical models from Franz Reuleaux’s collection. I saw a rumor on Breaking Smart that you could 3-D print these, but I’m not finding STL files or anything.
on 02015-11-17Timothy Schmidt scanned “1800 #mechanical movements, devices and appliances”, a 416-page #mecheng book from 1899. It’s hard to find a copy.
on 02015-08-16“507 #mechanical movements”, a 137-page #mecheng public-domain #ebook scanned by Google Books.
on 02015-08-1610MB catalog of Đức thắng Nguyễn’s #mechanical mechanism #video illustrations, in three PDF files, organized by topic. Including, say, a dozen or so designs for continuously variable transmissions (#cvt), a bunch of negative #stiffness mechanisms, and so on. Entirely rigid bodies as far as I can tell except for the occasional coil or leaf spring.
on 02015-08-15Đức thắng Nguyễn has made #video illustrations of 1700 #mechanical mechanisms over the last 13 years.
on 02015-08-15A #paper on negative-#stiffness #metamaterials (“structures”) through “constrained bistable structures” #3D printed in nylon with #SLS. The figures are at the end. Related to #Merkle’s buckling-spring #mechanical logic.
on 02015-08-12“Basic Fire Control Mechanisms”, a #mechanical #analog computation handbook from 1944, by the US Navy.
on 02015-08-10