Nylon Fibre Artificial Muscles — Powered by Lasers!

If only we had affordable artificial muscles, we might see rapid advances in prosthetic limbs, robots, exo-skeletons, implants, and more. With cost being one of the major barriers — in addition to replicating the marvel of our musculature that many of us take for granted — a workable solution seems a way off. A team of researchers at MIT present a potential answer to these problems by showing nylon fibres can be used as synthetic muscles.

Some polymer fibre materials have the curious property of increasing in  diameter while decreasing in length when heated. Taking advantage of this, the team at MIT were able to sculpt nylon fibre and — using a number of heat sources, namely lasers — could direct it to bend in a specific direction. More complex movement requires an array of heat sources which isn’t practical — yet — but seeing a nylon fibre dance tickles the imagination.

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A Trove Of 3D Printer Filament Test Data

We’re not sure what a typical weekend at [Walter]’s house is like, but we can probably safely assume that any activity taking place is at minimum accompanied by the hum of a 3D printer somewhere in the background.

Those of us who 3D print have had our experiences with bad rolls of filament. Anything from filament that warps when it shouldn’t to actual wood splinters mixed in somewhere in the manufacturing process clogging up our nozzles. There are lots of workarounds, but the best one is to not buy bad filament in the first place. To this end [Walter] has spent many hours cataloging the results of the different filaments that have made it through his shop.

We really enjoyed his comparison of twleve different yellow filaments printed side by side with the same settings on the same printer. You can really see the difference high dimensional tolerance, the right colorant mix, and good virgin plastic stock makes to the quality of the final print. Also, how transparent different brands of transparent actually are as well as the weight of spools from different brands (So you can weigh your spool to see how much is left).

The part we really liked was his list every filament he’s experienced in: PLA, ABS, PETG, Flexible, Nylon, Metal, Wood, and Other. This was a massive effort, and while his review is naturally subjective, it’s still nice to have someone else’s experience to rely on when figuring out where to spend your next thirty dollars.

Sinterit Pulls SLS 3D Printer Entry Level Price Down to Just $8k

Almost exactly two years ago, news of a great revolution in 3D printing carried itself through blogs and tech columns. Patents were expiring, and soon the ‘squirting filament’ printers would be overtaken by a vastly better method: selective laser sintering. In the last two years, the market has been markedly silent on the possibilities of SLS technology, until now, at least. Today, Sinterit is launching their first printer. It’s an SLS printer that builds objects by fusing nylon powder with a laser, producing things with much better quality than filament-based printers.

The Sinterit Lisa is a true laser sintering printer, able to create objects by blasting nylon powder with a 5W laser diode. Inside this box that’s about the same size as a laser printer is a CoreXY mechanism to move the laser diode around, heated pistons, cylinders, feed bed and print bed for keeping the print volume at the right temperature and the top layer perfectly flat. The layer thickness of the printer goes down to 0.06 mm, and the maximum print size is 13 x 17 x 13 cm. Material choice is, for now, limited to black PA12 nylon but other materials are being tested.

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Researchers Create Synthetic Muscle 100 Times Stronger Than the Real Thing

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A team of researchers at the University of Texas at Dallas have come up with an ingenious way to make a low-cost, high strength, artificial muscle. Their secret? Fishing line. The study was just published today in the journal Science, and the best part is they describe how to recreate it at home.

To create it, the researchers take regular fishing line (polyethylene or nylon string) and twist it under tension until it curls up into a tightly formed spring. It can then be temperature treated to lock in this position.

When heated again, the plastic tries to untwist — the peculiar thing is, this causes the entire coil to compress — think of it as Chinese finger-trap. Polyethylene and nylon molecules also contract lengthwise when heated. It can contract up to about 49%, with as much pulling power as 100 times its equivalent human muscle in weight. This equates to about 5.3 kilowatts of mechanical work per kilogram of muscle weight — similar to the output of a jet engine.

Stick around to see the video of how to make it — we’re excited to see what you guys think up for project applications!

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3D Printering: Alternative Filaments

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ABS and PLA are the backbones of the 3D printing world. They’re both easy to obtain and are good enough for most applications. They are not, however, the be-all, end-all filaments for all your 3D printing needs. Depending on your design, you may need something that is much tougher, much more flexible, or simply has a different appearance or texture. Here are a few alternative plastics for your RepRap, Makerbot, or other 3D printer:

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3D printing with Nylon for a more useful objects

[taulman] over on Instructables has been working on his own version of a 3D printer. Unlike the usual PLA or ABS filament all the RepRaps and Makerbots use, this printer uses nylon to make parts with very interesting properties.

Most extrusion printers are designed to print with ABS (a very hard plastic that melts around 220-230° C) or PLA (a somewhat softer plastic that melts at about 180° C). [taulman] is using Nylon 6, a very slippery and bendable plastic that melts around 320° C (about 600 degrees Fahrenheit). He’s doing this with a hot end of his own design and a ‘spiky’ extruder bolt that allows high-temperature thermoplastics to be extruded into any shape imaginable.

For the longest time, the 3D printer community has been using low-temperature thermoplastics such as PLA and ABS. There are obvious benefits to these materials: it’s pretty easy to source a spool of filament, and the low melting point of these plastics makes building a printer easier and safer. Now that [taulman] has the high-temperature plastic nut cracked, he’s moving on to easily-machiniable Delrin and transparent Polycarbonate. Very cool, and hopefully in a year’s time we’ll have a choice of what material to run in our printers.

After the break, there are a few videos [taulman] put up showing his printer at work and the properties of his 3D printed objects. It looks like [taulman] can print objects that are impossible on any other 3D printer we’ve seen; the flexible iPhone case probably couldn’t be made on any other DIY machine.

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Simple PCB vise

This one almost got relegated to a links post, but [Ken’s] simple PCB vise (PDF) is just so useful we had to give it a standalone feature. It works so well because he made every design feature count.

For instance, the groove the holds the PCB (almost impossible to see here but look at the diagrams in the PDF linked above) is cut with a dovetail bit, rather than just being a square rabbit. The clamping force is provided by that blue rubber band which simply hooks on a metal shelf peg on each side of the clamping plates. Those plates are machined out of polyethylene and slide nicely along the two nylon rods which keep them aligned. There’s really nothing to break or wear out here, except the rubber band with is easily replaceable. The rubber feet keep it from sliding across the bench as you work.

This is great for soldering, and would go right along with those diy smd parts clamps you made. It’s also a great way to hold onto your prototype boards when you’re working out the firmware.