Tame Your Flexible Filaments With This Belt-Drive Extruder

[Proper Printing] clearly enjoys pushing the boundaries of 3D printed materials, and sometimes this requires building custom 3D printers or at least the business end of them. Flexible filaments can be a bit of a pain to deal with, simply because most extruders are designed to push the filament into the hot end with a simple hobbed bolt (or pinch roller setup) and only work reliably due the rigidity of the plastic itself. Once you go flexible, the rigidity is reduced and the filament often deflects sideways and the extruder jams. The longer the filament path leading to the hotend, the harder it gets.  The dual belt drive extruder (they’re calling it ‘proper extruder’) grips the filament on two sides with a pair of supported belts, guiding it into the hotend without allowing it to deflect sideways. The extruder body and gears were resin printed (but, we checked — the design is suitable for FDM printing as well) proving that resin printing on modern printers, does indeed maintain adequate dimensional accuracy allowing the building of mechanisms, despite the naysayers! Continue reading “Tame Your Flexible Filaments With This Belt-Drive Extruder”

Gaskets, Can They Be 3D Printed?

Anyone who’s owned an older engine, whether it be in a car, motorcycle, or garden machine, will at some time have been faced with the need for a gasket. Even when the gasket is readily available there may be an imperative to fix the engine rather than wait for the part to arrive, so it’s common to make your own replacements. Simple ones are easy to cut from thin card, but if you’ve ever tried to do this with a really complex one you’ll know the pain of getting it right. This is the problem tackled in a video from [the_eddies], who has explored the manufacture of replacement gaskets by 3D printing.

The advantages of CAD and easy manufacture are obvious, but perhaps many common plastics might not perform well in hot or oily environments. For that reason he settles on TPU filament, and gives it a test in a bath of 2-stroke fuel mix to see how well it resists degradation. It passes, as it does also when used with a carburetor, though we’d be curious to see the results of a long-term test. We’ve placed the video below the break, so reach your own conclusions.

Gaskets have featured here before, and if you’re interested then there are other machines which can be used to make them.

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Printing Ceramics Made Easier

Creating things with ceramics is nothing new — people have done it for centuries. There are ways to 3D print ceramics, too. Well, you typically 3D print the wet ceramic and then fire it in a kiln. However, recent research is proposing a new way to produce 3D printed ceramics. The idea is to print using TPU which is infused with polysilazane, a preceramic polymer. Then the resulting print is fired to create the final ceramic product.

The process relies on a specific type of infill to create small channels inside the print to assist in the update of the polysilazane. The printer was a garden-variety Lulzbot TAZ 6 with ordinary 0.15mm and 0.25mm nozzles.

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Resilient AI Drone Packs It All In Under 250 Grams

When it was first announced that limits would be placed on recreational RC aircraft heavier than 250 grams, many assumed the new rules meant an end to home built quadcopters. But manufacturers rose to the challenge, and started developing incredibly small and lightweight versions of their hardware. Today, building and flying ultra-lightweight quadcopters with first person view (FPV) cameras has become a dedicated hobby onto itself.

But as impressive as those featherweight flyers might be, the CogniFly Project is really pushing what we thought was possible in this weight class. Designed as a platform for experimenting with artificially intelligent drones, this open source quadcopter is packing a Raspberry Pi Zero and Google’s AIY Vision Kit so it can perform computationally complex tasks such as image recognition while airborne. In case any of those experiments take an unexpected turn, it’s also been enclosed in a unique flexible frame that makes it exceptionally resilient to crash damage. As you can see in the video after the break, even after flying directly into a wall, the CogniFly can continue on its way as if nothing ever happened.

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Experiments In Soft Robotics

[Arnav Wagh] has been doing some cool experiments in soft robotics using his home 3D printer.

Soft robots have a lot of advantages, but as [Arnav] points out on his website, it’s pretty hard to get started in the same way as one might with another type of project. You can’t necessarily go on Amazon and order a ten pack of soft robot actuators in the way you can Arduinos.

The project started by imitating other projects. First he copied the universities who have done work in this arena by casting soft silicone actuators. He notes the same things that they did, that they’re difficult to produce and prone to punctures. Next he tried painting foam with silicone, which worked, but it was still prone to punctures, and there was a consensus that it was creepy. He finally had a breakthrough playing with origami shapes. After some iteration he was able to print them reliably with an Ultimaker.

Finally to get it into the “easy to hack together on a weekend” range he was looking for: he designed it to be VEX compatible. You can see them moving in the video after the break.

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The Golden Age Of Ever-Changing Computer Architecture

Given the accuracy of Moore’s Law to the development of integrated circuits over the years, one would think that our present day period is no different from the past decades in terms of computer architecture design. However, during the 2017 ACM Turing Award acceptance speech, John L. Hennessy and David A. Patterson described the present as the “golden age of computer architecture”.

Compared to the early days of MS-DOS, when designing user- and kernel-space interactions was still an experiment in the works, it certainly feels like we’re no longer in the infancy of the field. Yet, as the pressure mounts for companies to acquire more computational resources for running expensive machine learning algorithms on massive swaths of data, smart computer architecture design may be just what the industry needs.

Moore’s law predicts the doubling of transistors in an IC, it doesn’t predict the path that IC design will take. When that observation was made in 1965 it was difficult or even impossible to envision where we are today, with tools and processes so closely linked and widely available that the way we conceive processor design is itself multiplying.

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A Better Bowden Drive For Floppy Filaments

You might not think to use the word “rigid” to describe most 3D-printer filaments, but most plastic filaments are actually pretty stiff over a short length, stiff enough to be pushed into an extruder. Try the same thing with a softer plastic like TPE, though, and you might find yourself looking at this modified Bowden drive for elastomeric filaments.

The idea behind the Bowden drive favored by some 3D-printer designers is simple: clamp the filament between a motor-driven wheel and an idler to push it up a pipe into the hot end of the extruder. But with TPE and similar elastomeric filaments, [Tech2C] found that the Bowden drive on his Hypercube printer was causing jams and under-extrusion artifacts in finished prints. A careful analysis of the stock drive showed a few weaknesses, such as how much of the filament is not supported on the output side of the wheel. [Tech2C] reworked the drive to close that gap and also to move the output tube opening closer to the drive. The stock drive wheel was also replaced with a smaller diameter wheel with more aggressive knurling. Bolted to the stepper, the new drive gave remarkably improved results – a TPE vase was almost flawless with the new drive, while the old drive had blobs and artifacts galore. And a retraction test print showed no stringing at all with PLA, meaning the new drive isn’t just good for the soft stuff.

All in all, a great upgrade for this versatile and hackable little printer. We’ve seen the Hypercube before, of course – this bed height probe using SMD resistors as strain gauges connects to the other end of the Bowden drive.

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