Electrospinning Artificial Heart Valves

March 29, 2024 by Dan Maloney 10 Comments

When you think about additive manufacturing, thoughts naturally turn to that hot-glue squirting CNC machine sitting on your bench and squeezing whatever plastic doodad you need. But 3D printing isn’t the only way to build polymer structures, as [Riley] shows us with this fascinating attempt to create electrospun heart valves.

Now, you may never have heard of electrospinning, but we’ll venture a guess that as soon as you see what it entails, you’ll have a “Why didn’t I think of that?” moment. As [Riley] explains, electrospinning uses an electric field to build structures from fine threads of liquid polymer solution — he uses polycaprolactone (PCL), a biodegradable polyester we’ve seen used in other medical applications, which he dissolves in acetone. He loads it into a syringe, attaches the positive terminal of a high-voltage power supply to the hypodermic needle, and the negative terminal to a sheet of aluminum foil. The charge turns the PCL droplets into fine threads that accumulate on the foil; once the solvent flashes off, what’s left is a gossamer layer of non-woven plastic fabric.

To explore the uses of this material, [Riley] chose to make an artificial heart valve. This required a 3D-printed framework with three prongs, painted with conductive paint. He tried a few variations on the design before settling on a two-piece armature affixed to a rotating shaft. The PCL accumulates on the form, creating a one-piece structure that can be gingerly slipped off thanks to a little silicon grease used as a release agent.

The results are pretty impressive. The structure bears a strong resemblance to an artificial tricuspid heart valve, with three delicate leaves suspended between the upright prongs. It’s just a proof of concept, of course, but it’s a great demonstration of the potential of electrospinning, as well as an eye-opening look at what else additive manufacturing has to offer.

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Learning 3D Printing Best Practices From A Pro

May 26, 2023 by Tom Nardi 13 Comments

It might seem like 3D printing is a thoroughly modern technology, but the fact is, it’s been used in the industry for decades. The only thing that’s really new is that the printers have become cheap and small enough for folks like us to buy one and plop it on our workbench. So why not take advantage of all that knowledge accumulated by those who’ve been working in the 3D printing field, more accurately referred to as additive manufacturing, since before MakerBot stopped making wooden printers?

That’s why we asked Eric Utley, an applications engineer with Protolabs, to stop by the Hack Chat this week. With over 15 years of experience in additive manufacturing, it’s fair to say he’s seen the technology go through some pretty big changes. Hes worked on everything from the classic stereolithography (SLA) to the newer Multi Jet Fusion (MJF) printers, with a recent focus on printing in metals such as Inconel and aluminum. Compared to the sort of 3D printers he’s worked with, we’re basically playing with hot, semi-melted, LEGOs — but that doesn’t mean some of the lessons he’s learned can’t be applied at the hobbyist level. Continue reading “Learning 3D Printing Best Practices From A Pro” →

The Shuttle Engine Needed 3D Printing, But…

April 23, 2023 by Al Williams 14 Comments

If we asked you to design a circuit to blink a flashing turn signal, you would probably reach for a cheap micro or a 555. But old cars used bimetallic strips in a thermomechanical design. Why? Because, initially, 555s and microcontrollers weren’t available. [Breaking Taps] has the story of NASA engineers who needed some special cooling chambers in a rocket design for the Space Shuttle. Today you’d 3D print them, but in the 70s, that wasn’t an option. So they used wax. You can see a video about the process, including a build of a model rocket engine, in the video below.

The issue is the creation of tiny cooling channels in the combustion chamber. You can use additional thin pipes brazed onto the engine. However, there are several disadvantages to doing this way, but early rocket engines did it anyway. Having the cooling path integrated into the system would be ideal, but without 3D printing, it seems difficult to do. But not impossible.

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Teardown: 3D Printed Space Shuttle Lamp

August 17, 2021 by Tom Nardi 14 Comments

Since the very beginning, the prevailing wisdom regarding consumer desktop 3D printers was that they were excellent tools for producing prototypes or one-off creations, but anything more than that was simply asking too much. After all, they were too slow, expensive, and finicky to be useful in a production setting. Once you needed more than a few copies of a plastic part, you were better off biting the bullet and moving over to injection molding.

But of course, things have changed a lot since then. Who could have imagined that one day you’d be able to buy five 3D printers for the cost of the crappiest Harbor Freight mini lathe? Modern 3D printers aren’t just cheaper either, they’re also more reliable and produce higher quality parts. Plus with software like OctoPrint, managing them is a breeze. Today, setting up a small print farm and affordably producing parts in mass quantities is well within the means of the average hobbyist.

Space shuttle lamp — Flickering LEDs provide a sense of motion

So perhaps I shouldn’t have been so surprised when I started seeing listings for these 3D printed rocket lamps popping up on eBay. Available from various sellers at a wide array of price points depending on how long you’re willing to wait for shipping, the lamps come in several shapes and sizes, and usually feature either the Space Shuttle or mighty Saturn V perched atop a “exhaust plume” of white PLA plastic. With a few orange LEDs blinking away on the inside, the lamp promises to produce an impressive flame effect that will delight space enthusiasts both young and old.

As a space enthusiast that fits somewhere in between those extremes, I decided it was worth risking $30 USD to see what one of these things looked like in real life. After waiting a month, a crushed up box arrived at my door which I was positive would contain a tiny mangled version of the majestic lamp I was promised — like the sad excuse for a hamburger that McBurgerLand actually gives you compared to what they advertise on TV.

But in person, it really does look fantastic. Using internally lit 3D printed structures to simulate smoke and flame is something we’ve seen done in the DIY scene, but pulling it off in a comparatively cheap production piece is impressive enough that I thought it deserved a closer look.

Now it’s always been my opinion that the best way to see how something was built is to take it apart, so I’ll admit that the following deviates a bit from the rest of the teardowns in this series. There’s no great mystery around flickering a couple LEDs among Hackaday readers, so we already know the electronics will be simplistic in the extreme. This time around the interesting part isn’t what’s on the inside, but how the object itself was produced in the first place.

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Sawdust Printer Goes Against The Grain By Working With Wood Waste

June 13, 2021 by Kristina Panos 28 Comments

Wood-infused filament has been around for awhile now, and while it can be used to create some fairly impressive pieces, the finished product won’t fool the astute observer. For one thing, there’s no grain to it (not that every piece needs to show grain). For another, you can’t really throw it on a fire for emergency heating like you could with actual wood.

But a company called Desktop Metal has created a new additive manufacturing process for wood and paper waste called Forust (get it?) that gets a lot closer to the real thing. It might be an environmental savior if it catches on, though that depends on what it ends up being good for.

The company’s vision is to produce custom and luxury wood products — everything from sophisticated pencil cups to stunning furniture, and to take advantage of the nearly limitless geometry afforded by additive manufacturing. Forust uses the single-pass binder jetting method of 3D printing to lay down layers of sawdust and lignin and then squirt out some glue in between each one to hold them together.

Although Desktop Metal doesn’t mention a curing process for Forust in their press release, post-processing for solidity and longevity is the norm in binder jetting, which is usually done with ceramic or metal-based materials.

Let’s talk about those wood grains. Here’s what the press release says:

Digital grain is printed on every layer and parts can then be sanded, stained, polished, dyed, coated, and refinished in the same manner as traditionally-manufactured wood components. Software has the ability to digitally reproduce nearly any wood grain, including rosewood, ash, zebrano, ebony and mahogany, among others. Parts will also support a variety of wood stains at launch, including natural, oak, ash, and walnut.

Beauty and workability are one thing. But this will only be worthwhile if the pieces are strong. This is something that isn’t too important for pencil holders, but is paramount for furniture. Forust’s idea is to ultimately save the trees, but how are they going to get sawdust and lignin without the regular wood industry — they want to be circular and envision recycling of their goods at end-of-life into new goods

We wondered if the wood waste printer would ever become a thing. You know, there’s more than one way to print in sawdust — here’s a printer that stacks up layers of particle boards and carves them with a CNC.

Images via Forust

3D Printer As Robot: The Functograph

April 3, 2021 by Al Williams 12 Comments

A 3D printer is really a specialized form of robot. Sure, it isn’t exactly Data from Star Trek, but it isn’t too far from many industrial robots. Researchers from Meiji University made the same observation and decided to create a 3D printer that could swap a hot end for other types of robotic manipulators. They call their creation the Functgraph. (Video, embedded below.)

Some of the tasks the Functgraph can do including joining printed parts into an assembly, breaking support material, and more. The surprise twist is that — unlike traditional tool change schemes — the printer prints its own end effectors together with the print job and picks them up off the build plate.

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Sending 3D Printed Parts To Mars: A Look Inside JPL’s Additive Manufacturing Center

November 10, 2020 by Dan Maloney 5 Comments

With the Mars 2020 mission now past the halfway point between Earth and its destination, NASA’s Jet Propulsion Lab recently released a couple of stories about the 3D-printed parts that made it aboard the Perseverance rover. Tucked into its aeroshell and ready for its high-stakes ride to the Martian surface, Perseverance sports eleven separate parts that we created with additive manufacturing. It’s not the first time a spacecraft has flown with parts made with additive manufacturing technique, but it is the first time JPL has created a vehicle with so many printed parts.

To take a closer look at what 3D-printing for spaceflight-qualified components looks like, and to probe a little into the rationale for additive versus traditional subtractive manufacturing techniques, I reached out to JPL and was put in touch with Andre Pate, Additive Manufacturing Group Lead, and Michael Schein, lead engineer on one of the mission’s main scientific instruments. They both graciously gave me time to ask questions and geek out on all the cool stuff going on at JPL in terms of additive manufacturing, and to find out what the future holds for 3D-printing and spaceflight.

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