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tal@olio.cafe ⁨2⁩ ⁨weeks⁩ ago

considers

I think that with thermoplastic, the problem is that you’re extruding a liquid that hardens as it cools. Unless you have very good information about the particular filament used, a very good model of how it acts as it cools, good control over airflow, and good control over (or at least sensors to get a very good awareness of) environmental temperature, you’re going to have a hard time extruding something at precisely the right rate such that it cools into exactly the shape you want. Also, you’re facing the constraint of keeping the thermoplastic in the extruder at the right fluidity. Maybe you could…have the filament be melted, then enter some kind of heated pump that gives you more control over the flow rate than just the temperature does.

In theory, it’s possible to move a 3D printer’s extruder and extrude at just the right rate such that you could run a line from point A to point B without regard for support. But in practice, I think that current thermoplastic printers would have a long way to go before they could reliably do that.

That being said…

A printer that could print in spider silk — or a printer that could print in multiple materials, including spider silk — might have some neat applications.

https://www.science.org/content/article/black-widows-spin-super-silk

Need a strong elastic fiber? Try black widow silk. The thread spun by these deadly spiders is several times as strong as any other known spider silk–making it about as durable as Kevlar, a synthetic fiber used in bulletproof vests, according to a report presented here at the annual meeting of the Society for Integrative and Comparative Biology.

I mean, I’d kind of imagine that you could maybe even use that in some sort of composite, to strengthen other printed things in various ways.

Now I kind of want a black widow spider silk 3D printer.

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tal@olio.cafe ⁨2⁩ ⁨weeks⁩ ago
kagis

It does sound like there are people who have been working on synthesizing spider silk for some time. So maybe we’ll get there in our lifetimes.

https://old.reddit.com/r/askscience/comments/qiy6x/what_is_keeping_us_from_making_synthetic_spider/

Hey, I can tackle this one because I work in a lab where we ARE making synthetic spider silk.

First off, the collection of natural silk or the farming of spiders is difficult on a large scale. This is due to spiders being cannibalistic and territorial. So what we’ve done is create transgenic organisms that create the spider silk proteins for us. These organisms include goats, silkworms, bacteria and alfalfa.

Problems still exist overall. For example, for every organism, except silkworms, we must spin the protein fibers ourselves. This is the current bottleneck in the production line. After the long process of protein purification, the proteins are dissolved in an organic solvent, and pushed through a long thin needle into an alcohol coagulation bath. The fibers are then treated by different methods to try to increase the strength further. Currently, we can take 1 gallon of goats milk and purify between 1 and 10 grams of protein. From 1 gram of protein we an spin hundreds of meters of silk. The silk is not as strong as the native silk, but stronger than Kevlar and silkworm silk. We are currently working on optimizing this procedure, as well as up-scaling it.

The other promising organism is the transgenic silkworms. The benefit of the silkworms is they spin the fibers for us. The most recent data show that a fiber containing 5% spider silk proteins increase the strength of the silkworm silk by 50%. If we can increase the amount of protein in the silkworms, it may be the most promising way to produce large amounts of silk, due to the infrastructure for silk manufacturing already existing for silkworm cocoons.

Currently, I am working on a couple of projects. One is mixing different ratios of silkworm silk and spider silk (created from bacteria), and finding the changes in mechanical strengths. It is unlikely we can go much higher than 20% spider silk proteins with out competently knocking out the silkworm genes altogether (which may be a future project). Another project I am working on is trying to create a human ACL from transgenic silkworm silk/spider silk fibers. We will be cabling and braiding the fibers in different way to find the best method of creating ligaments.

So, in closing, we are making synthetic silks; however, only in the lab. Once the technology is optimized, it will be moved into industry and many different applications may come from it.

https://www.science.org/content/article/black-widows-spin-super-silk

The silk of the humble spider has some pretty impressive properties. It’s one of the sturdiest materials found in nature, stronger than steel and tougher than Kevlar. It can be stretched several times its length before it breaks. For these reasons, replicating spider silk in the lab has been a bit of an obsession among materials scientists for decades.

Now, researchers at the University of Cambridge have created a new material that mimics spider silk’s strength, stretchiness and energy-absorbing capacity. This material offers the possibility of improving on products from bike helmets to parachutes to bulletproof jackets to airplane wings. Perhaps its most impressive property? It’s 98 percent water.

“Spiders are interesting models because they are able to produce these superb silk fibers at room temperature using water as a solvent,” says Darshil Shah, an engineer at Cambridge’s Centre for Natural Material Innovation. “This process spiders have evolved over hundreds of millions of years, but we have been unable to copy so far.”

The lab-made fibers are created from a material called a hydrogel, which is 98 percent water and 2 percent silica and cellulose, the latter two held together by cucurbiturils, molecules that serve as “handcuffs.” The silica and cellulose fibers can be pulled from the hydrogel. After 30 seconds or so, the water evaporates, leaving behind only the strong, stretchy thread.

The fibers are extremely strong – though not quite as strong as the strongest spider silks – and, significantly, they can be made at room temperature without chemical solvents. This means that if they can be produced at scale, they have an advantage over other synthetic fibers such as nylon, which require extremely high temperatures for spinning, making textile production one of the world’s dirtiest industries. The artificial spider silk is also completely biodegradable. And since it’s made from common, easily accessible materials – mainly water, silica and cellulose – it has the potential to be affordable.

Shah and his team are far from the only scientists to work on creating artificial spider silk. Unlike silkworms, which can be farmed for their silk, spiders are cannibals who wouldn’t tolerate the close quarters necessary for farming, so turning to the lab is the only way to get significant quantities of the material. Every few years brings headlines about new inroads in the process. A German team has modified E-coli bacteria to produce spider silk molecules. Scientists at Utah State University bred genetically modified “spider goats” to produce silk proteins in their milk. The US army is testing “dragon silk” produced via modified silkworms for use in bulletproof vests. Earlier this year, researchers at the Karolinska Institute in Sweden published a paper on a new method for using bacteria to produce spider silk proteins in a potentially sustainable, scalable way. And this spring, California-based startup Bolt Threads debuted bioengineered spider silk neckties at the SXSW festival. Their product is made through a yeast fermentation process that produces silk proteins, which then go through an extrusion process to become fibers. It’s promising enough to have generated a partnership with outdoor manufacturer Patagonia.

But, as a 2015 Wired story points out, “so far, every group that’s attempted to produce enough of the stuff to bring it to the mass market, from researchers to giant corporations, has pretty much failed.”

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