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Scientists 3D print gunpowder substitute, achieve 420m/s bullet velocity - 3D Printing Industry:
Researchers from the Xi'an Modern Chemistry Research Institute in China have 3D printed a functional gun propellant using SLA technology. The gunpowder-esque substance is a carefully constructed blend of photopolymer resin, RDX (a high explosive), and other reactive additives. Initial gun testing of the 3D printed propellant has garnered some promising results, as the scientists managed to achieve a more-than-lethal muzzle velocity of 420m/s. This, of course, depends on your definition of 'promising'.
[...] Currently, the main ways to improve the ballistic efficiency and damage potential of propellants are to increase the burning surface or the burning rate. This is commonly done by foaming the propellants, coating them, or packing them in their casings in selective layers. According to the researchers, simply filling the cylindrical casing with a granular propellant works but is quite limited in its energy release efficiency. So, the team looked to 3D printing to see if it could pack a greater punch.
[...] Once the UV safety of the newly formulated explosive was confirmed, the team 3D printed a set of thin disks, each about 40mm in diameter. These disks could be stacked on top of each other to form a longer cylinder, resembling the body of a bullet casing. Each layer featured a honeycomb-like structure with holes and was about 5mm thick.
Then came time for the grand finale – the gun test. The cylindrical stack was loaded into a 30mm barrel with a 200g mass acting as the bullet, although at 200g it's probably closer to a mini cannonball. The team set up a high speed camera and an internal pressure gauge in the barrel before pulling the trigger. Once the smoke cleared, the researchers calculated a rather high pressure exponent value of 1.46 and a muzzle velocity of 420m/s, with plans to increase the chamber pressure in future tests.
Journal Reference:
Weitao Yang, Rui Hu, Lin Zheng, Guanghu Yan, Wenrong Yan. Fabrication and investigation of 3D-printed gun propellants [open], Materials & Design (DOI: 10.1016/j.matdes.2020.108761)
(Score: 5, Informative) by The Mighty Buzzard on Monday July 20 2020, @12:32PM (6 children)
Potassium nitrate, charcoal, sulfur. 75 : 15 : 10. Sodium nitrate works fine as well.
My rights don't end where your fear begins.
(Score: 2, Informative) by Anonymous Coward on Monday July 20 2020, @02:31PM
Since it can now be 3D printed, they're borrowing the method of how solid rocket propellants are formed with splines and voids that increase the surface burning area... creating higher thrust.
(Score: 1) by nostyle on Monday July 20 2020, @05:12PM
Stop the presses.
This is some explosive news.
Because what has been stifling the progress of humanity is the deficit of "ballistic efficiency and damage potential of propellants".
Our future looks brighter.
(Score: 0) by Anonymous Coward on Monday July 20 2020, @05:52PM
https://www.royalgunpowdermills.com/Pages/Category/history [royalgunpowdermills.com]
(Score: 2) by Immerman on Monday July 20 2020, @06:03PM (2 children)
Yeah, but there's always room to improve the fine art of murderology. Its not a controversial topic like health care access, worker's rights, or a functioning democracy.
Plus, we got to see the tiny intersection of researchers, stoners, and gun nuts in action!
(Score: 0) by Anonymous Coward on Monday July 20 2020, @06:15PM
People like you, who intentionally misunderstand things, or are just too dumb, cause a too many problems in this world.
(Score: 3, Insightful) by ChrisMaple on Tuesday July 21 2020, @05:10AM
Health care access and worker's rights aren't going to protect you and your precious democracy from the invader with better weapons.
(Score: 2, Funny) by Anonymous Coward on Monday July 20 2020, @12:42PM (1 child)
When can I order a spool of RDX from MatterHackers?
(Score: 2) by sjames on Monday July 20 2020, @07:41PM
Just be careful how you set the hotend temperature!
(Score: 3, Informative) by Snotnose on Monday July 20 2020, @12:48PM (12 children)
Which is on the slow side for a bullet. Then again, 200g is about a 7 oz projectile. Unless of course the 'g' stands for grains, in which case you're looking at about .40 S&W performance.
I came. I saw. I forgot why I came.
(Score: 1, Informative) by Anonymous Coward on Monday July 20 2020, @01:05PM (10 children)
Those are Chinese, they advanced in the third AD millennium and are using a sensible system of measurement units.
That g is indeed grams.
(Score: 2, Interesting) by Anonymous Coward on Monday July 20 2020, @01:32PM (9 children)
Sigh, such ignorance. The Chinese use at least 3 different systems of measure on a regular basis, metric, imperial and their traditional units. Also, scientific applications in pretty much every part of the world including the US tend to use metric. It's literally the only time when you can say "sensible unit of measure" in connection with the metric system without a negation of one of the two terms. The metric system is both incredibly arbitrary and inconvenient for most other applications.
(Score: 0) by Anonymous Coward on Monday July 20 2020, @01:59PM
Wow, thank you, well said. I was going to respond with: "typical tiring childish snipe at 'Americans' but newsflash: we use all of the measurement systems and don't whine about it."
(Score: 0) by Anonymous Coward on Monday July 20 2020, @04:24PM (3 children)
Like any other system.
Anything you don't know is inconvenient for you. People who learned the standard find it quite convenient. More convenient in fact than measuring things in big macs or school buses.
(Score: 0) by Anonymous Coward on Monday July 20 2020, @11:46PM (2 children)
That's brainwashing at work. People keep repeating the notion that the metric system is more logical and convenient, but there's no actual basis for the claims outside of a pretty narrow domain. If you're not doing science with it, then it's just not helpful. Nothing that typical people do in daily living benefits, it's just that most people outside of the US haven't experienced how convenient it is to have a system of measure that's more anthropocentric and logical.
I lived with the metric system for about a year and a half on top of the time I spent working with it in college and you'd have to pay me a lot of money as compensation for having to make do with such a poorly designed system of measure.
(Score: 1, Flamebait) by Azuma Hazuki on Tuesday July 21 2020, @01:13AM (1 child)
Basing things on powers of 10 makes a lot more sense from an anthropocentric point of view. Since, y'know, most people (cousin-raping Southerners aside...) have 10 fingers. It's a very natural system.
I am "that girl" your mother warned you about...
(Score: 0) by Anonymous Coward on Tuesday July 21 2020, @05:23PM
I don't know about you, but I never counted on my fingers as a child, and definitely would not as an adult.
(Score: 3, Insightful) by Immerman on Monday July 20 2020, @06:24PM (3 children)
I've got to say, that's the dfirst time I've heard metric called "arbitrary"
I mean sure, to a certain extent *every* unit of measure is arbitrary, but metric is at least consistent, both with different unit sizes (how many inches in a mile again? how about cubic inches per gallon, or gallons per cubic foot?), and with the relationships between units. The sizes are even largely based very closely on traditional European units:
1 decimeter = 1 hand
4L = 1 gal
1bar = 1 atmosphere (okay, so bar isn't technically an SI unit, but 100kPa is a lot cleaner conversion than 14.7..psi)
gravity ~=10m/s^2 instead of ~32ft/s^2
And of course Fahrenheit is *completely* arbitrary, with zero about 270 degrees too hot to be useful for anything other than measuring relative temperature differences.
Conversions aren't perfect of course, but they're also completely irrelevant unless you're trying to use both systems simultaneously
And of course imperial unit sizes are terrible - there's almost nothing that you'd weigh in pounds where you don't also want the remainder in ounces, or in feet where you don't also want inches. And of course inches are too big to be useful for almost anything, you always need fractions as well. Cooking is probably the one place where SI is (possibly) more convenient since it has such a plentitude of unit sizes in the range you use for cooking. Of course as soon as you try scaling the recipe you'd better be good with fractions and/or remember a host of conversion factors.
(Score: 0) by Anonymous Coward on Monday July 20 2020, @11:59PM (2 children)
I'm not surprised, most people have been brainwashed into thinking that the measures were defined in a sensible way. The moment we leave the Earth for a permanent colony on another planet, the metric measures are going to look far worse than the Imperial measures. Even now, the official Kilogram is a known problem as it's been observed to change mass by slight, but significant, amounts. And you have issues calibrating thermometers when you're not at sealevel.
Imperial measures are definitely not perfect, but basing most measures on estimates of human measures means that it's going to remain at least moderately useful on whatever planet we wind up living on. Plus, we have a number of useful estimating devices on us at all times.
(Score: 2) by ChrisMaple on Tuesday July 21 2020, @05:20AM
As of May 20, 2019, the kilogram is no longer defined by any physical object.
(Score: 2) by Immerman on Tuesday July 21 2020, @02:06PM
Imperial units will be completely arbitrary everywhere in the universe, while metric will just lose a few convenient local constant approximations like gravity.
You do realize the official pound, etc. suffer from the exact same drift issues as the kilogram used to (before they redefined the kilogram in terms of invariant physical constants.). *Any* physical reference unit will suffer from the exact same problem. And of course these days virtually all the imperial units are officially defined in terms of their metric alternatives anyway - their traditional definitions were useless for any purpose requiring high accuracy.
Meanwhile, all the closely related units in imperial are completely arbitrary - measures of length, area, and volume have large arbitrary constants connecting them, as do measures of the same quantity at different scales (e.g. inches, feet, yards, and miles) Quick, how many teaspoons in a cubic mile? I can tell you easily that there's 10^15 ml in a cubic km, and thus that a cubic km of water weighs roughly 10^12 kg.
There is something to be said for the high divisibility of base 12 - but it's used only sporadically in Imperial, and introduces lots of inconveniences when mixed with base-10 numbers.
The biggest objective complaint against metric I've heard is actually just a complaint about the rulers - they can be hard to read, and the lack of fractional subdivisions makes finding midpoints more difficult (important for building things) - but of course you can buy fractional metric rulers if you're one of the few people that has a frequent use for them.
(Score: 2) by number11 on Monday July 20 2020, @04:58PM
It's a 30mm bore. That's small cannon size (in WW2, 20mm and 40mm were popular close-in AA calibers). If it were a weapon, it would probably be an automatic cannon these days, with an explosive projectile. 200g doesn't sound out of line.
(Score: 5, Informative) by Booga1 on Monday July 20 2020, @01:06PM (11 children)
Yeah, that's not a bullet. Here's what some common caliber bullets are like(quick sourced off Wikipedia):
So, their bullet is about five times the size of the largest of what I would consider "normal" calibers in common usage. Still, the velocity holds up to subsonic handgun ammo.
(Score: 2) by Booga1 on Monday July 20 2020, @01:14PM (2 children)
Apologies for the short post, but I apparently mus-remembered the speed of sound which about 343 m/s, depending on altitude and temperature of course. So, strike the word subsonic off the comment...
(Score: 4, Interesting) by JoeMerchant on Monday July 20 2020, @01:19PM (1 child)
What I find lacking in TFS is a comparison of how standard gunpowder would perform in a similar application (equivalent volume of gunpowder propelling the same mass out of the same barrel...)
Україна досі не є частиною Росії Слава Україні🌻 https://www.pravda.com.ua/eng/news/2023/06/24/7408365/
(Score: 2, Funny) by Anonymous Coward on Monday July 20 2020, @02:01PM
I think the whole thing is a ploy by the Chinese to get Americans to try this and blow themselves up.
(Score: 3, Informative) by Muad'Dave on Monday July 20 2020, @01:17PM
Looking at the energy of that projectile, we get E = 0.5 m * v^2. For 0.2kg and 420 m/s that's 17.64 kJ. That's very close to the same as your .50 BMG bullet at the speed you specified.
(Score: 3, Informative) by c0lo on Monday July 20 2020, @01:25PM (2 children)
That's 179kJ
By comparison, this one has an energy of 17.6kJ
https://www.youtube.com/watch?v=aoFiw2jMy-0
(Score: 3, Informative) by c0lo on Monday July 20 2020, @01:30PM (1 child)
I'm off by one order of magnitude for BMG: 0.042*923*923/2 = 17890 J [google.com]
https://www.youtube.com/watch?v=aoFiw2jMy-0
(Score: 3, Funny) by Booga1 on Monday July 20 2020, @01:33PM
Just missing a . is all. Such a little, trifling thing. I'm sure nobody will notice around here. ;)
(Score: 1, Informative) by Anonymous Coward on Monday July 20 2020, @01:26PM (3 children)
And it was a 30mm barrel. The largest caliber in your list was the 50 BMG, which is 1/2 inch. or about 12.5 mm. What they used was much bigger than any gun you'd find in use today - outside of heavy military ordinance, or mini-cannons.
They also didn't mention barrel LENGTH. Barrel length is vital for bullet velocities. The longer the barrel, the longer the force is applied to the bullet, and the faster it goes. Once a bullet leaves the barrel it starts to slow down. Yes, assuming pressure can be maintained in the barrel behind the projectile, etc., etc.
(Score: 1, Informative) by Anonymous Coward on Monday July 20 2020, @03:44PM (1 child)
A little historical context, 30mm is the size of heavy WW2-era aircraft cannon designed to bring down heavy bombers or occasionally for ground attack. It is also the caliber of the GAU Gatling gun used on the A-10. More ordinary aircraft mounted cannon are 20mm. So, this is a military weapon only at current size.
(Score: 2) by Booga1 on Monday July 20 2020, @11:11PM
Now ya done gone and made me look it up. The A-10's GAU-8 Avenger uses 30×173mm according to Wikipedia. [wikipedia.org] I found this ammunition brochure [gd-ots.com] for the caliber, but I'm not 100% sure it's the exact stuff the A-10 uses. Still, it's at least a ballpark for the caliber.
Here's a couple of examples from the brochure:
So, faster and with weights above and below their 200 g projectile. Though, nobody would want to be on the receiving side of any of that!
(Score: 0) by Anonymous Coward on Tuesday July 21 2020, @07:01AM
Until bore friction causes the bullet to fuse to the barrel, creating a blockage, and a bomb instead of a gun. Or, as with Germans, you barrel is so long it droops. They call it, "The angle of the ballistics".
But, everyone is ignoring the nitro in the room! It's 3D printed! Put that in your 3D printed gun you downloaded off the internets, along with some 3D printed bullets, and 3D printed casing and primer, and smoke it! Oooogh, 3D printed concealed carry rig? 3D printed butt-plugs! And 3D printed, . . . never mind.
(Score: -1, Troll) by Anonymous Coward on Monday July 20 2020, @01:19PM (9 children)
I didn't know Chinamen were so interested in guns... we might make proper Americans out of them yet.
(Score: 3, Funny) by The Mighty Buzzard on Monday July 20 2020, @01:32PM (1 child)
They been doing explosives for a pretty damned long time.
My rights don't end where your fear begins.
(Score: 2) by c0lo on Monday July 20 2020, @01:36PM
Even rockets.
https://www.youtube.com/watch?v=aoFiw2jMy-0
(Score: 2) by c0lo on Monday July 20 2020, @01:41PM (1 child)
Recoil from this one 0.2kg * 420m/s = 84 kg*m/s - twice the kick from a 50 BMG: 42 g @ 923 m/s [soylentnews.org] - 38.766 kg*m/s
https://www.youtube.com/watch?v=aoFiw2jMy-0
(Score: 0) by Anonymous Coward on Tuesday July 21 2020, @05:54PM
It's probably useful for a 3D printed turret to be controlled remotely. Zip gun style for guerilla warfare.
(Score: -1, Flamebait) by Anonymous Coward on Monday July 20 2020, @01:57PM (4 children)
That would be ironic because the people in power in America are trying to turn us into Chinamen (President excluded).
(Score: 2, Funny) by c0lo on Monday July 20 2020, @02:03PM (3 children)
Indeed, the Russians will never allow their puppet being turn into a China man (large grin)
https://www.youtube.com/watch?v=aoFiw2jMy-0
(Score: 2) by RS3 on Monday July 20 2020, @02:11PM
Keep your friends close and your enemies closer.
(Score: -1, Flamebait) by Anonymous Coward on Tuesday July 21 2020, @01:27AM (1 child)
You're a pretty slow guy, so I'll bring you up to speed: the Federal investigation showed there was NOTHING to the Russian collusion smear. It was bullshit. Of course you'll keep repeating the lie because you have nothing and you REALLY need to believe in the lie.
(Score: 2, Touché) by c0lo on Tuesday July 21 2020, @02:42AM
Next you'll be saying that the Mueller report totally exonerate Trump.
https://www.youtube.com/watch?v=aoFiw2jMy-0
(Score: 3, Funny) by Bot on Monday July 20 2020, @04:52PM (2 children)
Slow but groooovy
Account abandoned.
(Score: 0) by Anonymous Coward on Monday July 20 2020, @08:09PM (1 child)
Makes me want to shoot up some heroin.
(Score: 2) by Bot on Tuesday July 21 2020, @11:33AM
Reported for hating on heroines, which is sexist - and racist since all heroines are unwhite.
Account abandoned.
(Score: 2) by krishnoid on Monday July 20 2020, @08:36PM
How about a factor of 3 or more [youtube.com]?
3d-printing something comparable to a foam/aerosol's air/fuel ratio and isotropic (?) distribution makes a lot of sense when tuning for combustion efficiency. Internal combustion is on its way out for cars (which already has electronic fuel injection anyway), but I have to wonder what other processes/products could benefit from this.
(Score: 2) by ElizabethGreene on Monday July 20 2020, @11:54PM (1 child)
It feels unlikely that we'll allow commercial sales of ammunition containing easily extracted RDX.
(Score: 2) by Booga1 on Tuesday July 21 2020, @01:53AM
Nah, why pay for all the wasted brass and lead? It would probably be easier and cheaper to make other explosives than to try extracting RDX from ammunition you can pick up at the store. You can already purchase bulk amounts of gunpowder [midwayusa.com] without too much hassle. Unless they offer the same bulk sales as the standard stuff, it won't be feasible.