Great point, though I think this isn’t a great example - it should be straightforward to machine that part with a 5 axis cnc since all of the suns rays pass straight through and an end mill could approach from each of those angles as well.
You can, but they usually require re-tapping / re-dieing. This is usually easier and less wasteful (from a material point of view) than tapping / dieing a drilled or lathed part, but involves careful calibration in order to end up with a good finish. If you don't really care about "machinist fit" threads you can usually get away with 3d printed threads, but they'll bind, or have lots of backlash, or both.
I don’t think there are full part builds related to this study. this group does these cool single track experiments where you can follow along with synchrotron x-rays and get really good structural data through the whole solidification process. So it’s more basic materials science than applied at this point.
> As a bonus, some compositions resulted in the formation of strength-inducing nanoparticles that, with the traditional method, require the steel to be cooled and then reheated.
Is this just a fancy way of saying it doesn’t require heat treatment?
An annoyance, but if they're heat treating in the printing step... that's 17-4 steel, but it will never be 17-4 PH, as there is no perception hardening step.
Also, "one of" should be emphasized there. 17-4 is very good common steel. But there are tons like inconel (a tradename for a 600 series), or maraging steels that beat in strength applications. It's good, but it's common good. Not common great. And certainly not exotic good.
As a machinist, you had better have a good plan before get into inconel. For 17-4, you can pretty much just have at it.
This isn't my area of expertise. The article mentioned that they could skip some sort of tempering/annealing step. Is that distinct from the PH step here?
There is no PH step here. That typically involves heating the metal and spraying it with a solution that contains different metals. Some steel is hard to heat treat in the typical way (heating/quenching), but precipitation hardening may work differently. It gets real science real fast.
I don’t know all the ins and outs, but I suspect the article was taking liberties in “just as good” being “the same”. That was my point, they might have made something great, but without sprinkling it was copper or chromium or whatever solution, it’s not PH.
I think you meant precipitation hardening. The article mentions that they can 3d print material that has a similar structure to 17-4 PH steel, with similar strength properties. They aren't specifically heat treating while printing, they're effectively printing heat treated material.
So I think you're right that it won't be 17-4 PH. It sounds like it could be just as strong without the need for heat treating. That's pretty cool.
2nd page of the paper has a decent description with data and a visual diagram of the process, it's worth checking out.
"Characterization of phase transformation dynamics of commercial additively manufactured 17–4 stainless steel (C_17–4) during laser melting. (a) Schematic
illustration of in-situ laser-melting X-ray diffraction experiment. A vertical laser beam scans the sample to create a localized melt pool. The micro-focused high-energy
X-ray beam is used to probe the phase transformation dynamics with a frame rate of 250 Hz. (b) Room temperature XRD pattern of as-solidified C_17–4 after laser
melting. (c) XRD intensity map (XRD peak intensity evolution as a function of time) during laser melting of C_17–4 from 0 s to 20 s. The liquid gap near 0.15 s
without any diffraction peaks denotes the period when all the material in the X-ray path was fully melted. The time axis is enlarged in the 0–1 s range to highlight the
phase transformation details during the initial solidification stage. (d) EBSD of as-printed C_17–4 microstructure displayed in inversed pole figure (IPF) coloring. (e)
EBSD of as-printed C_17–4 microstructure displayed in image quality (IQ) map. Martensite (α’) phase and a mixture of austenite (γ) and δ-ferrite (δ) phases were
pointed out in the microstructure. (f) EBSD phase map of as-printed C_17–4. (g) XRD intensity evolution from (c) during solidification. The time axis is enlarged in the
0–1 s range. The uncertainty for BCC intensity measurement is 1 %. The uncertainty for FCC intensity measurement is 2 %."
Oh absolutely. If you’re using it in production manufacturing, $100-250k is a small startup cost. I was thinking more of personal ownership like with an FDM 3D printer. Maybe one day!
If this is interesting to anybody, CGS recently created 3D printed suppressors using direct metal laser sintering (DMLS), but with Titanium instead of SS [0]. It allows for new geometries to suppress the expanding gasses that just weren't possible with CNC'd parts welded together. SIG also started producing suppressors with DMLS [1].
I don't have one (yet), but the results on sound signature look to be pretty impressive [2].
I'm in California so I can't suppress my firearms because that would put the rest of the population in grave danger. That being said, the most impressive thing of the sintered suppressors rather than the sound signature for me was the reduction in blowback. I heard them on pistols and semi-auto rifles though, I suppose to truly hear it I should have seen it on a bolt action.
It's not a fetichism to want to add a safety device to an already dangerous hobby or work tool. To own a suppressor _in the United States of America_ you need to pass a BATFE background check that lasts a year or more. It's a registered item and has a 200 dollar tax stamp. And that's a federal law. What gains in "the safety of the public" are made by making it outright illegal when you already have to do that to have one is at least debatable.
What is that argument? Do you also want to be allowed to drive an M1 Abrams because the Army use them? Legalize depleted Uranium APFSDS, it will be OK, there is a background check.
They make guns quieter and reduce recoil. All around more pleasant to shoot and reduce hearing damage. Guns are loud enough that exposure to even a few rounds in close quarters can cause hearing damage so suppressors should be in regular use as safety devices. They don't make guns safe without earpro, they don't make them silent, they don't even make them that quiet. You will still know if one goes off nearby. This is one of the things about hollywood that pisses off everyone who knows squat about guns, and why we try to refer to them as suppressors rather than "silencers".
They are in fact basically never used for clandestine violence in places where they are legal (which is most of the US). On the other hand, there is a clear legitimate use of them: protection of hearing when you are shooting your own guns for fun, which is a legitimate activity that millions of Americans engage in every day.
Banning suppressors is kinda like as if European countries today banned possession of English longbows. These very much can be effectively used for violence, as Agincourt has shown. However, nowadays, they emphatically are not used for that, and if modern European government loudly declared a war on longbows, and went after the owners, one would think that they went crazy: shooting longbows is a pastime of medieval reenacters, not criminals.
Suppressors are legally required in many european areas, and completely unrestricted in many countries even with restrictive gun laws. They are primarily a nuisance reduction and hearing safety device. The US's strict regulations mostly stem from people watching spy movies and failing to understand that they are not realistic.
California, a state known for regulations that ostensibly promote safety, has banned safety devices despite their already being extremely heavily regulated at the federal level.
I have a Helios QD Ti suppressor (same company, also 3D printed out of titanium) - just got ATF approval after about 6-7 months. It was pretty pricey (around $1300 IIRC), but it's very cool. Super lightweight, suppresses very effectively. Almost feels like dense plastic because it's so light. Sheds heat very quickly - safe to touch much faster than my Omega 300. They claim it's good up to 300 Norma Magnum, which is extremely impressive for the weight.
The American suppressor market is super interesting, because the $200 flat tax, extreme physical stresses, and low weight limits conspire to incentivize some of the most advanced high-temperature high-stress metallurgy outside of jet engines. In most other countries, where suppressors are unrestricted or even required (!), it seems like there's not nearly as much incentive to go straight to the ultra-high-end like most American suppressor mfrs have done.
I'm reminded a bit of NASA's work with 3D printing high temperature superalloys [0].
One difference is, NASA's work uses Hot isostatic pressing [1], a post-processing step that homogenizes the part. Whereas it sounds like this work is trying to dial in the composition such that they can get acceptable performance without any post-processing.
Tesla went through a similar thing with their Gigacastings. The only reason making such large die-cast parts is practical for them is, they put a lot of work into the material science to come up with a composition they gave the desired properties without any post-processing such as heat treatment.
The really cool thing NASA is doing, though, is coating the metal powder with nanoscale ceramic particles, which get dispersed throughout the part. That's something that can't be done with traditional manufacturing at all (the ceramic particles would separate out of molten metal rather than staying dispersed). With 3D printing, each little melt pool is too small for the ceramic particles to migrate too far, and after HIP they end up at the grain boundaries. Using that approach, they developed an alloy with higher ultimate tensile strength and vastly higher (x1000) resistance to creep at high temperatures (1100 C) compared to the best available superalloys.
> Using that approach, they developed an alloy with higher ultimate tensile strength and vastly higher (x1000) resistance to creep at high temperatures (1100 C) compared to the best available superalloys
That sounds really cool. Do you think this will allow us to build jet engines with higher operating temperatures, improving efficiency of electricity generation and plane travel?
I'm really amazed they can retain the phase of the material this way. When I learned about annealing different forms of steel in college materials class, I thought the entire object had to participate in the phase change. The fact they can preserve the structure not only at each 2D layer, but also at the junction of those layers in the 3rd-D really blows my mind. It's like the whole game of different steel phases is up for re-analysis when produced this way.
This is the future. We aren't even remotely close to scaling up and optimizing this kind of manufacturing.
Probably a dumb question (it’s a decade since my last materials class): why can’t you laser scinter during the printing and then heat treat in an oven to regain material properties?
Not a dumb question at all (despite the apparent down-votes). NASA have developed advanced techniques for doing this, and annealing sintered parts is actually a fairly common procedure as far as I can tell.
Is this a meme? This exact comment can be made about every single technological advance.
Humans create a better vaccine? "This is great, but we should be aware there are real and dangerous consequences as this technology advances."
Humans create more efficient solar cells? "This is great, but we should be aware there are real and dangerous consequences as this technology advances."
I never know when I'm replying to something that may be tongue in cheek or sarcastic. I'd suggest that we need better NLP tools to extract semantic meaning from web comments, but "we should be aware there are real and dangerous consequences as this technology advances."
On-demand high performance steel parts are a really exciting prospect and these results look impressive.
One of the difficulties in adoption I see is finding ways to assure the process and the materials that industry will trust and adopt.
Conventional procurement of exotic or high-performance/high-spec materials can typically include destructive and non-destructive testing to confirm properties at different stages in the supply chain. This is relatively straight forward if you are getting bar or plate stock. You take some bits off and test those separately knowing everything from the same mother-plate will perform the same.
In an additive process, I don't know what that looks like, or what would satisfy those who need it (usually insurance companies). Do you print an extra tab onto the part, or a seperate piece in the same print run? Or is it the consumables (i.e. the metal powder) that you QA, similar to how welding consumables are QAed. Maybe a combination? Either way, it could be a while before industry adopts a standard approach to this.
In a similar but different vein, Modumetal use nanolamination to get the structures they need. I've always wondered why they don't try to match to current steel specs, maybe they can't, maybe it's not a business model that would work for them.
https://www.modumetal.com/
68 comments
[ 3.4 ms ] story [ 127 ms ] threadI'm assuming there would be features that need to be cleaned up after a print, but this looks incredible.
I wonder what the cost savings are like vs a 6dof CNC mill for parts that can be made that way.
6-axis, dof is the wrong term here.
Someone else posted a link to the paper
Is this just a fancy way of saying it doesn’t require heat treatment?
Also, "one of" should be emphasized there. 17-4 is very good common steel. But there are tons like inconel (a tradename for a 600 series), or maraging steels that beat in strength applications. It's good, but it's common good. Not common great. And certainly not exotic good.
As a machinist, you had better have a good plan before get into inconel. For 17-4, you can pretty much just have at it.
There is no PH step here. That typically involves heating the metal and spraying it with a solution that contains different metals. Some steel is hard to heat treat in the typical way (heating/quenching), but precipitation hardening may work differently. It gets real science real fast.
I don’t know all the ins and outs, but I suspect the article was taking liberties in “just as good” being “the same”. That was my point, they might have made something great, but without sprinkling it was copper or chromium or whatever solution, it’s not PH.
So I think you're right that it won't be 17-4 PH. It sounds like it could be just as strong without the need for heat treating. That's pretty cool.
https://tsapps.nist.gov/publication/get_pdf.cfm?pub_id=93265...
"Characterization of phase transformation dynamics of commercial additively manufactured 17–4 stainless steel (C_17–4) during laser melting. (a) Schematic illustration of in-situ laser-melting X-ray diffraction experiment. A vertical laser beam scans the sample to create a localized melt pool. The micro-focused high-energy X-ray beam is used to probe the phase transformation dynamics with a frame rate of 250 Hz. (b) Room temperature XRD pattern of as-solidified C_17–4 after laser melting. (c) XRD intensity map (XRD peak intensity evolution as a function of time) during laser melting of C_17–4 from 0 s to 20 s. The liquid gap near 0.15 s without any diffraction peaks denotes the period when all the material in the X-ray path was fully melted. The time axis is enlarged in the 0–1 s range to highlight the phase transformation details during the initial solidification stage. (d) EBSD of as-printed C_17–4 microstructure displayed in inversed pole figure (IPF) coloring. (e) EBSD of as-printed C_17–4 microstructure displayed in image quality (IQ) map. Martensite (α’) phase and a mixture of austenite (γ) and δ-ferrite (δ) phases were pointed out in the microstructure. (f) EBSD phase map of as-printed C_17–4. (g) XRD intensity evolution from (c) during solidification. The time axis is enlarged in the 0–1 s range. The uncertainty for BCC intensity measurement is 1 %. The uncertainty for FCC intensity measurement is 2 %."
Maybe someday it'll be as affordable as FDM is now.
But the raw parts are probably an order of magnitude cheaper, so price should come down to those levels if production scales up.
I don't have one (yet), but the results on sound signature look to be pretty impressive [2].
[0]: https://cgsgroup.com/product/hyperion/
[1]: https://www.sigsauer.com/suppressors.html
[2]: https://pewscience.com/sound-signature-reviews-free/sss-6-71...
For example the foam used in the below one wouldn't be useful for a kitchen hood fan.
https://www.amazon.com/VIVOSUN-Noise-Reducer-Silencer-Inline...
?
Also if they are so dangerous maybe they shouldn't be putting them in the AR-15s of SFPD SWAT like you can see here: https://www.sfchronicle.com/bayarea/article/At-Outside-Lands...
What is that argument? Do you also want to be allowed to drive an M1 Abrams because the Army use them? Legalize depleted Uranium APFSDS, it will be OK, there is a background check.
Are there legitimate uses of a suppressor I'm unaware of, or are they truly only useful for clandestine violence?
Banning suppressors is kinda like as if European countries today banned possession of English longbows. These very much can be effectively used for violence, as Agincourt has shown. However, nowadays, they emphatically are not used for that, and if modern European government loudly declared a war on longbows, and went after the owners, one would think that they went crazy: shooting longbows is a pastime of medieval reenacters, not criminals.
Firearms with suppressors are still very loud (>130 decibels or about as loud as an ambulance siren) [1].
[1]: https://en.wikipedia.org/wiki/Silencer_(firearms)#Effectiven...
The American suppressor market is super interesting, because the $200 flat tax, extreme physical stresses, and low weight limits conspire to incentivize some of the most advanced high-temperature high-stress metallurgy outside of jet engines. In most other countries, where suppressors are unrestricted or even required (!), it seems like there's not nearly as much incentive to go straight to the ultra-high-end like most American suppressor mfrs have done.
https://makezine.com/article/digital-fabrication/machining/1...
One difference is, NASA's work uses Hot isostatic pressing [1], a post-processing step that homogenizes the part. Whereas it sounds like this work is trying to dial in the composition such that they can get acceptable performance without any post-processing.
Tesla went through a similar thing with their Gigacastings. The only reason making such large die-cast parts is practical for them is, they put a lot of work into the material science to come up with a composition they gave the desired properties without any post-processing such as heat treatment.
The really cool thing NASA is doing, though, is coating the metal powder with nanoscale ceramic particles, which get dispersed throughout the part. That's something that can't be done with traditional manufacturing at all (the ceramic particles would separate out of molten metal rather than staying dispersed). With 3D printing, each little melt pool is too small for the ceramic particles to migrate too far, and after HIP they end up at the grain boundaries. Using that approach, they developed an alloy with higher ultimate tensile strength and vastly higher (x1000) resistance to creep at high temperatures (1100 C) compared to the best available superalloys.
[0]: https://www.youtube.com/watch?v=2TapNnQZ9Ek
[1]: https://en.wikipedia.org/wiki/Hot_isostatic_pressing
That sounds really cool. Do you think this will allow us to build jet engines with higher operating temperatures, improving efficiency of electricity generation and plane travel?
This is the future. We aren't even remotely close to scaling up and optimizing this kind of manufacturing.
Humans create a better vaccine? "This is great, but we should be aware there are real and dangerous consequences as this technology advances."
Humans create more efficient solar cells? "This is great, but we should be aware there are real and dangerous consequences as this technology advances."
I never know when I'm replying to something that may be tongue in cheek or sarcastic. I'd suggest that we need better NLP tools to extract semantic meaning from web comments, but "we should be aware there are real and dangerous consequences as this technology advances."
One of the difficulties in adoption I see is finding ways to assure the process and the materials that industry will trust and adopt.
Conventional procurement of exotic or high-performance/high-spec materials can typically include destructive and non-destructive testing to confirm properties at different stages in the supply chain. This is relatively straight forward if you are getting bar or plate stock. You take some bits off and test those separately knowing everything from the same mother-plate will perform the same.
In an additive process, I don't know what that looks like, or what would satisfy those who need it (usually insurance companies). Do you print an extra tab onto the part, or a seperate piece in the same print run? Or is it the consumables (i.e. the metal powder) that you QA, similar to how welding consumables are QAed. Maybe a combination? Either way, it could be a while before industry adopts a standard approach to this.
In a similar but different vein, Modumetal use nanolamination to get the structures they need. I've always wondered why they don't try to match to current steel specs, maybe they can't, maybe it's not a business model that would work for them. https://www.modumetal.com/