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How to 3D-print one of the strongest stainless steels
- TOMDM 4y agoAre there any pictures of a finished part? I'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.
- monkpit 4y agoNot only that, but if you can print finished parts you can engineer parts that cannot be physically machined.
- TOMDM 4y agoYeah, the ability to rapid prototype parts with occluded cavities that can't be machined by a CNC makes this a compelling capability all on its own.
- dekhn 4y agoExample: https://www.thingiverse.com/thing:1068443 https://www.thingiverse.com/thing:1068443 if not impossible, would be very difficult to machine, but is straightforward for a printer.
- etrautmann 4y agoGreat 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.
- ezekg 4y agoA better example would be https://www.thingiverse.com/thing:220785 https://www.thingiverse.com/thing:220785
- SV_BubbleTime 4y ago>6dof CNC mill 6-axis, dof is the wrong term here.
- defterGoose 4y ago5-axis. No one uses Stanford arms for milling strong materials. The sixth axis would be redundant with the spindle rotation anyway.
- SV_BubbleTime 4y agoI was correcting one thing at a time. We use a 6-axis laser at my work, I’m only hobbiest machinist level at best.
- TOMDM 4y agoEither way I appreciate the corrections from both of you!
- amelius 4y agoI wonder if you can make screw threads and how fine using this technique.
- Intermernet 4y agoYou 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.
- rsfern 4y agoI 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. Someone else posted a link to the paper
- monkpit 4y ago> 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?
- SV_BubbleTime 4y agoAn 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.
- kansface 4y agoThis 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?
- SV_BubbleTime 4y agoRight. 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.
- jseutter 4y agoI 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.
- adrian_b 4y agoNon-pay-walled version of the research paper: https://tsapps.nist.gov/publication/get_pdf.cfm?pub_id=932657 https://tsapps.nist.gov/publication/get_pdf.cfm?pub_id=93265...
- bozhark 4y ago2nd 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 %."
- convolvatron 4y agothats insane. its animated crystallography.
- abdullahkhalids 4y agoAnyone have a rough idea of how much such a printer would cost?
- ezekg 4y agoA direct metal laser sintering (DMLS) machine costs >$100k. Maybe someday it'll be as affordable as FDM is now.
- abdullahkhalids 4y agoThat doesn't sound too expensive, given the temperatures and safety features involved. But the raw parts are probably an order of magnitude cheaper, so price should come down to those levels if production scales up.
- ezekg 4y agoOh 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!
- ezekg 4y agoIf 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]. [0]: https://cgsgroup.com/product/hyperion/ https://cgsgroup.com/product/hyperion/ [1]: https://www.sigsauer.com/suppressors.html https://www.sigsauer.com/suppressors.html [2]: https://pewscience.com/sound-signature-reviews-free/sss-6-71-cgs-hyperion-minifix-300blk https://pewscience.com/sound-signature-reviews-free/sss-6-71...
- adolph 4y agoI wonder if the methods could be used for acoustic suppression of other things, like fans. 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/dp/B01CTM0J70?th=1 https://www.amazon.com/VIVOSUN-Noise-Reducer-Silencer-Inline...
- mhb 4y agoDan Gelbart on metal 3D printing: https://www.youtube.com/watch?v=nyYcomX7Lus https://www.youtube.com/watch?v=nyYcomX7Lus
- c_o_n_v_e_x 4y agoFor those who don't know, Gelbart's videos are amazing on manufacturing methods, making prototypes, etc. A god of hardware IMO. https://makezine.com/article/digital-fabrication/machining/18-lessons-smart-prototyping-self-made-billionaire/ https://makezine.com/article/digital-fabrication/machining/1...
- dkbrk 4y agoI'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. [0]: https://www.youtube.com/watch?v=2TapNnQZ9Ek https://www.youtube.com/watch?v=2TapNnQZ9Ek [1]: https://en.wikipedia.org/wiki/Hot_isostatic_pressing https://en.wikipedia.org/wiki/Hot_isostatic_pressing
- xyzzyz 4y ago> 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?
- sbf501 4y agoI'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.
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- zactato 4y agoProbably 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?
- Intermernet 4y agoNot 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.
- saboot 4y agoThis is great, but we should be aware there are real and dangerous consequences as this technology advances.
- Intermernet 4y agoIs 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."
- saboot 4y agoFor 3D printing of high strength materials specifically, it easily allows a way to bypass all existing export control laws
- jjk166 4y agohttps://xkcd.com/1215/ https://xkcd.com/1215/
- saboot 4y agoAs I previously mentioned in the other reply, the specific reason with this technology is the complete circumvention of all export control laws
- triggercut 4y agoOn-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/ https://www.modumetal.com/