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Quote from: gongora on 04/12/2017 01:14 amQuote from: acsawdey on 04/11/2017 01:26 amAnd, it's largely 3-d printed.The only information I've seen for the 3D printing is 40% of the demonstrator engine by mass, and the notes from Elon's NRO talks that 3D printing doesn't work nearly as well for Raptor as it does for SuperDraco. They can't just scale it up a little and hit the Print button.Yup. And 3D printing produces worse strength than forging (for example). And you're limited in your alloy selection.
Quote from: acsawdey on 04/11/2017 01:26 amAnd, it's largely 3-d printed.The only information I've seen for the 3D printing is 40% of the demonstrator engine by mass, and the notes from Elon's NRO talks that 3D printing doesn't work nearly as well for Raptor as it does for SuperDraco. They can't just scale it up a little and hit the Print button.
And, it's largely 3-d printed.
Um, yeah, I know all about those types of additive manufacturing. It is, in fact, my job.Additive can compete with and exceed /cast/ properties, but forgings are much stronger due to an aligned grain structure. And this is something that simply cannot be done to the same degree with additive approaches.Again, additively manufactured metal parts are significantly inferior to forged metal parts.
Quote from: Robotbeat on 04/13/2017 05:26 pmUm, yeah, I know all about those types of additive manufacturing. It is, in fact, my job.Additive can compete with and exceed /cast/ properties, but forgings are much stronger due to an aligned grain structure. And this is something that simply cannot be done to the same degree with additive approaches.Again, additively manufactured metal parts are significantly inferior to forged metal parts.The material as manufactured with additive is inferior to forging, but part properties are a function of both material and geometry. AM allows geometries that are infeasible or completely impossible with forging. So it's possible to make a part with AM that is far superior to a forging serving the same purpose - especially for extremely complex integrated parts, like Raptor appears to use.
Additive can compete with and exceed /cast/ properties, but forgings are much stronger due to an aligned grain structure. And this is something that simply cannot be done to the same degree with additive approaches.Again, additively manufactured metal parts are significantly inferior to forged metal parts.
Tensile mechanical properties of selective laser-melted Hastelloy® X alloy in as-deposited condition and after hot isostatic pressing (HIP) have been studied at ambient and elevated temperatures. Room temperature four-point bending and tension–tension fatigue properties have also been investigated in as-deposited condition and after HIP. The yield strength of the as-deposited selective laser-melted Hastelloy® X specimen is higher than the heat-treated (hot forged) samples. The ultimate strength is also higher than that of the hot forged samples while the elongation property is lower. This can be attributed to its ultrafine microstructure caused by rapid solidification, which is characteristic of the selective laser melting process. It is also found that the mechanical properties (tensile and fatigue) do not vary with samples built in different bed locations.
Quote from: Robotbeat on 04/13/2017 05:26 pmAdditive can compete with and exceed /cast/ properties, but forgings are much stronger due to an aligned grain structure. And this is something that simply cannot be done to the same degree with additive approaches.Again, additively manufactured metal parts are significantly inferior to forged metal parts.https://link.springer.com/article/10.1007%2Fs00170-011-3423-2?LI=trueQuoteTensile mechanical properties of selective laser-melted Hastelloy® X alloy in as-deposited condition and after hot isostatic pressing (HIP) have been studied at ambient and elevated temperatures. Room temperature four-point bending and tension–tension fatigue properties have also been investigated in as-deposited condition and after HIP. The yield strength of the as-deposited selective laser-melted Hastelloy® X specimen is higher than the heat-treated (hot forged) samples. The ultimate strength is also higher than that of the hot forged samples while the elongation property is lower. This can be attributed to its ultrafine microstructure caused by rapid solidification, which is characteristic of the selective laser melting process. It is also found that the mechanical properties (tensile and fatigue) do not vary with samples built in different bed locations.
https://link.springer.com/article/10.1007%2Fs00170-011-3423-2?LI=trueQuoteTensile mechanical properties of selective laser-melted Hastelloy® X alloy in as-deposited condition and after hot isostatic pressing (HIP) have been studied at ambient and elevated temperatures. Room temperature four-point bending and tension–tension fatigue properties have also been investigated in as-deposited condition and after HIP. The yield strength of the as-deposited selective laser-melted Hastelloy® X specimen is higher than the heat-treated (hot forged) samples. The ultimate strength is also higher than that of the hot forged samples while the elongation property is lower. This can be attributed to its ultrafine microstructure caused by rapid solidification, which is characteristic of the selective laser melting process. It is also found that the mechanical properties (tensile and fatigue) do not vary with samples built in different bed locations.
Surely comparing the different process strengths is mostly irrelevant - just use the one that is strong enough? And if its AM, then fill yer boots?
Quote from: Rei on 04/17/2017 09:12 amQuote from: Robotbeat on 04/13/2017 05:26 pmAdditive can compete with and exceed /cast/ properties, but forgings are much stronger due to an aligned grain structure. And this is something that simply cannot be done to the same degree with additive approaches.Again, additively manufactured metal parts are significantly inferior to forged metal parts.https://link.springer.com/article/10.1007%2Fs00170-011-3423-2?LI=trueQuoteTensile mechanical properties of selective laser-melted Hastelloy® X alloy in as-deposited condition and after hot isostatic pressing (HIP) have been studied at ambient and elevated temperatures. Room temperature four-point bending and tension–tension fatigue properties have also been investigated in as-deposited condition and after HIP. The yield strength of the as-deposited selective laser-melted Hastelloy® X specimen is higher than the heat-treated (hot forged) samples. The ultimate strength is also higher than that of the hot forged samples while the elongation property is lower. This can be attributed to its ultrafine microstructure caused by rapid solidification, which is characteristic of the selective laser melting process. It is also found that the mechanical properties (tensile and fatigue) do not vary with samples built in different bed locations.What's the ultimate tensile strength in MPa of this printed sample?I'm distrustful when actual figures are not given in the summary.
Seems to me the summary calling the HIP treated part "hot forged" is confusing things.
You could read more than the summary if you wanted, it's not an incredibly long paper 923-937 MPa, depending on where on the sample they tested.
Quote from: JamesH65 on 04/18/2017 12:00 pmSurely comparing the different process strengths is mostly irrelevant - just use the one that is strong enough? And if its AM, then fill yer boots?Anything can be strong enough if you make it beefier...Saving mass is not the only consideration, but it's right up there at the top of the list.
Quote from: Rei on 04/18/2017 03:17 pmYou could read more than the summary if you wanted, it's not an incredibly long paper 923-937 MPa, depending on where on the sample they tested.US$ 39.95 to read a 7-page paper? No thanks. But thank you for giving us a few numbers.
I read the article. AM parts get higher strength than regular parts, but if you cold forge (cold draw) the metal, you get 1100MPa ultimate strength, which is a good 20% stronger than the figure they use in the paper (780MPa, I think?). Heat aging the metal also helps a lot.So I feel vindicated. The right kind of forging definitely produces a much stronger part than a mere AM part, even if you HIP the AM part.
Responsibilities:* Work with design engineers to develop and document test procedures* 50% hands on working with hardware, 50% control systems/operation work* Perform tests according to procedure* Design fixtures and adaptors needed to perform tests