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Jeff Findley wrote:
Also, the other option that 3D printing opens up is more shape optimized parts. These things are optimized so that "useless" mass is simply gone from the design. They tend to look "organic" rather than "machined" due to their complex shapes. I've heard this called "light-weighting" parts from management types. Sometimes you light-weight a part too far. Back in 1985, my mechanic called me in to look at a repair. The new brake disk was much heavier and much less "organic". But the original one warped because it didn't have enough mass to absorb the heat till it could be radiated away, and the manufacturer provided a much simpler but heavier replacement part. The new part was so much different looking than the original one that he wanted my permission to proceed. (As a 400 pound guy who likes to drive econobox microcars, I always seem to have alignment and brake problems only on the front left. Hmmm?) -- We are geeks. Resistance is voltage over current. |
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David Mitchell wrote:
wrote: And about the only place where weight matters that much is in things that fly and in that case useless mass is already gone from the design without the expense of 3D printing. Have you ever looked at the interior structures of an aircraft? 3D printing is, and always will be, a niche manufacturing method. "Nobody needs more than 640K" I don't really think it's sensible to say "never" wrt technology - you're judging a very immature technology The Altair was obsolete in two years. The Apple ][ was obsolete in five, though genius level reworkings kept it going for what, 12? The context for that quote was the decision to build a computer with ten times the memory capacity of the normal business computer out there at the time, with the expectation that they would totally revamp the design in a few years. Remember that was the time when Microsoft bet big on Unix as the next big thing. Nobody expected to be finding ISA compatible computers running a compatible OS 35 years later. The biggest problem wrt printing vehicles will, I suspect, be the legislation governing safety. -- We are geeks. Resistance is voltage over current. |
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In sci.physics JF Mezei wrote:
On 2017-07-04 14:02, wrote: Nope, economics. It takes a fraction of a second to stamp out a sheet metal automobile body part out of standard sheet metal stock. But for prototyping, 3D printing is amazing tech even if when mass production starts, it uses old fashioned manufacturing for large volumes. And in low production scenarios (such as rockets), 3D printing could become very interesting. However, it does compete against CAD/CAM machinery that can do some types of parts more efficiently than 3D print. No, as a niche technique it does not compete with much of anything. -- Jim Pennino |
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In sci.physics JF Mezei wrote:
On 2017-07-04 14:19, wrote: Metal powder deposition and laser or electron beam sintering. BTW, metal powders tend to be explosive. Thanks. Does this really produce parts that are on par with those produced with conventional means when it comes to force/strength/endurance (especially when it comes to re-usable engines) ? It depends on what you mean by "on par". It appears so as SpaceX uses it, but just wondering if the physics of melting layers of powder yields the same strength a a solid block that is machine tooled. It doesn't matter if it is the same strength as long as it is strong enough for the purpose. Also, if it is powder, how do they make a "roof" over empty spaces (such a the top of a horizontal cylendrical pipe inside the unit). Make the part upside down so the "roof" is a "floor" during printing. -- Jim Pennino |
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JF Mezei wrote:
On 2017-07-04 14:19, wrote: Metal powder deposition and laser or electron beam sintering. BTW, metal powders tend to be explosive. Thanks. Does this really produce parts that are on par with those produced with conventional means when it comes to force/strength/endurance (especially when it comes to re-usable engines) ? It appears so as SpaceX uses it, but just wondering if the physics of melting layers of powder yields the same strength a a solid block that is machine tooled. "Compared with a traditionally cast part, a printed valve body has superior strength, ductility, and fracture resistance, with a lower variability in materials properties. The MOV body was printed in less than two days, compared with a typical castings cycle measured in months." http://www.spacex.com/news/2014/07/3...chamber-crewed So with regard to Chimp's claim of 'slower' and your concern about 'weaker', SpaceX says bull****. Also, if it is powder, how do they make a "roof" over empty spaces (such a the top of a horizontal cylendrical pipe inside the unit). Silly question. How do you make an igloo? Same thing but with much tinier blocks. -- "Some people get lost in thought because it's such unfamiliar territory." --G. Behn |
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John Larkin wrote:
On Tue, 4 Jul 2017 18:02:47 -0000, wrote: I fail to understand why geeks think 3D printing is the ultimate answer to manufacturing when it is in fact slow and expensive. There is one very successful additive manufacturing process: casting. It is slow and expensive, *at the moment*, but it won't always be; and one of the ways it will start to be rapid and cheap is by fabricating things which make other things. So, for example, it will make moulds, and the machinery to use them, which will combine the advantages of bespoke design with the speed and low-cost of traditional manufacturing. Similarly, it will fabricate machines which wind, for example, copper wire onto cast armatures. |
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