Arup uses 3D printing to create structural steel components
Arup has developed a method for 3D printing steel elements
Arup says it has developed a 3D printing technique for creating structural steel elements to be used in construction. Although laser sintering has been used elsewhere, Arup believes this is the first time it has been used for this purpose. The technique could reduce energy usage, costs and waste.
Arup's research was carried out with a number of partners, including engineering design software and consulting firm WithinLab, 3D printing experts CRDM and manufacturing solutions company EOS. The research focused on applying an existing laser sintering technique, which was initially developed by EOS, in a construction setting.
The technique uses a laser to heat up and melt a fine layer of steel powder that then solidifies to form part of the structure. A new layer of powder is then added and the structure is gradually built up. The technique allows for building up a structure in a very precise way and, for this reason, a similar approach is used by German company 3D MicroPrint to create very small metal components. As such, Arup believes that this method has particular value for creating very intricate or complex structural elements and may have applications that have, as yet, not been considered.
"By using additive manufacturing we can create lots of complex individually designed pieces far more efficiently," says Salomé Galjaard, a team leader at Arup. "This has tremendous implications for reducing costs and cutting waste. But most importantly, this approach potentially enables a very sophisticated design, without the need to simplify the design in a later stage to lower costs."
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Stu is a tech writer based in Liverpool, UK. He has previously worked on global digital estate management at Amaze and headed up digital strategy for FACT (Foundation for Art and Creative Technology). He likes cups of tea, bacon sandwiches and RSS feeds.
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not new. http://en.wikipedia.org/wiki/Direct_metal_laser_sintering
It would be interesting to see the results of various load tests.
DB - It not be totally new, but if they get this idea working well, all sorts of costly casting and part assembling processes will not be needed, hopefully dropping the costs of many items.
Too many machine parts are made from tiny components as there is no way to "work around corners" or "put tools into closed spaces" so costs rise along with the difficulty.
I am curious about the strength of such structural elements. Being no expert I wonder if these could be used for critical load bearing parts? Can they match (or even surpass?) the structural properties of classic metal parts used in construction? Other than that, I think the technology has a bright future in construction which is by large extent based on custom work (at least compared to autoindustry etc.).
@ Short Fuse
I've seen DMLS parts properties being listed as % of the same properties from parts made by casting, that are usually lower than those of machined parts that are usually lower than those of parts forged to shape...
With DMLS you end up with a structure that might have a certain degree of porosity, you might increase the density through Hot Isostatic Pressing (HIP) but still it won't match the structural properties of traditionally manufactured metal parts.
On the other hand what you get is a much greater freedom of design, as shown by the example pictured.
What worries me is that today there is a restricted set of components that can be bolted/welded together to form structural members. Thus, when the known structural strength of the steel used in them is added to the equation, it is possible to define quite precisely what their failure pattern will be and thus whether they are strong enough.
A completely different situation exists with these members. Imagine the hoops a designer had to go through in order to sign off the above design as being of sufficient strength to resist the loads it was going to meet in service.
I don't know, but I imagine that being sintered, crack propagation will be a major consideration of the designers wishing to specify such components. Sometimes progress takes one a step too far.
@ Mel Tisdale & Giolli Joker - Classic laser sintering will create a porous metal as you say, but there are new processes that do not. Electron beam fusing melts the layer entirely as well as a tiny part of the previous layer so the final part is actually one solid peice of metal. Laser sintering has also been advanced to fusion by allowing the beam to linger slightly longer on target accomplishing the same affect.
If traditional sintering were used the new SpaceX Super Draco thrusters would break very quickly due to cryo cooled liquids infiltrating the metal. The new fusing methods are what enable their 3d printed motors to function.
By printing the component you can get shapes that can not be put together in other way and having a single piece instead of several pieces held together by fasteners you could end up with lighter structures per strength even if the metal is not as strong.
I am dead certain that we can make gains with this technology as far as the artistic as well as the strength and safety of numerous products. But as we create new shapes that do not have a clearly identifiable history there will be commercial issues on how to order parts made with 3d printing. Your new, wonderful L bracket may look nothing like a traditional L bracket. So how do you order three hundred more of the same? I have seen pics on wonderful, structural beams that would defy any machine shop due to their intricate and complex variety of shapes. Walls can be a continuous sculpture as can ceilings. And that is without adding complexity or cost to a structure. No technology comes close to 3d printing.
Regarding the strength of 3D printed metal components, General Electric and Snecma have a common facility in Toulouse where they are making the turbofan blades for their jet engines in one piece instead of about 200 pieces, they claim, stronger, faster, lighter and cheaper.
Also BAE and Lockheed Martin are using 3D printing:
I would think a metallurgist would have to be involved to ascertain the strength of sintered versus CNC machines or cast steel - instinct (for that that's worth) tells me that sintered is not going to have the same strength since the at the molecular level the crystals of metal are being added a minute layer at a time.
So for decorative stuff, this could be dandy. For prototyping, to make a working model (the next Wankel engine, perhaps) it might work s well. But for a real-world full time part of some structure or machine, I would think the 3D approach would not be appropriate.
That said, to answer @Jim, to order 300 more of whatever you designed simply enter 300 in the "how may copies" field - after all, on that level the 3D digital file is no different than the Word file you can print any number of times.
Thanks for the information. Do you happen to know how the strength of this fused material you discuss compares with that of a cast component or a forged or rolled steel component? I guess it might have the best of both worlds, but, again, I have to admit that I do not know.
I suppose I am still concerned about their use in building construction because it will probably be necessary to test one to destruction in order to confirm the finite element analysis results, which could add to the costs significantly.
I'm waiting for a 3D printer that can weave composite fibers in their proper stronger than steel orientation.
I don't see why this should be any weaker than parts made by any other method. How is it any different from say casting or forging ? Both may need further handling like annealing / tempering / machining, In fact because of laser sintering on every thin layer of powder material there will be a lot less residual stress within the components. May not even need tempering which brings more distortion and has to be done under expensive and time consuming controlled condition.With trial and error they will come up with the correct composition of the powder being used.
Sorry guys, you can pack your slide rule and even calculators away.
For parts like this you can only use FEA methods for stress analysis.
The advantage to be gained is that you can design your parts to exactly match the load path and minimize the stress raisers. - Look at those nice big radii.
This technology also finally opens the door for the easier manufacturability of parts from Titanium and other strong alloys.
One more thing, the advantage of this method of manuf as opposed to casting is that there would be no random porosity. You will now know exactly what your part is looking like on the inside, no unwelcome surprises.
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