| Oct 07, 2023 |
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(Nanowerk Information) Researchers on the Division of Power’s Oak Ridge Nationwide Laboratory, in collaboration with NASA, are taking additive manufacturing to the ultimate frontier by 3D printing the identical form of wheel because the design utilized by NASA for its robotic lunar rover, demonstrating the know-how for specialised components wanted for area exploration.
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The additively manufactured wheel was modeled on the present, lightweight wheels of the Volatiles Investigating Polar Exploration Rover, or VIPER, a cell robotic NASA plans to ship in 2024 to map ice and different potential assets on the south pole of the moon. The mission is meant to assist decide the origin and distribution of the moon’s water and whether or not sufficient may very well be harvested from the moon’s floor to help individuals residing there.
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| In only a few days, ORNL researchers used powder mattress printing to create this lunar rover wheel based mostly on a NASA design. (Picture: Carlos Jones, ORNL)
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Whereas the prototype wheel printed at DOE’s Manufacturing Demonstration Facility, or MDF, at ORNL is not going to really be used on the NASA Moon mission, it was created to fulfill the identical design specs because the wheels made for NASA’s VIPER. Extra testing is deliberate to validate the design and fabrication methodology earlier than utilizing this know-how for future lunar or Mars rovers or contemplating it for different area purposes, equivalent to massive structural parts.
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Additive manufacturing can cut back vitality use, materials waste and lead time, whereas enabling design complexity and the tailoring of fabric properties. MDF is on the forefront of this effort, growing the know-how for over a decade for a variety of purposes within the clear vitality, transportation and manufacturing sectors. MDF researchers printed the rover wheel prototype at ORNL in Fall 2022. A specialised 3D printer used two coordinated lasers and a rotating construct plate to selectively soften steel powder into the designed form.
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Typical steel powder mattress techniques function in steps: In a machine the dimensions of a cupboard, they rake a layer of powder over a stationary plate. Then a laser selectively melts a layer earlier than the plate lowers barely and the method repeats. The printer used for the rover wheel prototype is massive sufficient for an individual to enter and is exclusive in its capacity to print massive objects whereas the steps happen concurrently and constantly, mentioned Peter Wang, who leads MDF improvement of latest laser powder mattress fusion techniques.
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“This dramatically will increase the manufacturing charge with the identical quantity of laser energy,” he mentioned, including that deposition happens 50% sooner. “We’re solely scratching the floor of what the system can do. I actually suppose that is going to be the way forward for laser powder mattress printing, particularly at massive scale and in mass manufacturing.” Wang and undertaking staff members not too long ago printed a examine, discovered right here, analyzing the scalability of the know-how for printing parts like electrical motors.
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Though the machine is exclusive, a key to the success of the undertaking was researchers’ experience in course of automation and machine management. They used software program developed at ORNL to “slice” the wheel design into vertical layers, then steadiness the workload between the 2 lasers to print evenly, attaining a excessive manufacturing charge, leveraging a computational approach not too long ago submitted for patent safety.
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The prototype wheel, one of many first components produced by the system, demonstrates the worth of interagency collaboration. “The undertaking with NASA actually propelled the know-how ahead,” mentioned Brian Gibson, the researcher who led the rover wheel undertaking for ORNL, calling it a milestone. “It was nice to attach a functionality with a growing want, and the staff was excited to be making a prototype element with area exploration purposes.”
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| Additive manufacturing permits positive design particulars, equivalent to wavy tread on a domed form, to be integrated into the prototype lunar wheel. (Picture: Carlos Jones, ORNL)
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Manufactured from a nickel-based alloy, the prototype wheel is about 8 inches extensive and 20 inches in diameter – a lot bigger than typical components printed with steel powder mattress techniques. Making it required the flexibility to print small geometric options unfold over a big work space. Additive manufacturing enabled better complexity within the rim design with out added value or manufacturing issue, Gibson mentioned.
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Compared, the 4 VIPER wheels that may churn via moon mud subsequent 12 months required a number of manufacturing processes and meeting steps. VIPER’s 50-piece wheel rim is held along with 360 riveted joints. The manufacturing course of required difficult and time-intensive machining to be able to meet the mission’s rigorous necessities.
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If NASA testing proves the 3D-printed prototype to be as strong as conventionally constructed wheels, future rovers might as an alternative use a single printed wheel rim, which took ORNL 40 hours to fabricate. Via the undertaking, ORNL and NASA engineers additionally explored printing exact design options, equivalent to angled sidewalls, a domed form and wavy tread to extend the wheel’s stiffness. These traits are troublesome to include within the present VIPER wheel design utilizing conventional fabrication strategies. Regardless of enabling a extra advanced spoke sample and spoke locking options to the wheel, 3D printing simplified and diminished the price of the wheel design and made remaining meeting simpler.
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“Numerous these wheel options have been put in simply to focus on what you are able to do with additive manufacturing,” mentioned Richard Hagen, a mechanical design engineer for NASA and additive manufacturing lab supervisor at NASA’s Johnson House Middle in Houston. “It allows you to simply implement design options which might be onerous to implement with conventional tooling or perhaps a historically machined half.” ORNL’s capacity to print massive objects demonstrates the potential of additive manufacturing know-how for producing a lot bigger rover wheels for each lunar and Martian missions, Hagen mentioned.
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A problem is that the specialised printer solely builds with sure supplies – on this case, a nickel-based alloy – so the 3D-printed wheel is 50% heavier than the aluminum VIPER wheel, whereas printed at an analogous thickness.
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NASA plans to check the 3D-printed wheel’s efficiency on a rover both within the rock yard at NASA’s Johnson House Middle or in an enormous “sandbox” of simulated lunar rocks and soil at a contracted check facility. Evaluators will assess the wheel’s maneuverability, pivoting resistance, sideways slippage, slope climbing and different efficiency metrics.
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Hagen mentioned additive manufacturing gives the benefit of fast design updates in response to testing. It may well additionally incorporate extra complexity, equivalent to a suspension system, with out including weak factors.
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Hagen mentioned crewed analysis stations positioned on the moon as a part of the company’s Artemis Program will want off-planet manufacturing functionality. “Having the ability to construct components in area for repairs will probably be necessary, since you simply can’t take sufficient spares,” he mentioned. “Powder, pellets or filament for printing are lots simpler to pack and would permit for extra flexibility.”
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“Additive manufacturing gives the flexibleness that in case you have the feedstock, you might make any alternative half you want, whether or not in area or on Earth,” Gibson mentioned. It is a purpose additive manufacturing has generated important curiosity for a spread of alternative wants, from quickly manufactured tooling to hard-to-source castings and forgings. For area exploration and habitation, 3D printers might ultimately use native materials from the moon or Mars as a feedstock.
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