ADVANCED MATERIALS & PROCESSES | NOVEMBER/DECEMBER 2023 52 3D PRINTSHOP REINVENTING A LUNAR WHEEL WITH 3D PRINTING Researchers at the Department of Energy’s Oak Ridge National Laboratory have used 3D printing to recreate a wheel design used by NASA for its robotic lunar rover. The additively manufactured wheel was modeled on the existing, lightweight wheels of the Volatiles Investigating Polar Exploration Rover, or VIPER, a mobile robot NASA plans to send in 2024 to map ice and other potential resources at the south pole of the moon. The wheel was printed at the DOE’s Manufacturing Demonstration Facility (MDF) using a specialized 3D printer with two coordinated lasers and a rotating build plate to selectively melt metal powder into the designed shape. Peter Wang, who leads MDF development of new laser powder bed fusion systems notes that “this dramatically increases the production rate with the same amount of laser power,” adding that deposition occurs 50% faster. “We’re only scratching the surface of what the system can do. I really think this is going to be the future of laser powder bed printing, especially at large scale and in mass production.” Although the machine is unique, a key to the success of the project was researchers’ expertise in process automation and machine control. They used software developed at ORNL to “slice” the wheel design into vertical layers, then balance the workload between the two lasers to print evenly, achieving a high production rate, leveraging a computational technique recently submitted for patent protection. ornl.gov. LIFELIKE WEARABLE MATERIAL ACTS LIKE TISSUE Engineers at Lawrence Livermore National Laboratory (LLNL) and Meta have developed a material that acts like biological tissue, essentially combining soft and stiff characteristics in one. LLNL engineer Sijia Huang says the technique works by manipulating the intensity of light applied to a photopolymer resin though the digital light processing 3D printing process—a layer-by-layer technique that can rapidly produce parts by projecting light into a liquid resin—to modulate the deposited plastic material. A lower light intensity results in a softer material, while a higher light intensity results in a stiffer material. To demonstrate the potential, engineers at Meta used the material to 3D-print an inexpensive braille display that could be worn on a single finger and connected to a smartphone and an air pump. When text is transmitted via the phone, sections of the wearable fill with air, causing it to deform and create braille letters, enabling a sightless person to “read” the text through the device. To allow the device to function, researchers needed to vary the stiffness in a single device so it would deform differently when air is pumped into the device, Huang adds. The material is stretchable to around 200 times its original properties, and as its gradient transitions from soft to stiffer material, its toughness increases by 10 times. Huang says the material could be tailored for energy- absorbing materials, soft robotics, and wearable electronic devices. llnl.gov. A 3D-printed device worn on the finger can ‘translate’ text messages to braille by filling the device with air at strategic points. Courtesy of Lawrence Livermore National Laboratory. Additive manufacturing allows fine design details, such as wavy tread on a domed shape, to be incorporated into the prototype lunar wheel. Courtesy of Carlos Jones/ORNL. ImplementAM, a provider of educational one-day workshops focused on 3D printing and additive manufacturing technologies, has been acquired by the Society of Plastics Engineers (SPE). This is SPE’s second acquisition in additive manufacturing, following its purchase of 3Dnatives earlier this year. Together, the shared goal of the three businesses is to bridge the gap between traditional manufacturing-based businesses and additive manufacturing, offering innovative ways to enhance manufacturing processes. 4spe.org. BRIEF
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