October_AMP_Digital

4 8 A D V A N C E D M A T E R I A L S & P R O C E S S E S | O C T O B E R 2 0 1 7 3D PRINTSHOP NEW PHOTOINITIATOR OFFERS HOPE FOR BIOMEDICAL ADVANCEMENTS Researchers at the Hebrew Uni- versity of Jerusalem’s Center for Nano- science and Nanotechnology may have solved one of the biggest challenges in the pursuit of advanced biomedical materials and structures. Although 3D printing holds great promise for fabri- cating components from organic mate- rials, the lackof a suitablephotoinitiator has so far prevented the type of break- throughs that have been envisioned— medical wonders like personalized tis- sues, bone plates, tendons, ligaments, and even entire organs. The delicate nature of such structures requires spe- cial scaffolding and a buoyant printing medium, namely water, where ordinary photoinitiators are ineffective. To address this need, researchers developed a water-soluble photoiniti- ator containing nanoparticles—hybrid strings of semiconductor and metal A NASA engineer prepares to test a high-power thruster based on Hall e ect rocket with magnetic shielding technology. Novel engine designs and the development of advancedmaterials such as high-temperature ceramics are a critical pathway for future deep space explorations. atoms—that develop charge and react catalytically when exposed to light. The new photoinitiator has tunable prop- erties and a wide excitation window stretching from the visible to UV range. It is also highly sensitive to light and its strong photocatalytic response increas- es printing efficiency while reducing the amount of materials required to create final parts. www.nano.huji.ac.il. NAVAL TEAM PRINTS SUBMERSIBLE HULL An engineering team led by mem- bers of the Naval Surface Warfare Cen- ter’s Disruptive Technology Laboratory has been recognized for its efforts in additive manufacturing. The group de- signed and printed a full-scale metal hull, which at 30-ft long is the largest naval asset ever produced using addi- tive technology. The proof-of-concept design is based on the Navy’s Mark 8 Mod 1 SEAL delivery vehicle, a manned submersible developed for special op- erations. It was printed in six sections on the big-area additive manufacturing ORNL’s big-area additive manufacturing platformprinted a 30- submersible hull modeled aer the U.S. Navy’s SEAL delivery vehicle. The project team re- ceived a Commander’s Award for Innova- tion fromNaval Sea Systems Command. (BAAM) platform at Oak Ridge Nation- al Laboratory. ORNL also helped with process modeling and used its pulsed neutron reactor to obtain detailed im- ages of residual stress in several proto- types produced by the team. The demo is the first step in the development of disposable or limited-use assets that can be reconfigured at the end of their mission. navy.mil. NASA LAUNCHES CERAMIC AM PROGRAM NASA has selected a commercial partner to begin building and testing 3D-printed ceramic rocket engine com- ponents. The work, awarded to HRL Laboratories LLC, Malibu, Calif., is part of NASA’s Space Technology Research, Development, Demonstration, and In- fusion program. HRL will build on its experience with preceramic resins that can be patterned using additive tech- niques then converted to a high-tem- perature ceramic state. With NASA sup- port, HRL researchers will produce re- inforced ceramic structures suited for advanced propulsion applications. The two-year project will also investigate novel rocket engine designs made pos- sible with high-temperature ceramics and assess associated performance im- provements. hrl.com. A novel photoinitiator (top le) contains tiny gold-tipped, cadmium-sulfide rods that absorb light, converting photonic energy to catalytic polymerization reactions. Plot on right compares absorption spectra of several photo- initiators. Plots in red and black corre- spond to initiators containing nanopar- ticles. TEM image is inset. Across the bottom: a spiral produced by two-photon polymerization, an aerogel in UV light, and a geodesic structure, all made with the new photoinitiator.