Rare Earth Aluminate Composites

These patented gear bearings provide superior speed reduction in a small package. They form rolling friction systems that function both as gears and bearings and are compatible with most gear types, including spur, helical, elliptical, and bevel gears. These self-synchronized components can be in the form of planets, sun, rings, racks, and segments thereof. The design reduces micro chatter and eliminates rotational wobble to create smooth and precise control. It offers tighter mesh, more even gear loading, and reduced friction and wear. Gear bearings eliminate separate bearings, inner races, and carriers, as well as intermediate members between gears and bearings. Load paths go directly from one gear bearing component to another and then to ground. By incorporating helical gear teeth forms (including herringbone), gear bearings provide outstanding thrust bearing performance. They also provide unprecedented high- and low-speed reduction through the incorporation of phase tuning. Phase tuning allows differentiation in the number of teeth that must be engaged govbetween input and output rings in a planetary gearset, enabling successful reduction ratios of 2:1 to 2,000:1. They provide smooth and accurate control with rifle-true anti-backlash. This produces a planetary transmission with zero backlash. The gear bearing technology is based on two key concepts: the roller gear bearing and the phase-shifted gear bearing. All designs are capable of efficiently carrying large thrust loads. Existing gear systems have drawbacks including weak structures, large size, and poor reliability, as well as high cost for some types (e.g., harmon-ic drives). Gear bearings solve these problems with simpler construction, fewer parts, and superior strength. By selecting the appropriate manufacturing method and materials, gear bearings can be tailored to benefit any application, from toys to aircraft.

60NiTi, which contains 60% nickel and 40% titanium, is a superelastic intermetallic material for use in bearings, gears, and other mechanical systems. When properly processed, 60NiTi is hard, lightweight, electrically conductive, highly corrosion resistant, readily machined prior to final heat treatment, non-galling, and non-magnetic. 60NiTi was previously considered difficult to machine, partly because of issues with residual stresses and quench cracking. Modern ceramic processing methods, co-developed by NASA Glenn, now enable 60NiTi bearings to be easily manufactured. In addition, a method is available for pre-stressing the materials to increase their durability. Bearing-grade 60NiTi is manufactured via a patented, high-temperature powder metallurgy (PM) process. Pre-alloyed 60NiTi powder is hot isostatic pressed (HIPed) into various shapes and sizes depending upon the desired end product. To make 60NiTi balls, the powder is HIPed into rough, spherical ball blanks that are then ground, polished, and lapped. Because the PM process yields ball blanks that have isotropic mechanical properties, high-quality (Grade 5) ball bearings can be readily produced. The finished 60NiTi balls are bright and shiny in appearance and resemble conventional polished steel balls. The manufacture of 60NiTi balls is a fully commercialized process, and many standard ball sizes are available. The material can also be shaped into other metallic components, such as gears, sliding bearings, actuators, and drives.

EBAM technology is capable of making full-density, functional metallic components for numerous engineering applications; the technology is particularly advantageous in the aerospace, automotive, and biomedical industries where high-value, low-volume, custom-design productions are required. A key challenge in EBAM is overcoming deformation of overhangs that are the result of severe thermal gradients generated by the poor thermal conductivity of metallic powders used in the fabrication process. Conventional support structures (Figure 1a) address the deformation challenge; however, they are bonded to the component and need to be removed in post- processing using a mechanical tool. This process is laborious, time consuming, and degrades the surface quality of the product. The invented support design (Figure 1b) fabricates a support underneath an overhang by building the support up from the build plate and placing a support surface underneath an overhang with a certain gap (no contact with overhang). The technology deposits one or more layers of un-melted metallic powder in an elongate gap between an upper horizontal surface of the support structure and a lower surface of the overhang geometry. The support structure acts as a heat sink to enhance heat transfer and reduce the temperature and thermal gradients. Because the support structure is not connected to the part, the support structure can be removed freely without any post-processing step. Future work will compare experimental data with simulation results in order to validate process models as well as to study process parameter effects on the thermal characteristics of the EBAM process.

Free form fabrication of articles often requires the application of heat to melt the fabrication material feedstock, and controlled cooling to ensure that once the material is put into place, the fabricated structure does not suffer from distortion. Investigators at LaRC have developed a simple method to apply localized heat, by using an electrically conductive nozzle and a conductive plate as the electrodes for electrically conductive filaments. This method is intended to be used for laying down electrically conductive filaments in a fast, accurate and controlled manner with localized heat.

NASA developed this High Flow Differential Cleaning technology in response to in-house needs for a more automated and effective method to remove stubborn particles from complex parts fabricated using powder-bed-fusion equipment. The invention uses a large volume of pressurized air to quickly enter a cleaning chamber. Based on the Bernoulli principle and Continuity equation, the high flow results in significant air velocity and a decrease in pressure when airflow passes through smaller component orifices, which in turn removes remnant powder from the part. In one embodiment, the invention consists of a (1) high-pressure air compressor with ISO 8573 Class 2 drying capability, (2) a large pressure chamber with a fast-actuated valve system to, (3) a cleaning chamber containing various sensors, injection systems, (4) a test fixture designed for easy orientation adjustments, and (5) an expansion chamber allowing air to expand and drop in velocity, particles to settle, and filtered air to re-enter the room. This NASA technology can be implemented as a standalone cleaning system for powder bed fusion additively manufactured parts, or could be integrated into a packaged post-processing system offering. CT scans of complex NASA parts cleaned using a proof-of-concept system based upon the invention revealed very promising results. NASA welcomes industry to test the cleaning speed and efficacy of the technology under an evaluation license.