Enabling additive manufacturing part inspection of digital twins via collaborative virtual reality
Not Available
42 ENGINEERING↗
Engineering topics
Au, Brian
Publications and source records attributed to Au, Brian.
Spray System Documentation
The intent of this document is to provide background information on key design decisions for the Automatic Spray System, developed at LLNL. The document will overview mechanical, electrical, and toolpath critical decisions. The purpose of this design is to repeatably and uniformly spray parts with a variety of materials. The main aspects of the design are an atomizing air siphon spray nozzle and two rotary axes, C and B. Both axes are controlled by a NEMA17 stepper motor. The C axis is essentially a turntable that rotates the part to be sprayed. The B axis is where the atomizing spray nozzle is attached to the “crawler,” which is a stepper motor on an internal gear. Traditionally, spraying of hemispherical mandrels was done by a trained operator. Depending on the operator, there may be varying thickness in the spray coating. Moving towards an automated spraying system will reduce this variability and increase thickness consistency and uniformity.
42 ENGINEERING↗
Optimizing exposure times of structured light metrology systems using a digital twin
Not Available
36 MATERIALS SCIENCE↗
Refractive index matched polymeric and preceramic resins for height-scalable two-photon lithography
Studying the effect of resin RI on print fidelity. Chemically modifying RI resins to demonstrate 3D structures print without height limitation resulting on ceramic and nonceramic print as tall as 2.5 mm with sub-micron features.
37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CH↗
White-light interferometry for early-stage metal oxide growth characterization
Oxidation of metals can provide a functional oxide film or an oxide layer that can lead to material degradation causing performance limiting concerns. Because of the technological and economic impacts of oxidation, understanding early-stage oxidation growth and its mechanisms is of high importance. Unfortunately, poor empirical data during early-stage oxidation has left our current understanding of oxidation incomplete and woefully inadequate. Measurement techniques previously used for oxidation kinetics characterization include microbalance, x-ray diffraction, Fourier-transform infrared spectroscopy, and spectroscopic ellipsometry. However, these techniques lack the necessary time-resolution or vertical resolution in addition to not providing any spatial data, which is essential to early-stage oxidation studies to understand both oxidation kinetics and mechanisms. Here, a novel rapid and surface-sensitive data collection technique that provides three-dimensional spatial data of a growing oxide layer with sub-nanometer thickness resolution using white-light interferometry has been developed. This technique will be the first technique capable of providing real-time spatial results of early-stage oxidation growth. The effectiveness of this characterization tool is shown by observing the early-stage oxidation kinetics and film cracking of uranium heated to 90 °C under 500 torr of pure O 2 . Initially a parabolic oxidation growth is observed. Once the oxide layer reaches ≈ 30 nm, the epitaxial stresses between the uranium substrate and oxide film layer causes localized cracking in addition to the observed transition of the parabolic growth rate to a linear growth rate. The results of the white-light interferometry are verified by glancing incidence x-ray diffraction.
47 OTHER INSTRUMENTATION↗
High-Speed Direct Laser Writing of Silver Nanostructures via Two-Photon Reduction
Despite the widespread use of metallic nanostructures in several emerging applications, high-throughput template-free fabrication techniques that are capable of patterning arbitrarily complex nanostructures are lacking. Two-photon reduction-based direct laser writing is a promising technique due to its ability to fabricate geometrically intricate metallic structures with sub-diffraction nanoscale features. Unfortunately, the extremely low writing speed of ≈10 μm s -1 makes this process impractical for large-scale manufacturing. The operating speed is currently limited by a lack of photoresist materials that can operate under high-speed writing conditions. Herein, a silver-containing aqueous photoresist recipe is presented that increases the writing speed to 1 cm s -1 while maintaining the ability to fabricate sub-diffraction silver nanowires as thin as 500 nm. In addition, the electrical conductivity of the printed silver is within one-fifth that of bulk silver. Strikingly, it is demonstrated here that the conventional design rule of using surfactants to promote high-quality printing is faulty under high-speed conditions. Instead, surfactants limit the throughput and are eliminated to enable high-speed writing. The 1000× throughput scale-up presented here significantly improves our ability to transition nano-enabled devices from research laboratories to real-world adoption.
36 MATERIALS SCIENCE↗