Home

High-Velocity, Pulsed Wire Arc Spray

Higher spray velocity should result in superior deposits. A high-velocity, pulsed wire arc spraying apparatus has been proposed and partly developed in an effort to improve the quality of coatings deposited by thermal spray techniques. In this apparatus, material from a wire arc is atomized and propelled toward a deposition substrate by a repetitively pulsed plasma jet. As explained below, this development is prompted by (1) the observation that the particle velocities attainable in traditional wire arc spraying are too low to enable the deposition of dense, high-quality coating materials that are often desired and (2) the expectation that higher spray velocities should result in superior coatings.

Posted in: Manufacturing & Prototyping, Briefs

Read More >>

Thermal Spray Formation of Polymer Coatings

This innovation forms a sprayable polymer film using powdered precursor materials and an in-process heating method. This device directly applies a powdered polymer onto a substrate to form an adherent, mechanically-sound, and thickness-regulated film. The process can be used to lay down both fully dense and porous, e.g., foam, coatings. This system is field-deployable and includes power distribution, heater controls, polymer constituent material bins, flow controls, material transportation functions, and a thermal spray apparatus.

Posted in: Manufacturing & Prototyping, Briefs

Read More >>

Improved Gas Filling and Sealing of an HC-PCF

Compact hermetic joint is formed to seal connectorized all-fiber gas reference cell. An improved packaging approach has been devised for filling a hollow-core photonic-crystal fiber (HC-PCF) with a gas, sealing the HC-PCF to retain the gas, and providing for optical connections and, optionally, a plumbing fitting for changing or augmenting the gas filling. Gas-filled HC-PCFs can be many meters long and have been found to be attractive as relatively compact, lightweight, rugged alternatives to conventional gas-filled glass cells for use as molecular-resonance frequency references for stabilization of lasers in some optical-metrology, lidar, optical-communication, and other advanced applications. Prior approaches to gas filling and sealing of HC-PCFs have involved, variously, omission of any attempt to connectorize the PCF, connectorization inside a vacuum chamber (an awkward and expensive process), or temporary exposure of one end of an HC-PCF to the atmosphere, potentially resulting in contamination of the gas filling. Prior approaches have also involved, variously, fusion splicing of HC-PCFs with other optical fibers or other termination techniques that give rise to Fresnel reflections of about 4 percent, which results in output intensity noise.

Posted in: Manufacturing & Prototyping, Briefs, TSP

Read More >>

Capillography of Mats of Nanofibers

These mats can be the basis of small devices and instruments. Capillography (from the Latin capillus, “hair”, and the Greek graphein, “to write”) is a recently conceived technique for forming mats of nanofibers into useful patterns. The concept was inspired by experiments on carpetlike mats of multiwalled carbon nanotubes. Capillography may have the potential to be a less-expensive, less- time-consuming alternative to electron- beam lithography as a means of nanoscale patterning for the fabrication of small devices and instruments.

Posted in: Manufacturing & Prototyping, Briefs, TSP

Read More >>

Electron-Beam Welding of Superalloys at High Temperatures

Strain age cracks can be prevented. Electron-beam welding at high temperatures has been found to be a suitable process for joining structural components made by casting certain superalloys. This process can be used in the fabrication of superalloy parts that must withstand high operating temperatures. Examples of such parts include exhaust ducts of advanced aerospace engines and end caps on turbine buckets.

Posted in: Manufacturing & Prototyping, Briefs, TSP

Read More >>

Software for Optimized Flattening From 3D to 2D

Manufacturing considerations can be taken into account in designing minimally wasteful 2D patterns. A computer program offers enhanced capabilities for calculating two-dimensional (2D) patterns needed to construct specified three-dimensional (3D) surfaces to within acceptably close approximations, with minimal waste of sheet material. Examples of complexly shaped sheet-material items that could be designed by use of this program include aircraft fuselages, hulls of ships, clothing, and automotive bodies.

Posted in: Manufacturing & Prototyping, Briefs, TSP

Read More >>

Photolithographic Fine Patterning of Difficult-To-Etch Metals

Copper is used as a liftoff material. A process that includes photolithography, liftoff, etching, and sputter deposition has been developed to enable the fabrication of thin, finely patterned layers of gold, platinum, and other difficultto- etch materials in advanced miniature sensors and associated electronic circuitry. Heretofore, photolithography has been used in conjunction with liftoff and etching to produce finely detailed structures in easy-to-etch materials. The present process is needed because conventional photolithography cannot be used to pattern difficult-to-etch materials and the alternative processes heretofore available for patterning difficult-to-etch materials are limited to spatial resolution of about 0.005 in. (≈0.13 mm) or coarser.

Posted in: Manufacturing & Prototyping, Briefs, TSP

Read More >>