Manufacturing & Prototyping

Shape Memory Polymer Process Development

This work introduces a simple technique of separately fabricating electrospun short fibers. This technique employs a paper mesh, which is placed between the needle tip and counter electrode of the electrospinning unit. Usability of this technique was examined by fabricating fine fibers consisting of different kinds of polymers.

Posted in: Briefs, Manufacturing & Prototyping, Fabrication, Fibers, Polymers, Smart materials

Surface-Plasmon-Enhanced Organic Thin-Film Solar Cells

Fabrication of two-dimensional metal nanoparticle arrays was achieved both by thermal annealing and nanosphere lithography techniques, which are both very fast and economic. The surface plasmon resonance of the fabricated nanostructure was analyzed experimentally by optical absorption spectroscopy and theoretically by three-dimensional finite-difference time-domain (FDTD) calculation. The surface plasmon resonance frequency of the metal nanos- tructure can be modified to match the solar spectrum by adjusting several processing parameters. These results will provide a database of the surface plasmon resonance of different metal nanoparticle arrays with different sizes and shapes.

Posted in: Briefs, Manufacturing & Prototyping, Finite element analysis, Data acquisition and handling, Spectroscopy, Fabrication, Nanomaterials

Solution Deposition Methods for Carbon Nanotube Field-Effect Transistors

Extensive research has been done on carbon nanotube field-effect transistors (CNTFETs), which may revolutionize electronics. Single-walled carbon nano-tubes (SWNTs) act as the channel between the source and the drain of the transistor device. CNTFETs can have very high on/off current ratios, but the presence of metallic CNTs, in addition to semiconducting CNTs, reduces the on/off ratio significantly. Therefore, the CNT thin film has a major influence on the transistor behavior and must be carefully developed.

Posted in: Briefs, Manufacturing & Prototyping, Transistors, Nanomaterials

Micro-Propulsion Devices Made of Low-Temperature Co-Fired Ceramics

In the satellite industry, the trend is towards decreasing the size of satellites and clustering of small satellites. Technological advancements in microelectronics have made it more economical to launch a cluster of satellites with a single vehicle rather than the traditional one satellite per vehicle. A small satellite cannot carry a large quantity of fuel or batteries for power so it will require an alternative propulsion system for station-keeping and orbital corrections. The current micro-propulsion alternatives include miniaturized versions of Hall Effect thrusters, plasma thrusters, and chemical devices. These devices are commonly fabricated as microelectromechanical system (MEMS) devices using silicon.

Posted in: Briefs, Manufacturing & Prototyping, Downsizing, Microelectricmechanical device, Product development, Ceramics, Silicon alloys, Satellites

Microfabrication and Testing of a Thermoelectric Device for Generating Mobile Electrical Power

Several attractive features of thermo-electric (TE) technology include no moving parts, light weight, modularity, covertness, silence, high power density, low amortized cost, and long service life with no required maintenance. Many of the potential uses for mounted/ dismounted power, such as recharging batteries, are therefore ideal for TE technologies. However, these applications will require more interconnected, smaller-scale modular devices than are currently available. Most commercial off-the-shelf (COTS) TE devices are optimized for cooling, not for generating power, so new device structures with materials and geometries better optimized for power generation are needed for broader use of TE technologies.

Posted in: Briefs, Manufacturing & Prototyping, Architecture, Fabrication, Electro-thermal engines, Test procedures

Manufacturing Cylindrical Parts Using Deep Draw Technology

In applications where product performance is mission critical, commercial, military, and aerospace companies require technology to manufacture deep- drawn cylindrical product components. Conventional production alternatives such as impact, spinning, and supplemental annealing processes often do not deliver reliable results for certain applications.

Posted in: Briefs, Manufacturing & Prototyping, Molding, Production engineering, Parts

Fabricating Biologically Inspired Artificial Haircell Sensors

As electronics packaging and equipment have decreased in size and weight, so have the potential dimensions of unmanned aircraft. Specifically, a classification of micro air vehicles (MAVs) has emerged that limits the scale of the aircraft to approximately 6" (15 cm). A project is underway aimed at developing artificial haircell flow sensors following biological inspiration of insect flow sensors, and demonstrate the potential of these sensors for controlling the flight of MAVs.

Posted in: Briefs, Manufacturing & Prototyping, Downsizing, Sensors and actuators, Biological sciences, Unmanned aerial vehicles

Improvements in Manufacturing BMI/Fiber Composites Using AFP

A program now in progress is dedicated to making improvements in automated fiber placement (AFP) for the manufacture of advanced composite-material (matrix/fiber) structural components — especially skin and shell components for aircraft. [In AFP, a composite-material part is formed by laying down fiber tow or tape pre-impregnated with a matrix resin (“prepreg”) onto a mandrel that defines the shape of the part.] Improvements are sought for the following reasons:

Posted in: Briefs, Manufacturing & Prototyping

Patterning of Polycrystalline Bi2Te3 Thin Films on Silicon

Experiments in patterning of thin films of polycrystalline bismuth telluride (Bi2Te3) on silicon substrates have been performed. Bi2Te3 is representative of a family of thermoelectric materials that are well suited for use in extracting electric energy from thermal gradients associated with flows of waste heat at temperatures in the approximate range of 0 to 150°C. Techniques and processes for fabricating macroscopic thermoelectric devices from bulk thermoelectric materials are mature and well known, but the same cannot yet be said concerning the fabrication of microscopic thermoelectric devices. The experiments reported here were performed as part of a continuing effort to develop capabilities for fabrication (including mass production) of microscopic thermoelectric devices, with a view toward eventually enabling the incorporation of them as integral parts of micro-electromechanical systems (MEMS) that could also include heat exchangers, sensors, actuators, and/or flow channels. Thus, the development of microscopic thermoelectric devices could benefit from the established industrial infrastructure for manufacturing MEMS and other silicon-based microsystems.

Posted in: Briefs, Manufacturing & Prototyping

Progress Toward Carbon-Nanotube Arrays for Probing Cells

Progress has been reported in research oriented toward the goal of fabricating arrays of interconnected single-walled carbon nanotubes (SWNTs) that could serve as probes for measuring localized events within living cells. As used here, "interconnected" signifies mechanically and electrically connected to patterned metal films (interconnections) that lead to contact pads, which, in turn, enable electrical connection to external electronic instrumentation. This research poses a high economic risk because it entails pushing several technological disciplines beyond their present limits. There is no previously reported combination of fabrication techniques and processes for producing carbon nanotubes that have the required properties at the required positions and orientations on patterned metal films.

Posted in: Briefs, Manufacturing & Prototyping, Architecture, Sensors and actuators, Biological sciences, Fabrication, Metals, Nanomaterials