Manufacturing & Prototyping

Fiber Metal Laminates Made by the VARTM Process

Fiber metal laminates combine the best properties of the metal and composite.

Langley Research Center, Hampton, Virginia

Fiber metal laminates (FMLs) are multicomponent materials utilizing metals, fibers, and matrix resins. Tailoring their properties is readily achievable by varying one or more of these components. Two new processes for manufacturing FMLs using vacuum assisted resin transfer molding (VARTM) have been developed.

Posted in: Briefs, TSP, Manufacturing & Prototyping, Manufacturing processes, Coatings, colorants, and finishes, Fibers, Metals, Resins

Method to Produce Copper Nanowires for Interconnect Applications

Ames Research Center, Moffett Field, California

Copper replaced aluminum nearly two decades ago as interconnect material in integrated circuit manufacturing due to its better electrical conductivity. The size of the interconnect wire has been steadily decreasing as Moore’s law has been progressing through various feature size generations. The diameter of the interconnect structure is further expected to decrease as silicon technology is poised to march through a few more generations. Alternatives to copper have been reported—notably, materials such as carbon nanotubes. Their success has been limited, and carbon nanotubes have not been integrated into manufacturing practice.

Posted in: Briefs, Manufacturing & Prototyping, Wiring, Copper, Nanomaterials

Development of a Precision Thermal Doubler for Deep Space

A copper thermal doubler is used to spread the thermal loads.

Thermal requirements and a need for a very flat mechanical interface led to the development of a copper doubler for the titanium vault on the Juno Spacecraft. The vault is designed to contain the science instruments on the spacecraft, protecting them from damage due to the extreme radiation environment of Jupiter. The titanium used in the vault creates unwanted thermal effects due to the poor thermal conductivity of titanium. To remove heat from the telecommunication equipment mounted to the interior of the vault, a copper thermal doubler was used to spread the thermal loads over the entire area of the radiator (located on the outside of the vault), which decreased the effective thermal resistance through the vault wall. A method of bonding a copper doubler to the titanium preserves the mounting interface flatness to less than 0.005 in. (0.13 mm) while providing a superior thermal path to the radiators, which are fitted with thermal control louvers. The precisely controlled titanium surface, and that of the milled copper doubler with integral spacing features, provides the mechanical interface flatness, structural integrity, and thermal performance required by the telecommunications subsystem.

Posted in: Briefs, TSP, Manufacturing & Prototyping, Thermal management, Milling, Copper, Insulation, Titanium, Spacecraft

Improving Friction Stir Welds Using Laser Peening

This technique can be used in any application of friction stir welding, including automotive, railroad, and maritime industries.

Friction stir welding (FSW) has emerged as a promising solid-state process with encouraging results, particularly when used on high-strength aerospace aluminum alloys that are generally difficult to weld. Laser peening has been applied to the mechanical and fatigue properties of welded joints. Laser peening introduces a compressive residual stress at the surface that can extend several millimeters or deeper into the material. These residual stresses resulting from laser peening can be significantly higher and deeper than for conventional shot peening, resulting in superior mechanical and fatigue properties in FSW.

Posted in: Briefs, TSP, Manufacturing & Prototyping, Finite element analysis, Peening, Welding

Methodology of Evaluating Margins of Safety in Critical Brazed Joints

This methodology provides a guide consisting of design, testing, and structural analysis steps developed to assure positive strength margins of safety (MS) in critical brazed joints used for assembly of flight and non-flight structures.

Posted in: Briefs, TSP, Manufacturing & Prototyping, Finite element analysis, Joining, Parts

Ion Milling On Steps for Fabrication of Nanowires

This process could readily be scaled up for mass production.

Arrays of nanowires having controlled dimensions can now be fabricated on substrates, optionally as integral parts of multilayer structures, by means of a cost-effective, high-yield process based on ionmilling on steps. Nanowires made, variously, of semiconductors or metals are needed as components of sensors and high-density electronic circuits.

Posted in: Briefs, TSP, Manufacturing & Prototyping, Fabrication, Milling, Metals, Nanomaterials, Semiconductors

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