Manufacturing & Prototyping

A New Process for Fabricating Random Silicon Nanotips

This process is relatively simple and inexpensive. An improved process for the fabrication of random arrays of silicon nanotips has been demonstrated to be feasible. Relative to other such processes, this process offers advantages of low cost and simplicity. Moreover, this process can readily be combined with other processes used to fabricate integrated circuits and other monolithic silicon structures.

Posted in: Manufacturing & Prototyping, Briefs

Read More >>

Resin-Transfer-Molding of a Tool Face

A resin-transfer-molding (RTM) process has been devised for fabricating a matrix/graphite-cloth composite panel that serves as tool face for manufacturing other composite panels. Heretofore, RTM has generally been confined to resins with viscosities low enough that they can readily flow through interstices of cloth. The present process makes it possible to use a high-temperature, more-viscous resin required for the tool face. First, a release layer and then a graphite cloth are laid on a foam pattern that has the desired contour. A spring with an inside diameter of 3/8 in. (˜9.5 mm) is placed along the long dimension of the pattern to act as a conduit for the resin. Springs with an inside diameter of 1/4 in. (˜6.4 mm) are run off the larger lengthwise spring for distributing the resin over the tool face. A glass cloth is laid on top to act as breather. The whole layup is vacuum-bagged. Resin is mixed and made to flow under vacuum assistance to infiltrate the layup through the springs. The whole process takes less than a day, and the exposure of personnel to resin vapors is minimized.

Posted in: Manufacturing & Prototyping, Briefs

Read More >>

Automated Rapid Prototyping of 3D Ceramic Parts

Unlike in prior rapid-prototyping processes, there is no manual stacking of sheets. An automated system of manufacturing equipment produces three-dimensional (3D) ceramic parts specified by computational models of the parts. The system implements an advanced, automated version of a generic rapid-prototyping process in which the fabrication of an object having a possibly complex 3D shape includes stacking of thin sheets, the outlines of which closely approximate the horizontal cross sections of the object at their respective heights. In this process, the thin sheets are made of a ceramic precursor material, and the stack is subsequently heated to transform it into a unitary ceramic object.

Posted in: Manufacturing & Prototyping, Briefs

Read More >>

Templates for Fabricating Nanowire/Nanoconduit-Based Devices

Prior templating processes are being extended to finer spatial resolutions. An effort is underway to develop processes for making templates that could be used as deposition molds and etching masks in the fabrication of devices containing arrays of nanowires and/or nanoconduits. Examples of such devices include thermoelectric devices, nerve guidance scaffolds for nerve repair, photonic-band-gap devices, filters for trapping microscopic particles suspended in liquids, microfluidic devices, and size-selective chemical sensors. The technology is an extension of previous work conducted by JPL, UCSD (University of California, San Diego), and Paradigm Optics Inc., which developed a process to fabricate macroporous scaffolds for spinal-cord repair.

Posted in: Manufacturing & Prototyping, Briefs

Read More >>

Measuring Vapors To Monitor the State of Cure of a Resin

Excess curing time would no longer be needed as margin against uncertainty. A proposed noninvasive method of monitoring the cure path and the state of cure of an epoxy or other resin involves measurement of the concentration(s) of one or more compound(s) in the vaporous effluent emitted during the curing process. The method is based on the following general ideas:

Posted in: Manufacturing & Prototyping, Briefs

Read More >>

Manufacture of Regularly Shaped Sol-Gel Pellets

For mass production, an extrusion process is superior to a spray process. An extrusion batch process for manufacturing regularly shaped sol-gel pellets has been devised as an improved alternative to a spray process that yields irregularly shaped pellets. The aspect ratio of regularly shaped pellets can be controlled more easily, while regularly shaped pellets pack more efficiently. In the extrusion process, a wet gel is pushed out of a mold and chopped repetitively into short, cylindrical pieces as it emerges from the mold. The pieces are collected and can be either (1) dried at ambient pressure to xerogel, (2) solvent exchanged and dried under ambient pressure to ambigels, or (3) supercritically dried to aerogel. Advantageously, the extruded pellets can be dropped directly in a cross-linking bath, where they develop a conformal polymer coating around the skeletal framework of the wet gel via reaction with the cross linker. These pellets can be dried to mechanically robust X-Aerogel.

Posted in: Manufacturing & Prototyping, Briefs

Read More >>

Improved Fabrication of Lithium Films Having Micron Features

Dry chemicals and a dry process are used to prevent undesired reactions. An improved method has been devised for fabricating micron-dimension Li features. This approach is intended for application in the fabrication of lithium-based microelectrochemical devices — particularly solid-state thinfilm lithium microbatteries.

Posted in: Manufacturing & Prototyping, Briefs

Read More >>