Patrick N. Keifer

Imaging indicator for ESD safety testing.

This report describes the development of a new detection method for electrostatic discharge (ESD) testing of explosives, using a single-lens reflex (SLR) digital camera and a 200-mm macro lens. This method has demonstrated several distinct advantages to other current ESD detection methods, including the creation of a permanent record, an enlarged image for real-time viewing as well as extended periods of review, and ability to combine with most other Go/No-Go sensors. This report includes details of the method, including camera settings and position, and results with wellcharacterized explosives PETN and RDX, and two ESD-sensitive aluminum powders.

Sacrificial layer for the fabrication of electroformed cantilevered LIGA microparts

The use of silver filled PMMA as a sacrificial layer for the fabrication of multilevel LIGA microparts is presented. In this technique, a bottom level of standard electroformed LIGA parts is first produced on a metallized substrate such as a silicon wafer. A methyl methacrylate formulation mixed with silver particles is then cast and polymerized around the bottom level of metal parts to produce a conducting sacrificial layer. A second level of PMMA x-ray resist is adhered to the bottom level of metal parts and conducting PMMA and patterned to form another level of electroformed features. This presentation will discuss some the requirements for the successful fabrication of multilevel, cantilevered LIGA microparts. It will be shown that by using a silver filled PMMA, a sacrificial layer can be quickly applied around LIGA components; cantilevered microparts can be electroformed; and the final parts can be quickly released by dissolving the sacrificial layer in acetone.