Three Dimensional Imaging of LIGA-Made Microcomponents

Abstract

Nickel and nickel-alloy microparts sized on the order of 5–1000 microns have been imaged in three dimensions using a new microscopic technique, Digital Volumetric Imaging (DVI). The gears were fabricated using Sandia National Laboratories’ LIGA technology (lithography, molding, and electroplating). The images were taken on a microscope built by Resolution Sciences Corporation by slicing the gear into one-micron thin slices, photographing each slice, and then reconstructing the image with software. The images were matched to the original CAD (computer aided design) model, allowing LIGA designers, for the first time, to see visually how much deviation from the design is induced by the manufacturing process. Calibration was done by imaging brass ball bearings and matching them to the CAD model of a sphere. A major advantage of DVI over scanning techniques is that internal defects can be imaged to very high resolution. In order to perform the metrology operations on the microcomponents, high-speed and high-precision algorithms are developed for coordinate metrology. The algorithms are based on a least-squares approach to data registration the {X,Y,Z} point clouds generated from the component surface onto a target geometry defined in a CAD model. Both primitive geometric element analyses as well as an overall comparison of the part geometry are discussed. Initial results of the micromeasurements are presented in the paper.

Modeling liquid porosimetry in modeled and imaged 3-D fibrous microstructures

“…(8). Unlike all previous published works, k is not treated as a constant number in the current work.…”

“…Note here that the PDFs shown in these figures closely resemble a Gamma distribution, as given in Eq. (8). This analysis shows that the shape factor, k, is not a constant value as assumed by some authors.…”

“…Digital volumetric imaging (DVI) [Microscience Group Inc.], is a block-face fluorescence imaging technique [8]. In this technique, the material, embedded in a polymeric resin, is repeatedly sectioned and imaged.…”

“…Parameters used in Eq (8). to obtain probability density function of pore diameters of nonwoven fabrics λ (micron −1 )…”

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