Rapid replication of powder composite high-aspect-ratio microstructures using silicone rubber micromolds

A microfabrication process allowing rapid replication of high aspect ratio powder composite microstructures is developed using silicone rubber casting. Potential applications include the elimination lead in medical imaging instruments, such as anti-scatter grids for X-ray imaging and collimators for nuclear imaging. In this paper, we demonstrated the high precision fabrication of grids and collimators using high density tungsten powder composite of about 9–9.5 g/cm3 or greater. Aspect ratio of 15:1 was demonstrated for a single piece and larger aspect ratio was achieved by precision stacking of many layers. The demonstrated replication process provides low cost, mass production of high-aspect-ratio microstructures.