Advanced Technology and Manufacturing Institute (ATAMI)

Microchannel arrays are being developed across a wide spectrum of microfluidic applications including blood processing, fuel cells and thermal management among many others. Typical arrays are based on a flat laminated architecture produced in a vacuum hot press (VHP) through solid-state diffusion bonding. Due to the cylindrical nature of certain microfluidic applications, such as chemical processing within chemical facilities and heat rejection within Stirling cycle engines, the packaging of microchannel devices within cylindrical geometries would greatly simplify interconnect to other systems and expand practical application. This thesis describes the development of a novel technique for axisymmetric diffusion bonding capable of producing cylindrical microchannel arrays. Uniaxial bonding pressure is converted to axisymmetric pressure through an expandable cylinder, the design of which was aided by finite element analysis. Cylindrical test articles were produced by patterning thin metal foils by laser machining a single roll of metal shim stock, which was then coiled within an outer tube shell and axisymmetrically bonded with a VHP to produce a cylindrical microchannel array. Further, a mathematical model was developed to provide a means of channel alignment during device design. Bonding results show quality bond lines with minimal void fractions and good agreement with the channel alignment model. This new architecture provides a robust means for producing cylindrical microfluidic devices by microlamination using traditional equipment.