Engineering topics
Publications and source records attributed to Keicher, David M..
Hybrid additive featured plates used to form an overall microchannel heat exchanger and corresponding method of manufacture are disclosed. Various additive manufacturing (AM) techniques may be used to form walls defining microchannel features on a plate substrate. The manufacturing method is a hybrid process in that leverages both additive and conventional manufacturing techniques to minimize both cost and fabrication time.
Hydrodynamic focusing of two fluid steams provides a novel micro printing technology for printed electronics and other high performance applications.
Additive Manufacturing (AM) can create novel and complex engineered material structures. Features such as controlled porosity, micro-fibers and/or nano-particles, transitions in materials and integral robust coatings can be important in developing solutions for fusion subcomponents. A realistic understanding of this capability would be particularly valuable in identifying development paths. Major concerns for using AM processes with lasers or electron beams that melt powder to make refractory parts are the power required and residual stresses arising in fabrication. A related issue is the required combination of lasers or e-beams to continue heating of deposited material (to reduce stresses) and to deposit new material at a reasonable built rate while providing adequate surface finish and resolution for meso-scale features. Some Direct Write processes that can make suitable preforms and be cured to an acceptable density may offer another approach for PFCs.
The invention provides pneumatic shuttering of a focused or collimated aerosol particle stream. The aerosol stream can be collimated by an annular sheath of inert or non-inert gas. The apparatus propagates a sheathed aerosol stream through a series of aerodynamic lenses along the axis of a flow cell. The final lens is typically positioned above a substrate, so that direct material deposition is provided. A substantially perpendicularly-flowing gas external to the aerodynamic lens system is used to redirect the particle stream away from the flow axis and through an exhaust port, thereby shuttering the collimated aerosol stream. The pneumatic shutter enables printing of discreet structures, with on/off shuttering times of approximately 1 to 100 milliseconds.