EUROPEAN CONGRESS AND EXHIBITION ON ADVANCED MATERIALS AND PROCESSES - EUROMAT 2021

Current freeform microfabrication methods are either sequential two-dimensional layering processes, or are experimental methods that have difficulty in producing at industrially viable speed three-dimensional parts of dense metal with a spatial resolution of one micrometre or less. We show that metal casting provides an alternative approach for the three-dimensional freeform fabrication of dense metal components with micrometric resolution. High-temperature metal casting has so far resisted downscaling to the micron-scale because at that scale capillary phenomena interfere both with melt flow and with precise fine-scale mold production. We combine femtosecond laser micro-machining of glass molds with metal pressure infiltration to produce glass/metal combinations that can serve together in microdevices or can yield cast metal microparts after selective mold dissolution. Dense 3D parts of arbitrary shape and made of silver, copper, gold and their alloys are demonstrated, with features of size down to ~1.5 µm. This gives microfabrication the same ability to turn, as is done in macro-scale fabrication, to casting when geometrically complex metallic parts are to be produced.