Abstract: An apparatus for forming three-dimensional objects includes a crucible (1) for holding a molten material; a conically-shaped orifice (1a) having a fixed outlet diameter (do) at the bottom of the crucible through which a jet (50) of the molten material flows towards the substrate; and an oscillating mechanical member (5) for breaking the flow of molten material into the molten material drops (60). The oscillating mechanical member further includes a conically-shaped head (5a) for cooperating with the orifice (1a) and for varying the effective size of the orifice. The conically-shaped head includes a slanted radial portion (5c) and a tip portion (5b) extending through the orifice. The effective diameter (deff) of the jet is defined by the relationship deff=[d02?(d0?? tan ?)2]1/2, wherein ? represents the amount of the tip portion extending through the orifice, and ? represents a slant angle corresponding to the slanted radial portion of the conically-shaped head.

Abstract: A method and apparatus for efficiently and rapidly mixing liquids in a swirling flow micro system is disclosed. The micro mixer disclosed is a passive mixer of planar structure for simpler configuration and fabrication. The streams injected tangentially into the mixing chamber produce circular multi-lamination for effective mixing of the injected streams. The injection velocity and position can be altered by adjusting the contour and exit area of the nozzles. The planar mixer can be fabricated by the normal photolithography process in conjunction with anodic bonding. More economically the layered structures of the mixer can also be fabricated in thin plastic sheets using stamping, embossing or other thermal deformation techniques. The different layers are thermally bonded for mass production.