Extruded structure with equilibrium shape

A method for manufacturing an extrusion head for a micro extrusion apparatus, the method comprising:

• etching a first sheet such that an elongated trench is defined in a surface of the sheet, the elongated trench having an open end disposed at a side edge of the sheet and an opposing closed end, the elongated trench having a generally semi-cylindrical surface;
• etching a second sheet such that the second sheet includes an inlet port passing entirely through the second sheet;
• and
• bonding the first sheet to the second sheet such that the inlet port is aligned with the closed end of the elongated trench, and such that a flat surface portion of the second sheet is disposed opposite to the elongated trench between the inlet port and the side edge, whereby the elongated trench and the flat portion of the second sheet form a fluidic channel that extends between the inlet port and an outlet orifice located at the side edge, wherein the outlet orifice has a flat edge formed by a side edge of the second sheet, and an oblique edge formed by the an end of the elongated trench.

A method for forming a plurality of parallel elongated extruded structure on a substrate such that each of the plurality of parallel elongated extruded structures has an equilibrium shape, the method comprising:

• positioning an extrusion head adjacent to a surface of the substrate such that each of a plurality of outlet orifices defined by the extrusion head are disposed at a predetermined distance over the surface, wherein the extrusion head includes:
• a first sheet having a planar first surface and a first side edge;
• a second sheet having a planar second surface and a second side edge,
• wherein the second sheet is mounted on the first sheet such that a flat portion of the second surface abuts the first surface, and
• wherein the second surface of the second sheet defines a plurality of elongated parallel trenches, each elongated trench extending from an associated closed end to the second side edge and having a concave oblique surface extending from the closed end to the second side edge, thereby forming an associated fluidic channel having an associated said outlet orifice including a straight first edge defined by the first sheet, and an oblique second edge defined by the elongated trench;
• and
• moving the extrusion head relative to the substrate while forcing material through the fluidic channel associated with each of the plurality of elongated parallel trenches such that material is extruded from the plurality of outlet orifices and forms said plurality of parallel elongated extruded structures on the substrate, wherein each of the extruded high-aspect ratio structures has a flat lower surface that is in contact with the surface of the substrate, and an upper surface that is shaped by the oblique second edge of the outlet orifice and faces away from the substrate.