Extrusion head with planarized edge surface

A method for fabricating an extrusion head for a micro extrusion apparatus, the extrusion head having a plurality of fluidic channels for extruding material on a substrate, the method comprising:

• forming a first sheet such that the first sheet defines at least one reference surface and an extrusion cavity including an outlet region such that the reference surface is disposed in proximity to the outlet region;
• securing the first sheet between second and third sheets to form said extrusion head such that the extrusion cavity and one or more of the second and third sheets form an associated fluidic channel, and such that side edges of the first, second and third sheets collectively form an edge surface of the extrusion head, wherein the side edge of the first sheet defines both an outlet orifice communicating with said outlet region of the extrusion cavity and a notch, wherein the reference surface is disposed in the notch such that the reference surface is indented from the edge surface by an initial distance, and the reference surface is offset from the edge surface by a portion of side edge of the first plate;
• and
• trimming the edge surface of the extrusion head by removing material from the side edges of the first, second and third sheets until the reference surface is separated from the edge surface by a predetermined distance, the predetermined distance being less than the initial distance.