extrusion

n. forcing out; squeezing out by applying pressure; bulge, bump; shaping of material (metal or other material) by forcing it through a die; process of extruding; expulsion

For the process that creates volcanic rock, see extrusive (geology). Extrusion is a manufacturing process used to create long objects of a fixed cross-sectional profile. A material, often in the form of a billet, is pushed and/or drawn through a die of the desired profile shape. Hollow sections are usually extruded by placing a pin or piercing mandrel inside of the die, and in some cases positive pressure is applied to the internal cavities through the pin. Extrusion may be continuous (producing indefinitely long material) or semi-continuous (producing many short pieces). Some materials are hot drawn while others may be cold drawn. The feedstock may be forced through the die by various methods. A single or twin screw auger, powered by an electric motor, or a ram, driven by hydraulic pressure (for steel alloys and titanium alloys for example), oil pressure (for aluminum), or in other specialized processes such as rollers inside a perforated drum for the production of many simultaneous streams of material.
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n. extrusion, forcing out; expulsion

n. extrusion, forcing out; expulsion

(n.)
The act of thrusting or pushing out; a driving out; expulsion.