- Cold drawing
Cold drawing is a manufacturing process involving extrusion of a material into a long filament, often for the purpose of increasing the strength of the material.
Cold drawing is primarily used in manufacturing
polymer plastic fiber s. The process was discovered byJulian Hill in 1930 while trying to make fibers from an earlypolyester , a precursor tonylon . It is performed after the material has been "spun" into filaments. Here, spinning does not mean twisting finetextile filaments, but rather extrusion of a polymermelt through pores in industrialspinneret s. During this process, the individual polymer chains tend to align because of viscous flow. If subjected to cold drawing afterward, the fibers align further, increasing their crystallinity, [http://aml.arizona.edu/classes/mse222/1998/nylon66/mse222.htm] and the material acquires additionaltensile strength . [http://www.chemheritage.org/EducationalServices/nylon/chem/cold.html]Cold drawing is also used in cable core production. Starting from a 1 cm (0.4 inch) thick
copper wire, the wire is slowly drawn more and more, and eventually small, thin wires of 1 micrometer in diameter can be obtained.External links
* [http://aml.arizona.edu/classes/mse222/1998/nylon66/mse222.htm Nylon crystallinity]
* [http://www.chemheritage.org/EducationalServices/nylon/chem/cold.html Cold drawing of nylon]
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