Cold drawing 2319287 217314348 2008-06-05T14:26:06Z Dumelow 805775 fix link to dab page '''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 by [[Julian Hill]] in [[1930]] while trying to make fibers from an early [[polyester]], a precursor to [[nylon]]. It is performed after the material has been "spun" into filaments. Here, spinning does not mean [[spinning (textiles)|twisting]] fine [[textile]] [[Filament (textiles)|filaments]], but rather extrusion of a polymer [[melt]] through pores in [[industry|industrial]] [[spinneret]]s. During this process, the individual polymer chains tend to align because of [[viscosity|viscous]] [[rheology|flow]]. If subjected to cold drawing afterwards, the fibers align further, increasing their crystallinity,[http://aml.arizona.edu/classes/mse222/1998/nylon66/mse222.htm] and the material acquires additional [[tensile 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|Cu 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] {{industry-stub}} [[Category:Metal forming]] [[de:Kaltumformung]]