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 fibers. 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 twisting fine textile filaments, but rather extrusion of a polymer melt through pores in industrial spinnerets. 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 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 wire, the wire is slowly drawn more and more, and eventually small, thin wires of 1 micrometer in diameter can be obtained.

External links

• Nylon crystallinity
• Cold drawing of nylon

de:Kaltumformung