Optical fiber manufacturing (Corning) (canonical)

Used twice. At §4.p3, as the rare example of true uniaxial drawing in industry. At §6.p4, as the technological consequence of glass's high strain-rate-sensitivity exponent (m ≈ 0.8) — Newtonian flow lets Corning pull miles of fiber from a preform without a die, without necking.

That leads to biaxial straining, which is not something most of you have studied, but is critical to understanding deformation processing, particularly in sheet metal. Very rarely are we processing something by just pulling on it in one direction. There is one example I can think of. We make millions of feet every year of something that we pull on in one direction. Can anybody think of it? Optical fibers, very good. Corning takes optical fibers, they build up this composite layered glass and then they just pull it. Without a die, they just pull it into long thin fibers, and they put miles and miles of that all around the country every year. That's because glass is Newtonian flow, which is not all that different than superplasticity.