Extrusion of glass

Index matching between passive and active tellurite glasses for use in microstructured fiber lasers: Erbium doped lanthanum-tellurite glass

“…We used extrusion of rods from glass billets to determine the temperature-viscosity-curve for our glasses. The flow through dies with a circular channel obeys the Poiseuille law [13], which allows calculation of the glass viscosity at a fixed extrusion temperature from the extrusion speed and pressure as well as the die channel length and diameter. The temperature-viscositycurve η(T) of the base glass has been reported previously by Braglia et al [14].…”

Tellurite Glass Fibers for Mid-infrared Nonlinear Applications

“…The extrusion technique is a traditional method for making glass workpiece with simple or complex geometry [31]. As shown schematically in Fig.4, the solid glass billet is first loaded inside a metal sleeve.…”

Fluoride glass microstructured optical fiber with large mode area and mid-infrared transmission

“…Preliminary extrusion trials using fluorozircoaluminate glass from HOYA Co. showed that the glass temperature required for extrusion through complex stainless steel dies is above the onset of the glass crystallization. The high friction for glass flow through a stainless steel die [10] requires low glass viscosities of ϳ10 7 Pa s for complex dies (i.e., relatively high glass temperatures) to overcome the friction between the glass and the steel. However, for fluoride glass, these temperatures are within the surface crystallization region (Fig.…”

“…Graphite is an alternative die material, which to date has been used for extrusion of oxide and chalcogenide glass rods [10,12]. In contrast to steel, graphite is not wetted by glass, which considerably reduces the friction within a die [10], enabling the use of higher glass viscosity of ϳ10 8 Pa s (i.e., lower glass temperatures) for complex preform extrusion.…”

“…In contrast to steel, graphite is not wetted by glass, which considerably reduces the friction within a die [10], enabling the use of higher glass viscosity of ϳ10 8 Pa s (i.e., lower glass temperatures) for complex preform extrusion. Using graphite dies and the ZBLAN glass billets made, we extruded both crystal-free rods for bare (unstructured) fiber drawing and preforms with seven holes.…”