Method for stretching a glass rod

摘要

Control over the diameter variations in a glass rod (10) during the stretching thereof is accomplished by cooling the rod after heating and initial neck down of a portion (22) thereof. After cooling, the rod (10) is reheated, at a lower temperature sufficient to reflow the glass in the necked-down portion (22) thereof, and is then stretched to the desired final diameter. Heating the rod (10) at a lower temperature during stretching increases the viscosity thereof which reduces its response to the stretching conditions, thereby affording better control over diameter fluctuations.