Glass rod machining method and machining apparatus

摘要

To prevent constriction machining from reducing usage efficiency of a glass rod, provided is a glass rod machining method including softening of softening a portion of the glass rod by heating the portion of the glass rod, and constricting of forming a constricted shape in the glass rod by moving one end of the glass rod relative to the other end of the glass rod at a constriction speed satisfying a condition that a constriction load acting as a tensile force on the glass rod does not extend beyond a predetermined range. In this method, the constricting includes, when constriction speed increases, making an adjustment to decrease a heating temperature of the glass rod. This method may include determining of determining the heating temperature of the glass rod during the constricting by referencing a heating temperature table in which heating temperatures corresponding to the constriction speed are stored in advance.