| 摘要 |
<p>A method of reshaping a tube blank of amorphous, in particular glassy material without tools to form a rod by collapsing is known, in which method an underpressure below atmospheric pressure is maintained in the tubular part by continued evacuating during the collapsing, the blank being fed continuously, at a predetermined rotational rate, horizontally to a heating zone and its viscosity reduced there to such an extent that, owing to the difference in pressure between the underpressure and the outside pressure acting on the blank, the blank collapses in a collapsing region to form the rod and the rod is continuously drawn off, at a predetermined rotational rate, from the collapsing region. In order to produce homogeneous rod-shaped bodies from blanks in one operation and inexpensively by such a method, the outside dimensions and inside dimensions of the blank, the viscosity of the glassy material in the collapsing region, the difference in pressure between the underpressure and the outside pressure, the level of the underpressure, the drawing-off rate of the rod and the feeding rate of the blank as well as the rotational rates of rod and blank are chosen such that a stem of smaller cross-sectional dimensions than those of the rod is formed from the collapsing region counter to the drawing-off direction of the rod in the axis of the blank.</p> |
