METHOD AND APPARATUS FOR CORRECTING CROSS-SECTION OF OBJECT

摘要

The transverse cross section of a body (20) is modified by the steps of: a) determining the extent to which the body (20) has material in excess of a desired shape at a plurality of points, b) exposing the body (20) to a local heat source (10) having a temperature sufficiently high to remove material from the surface of the body (20), and c) moving the surface of the body (20) in relation to the source (10) at a speed which decreases in regions where the body (20) has material in excess of the desired shape so as to remove more material from such regions than from other regions. In a preferred embodiment, the body (20) is an optical fiber preform (20), the local heat source (10) is the fireball (12) of a plasma torch (10), and the body (20) is moved relative to the torch (10) by rotating the preform (20) at a controllable angular velocity while the torch (10) is translated along the length of the preform (20).