Laser beam severing of thin walled glass tube

摘要

A method of severing glass tubes of up to 0.5 mm wall thickness uses focussed and defocussed laser beams, the focussed beam evaporating the glass along the severing line. The novelty is that the defocussed beam passes continuously over the severing line region, and is defocussed such that its diameter on the tube surface is up to 50 times the tube wall thickness, and such that it heats the tube to greater than or equal to the glass transition temperature. Also claimed is an apparatus for severing glass tubes (1), which has a laser (10) with optical devices (14-18) for directing focussed and defocussed laser beams (21, 23) onto the tube surface, as well as equipment for rotating and positioning the tube (1), and/or equipment for moving the laser beams over the tube surface.