A new fire shaping approach to produce highly axisymmetric and reproducible nozzles

Abstract

In this work, we propose a new fire shaping approach for manufacturing glass nozzles that heats a rotating vertical capillary at the Top of a Lateral Flame (TLF). We use image analysis to evaluate its performance focusing on the reproducibility in the nozzle size and shape, and on its symmetry. Our results show that this new approach has satisfactory diameter reproducibility, and produces highly axisymmetric nozzles (with very little nozzle neck offset or misalignment). The shape reproducibility is very good for the same heating position, and additionally, it allows to produce nozzles of different shapes by working at different positions. TLF overcomes the problems of the previous fire shaping approaches, which used a vertical flame. In comparison with pulling, which is a well-established method, TLF has a similar diameter reproducibility and produces a superior symmetry.