Fiber-fed laser-heated process for printing transparent glass from single mode optical fiber

Abstract

This paper describes the additive manufacturing (AM) of glass using a fiber-fed laser-heated process. Stripped SMF-28 optical fiber with a diameter of 125 μm is fed into a laser generated melt pool. A CO2 laser beam is focused onto the intersection of the fiber and the work piece, which is positioned on a four-axis computer controlled stage. The laser energy at λ=10.6 μm is directly absorbed by the quartz fiber, locally heating the glass above its working point. Through the careful control of process parameters such as laser power, feed rate and scan speed, bubble free parts such as walls and lenses may be printed. These parts are assessed on the grounds of their transmissivity and refractive index homogeneity, and issues unique to the process such as the thermal breakdown of the glass and refractive index mismatch present in SMF-28 are discussed.