Bubble Formation in Additive Manufacturing of Glass


Bubble formation is a common problem in glass manufacturing. The spatial density of bubbles in a piece of glass is a key limiting factor to the optical quality of the glass. Bubble formation is also a common problem in additive manufacturing, leading to anisotropic material properties. In glass Additive Manufacturing (AM) two separate types of bubbles have been observed: a foam layer caused by the reboil of the glass melt and a periodic pattern of bubbles which appears to be unique to glass additive manufacturing. This paper presents a series of studies to relate the periodicity of bubble formation to part scan speed, laser power, and filament feed rate. These experiments suggest that bubbles are formed by the reboil phenomena why periodic bubbles result from air being trapped between the glass filament and the substrate. Reboil can be detected using spectroscopy and avoided by minimizing the laser power while periodic bubbles can be avoided by a two-step laser melting process to first establish good contact between the filament and substrate before reflowing the track with higher laser power.

Meeting Name

SPIE Defense + Security 2016 (2016: Apr. 17-19, Baltimore, MD)


Mechanical and Aerospace Engineering

Research Center/Lab(s)

Intelligent Systems Center

Keywords and Phrases

3D printers; Bubble formation; Glass; Glass manufacture; Manufacture; Anisotropic material properties; Foam layers; Glass-manufacturing; Laser melting process; Laser process; Optical qualities; Periodic pattern; Spatial densities; Optical glass; Additive Manufacturing; Laser processing

International Standard Book Number (ISBN)


International Standard Serial Number (ISSN)

0277-786X; 1996-756X

Document Type

Article - Conference proceedings

Document Version


File Type





© 2016 SPIE, All rights reserved.

Publication Date

01 Apr 2016