To investigate the potential of additive manufacturing of glass, the Glass Competence Center, located at Technical University Darmstadt develops a machine which additively applies glass on a flat glass plate using fused glass deposition modelling.

First successful studies for the deposition of glass on glass were performed at the Massachusetts Institute of Technology, see [1]. Here it was shown that glass can form a material bond and become a monolithic component by extrusion of glass layers on top of each other.

The goal of this research is to extend this method to printing on and forming a material bond with a float glass plate.

In most additive manufacturing techniques, irregularities in the geometry are the weak point of the object due to the layer-by-layer manufacturing process. This also applies to additive manufacturing of glass. In fused glass deposition modelling, glass shards are heated to a viscosity of 104 dPa·s, the working point of glass. This fluid glass is extruded through a funnel on to a heated glass plate. The glass plate must also be heated in order to create this substance-to-substance bond between the glass plate and the additively fused glass. Especially for soda-lime-silica glass, see [2], and borosilicate glass, see [3], the glass plate must be heated globally to the glass transition temperature to avoid thermal breakage, and locally to an even lower viscosity to create a bond between the two components. The joining temperature, which is related to the viscosities of the glass, is a key parameter for fused glass deposition modelling. A weak bond will result if the joining viscosities of the materials do not match. [4]

The objective of this study is to find the temperature ranges that result in a strong bond while maintaining the shape of the geometry, with the goal of creating the smoothest surface possible, focusing on the substance-to-substance bond with a float glass plate. Therefore, optical studies of the geometry and mechanical tests are performed to determine the maximum load carrying capacity.

References

[1]

J. Klein, M. Stern, G. Franchin, M. Kayser, C. Inamura, S. Dave, J. C. Weaver, P. Houk, P. Colombo, N. Oxman and M. Yang, "Additive Manufacturing of Optically Transparent Glass," 3D Printing and Additive Manufacturing 2 (3), pp. 92-105, 2015.

[2]

DIN EN 572 - 1, Glas im Bauwesen -- Basiserzeugnisse aus Kalk-Natronsilicatglas - Teil 1: Definitionen und allgemeine physikalische und mechanische Eigenschaften, 2011.

[3]

DIN EN 1748 - 1 - 1, Glas im Bauwesen - Spezielle Basiserzeugnisse - Borosilicatgläser - Teil 1-1: Definitionen und allgemeine physikalische und mechanische Eigenschaften, 2004.

[4]

M. Seel, R. Akerboom, U. Knaack, M. Oechsner, P. Hof and J. Schneider, "Additive Manufacturing of Glass Components - Exploring the Potential of Glass Connections by Fused Deposition Modeling," Challenging Glass 6, 2018.