68th Annual Meeting of the APS Division of Fluid Dynamics (November 22, 2015 — November 24, 2015)

V0062: The molten glass sewing machine

Authors

• P.-T. Brun, Department of Mathematics, Massachusetts Institute of Technology
• Giorgia Franchin, Department of Industrial Engineering, University of Padova
• Michael Stern, Department of Mechanical Engineering, Massachusetts Institute of Technology
• Chikara Inamura, Media Lab, Massachusetts Institute of Technology
• Daniel Lizardo, Media Lab, Massachusetts Institute of Technology
• Markus Kayser, Media Lab, Massachusetts Institute of Technology
• John Klein, Media Lab, Massachusetts Institute of Technology
• Peter Houk, Department of Material Science and Engineering Glass Lab, Massachusetts Institute of Technology
• Neri Oxman, Media Lab, Massachusetts Institute of Technology

DOI: https://doi.org/10.1103/APS.DFD.2015.GFM.V0062

The viscous coiling instability of a thread of molten glass is harnessed to fabricate structured materials. Molten glass is poured from a nozzle and stretches under the action of gravity before impacting the base plate. The resulting fluid thread buckles into a coiling instability, similar to what is observed when pouring honey on toast. When the nozzle is translated this mundane situation evolves into three different patterns, repeating or alternating loops and meanders. Those patterns are rationalized using a geometrical model first derived for the viscous counterpart of this experiment, known as the fluid mechanical sewing machine. The ratio between the advection speed of the nozzle and the speed at which the thread impinges the substrate is key in the formation of these patterns, so that simple design guidelines may be provided even in the context of molten glass, whose rheology is non-uniform along the thread due to temperature gradients. Upon cooling, the patterns may be readily collected and used for a variety of applications.