Biaxial Strength of Float Glass Plates with Center Hole

Dr. Michael Emonds, Aachener Chemiche Werke
Dr. Suresh T. Gulati, Research Fellow & Consultant, Corning Inc.
Arto Kaonpää, Tamglass Ltd. Oy

Float glass plates with circular hole are commonly used in both automotive and architectural applications wherein the holes facilitate mounting and transfer of mechanical loads such as those induced by impact and vibrations. It is well known that the presence of a hole results in stress concentration which reduces the strength and load carrying capacity of plate in the vicinity of the hole. This is further exacerbated by the flaws associated with drilling and chamfering of the hole, i.e. finishing quality of the hole. The latter, of course, depends on factors like drill size and speed, feed rate, type of coolant used and the quality of chamfering tool.

The key objective of our paper is to quantify the effect of the coolant by measuring the biaxial strength of 20 cm x 20 cm x 3.8 mm thick float glass plates with center holes of two different diameter, namely 5 mm and 11 mm and with and without 45° chamfer. The strength measurements are carried out by flexing the glass plates in a ring-on-ring fixture. The effect of two different coolants (2% and 4% concentration) and water is quantified by measuring the strength and comparing it to that of identical plates with no hole at the center. In this manner the coolant chemistry, drill speed, feed rate and chamfer quality can be optimized by minimizing the severity of flaws and maximizing biaxial strength in the vicinity of the hole.

Full-Text Article [656 KB]

The Authors

	Dr. Michael Emonds Specialist ACW Dr. Michael Emonds is a skilled specialist in preprocessing of glass. He has worked for Aachener Chemische Werke (ACW) since 1993. His knowledge comprises cutting fluids, coolants and interleavants as... Read more
	Mr. Suresh Gulati Research Fellow/Consultant Corning Incorporated Dr. Gulati obtained his B.S. degree in mechanical engineering from University of Bombay (India), M.S. degree from Illinois Institute of Technology (Chicago, USA), and Ph.D degree in Applied Mechanics... Read more
	Mr. Arto Kaonpää product development Tamglass Engineering Ltd Oy I have 30 years of experience in glass processing business. I have been dealing with both architectural and automotive glass products in production and in R&D. Today my area of special expertize is... Read more