Effect of Coolants on Edge Quality of Float Glass

S.T. Gulati, Arto Kaonpää, Michael Emonds

The edge quality of float glass plays an important role in the manufacture of automotive windshields as well as in tempering of sidelites and backlites. It is controlled by scoring tool, rate of scoring, type and amount of coolant used and handling of the edge. An effective method for quantifying the edge quality is to measure its strength in 4-point bending using a specially designed fixture that stresses the entire
surface of the edge. This paper will present edge strength data for 4 mm thick float glass as function of different coolants including water. A sample size of 10 specimens was used to obtain statistically significant data to help study the effect of different coolants. All of the fracture origins were found on the edges and were analyzed for mirror/mist boundary. The strength values were obtained from the load at failure and compared with those estimated from mirror radius measured from the fracture surface. Good agreement was found.

Our data show that both the chemical formulation and concentration of coolant used affect the edge strength which, in turn, depends on edge defects. Both coolants improved the mean, maximum and minimum edge strength. This implies that both coolants reduce flaw severity by reducing friction and the grinding force. Fractographs of fracture origins will also be shown to demonstrate the benefi cial effect of coolants.

Full-Text Article [195 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