Effects of Thermal Conditions on Sink-Mark Generation of Press-Formed Glass. Measurement of Temperature of Glass and Generation Process of Sink-Mark.
Kentaro Tatsukoshi, Yasuo Kurosaki, Isao Satoh, Yasuo Satoh · TRANSACTIONS OF THE JAPAN SOCIETY OF MECHANICAL ENGINEERS Series B · 1996
We presents an experimental study on effects of thermal conditions on the sink-mark generation of press-formed glass products. In experiments, the temperature of pressed glass was measured with variation of the initial temperature of the plunger and the pressing duration. The depth of the sink-mark was continuously investigated using laser displacement sensors. Obtained results are summarized as follows : (1) The temperature of the glass surface decreases dramatically during pressing. After pressing, it rises again because of reheating. However at the center of the glass, reheating is not observed. (2) The sink-mark grows up only when the temperature of the glass surface is above 700°C. In order to suppress the generation of the sink-mark, it is important to keep the temperature of the glass surface below 700°C or to shorten the period during which it is above 700°C.