| 摘要 |
<p>PROBLEM TO BE SOLVED: To form a semiprocessed goods product with the shrinks generated on the surface of a pressed glass effectively decreased and reduced in grinding margin in shaping the glass product by a direct pressing method. SOLUTION: This method is composed of a stage for supplying molten glass on the forming faces of a lower die, a stage for controlling the glass temp. so that the temp. of the inside of glass is brought close to that of the peripheral part and a stage for pressing the glass by the forming faces of the upper die and lower die, when viscosity of the temp.-controlled glass is within 103.5-106.5 poise. Since the temp. of the inside of glass is brought close to that of the peripheral part and the glass is pressed with a relatively high viscosity, the heat contraction quantity of the pressed glass is made small, and the difference in heat contraction quantity between the inside and peripheral part of the glass is decreased. Consequently, the generation of shrinks on the glass surface is reduced.</p> |
