METHOD TO FORM LARGE-SIZE PARTS FROM SHEET NON-ALIGNED ORGANIC GLASS Russian patent published in 2011 - IPC B29C49/00 B29C51/00 

FIELD: construction.

SUBSTANCE: preliminary bending of glass to single curvature is carried out using "cold forming" pattern, then a semi-cylindrical stock is pressed in a tight accessory, heated using "hot forming" pattern, glass is given its final shape by pneumatic forming. "Cold forming" is carried out at least in five stages after full heating of glass for at least two hours with intervals from 30 to 60 minutes. After the last stage completion glass is annealed for 4.5÷6 hours, smoothly cooled down to 20-40°C, placed into the second stage accessory at the time that does not exceed 45÷48 hours prior to pneumatic forming start, annealing is carried out in free condition at the temperature that is 30÷40°C lower than the softening temperature with subsequent slow cooling in a thermal cabinet to the temperature that is not higher than 30÷40°C. Final annealing is carried out after additional forming in an accessory for thermal treatment at the temperature that is 20÷30°C lower than the temperature of glass softening for two-three hours.

EFFECT: high optical parameters of non-aligned organic glass.