Fig. 1. Schematic diagram of glass molding principle. (a) Heating; (b) compression; (c) annealing; (d) mold unloading

Fig. 2. Generalized Maxwell model of five elements

Fig. 3. Simulation model of glass molding

Fig. 4. Overall equivalent stress change during the molding process. (a) Equivalent stress when AB contacts the preform; (b) equivalent stress immediately before BC contacts the preform; (c) equivalent stress when BC contacts the preform; (d) equivalent stress during mold clamping

Fig. 5. Changes in stress at the upper and lower center points of glass preforms

Fig. 6. Effect of temperature on stress of mold and preform

Fig. 7. Effect of molding rate on stress of mold and preform

Fig. 8. Effect of friction factor on stress of mold and preform