The setting of tempering furnace heating time depends on the actual situation. The size of a single pane glass or the number of glass sheets loaded in the batch will have significant impact on the length of the heating time required. Therefore, adjustments should be made according to the actual situation in operation. Larger glass panels require longer heating time. When the shape of the glass panel is close to the square, it is recommended to use low temperature and extended heating time. This is because the heat in the heating chamber is transmitted gradually from the edge to the center of the glass. If the heating time is too short, the center area may not have time to absorb sufficient heat, resulting in explosion after leaving the heating chamber or glass panel spherically curved after tempering.