Annealing furnace temperature difference problem Generally, the temperature distribution of the annealing furnace section of glass products is very uneven. The temperature near the two sides is generally lower, and the center temperature is generally higher. This makes the temperature of the product uneven, especially in the chamber annealing furnace. For this reason, when designing the annealing curve, the slow cooling rate should be lower than the actual allowable stress, and generally half of the allowable stress is used for calculation. Ordinary products can take the allowable stress value of 5 to determine the heating speed and fast cooling speed, and the influence factors of the temperature difference of the annealing furnace should also be considered.