Glass surface uneven local temperature caused by poor control methods. When the saddle shape appears after tempering of the glass, it indicates that the temperature of the edge of the glass is lower than the middle temperature when the glass is heated. The appearance of this condition is generally caused by the poor heat insulation of the furnace section of the tempering furnace, and it is necessary to control the computer at this time. Turn on the temperature adjustment function in the furnace area to increase the set point temperature of the furnace edge. When the shape of the pan bottom appears after the tempering of the glass, the shrinkage of the edge of the glass is too large, and the temperature of the edge of the glass is higher than that of the central temperature. In this case, the setting value of the temperature in the computer area is first observed, and it is confirmed that the temperature is not due to the temperature setting. After setting the parameters, the air furnace is operated to one or two furnaces so that the temperature distribution in the furnace can be evenly distributed. This ensures that the temperature distribution in the furnace is uniform.