Do you know the reason for the problem of poor flatness of tempered glass that we use in our daily lives? Today, let's take a closer look.

The problem of poor flatness of tempered glass can be divided into two categories:

The first type is the problem of poor flatness of curved tempered glass. For such problems, the conformity target is generally considered. When the conformity of curved tempered glass products does not meet the planning requirements, the following three phenomena will mainly occur:

(1) There is a distortion error between the glass product and the planning requirements. This indicates that the orientation of the glass that needs to be bent and tempered on the roller conveyor is not placed correctly, and the center line of the glass's curvature is not parallel to the roller conveyor. If this situation occurs, the operator needs to adjust the orientation of the glass on the loading platform from scratch to make the center line of the glass's curvature parallel to the roller conveyor.

(2) The depth and complexity of glass products and planning are different. This indicates that there is a problem with the parameter setting of the tempering process: during the heating stage, the heating temperature of the glass is not sufficient; During the cooling stage, the main issue is that the upper and lower air vents of the grille are not synchronized when blowing air. During blowing, one opens the air vent first and the other opens it later. If the lower air outlet is opened first to blow air, the depth of curvature of the formed glass will increase. Conversely, if the upper air outlet is opened first to blow air, the depth of curvature of the formed glass will decrease and not form an arc according to the planned depth. At this moment, the operator can adjust the process parameters from scratch and adjust the bending depth of the glass appropriately.

(3) The surface quality of the glass product does not meet the planning requirements.

The operator can adjust the winding time and rapid cooling time of the heating section appropriately, or adjust the tension of the winding section transmission chain, and solve such problems by adjusting the tempering process parameters or equipment.

The second type is the problem of poor flatness of flat tempered glass. There are mainly five types of such problems:

(1) Glass deformation caused by temperature difference between the upper and lower surfaces during heating

① The tempered glass panel is curved upwards. This phenomenon is due to the fact that after being heated in the heating furnace, the temperature of the upper surface of the glass is higher than that of the lower surface. Glass that maintains this temperature condition enters the cooling chamber for cooling. During the cooling process, when the cooling temperature of the upper and lower surfaces of the glass is combined with wind pressure and other conditions, due to the high temperature of the upper surface of the glass, the shortening of the upper surface after cooling is greater than that of the lower surface, resulting in a phenomenon of upward bending and deformation of the glass surface.

Given this situation, it is possible to increase the temperature at the bottom of the heating furnace and minimize the temperature difference between the upper and lower surfaces of the glass.

② The tempered glass panel is curved downwards. This phenomenon is due to the fact that after being heated in the heating furnace, the temperature of the lower surface of the glass is higher than that of the upper surface. Glass that maintains this temperature condition enters the cooling chamber for cooling. During the cooling process, when the cooling temperature of the upper and lower surfaces of the glass is combined with the wind pressure and other conditions, due to the high temperature of the lower surface of the glass, the shortening of the lower surface after cooling is greater than that of the upper surface, resulting in a downward bending deformation of the glass plate. In this situation, the temperature at the bottom of the heating furnace can be lowered to minimize the temperature difference between the upper and lower surfaces of the glass.

(2) Glass deformation caused by temperature difference between the center and edges during heating

After being heated in the heating furnace, if the temperature of the central part of the glass is higher than that of the edges, the shortening of the central part with higher temperature on the glass will be greater than that of the lower temperature edges during the cooling process. When the glass is cooled to room temperature, the size of the edges of the glass will be larger than that of the central part, causing greater compressive stress at the edges of the glass, and then presenting a phenomenon of downward bending deformation of the glass plate.

Similarly, when glass is heated in a furnace, if the temperature at its edges is higher than that at the center, during the cooling process, the shortening of the central part with higher temperature on the glass will be greater than that of the lower temperature edges. When the glass is cooled to room temperature, the scale of the central part of the glass will be larger than that of the edges, creating a larger tensile stress at the edges of the glass, and then exhibiting a phenomenon of upward bending deformation of the glass surface.

Article source: Tempered glass coverhttp://www.yinghuade.com/