How To Improve The Flatness of Tempered Glass? What Are The Methods for Adjusting The Flatness of Tempered Glass?

The flatness of tempered glass is directly related to its quality, and the flatness of glass is not solely controlled by the quality of the glass tempering furnace, but is determined by multiple influencing factors. So how to improve the flatness of tempered glass?

1. Methods for improving the flatness of tempered glass

1.1. Improve the uniformity of heating furnace temperature

The uniformity of furnace temperature in glass tempering furnace is a key factor affecting the flatness and stress spots of tempered glass. The matrix heating method should be used to finely control the furnace temperature in the heating area, using a strong convection tempering furnace. Because if the temperature of the furnace rises and falls, it will cause the glass to bend; If the furnace temperature is high in the front and low in the back, it may cause ripples or glass explosions. This is the overall poor uniformity of the furnace, and this temperature non-uniformity will inevitably be reflected in the stress spots. We know that stress spots are formed during the cooling process of high temperature decreasing to low temperature during the tempering process. Even if you blow evenly, but the furnace temperature is uneven, stress spots will also appear.

1.2. Improve the stability of heating furnace temperature

The flatness of tempered glass depends on the symmetry of the upper and lower temperatures. The fluctuation of furnace temperature may affect the flatness and waviness of tempered glass. High temperatures have waviness, while low temperatures cause furnace explosion. So maintaining the stability of the glass tempering furnace temperature can improve the flatness of the glass tempering furnace.

1.3. Improve the uniformity of blowing

If the blowing air in the fiberglass furnace is uneven, it may cause the glass to curl up or down, affecting the flatness of the glass and producing stress spots. To ensure the flatness of the fiberglass tempering furnace, the temperature of the air in various parts of the furnace should be fully considered, effectively ensuring the overall uniformity of the blowing air.

1.4. Ensure the flatness of the ceramic rollers

Rather than maintaining the flatness of the ceramic roller path, it is more important to maintain the smooth and rapid cooling of the glass by the wind grille, the flatness of the roller path, and the accuracy of installation. The combination of these factors can achieve the flatness of tempered glass.

1.5. Control the stability of the furnace body

During the heating and tempering process of glass, some processes require the glass to be in a critical state, making it relatively soft. If there is a slight vibration on the ceramic roller, the burnt soft glass will definitely deform if it shakes on top. The furnace roller conveyor is like this, and the air grate roller conveyor is also like this. To maintain the stability of the furnace body, the flatness of the tempering furnace can be improved.

1.6. Using the wind deflector of the air collection box to improve flatness

The wind deflector of the collection box can be used to adjust the flatness of the tempered glass. When the wind deflector is in the middle position of the collection box, the corresponding pointer indicates zero. When the wind deflector moves upwards, the pointer reading points to a positive value, and when the wind deflector moves downwards, the pointer reading is negative. If the tempered glass is bent upwards, it indicates that the wind pressure on the upper part of the tempered section's wind grille is low. At this time, adjust the wind deflector to move downwards, that is, adjust it in the negative direction. When turning downwards, adjust the wind deflector to move in a straight direction.

2. The reasons for poor flatness of tempered glass

2.1. Curved tempered glass

2.1.1. The finished glass has distortion deviation from the design requirements. This indicates that the glass that needs to be bent and tempered is not placed correctly on the roller conveyor, and the centerline of the glass bending is not parallel to the roller conveyor.

2.1.2. The finished glass has a different bending depth from the design. This indicates that there is a problem with the setting of tempering process parameters: during the heating stage, the heating temperature of the glass is not enough; In the cooling stage, the main issue is that the upper and lower air vents of the air grid are not synchronized when blowing. When blowing, one opens the air first and the other opens the air later. If the lower air outlet is opened for blowing first, the bending depth of the formed glass will increase. Conversely, if the upper air outlet is opened for blowing first, the bending depth of the formed glass will decrease and will not form an arc according to the design depth.

2.1.3. The surface quality of the finished glass does not meet the design requirements. Operators can adjust the bending time and rapid cooling time of the heating section, or the tension of the transmission chain in the bending section, and solve such problems by adjusting the tempering process parameters or equipment.

2.2. Flat tempered glass

The main reasons for the surface unevenness of flat tempered glass are the glass deformation caused by the temperature difference between the upper and lower surfaces during heating, and the glass deformation caused by the temperature difference between the middle and edges during heating, both of which are related to the uneven temperature of the furnace body.

Of course, besides knowing how to improve the flatness of the glass tempering furnace, it is also important to understand the factors that may cause surface roughness of tempered glass.