Toughened glass, as the most important form of safety glass, is widely used in various fields of doors, windows and curtain walls. Toughened glass with poor flatness will cause reflection optical deformation of glass, affect the appearance quality of doors, windows and curtain walls, and optical distortion of glass, further affecting the visual effect of doors, windows and curtain walls. In addition, the tempered glass with poor flatness will also have an impact on the installation effect, so it is very important to control the flatness of the tempered glass in the field of doors, windows and curtain walls.
I. The key to the flatness control of tempered glass is the quality of tempered glass. If the bending degree of tempered glass is controlled below 0.15, the flatness of tempered glass will be better improved.
II. Details control method of toughened glass:
1. Countermeasures for deformation of heating roller table: allow the roller table enough time to preheat before glass tempering, make the roller table evenly heated, eliminate the stress and reduce the stress deformation of the roller. For the wear of roller table, the whole roller shall be polished when cleaning the roller to avoid grinding the part of the roller as much as possible, so as to make the roller wear evenly and keep the consistency of the roller. And check and adjust the height of the roller table from time to time, so that the upper surface of the roller table is a plane during operation, so as to maintain the flatness of the glass surface. The structure of the air grid roller table is to wrap nylon rope on the surface of the metal roller table as the heat insulation material. The glass is easy to cut off the nylon rope when it explodes in the air grid, resulting in uneven surface of the roller table. It is necessary to repair and replace the nylon rope in time.
2. Control measures for thermal deformation caused by uneven heating temperature
(1) for the temperature difference between the upper and lower surfaces, when the glass is bent upward, it means that the temperature of the upper surface of the glass is high. The temperature of the upper surface should be reduced, and the temperature of the lower surface should be increased properly to keep the heating temperature of the whole glass unchanged; when the glass is bent downward, it means that the temperature of the lower surface and the upper surface should be reduced properly, and the temperature of the upper surface should be increased at the same time. If the yield and quality of tempering are affected when the temperature is adjusted, the heating time can be extended or reduced appropriately.
(2) for the glass deformation caused by the temperature difference between the middle and the edge, if the glass is saddle shaped, it means that the furnace body is not well insulated or the edge of the temperature setting value is low, the temperature setting value of the edge needs to be adjusted; if the glass is bottom shaped, if it is caused by the thermal history, the glass needs not to be stacked temporarily, run the furnace empty first, make the temperature distribution in the furnace uniform, and then If the temperature setting is a problem, adjust the temperature setting parameters to make the temperature distribution in the furnace uniform.
(3) in view of the random temperature unevenness, it is necessary to repair the equipment in time to avoid the bad condition of the equipment. The glass slag near the temperature sensor is often cleaned to ensure that the temperature sensed by the temperature sensor is the accurate furnace temperature. At the same time, it is necessary to avoid stacking multiple furnaces in the same state on the upper plate.
3. Control measures for thermal deformation caused by uneven cooling. For the uneven stress in the cooling process, the cooling rate of the glass surface can be adjusted by adjusting the wind pressure of the wind grid. If the glass is bent downward, it can be adjusted by increasing the wind pressure at the bottom of the windshield to increase the cooling rate of the lower surface of the glass; if the glass is bent upward, it needs to be adjusted by increasing the wind pressure at the top of the windshield to increase the cooling rate of the upper surface of the glass.
HHG is a professional glass manufacturer and glass solution provider include range of tempered glass, laminated glass, textured glass and etched glass. With more 20 years development, there are two produce lines of pattern glass ,two lines of float glass and one line of restoration glass. our products 80% ship to overseas, All our glass products are strict quality control and carefully packed in strong wooden case, ensure you receive the finest quality glass safety in time.