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Glass Cutting machine Manufacturers introduce the reasons for the bending of tempered glass
- 2018-05-28-

  Glass Cutting MachineFactory ye Tuo introduced tempered glass is actually a kind of prestress, in order to improve the strength of the glass, usually using chemical or physical methods, the glass surface to form compressive stress, glass under the external forces to offset the first surface stress, thereby enhancing the bearing capacity, enhance the glass itself resistance to wind pressure, the thermal, shock and so on.

The deformation of tempered glass mainly comes from the aspect of Lai, the first is the precision of the roller road, and the other is the problem of uneven stress.

1th, the roller road problems caused by poor tempered glass roughness

Glass cutting Machine Manufacturers ye Tuo introduction heating roller deformation usually, the roller path of the horizontal roller tempering furnace is made of fused quartz or ceramic material, it has good heat shock resistance and thermal stability, but due to the uneven of its internal structure, it may cause thermal deformation during heating especially at high temperature. The heat deformation of the roller path will inevitably cause the bending of the rollers, and the glass which is moving on its surface is deformed.

2nd, thermal deformation caused by uneven heating temperature

When the glass is heated, there is a temperature difference between the upper and lower surfaces when the glass is passed to the heating roller, the lower surface of the glass is in contact with the roller, and the heating roller is directly transmitted to the glass for heat exchange, the upper surface of the glass is heating the upper surface of the glass by the way of heat radiation, the heat transfer rate of the lower surface is higher than the heat transfer speed of the upper surface, When the heat balance is not taken, the upper surface temperature of the glass is lower than that of the lower surface, while the glass is a typical elastomer when the heating begins, and the coefficient of thermal expansion of the glass is higher (the linear expansion coefficient of the glass is 9x10/. C), because the lower surface temperature is higher than the upper surface temperature, the lower surface expansion speed is higher than the upper surface, so that the glass upward bending is the glass around the roller, forming the middle of the glass is heated and only the middle by the roller support, when the glass is continued to heat and the roller contact position first reached the softening temperature and bear the full weight of glass, The middle of the glass will occur "flow" deformation, the middle of the question of thinning resulting in the roller track or even optical deformation, on the other hand, when the glass is all heated to the softening temperature after the glass flattening, but the temperature does not disappear, This kind of glass with temperature difference is cooled evenly to room temperature when the glass hot surface contraction is larger than the cold noodles contraction and forms the bending to the hot surface.

3rd, thermal deformation caused by uneven cooling

Glass cutting machine Manufacturers ye Tuo introduced tempered glass is the existence of permanent stress of glasses, deformation is also generated when the stress in the glass is unbalanced: when the compressive stress on the upper surface is greater than the compressive stress of the lower surface, the equilibrium stress glass is bent downward, and the same time the compressive stress of the surface is greater than that of the upper surface, the equilibrium stress glass is bent upwards, Glass in the cooling process due to the uneven cooling speed of the upper and lower surfaces, the cooling speed of the surface produces more stress than the slow cooling surface.