What are the production precautions for glass during tempering?

　　Most manufacturers use horizontal tempering furnace to produce tempered glass.In terms of temperature control,there are two basic requirements for the use of horizontal tempering furnace.First of all,the temperature of each part of the glass surface should not vary too much,that is,it should be uniformly heated;Secondly,the glass must be quickly heated to the required temperature.

　　The temperature control in tempering process is carried out around these two core aspects.

　　1.Uniform heating

　　1.Avoid the influence of temperature difference between the upper and lower surfaces of glass on the toughening effect of glass.If the temperature difference between the upper and lower surfaces is too large,it is easy to cause concave convex deformation and even breakage of the glass.In the production process,the following two points should be achieved:first,the arrangement of each furnace of glass and the interval time of each furnace should be uniform;Second,in order to ensure the uniformity and consistency of roller temperature and avoid excessive roller temperature between glass plates,if longitudinal phenomenon occurs during placement,the gap shall be filled when the glass furnace is put down.

　　2.When the glass just enters the furnace body,the convection heating mode should be added at this time to open the upper and lower heat balance.Through the high-temperature hot air circulation system in the furnace,the hot air circulation of the high-temperature air in the furnace can effectively solve the problem of large temperature difference at various points of the glass.

　　When the lower half section is heated,the temperature difference at each point of the glass is not obvious,which is mainly to improve the heating speed.Each heat balance can be closed until the glass temperature is consistent with the set furnace temperature,and the heating process will end.

　　III.If the glass edge is convex or concave,we can control it from two aspects.On the one hand,it can increase the heat balance pressure in the furnace and increase the convection heat transfer,so as to adjust the heat balance in the furnace and reduce the temperature difference between the middle and edge of large-area glass.On the other hand,the heating time of the glass can be appropriately prolonged to reduce the temperature difference between the middle and edge of the glass.

　　2.Heating temperature

　　1.The thinner the tempered glass,the higher the heating temperature.The thicker the glass,the lower the heating temperature.Therefore,as far as tempered glass technology is concerned,it is not clear which temperature setting is appropriate.The choice of temperature largely depends on the quality of raw glass and the process parameters adjusted by operators.You can find the process parameters on the Internet.I will not describe them here.In actual production,the adjustment of heating temperature is mainly realized by the adjustment of heating time.Master the basic calculation method of heating time.

　　2.The bottom temperature measured by the heating system is not the roller temperature,but the average temperature after the heating element at the bottom of the tempering furnace compensates the heat absorbed by the roller glass.For this reason.The measured temperature is generally higher than the measured upper temperature,so the upper heating temperature is generally higher than the lower heating temperature setting value.

　　III.Avoid electric furnace overload.Under normal operation,there is always glass heat absorption in the heating area of the electric furnace's centralized heating element.There is always glass in this area of the electric furnace.If the heat consumption in a certain area of the electric furnace exceeds the heating effect,the temperature in that area will begin to drop until the temperature is balanced.Therefore,when the electric furnace is overloaded,the glass in the cooling section will be broken.