How to control the quality of tempered glass
With the wide application of tempered glass in daily life, the requirements for its quality are getting higher and higher, which makes the tempered glass production enterprises pay more attention to the quality control of glass. The key of quality control often depends on the quality of the process. It is necessary for glass to be heated to the corresponding temperature. The temperature of each part of the glass surface should be uniform and the difference should not be too large. To manipulate this data, three factors must be mastered.
First, according to the load of the electric furnace, select the reasonable heating temperature and effectively control the temperature in the furnace. Conduction, radiation and convection are the main factors for glass heating in tempering furnace. The electric furnace load here refers not to the area occupied by glass in the electric furnace, but to the relationship between glass thickness, heating temperature and heating time. At present, the heating section of tempered electric furnace used by most manufacturers can be generally divided into many very small heating zones. Normally, in the heating zone of the central heating element of the electric furnace, there is always glass in the heating zone. In the furnace zone, there is always glass, which is regional, and the heating effect is regional. If the heat consumption of a certain area in the electric furnace exceeds the heating effect, The temperature in this area begins to decrease, which is the phenomenon of overload. The success of glass tempering depends primarily on the lowest temperature of glass plate. Once the furnace is overloaded, the temperature of the furnace will decrease, which will cause the glass to break when it is cooled in the cooling section.
Second, choose a reasonable heating time. The heating power of tempering furnace is certain. The heating time of glass with 6 mm thickness is about 35-40 seconds per millimeter thickness. For example, the heating time of glass with 6 mm thickness is about 6*38 seconds = 228 seconds. This calculation method is suitable for plain tempered glass with thickness less than 12 mm. When the thickness of glass is 12-19 mm, the basic calculation method of heating time is about 40-45 seconds per 1 mm thickness of glass.