With the widespread application of tempered glass in daily life, the demand for its quality is becoming increasingly high, which makes tempered glass production enterprises pay more attention to the quality control of glass. The key to quality control often depends on the quality of the process. Glass must be heated to the appropriate temperature, and the temperature of each part of the glass surface should be uniform and not too different. To control this data, three factors must be mastered.

Firstly, based on the load condition of the electric furnace, select a reasonable heating temperature and effectively control the temperature inside the furnace. The heating of glass in a tempering furnace primarily involves conduction, radiation, and convection. The electric furnace load referred to here does not refer to the area occupied by the glass in the electric furnace, but to the relationship between the glass thickness, heating temperature, and heating time. At present, the heating section of the tempered steel electric furnace used by most manufacturers can generally be divided into many small heating zones. Under normal circumstances, there is always glass absorbing heat in the heating area of the central heating element of the electric furnace, and there is always glass present in the electric furnace area. This is regional, and the heating effect is also regional. If the heat consumption in a certain area of the electric furnace exceeds the heating effect, the temperature in that area begins to decrease, which is the overload phenomenon. The success of glass tempering mainly depends on the location where the glass plate temperature is the lowest. Once the electric furnace experiences overload, the temperature of the electric furnace will decrease, causing the glass to break when cooling in the cooling section.

Secondly, choose a reasonable heating time. The heating power of the tempering furnace is fixed, and the generally set heating time is about 35-40 seconds per millimeter thickness of glass. For example, the heating time for 6mm thickness glass is about 6 × 38 seconds=228 seconds. This calculation method is suitable for general flat tempered glass with a thickness less than 12mm. When the thickness of the glass is 12-19mm, the fundamental calculation method for heating time is about 40-45 seconds per 1mm thickness of glass.

Thirdly, to achieve uniform heating, the placement of glass on the wafer placement table is also important. The reasonable placement of glass chips is primarily to ensure the uniformity of longitudinal and transverse loads inside the electric furnace, that is to say, the placement of glass chips in each furnace and the gaps between each furnace should be uniform at all times.

Secondly, the glass should be cooled at the fastest possible cooling rate, which depends on the thickness and other properties of the glass. The cooling of both sides of the glass should be balanced; The ideal cooling medium for the cooling stage during the tempering process is dry cold air, and the approximate cooling capacity per unit area is confirmed. Therefore, the cooling capacity required for 5mm glass is more than twice that of 6mm glass.

Finally, during the tempering process, the glass must move continuously, and there should be no scratches or deformation marks on the surface of the glass. This motion includes the thermal swing motion of the glass inside the heating furnace, which is to evenly heat the various parts of the glass surface; This also includes the cold swing motion of the glass in the air-cooled section to ensure uniform fragmentation of the glass. The original glass should not have scratches, bubbles, etc., as these conditions can cause the glass to break.

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