After the glass sheet is treated by glass tempering furnace, the pitting phenomenon will appear. The pitting phenomenon is also a kind of appearance quality defect of tempered glass. The following main reasons are listed as follows: moisture-proof powder on glass is damped and pasted on glass or there are impurities on glass surface, which are not cleaned before tempering; insulating sponge falls off in the upper furnace of heating furnace; glass is not cleaned after edge grinding, and after long storage, the residual glass powder dry knots on it, but not before tempering. Cleaning clean; ceramic roller in heating furnace has not been properly cleaned, resulting in the accumulation of dirt on it; glass explosion furnace, the roller residual micro-glass slag.

The pitting of tempered glass can be divided into two types: one is dense. Usually the pitting points are concentrated in orange peel shape, which is due to the long heating time of glass tempering furnace or the high heating temperature of tempering furnace. This situation can be solved by adjusting the heating time or temperature parameters of the steelmaking equipment. The other is decentralized.

Individual pitting points are star-like distribution, which is due to the glass tempering equipment on the table or roller surface is not clean, or under the grille roller is not clean. In order to reduce the occurrence of pitting, FRP enterprises can establish a roll cleaning system and regularly clean the roller table of FRP furnace.