After being processed in a tempering furnace, the original glass will exhibit pitting, which is actually a manifestation of the appearance quality defect of tempered glass. Generally, appearance quality defects are related to the production operation of the tempering furnace and the control of various parameters. Below, we will analyze the reasons and solutions for the occurrence of pitting in the glass tempering process.

1. The reasons for the occurrence of pitting during the glass tempering process

1.1. Glass surface impurities:

There is moisture-proof powder sticking to the glass due to moisture on the original glass sheet, or there are other impurities on the glass surface that have not been cleaned before tempering.

1.2. Insulation cotton peeling off:

The heating part of the tempering furnace is equipped with insulation cotton on the furnace. The insulation cotton, which has been used for a long time or has shed tissue due to high-temperature oil, falls onto the glass during the fiberglass protection process and is fixed on the glass surface after heating, forming pitting points.

1.3. Incomplete cleaning:

The glass is not cleaned after grinding, and during long-term storage, the remaining glass powder on the glass dries and remains on the original glass sheet, which is fixed on the glass surface by the heating section at high temperature and forms pitting.

1.4. Ceramic roller dirt:

If the roller conveyor of the tempering furnace is not regularly cleaned, during the early operation process, due to incomplete cleaning after the blast furnace, the melted glass fragments will be heated out of the furnace again with the new glass, forming pitting on the glass.

1.5. More sulfur dioxide is introduced:

We usually use the introduction of sulfur dioxide to clean the dirt on the roller conveyor. However, due to the strong corrosiveness of sulfur dioxide, excessive introduction will corrode the surface of the roller conveyor and leave spots, leaving spots when tempered glass passes through.

1.6. Long heating time:

Glass heated for too long in a tempering furnace can also easily show pitting or other external damage on the surface.

2. Solution to the occurrence of pitting during glass tempering process

2.1. Dense pitting

Dense pitting is usually more concentrated, which can be solved by adjusting the heating time and temperature of the equipment due to long heating times or high temperatures in the tempering furnace. The specific temperature and heating time adjustment can be determined based on the parameters of the batch of glass with better tempering effect.

2.2. Dispersed pitting

Scattered pitting is usually distributed in a star pattern, not concentrated and irregular. This situation is mostly caused by the unclean surface or raceway of the glass tempering furnace. Regular cleaning and maintenance work should be completed for the glass tempering furnace.

2.3. Occasional numbness

If it doesn't happen every time, just after introducing sulfur dioxide and ensuring that the roller and countertop are clean, it may be because too much sulfur dioxide is introduced, causing corrosion to the roller and affecting the flatness of the glass surface, forming spots. At this time, the roller can be repaired or replaced according to the situation. In addition, regular maintenance should be carried out on the glass tempering furnace, insulation cotton, and roller conveyor. If any damage is found, it should be replaced in a timely manner. At the same time, the cleanliness of the original glass sheet should be controlled to ensure the cleanliness before entering the furnace.

The above is a sharing by glass tempering furnace manufacturers on the reasons and solutions for the occurrence of pitting during the glass tempering process, hoping to help everyone solve the problem of pitting in tempered glass.