Are You Aware of the Common Quality Defects in Laminated Glass Production?

During the production process of laminated glass, there are typically two quality defects: appearance and performance. Let’s discuss the causes of each deficiency below.

Defects in the float glass

As the float glass for laminated glass, it must meet usage requirements. Optical deformation, air bubbles, stones, waves, etc., are inherent to the float glass. Therefore, strict inspection should occur on the glass during production, and unqualified float glass should be removed.

Float glass


The cleanliness of the cutting and unloading platforms largely determines the number and size of blemishes during the cutting stage. The reason for defects during the edge grinding stage is that the glass debris is not processed, and the belt pressure of the edge grinding machine is set too high, which crushes the edges of the glass.



The main reason for this problem is that the position of the air knife during the edge grinding and cleaning process is incorrect, and the wind pressure is too high, which causes the water on the glass surface not to be blown dry.


Bubbles are small spherical shapes formed by air or other volatile gases, and they can appear anywhere in the middle or edge of the interlayer. There are two primary causes of this defect. First, poor exhaust during the laminating process can cause bubbles to form. This can be due to incorrect rolling speed and temperatures that are too high or too low. Second, bubbles can form if the film texture is too fine.


Air pockets

Air pockets are non-spherical pockets of air that appear on the inner surface of the glass, and they can be irregular in size and shape. Air pockets can occur anywhere in the middle or edge of the laminated glass, and sometimes film lines can be seen. There are several causes of air pockets. First, gaps between paired glass sheets can cause air pockets to form. Second, foreign objects on the surface of the glass or film can also lead to air pockets. Finally, dents or bumps on the film or glass can cause air pockets to form.


After the laminated glass is completed or installed, the glass and the film are separated. The main reason for degumming is that the adhesion between the laminated glass film and the glass is too low.

Lack of glue at the edge

Lack of glue at the edge is a common quality defect that can occur during or after pre-pressing and degassing or after high-temperature and high-pressure treatment. There are two primary causes of this defect. First, it may occur after pre-pressing and degassing due to the wrong position of the film on the glass or edge trimming of the film that is too close to the edge of the glass. This can cause excessive film shrinkage, resulting in a lack of glue at the border. Second, it may occur after high temperature and high pressure due to the flow of the edge film caused by the high temperature of the autoclave.

Rainbow phenomenon

SGP film laminated glass may exhibit a partially visible rainbow defect; The uneven thickness and residual stress of the film at different positions during autoclave treatment cause this defect.

Low transparency

The transparency of the finished SGP film laminated glass is weakened, and high fog appears. Slow or uneven cooling rates cause this defect during the autoclave process.

At VSOM GLASS, we take great pride in our laminated glass production. We have a rigorous quality control process to ensure that our products are free from common defects and meet the highest standards of quality. Our commitment to excellence has made us a trusted name in the industry, and we are confident that our customers will be satisfied with the performance and appearance of our laminated glass products.