1. Poor flatness of tempered glass can leave the glass surface uneven, causing optical distortion of the final products, like windows, doors, curtain walls, etc.

2. When tempered glass is used in laminated glass, it will cause uneven thickness between two layers after lamination, causing optical distortion and further affecting the visual effect of the final product. Local unevenness of the laminated glass will also affect its bonding performance between the two layers.

3. In case that tempered glass is used in insulating glass, the poor flatness of the tempered glass will cause uneven sealant application when the glass panes are insulated together, affecting the quality of appearance and sealing. It may also cause excessive thickness in certain areas and affect the installation.