1.If the scratch occurs in the longitudinal direction of the tempered glass:
Check whether there is debris on the rollers in the heating oven and cooling section;
Check if there are foreign objects or broken glass pieces between the rollers in the heating oven and cooling section;
Check if the heating oven door is in contact with the upper or lower surface of the glass.
2.If the scratch occurs in the lateral direction of the tempered glass:
Check whether the glass in the heating oven bumps into the furnace door;
Check if the drive encoder of the furnace works properly;
Check if the data of the photoelectric switch at the entrance of the furnace is correct.