The appearance of Color Coated Aluminum Coil is still important, but when defects appear, what causes them? 1. Incorrect roll shape for folding (folding) of color coated aluminum coil, such as heating of calender bearing; 2. Bubbles on the surface of the aluminum ingot, and there is a dirty east at the scraggy on the surface of the ingot; 3. The heating time of color coated aluminum coil is too...