The production process of the wholesale color coated aluminum coil is relatively strict. Only color-coated aluminum coils need a lot of treatment before they are coiled. Then how to test the quality of the color coated aluminum coil?
1. Physical test
Physical testing is important to check that the paint has been applied and cured properly to perform well during end use.
2. Visual inspection
Visual inspection is important to confirm the absence of unacceptable visual defects, as coated aluminum coil must meet aesthetic requirements as well as performance-related requirements.
1. Film thickness
The proper paint film thickness is critical to the long-term performance of the paint film. For primers, low film thicknesses may result in premature corrosion or poor adhesion. For topcoats, low film thicknesses may cause premature failure due to weathering.
2. Color
One of the main reasons for purchasing prepainted aluminum coil is for its various bright colors. Since it is common for customers to match prepainted metal to other components of a building, matching specified color standards is important to the aesthetics of the final assembled product.
Color must be consistent across the width of the strip and different aluminum coils. Many factors can affect color: paint formulation and quality, film thickness, substrate color, curing temperature (PMT) and dwell time in the curing oven, and even contamination from other paints.
3. Gloss
Gloss consistency is important to provide clients with a uniform look. The final product may consist of several components made from different coils. If the gloss level is not consistent, the final product will have a poor appearance and will not look good.
4. Adhesion
Several tests are performed to check various aspects of adhesion, including T-bend, impact and various scratch tests. One of the main advantages of prepainted coil is that it can be formed after painting, so these tests are very important to ensure that the paint will not be damaged or removed during subsequent processing.
Factors that affect adhesion include paint formulation, film thickness, curing temperature (PMT), line speed, quality of treatment, plain aluminum coil quality, and cleanliness.
5. Curing degree
Curing is a term referring to the degree to which a material transitions from its initial state to its final cured state.
All coil coatings are baked, during which two things happen:
1) The solvent in the paint evaporates and burns in the afterburner.
2) Chemical reactions in the paint film bring the resin molecules together (polymerize or crosslink) to form a strong crosslinked solid paint film.
In general, there is no direct way to measure the degree of crosslinking. But comprehensive tests can indicate whether a coating is under-cured or over-cured, such as MEK rub, pencil hardness and adhesion.
Uncured paint will tend to be soft and will not withstand molding or weathering during its end use. Overcured paint tends to become brittle and can be damaged during molding or weathering.
Haomei Aluminum fully flows these standards to ensure wholesale aluminum coil quality. Welcome to leave message below to inquire what you need.