Analysis of common quality problems of colored aluminum coils
During the colored aluminum coil coating process, the surface coating of the aluminum coil may have quality problems due to improper operation (such as bubbles on the surface, loose paint film, etc.). As an aluminum coil manufacturer, we should find out the cause of the problem and strengthen the production process control to solve it in time to ensure high quality.
Surface Bubbles
There is paint on both sides of the color-coated aluminum coil, and bubbles appear after drying.
Reason：The raw material has burrs, is stained with too much paint, and has gaps on both sides.
Color difference
The color of the colored coil after molding is quite different from the standard color card or the customer's sample.
Reason：The reason for the large color difference of colored aluminum coils may be that the coating thickness is too thick or too thin, or that the same batch of coatings are not used during production, or that the viscosity is not stirred evenly during dilution.
Poor gloss
The range of gloss appears abnormal.
Reason：The reason for poor gloss of colored aluminum coils may be improper coating thickness or improper curing conditions or insufficient mixing of the coating.
Orange peel
The dried surface coating of colored aluminum coils is as rough and uneven as orange peel.
Reason：The wet film applied is too thick or the coating viscosity is high.
Pockmarks
There are foreign objects as big as rice grains protruding from the surface of the colored aluminum coil.
Reason：The aluminum coil is not properly washed during pretreatment or the coating is mixed with debris or different types of coatings
Poor Bending
When the colored aluminum coil sample was bent 180 degrees for the test, the coating at the processed part cracked and peeled off.
Reason：The reason why the color-coated aluminum coil has poor bending performance may be that the aluminum coil coating thickness is too thick or over-baked, or the coating batch is different.
Poor hardness
Use the pencil to scratch the surface of the color-coated aluminum coil with force, leaving scratches on the surface after wiping off.
Reason: The reason for the poor hardness of color-coated aluminum coils is that the furnace temperature is low during baking, the heating conditions do not meet the requirements, and the coating is not fully cured.
Poor solvent
resistance
The paint on the colored aluminum sample fell off in spots when wiped with MEK.
Reason：The reason for the poor solvent resistance of colored aluminum coils may be that the pre-treatment cleaning is not clean, the baking temperature does not meet the requirements, and the curing operation of the coating is improper.
Impact failure
After the paint film is impacted in the reverse direction, part or all of the paint will fall off after being bonded with tape.
The aluminum coil was not handled properly during pretreatment, and the curing temperature was not cured as specified.
What Hanchen Metal can offer you?
Production Process
High quality aluminum coil raw materials are the foundation of production, and each coil of aluminum must undergo strict weighing and quality testing before being put into production to ensure that it meets production standards
The weighed aluminum coils are put into the uncoiler for uncoiling to prepare for subsequent processing. After uncoiling is completed, the aluminum coil enters the pretreatment stage.
Pretreatment includes degreasing, washing, light extraction, re-washing, drying, passivation and re-drying.This step is the key to ensuring the quality of color-coated aluminum coil products.
After the pretreatment is completed, the aluminum coil enters the coating stage. This stage is the core link in forming the decorative effect of roller-coated aluminum. The coating process uses an advanced four-roller coating process, including film fixing roller, a pick-up roll, a transfer roll and a coating roll.
After the coating is completed, the aluminum coil needs to go through a drying and cooling process. This step is to allow the coating to cure and adhere to the aluminum plate better, ensuring the durability and stability of the product.
We have carried out strict quality control on every production link to ensure that the products meet high standard quality requirements. Aluminum coils that pass the inspection will be coated and rolled to protect the coating from damage and facilitate subsequent transportation and use.
Products Inspection
To test whether the quality of color aluminum coils meets the standards and meets customer needs, mainly testing the surface quality of color aluminum coils including coating thickness, gloss, color, adhesion, etc. Common colored aluminum coil inspection methods include:
Substrate thickness measurement, Coating film thickness test, MEK test, Gloss test, T-bend, Pencil hardness test, Coin scratch test, reverse impact test.
Thickness inspection
Color comparison
Pencil hardness test
MEK Test
T-bend Test
Reverse impact test
Product Description
Product drawing
Basic feature
| Thickness | 0.15mm-2mm |
| Width | Max 1650mm |
| Color | Ral colors or based on requirements |
| Coating film | 15-60μm |
| Coating | PE, HDP, PVDF, etc |
| Alloy | AA1100, 3003, 3004 etc |
| Warranty | 15-30 years based on surface coating |
| Package | Eye to wall, eye to sky, coils on wooden pallet |
we are here for you