Chromatic Abrration Description
Chromatic Aberration refers to the difference between the hue, brightness and chroma of the painted aluminum coil coating film and the standard color card.
Chromatic Abrration standard
The CA (chromation abrration) value is used to measure the degree of color difference of an image. The lower the CA value, the better the quality of the paint film.
|
Chromatic Aberration Range(△E) |
Severity |
|
0-0.5 |
Insignificant |
|
0.5-1.0 |
Low. Hard to see unless you look for it. |
|
1.0-1.5 |
Moderate.Somewhat visible at high print magnifications. |
|
＞1.5 |
Highly.visible at high print magnifications. |
Methods for Inspect color difference
color card comparison
The observer compares the sample of the color aluminum coil with the Ral color card color number or the customer's product sample
Colorimeterdetection
The observer uses a colorimeter to objectively evaluate the color difference. By comparing the difference between the lightness L, red phase a (red-green), and blue phase b (yellow-blue) of the measured object and the standard, △L, △a, △b and color difference △E values are obtained. △E is not only used to control the color difference inspection of the whole vehicle, but is also widely used as an inspection for paint inspection.
What are the reasons for the CA between Painted aluminum coils?
The causes of color difference mainly come from two aspects: factors of the raw materials themselves and production process control.
The Reason of Raw Material
Different aluminum grades
Customers choose different aluminum systems because the gloss of the aluminum plate itself is different, which will also affect the color brightness.
Different paint batches
If customers place orders for the same color at different times and use it in the same project, there will be a significant color difference
Improper paint ratio
Improper paint ratio causes floating color and bleeding.
Floating color: Floating color is made by mixing pigments with large density differences, which easily produces pigment distribution differences between the upper and lower layers, making the surface and internal colors of the coating inconsistent
Bleeding: Bleeding is the color of the primer penetrating into the topcoat, which is the color of the topcoat being stained and discolored.
The Reason of Production Processing
Coating production process and adjustment are extremely important for controlling paint color difference. Most color difference problems are caused by improper production process operation.
Coating thickness
The thickness of the coating is closely related to the application environment. Factors such as the color of the substrate and the gloss change of the paint due to the thickness change must be fully considered in the paint toning and even the coating process.
Solvent evaporation rate
The volatilization of the solvent affects the surface leveling, gloss, and directional arrangement of the pigments and fillers of the coating, and then affects the hue of the color.
Hydrophilicity of the solvent
In a high-humidity environment, if a drastic temperature change is involved, during the solvent volatilization process, the coating surface will have a temperature difference due to the solvent volatilization, resulting in a thin layer of water mist on the coating surface, causing the coating to whiten and produce color differences.
Uniformity of coating
Different pigments have different effects on the color saturation due to the adjustment; the same color is easy to produce stains on the surface of the same board due to different construction methods, different operating habits and other factors, such as the thickness difference between different boards. These factors The resulting chromatic aberration can only be overcome by operating procedures or proficiency.
How to Shrink the chromatic aberration of Painted Aluminum Coil?
In addition to the reasons of the color difference between the color difference, the relevant production process is controlled and adjusted. It is also necessary to standardize the color difference detection to avoid due to errors or a single light source.
Controlling production processes
Topcoats of the same color should be purchased from the same manufacturer, and the inspection of paint purchase should be strengthened.
Paint dilution should strictly follow the standard and should not be too thin.
Try to avoid using paints with large density differences for color matching to prevent floating color and color bleeding of the paint.
The substrate should be processed properly before painting, flat and with consistent surface roughness
The tools should be thoroughly cleaned before painting, especially when changing colors, the paint pipeline must be cleaned to avoid color mixing.
Ensure continuous painting and less touch-up. If touch-up is required, it should be done on the surface with a clear dividing line. When repairing old equipment, try to use overall repair as much as possible.
The paint should be fully stirred before use, especially the composite paint, which can only be used after stirring.
The thickness of the paint film should meet the requirements of the process specifications and should not be too thick.
The drying time and temperature should be strictly controlled within the process time, and the drying specifications should be consistent.
Standardized chromatic Aberration detection
The detection instruments for different parts should be consistent.
The color card should be updated in time, and the standard version management should be standardized.
How does Hanchen control the CA of the paint film of Painted aluminum coils?
- For applications that require extremely high color difference of color aluminum coils (such as ΔE ≤ 0.4) or products with slight color difference but significant visual changes, quality control standards must be improved and visual inspection must be strengthened.
- For the application of general requirements for the color difference of colored aluminum coils, the color difference is controlled to ΔE≤1, and the color difference of some paint films is controlled to ΔE≤0.5. The inspector is required to compare the colors of the coated samples under different light sources, and the visual inspection is consistent. The color difference Control to ΔE≤0.5
There is color difference between batches in painting, and there is no guarantee that the color will be consistent with the paint film of the customer's previous batch of color-coated aluminum coils. Hanchen will customize pigment swatches in advance for large-volume customization customers to reduce color differences caused by different batches of paint.
Hanchen Metal will conduct sample coating before mass production to avoid obvious color differences in color pictures of aluminum coils due to color mismatch in the paint itself.
Strictly control the production process. Strict quality inspection of aluminum coils before coating ensures that the aluminum coils are flat and perfect. Strictly control the paint ratio, coating thickness and curing temperature during coating, and control color difference from every step of the production process.
About Hanchen Metal
Shandong Hanchen Metal Co.,Ltd is a professional color coated aluminum manufacturer integrating production, sales and trade. We have professional two automatic production lines with four-roller coating equipment. The whole production process has strict quality control and inspection. Our main products are aluminum coils and prepainted aluminum coils,widely used in metal roofing, aluminum ceiling, aluminum composite panel, aluminum sandwich panel, aluminum honeycomb panel and so on. We are committed to providing customers with high-standard products and satisfactory services and highly efficient solutions.
What Can Hanchen Provide for You?
Hanchen Metal is committed to providing customers with high standard color aluminum rolls and reliable after -sales service
Professional Processing
We have professional four-roller coating equipment and two automatic production lines, which greatly improve production efficiency
01
High Quality Product
We only select high-quality aluminum coils and conduct strict quality inspections before shipment to ensure product quality.
02
Stable Price
Hanchen Metal is a factory direct seller and will set prices based on the daily aluminum ingot prices. The prices are more reasonable, stable and cost-effective.
03
Perfect After-Sales
Whether before or after sales, we will respond to customers in a timely manner, answer questions and solve problems for customers in a timely manner
04
Production Processing
Inspect item
Color Comparison
Pencil Hardness Test
MEK Test
T-Bend Test
Reverse Impact Test
Our Painted Aluminum Coil
Basic feature
| Thickness | 0.15mm-2mm |
| Width | Max 1650mm |
| Color | Ral colors or based on requirements |
| Coating film | 20-60μm |
| Coating | PE, HDP, PVDF, etc |
| Alloy | 1100, 3003, 3004,3105,5052 etc |
| Warranty | 15-30 years based on surface coating |
| Package | Eye to wall, eye to sky, coils on wooden pallet |
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