How to use paint colorimeter to maintain consistency in automotive industry?

From:Linshang Time:2022/12/07 09:51:00 Browse:49

Cars play a very important role in our daily transportation. Whether it is a new car owner who considers the color of the car paint when choosing a car, or an old car owner who sprays and touches up paint when there is friction and corrosion, it is necessary to judge the color. During the spraying process of the car topcoat, due to the difference in the spraying process and the topcoat blending process, etc., it is easy to have inconsistent colors after spraying. In order to control the consistency of the color of the car topcoat, colorimeter can be used to test the color to test. This article introduces how it maintains color consistency based on the application of the car paint colorimeter in the car paint industry.

car paint
car paint

Causes of chromatic aberration in automotive topcoats

  • Coating thickness

    The coating thickness of automotive topcoat is related to the environment. Factors such as the color of the substrate and the gloss change of the paint due to the change in thickness must be fully considered in the paint coloring and even the painting process. 

  • Solvent evaporation rate 

    The volatilization of the solvent will affect the surface leveling, gloss and orientation of the pigments of the coating, and then affect the hue of the color.

  • Hydrophilicity of the solvent 

    In a high-temperature environment, if it involves a drastic change in high temperature, during the process of solvent volatilization, there will be a temperature difference on the surface of the coating due to the volatilization of the solvent, resulting in a thin layer of water mist on the surface of the coating. As a result, the coating is whitish and chromatic aberration occurs. 

  • Coating Uniformity

    Different pigments have different effects on color saturation; the same color is prone to stains on the surface of the same board due to different construction methods, different operating habits and other factors, or the color depth due to the difference in thickness between different boards, etc. , these factors will produce chromatic aberration.

How to maintain color consistency in the automotive painting industry

Judging the color difference generally uses visual inspection and instrument measurement.

If there is obvious color difference visible to the naked eye when the car is sprayed, stop painting immediately, clean up the painted part, and re-color; if the color of the paint is found to be wrong after spraying, it may be because the paint is not completely dry within one month, so the color is relatively weak deep. After a month, it is still obvious that the color is wrong and needs to be repainted, which is very time-consuming and labor-intensive.

The instrument measurement method recommends a car paint color difference detector: LS176B portable colorimeter, a professional instrument that can quickly measure the color difference that cannot be judged by the naked eye. The color difference can be controlled from the color adjustment of the paint, and the color adjustment can also be carried out through the LS176B during the painting process.

  1. If the brand manufacturer provides an exclusive color formula, it can be adjusted according to the formula;

  2. After toning, test on the sample board first, and compare the original color of the car body with colorimeter after spraying. For the choice of color difference detector, it is recommended to use the color difference meter with the principle of D/8 integrating sphere for detection. The D/8 colorimeter will be more accurate in measuring some pearlescent paints and high-gloss paints;

  3. Use the color difference comparison function of colorimeter, use the original car paint as the standard color, and the sprayed sample as the sample color for color difference comparison. Generally, the color difference value ΔE*ab is controlled below 1.5, so it is basically difficult to distinguish the color difference with the naked eye;

  4. Linshang's colorimeter series products all have the color deviation prompt function. If the color difference is within the unacceptable range, you can adjust the color according to the Lab color deviation prompt of the color difference comparison result until the color difference is controlled within the acceptable range. 

  5. If it is a very common car model, the color data can be stored in the personal color library of colorimeter in the form of model year, for subsequent use as a standard color. In addition, the color can be exported to the computer for storage, the exported data is in Excel format, and the color formula is noted in the exported data table for later color reference.

colormeter measured car paint color
colormeter measured car paint color

Color difference is inevitable, but it needs to be controlled within a reasonable range to keep the color consistent and not affect the appearance of the car. The following are prevention and remedies for color inconsistencies:

  1. Be sure to test on a sample board before spraying to ensure that the color matching is accurate.

  2. Use the spray method recommended in the technical data sheet.

  3. If there is difficulty in color matching, the "soft" spray method can be used.

  4. Sand the surface, adjust the topcoat color to a closer shade, then respray using the Soft or Port Spray method.

  5. Polish nearby surfaces clean to check color.

The car paint colorimeter is just an auxiliary tool. There are many factors that affect the color consistency of the whole car paint. To minimize the color difference, more depends on the experience of the paint master. The above is the whole content of how to use the car paint color difference detector to maintain the consistency of the car paint in the automotive industry. I hope it can help you!