Helicopter finish color matching method using a spectrophotometer and a color wheel

Abstract

The present application belongs to the field of helicopter repair paint blending, and particularly relates to a helicopter finish paint color matching method using a spectrophotometer and a color ring. The current color matching of repair paint has high requirements for manual work, is highly dependent, and has very low color matching efficiency. The present application first identifies each color number of paint in the color ring to establish a color ring; uses a spectrophotometer to measure the color coordinate values of the sample paint film and the original paint film respectively and records them; identifies the positions of the sample paint film and the original paint film in the color ring by means of marking lines; draws the mirror line of the color tone line of the sample paint film with the color tone line of the original paint film as the axis, which is the color tone line of the paint to be added; determines the corresponding paint color number to be added according to the color tone line of the paint to be added; adjusts the paint according to the weight ratio of 1:1; and then adjusts the brightness. The color matching method is accurate and fast, and greatly improves the work efficiency. It has high practical value in the helicopter painting process.

Description

Technical Field

[0001] This invention belongs to the field of helicopter repair paint formulation, specifically relating to a method for tinting helicopter topcoat using a spectrophotometer and a color wheel. Background Technology

[0002] During helicopter use and maintenance, scratches and paint chipping are inevitable, requiring repainting of damaged areas. Additionally, helicopter modifications necessitate repainting of the modified parts. Often, the color of the newly repaired paint differs significantly from the original, creating an uncoordinated appearance. To minimize or eliminate this disharmony, the common practice is to tint the repair paint, adding different proportions of other colored paints.

[0003] Color matching is generally carried out as follows: After spraying the new paint onto a test panel and drying it, visually compare it with the original paint film to preliminarily determine the difference in hue between the new and old paint films. Based on the hue difference (for example, the new paint film appears greener or darker than the original paint film), add a certain proportion of the missing color paint to the new paint. Then, spray the first mixed paint onto a color swatch and compare it with the original paint film to determine the color difference again. Repeat this process until the color difference between the new and old paint films is adjusted to an acceptable range.

[0004] The color matching of this type of repair paint requires high levels of manual skill and is highly dependent on manual labor. Moreover, the color matching efficiency is extremely low. It usually requires spraying the color sample more than a dozen times for comparison, which consumes a lot of labor and resources.

[0005] In addition, spectrophotometers are currently used to detect the color difference between new and old paint films, thereby determining whether the color difference between the new and old paint films is within the standard allowable range. The greatest function of a spectrophotometer is to quantify the hue difference between the sample color and the standard color, displaying it numerically (usually the difference in color space coordinate values ​​L*, a*, b* or tristimulus values ​​X, Y, Z). This color difference value is no longer the subjective color difference perceived during manual color comparison, thus providing guidance for color matching (because the color difference value can reflect the hue missing (or added) compared to the standard color). However, because helicopter paint has extremely high performance requirements, it is generally a finished paint and cannot be directly mixed with pigments like civilian paints such as automotive paint. Paint mixed by directly adding pigments cannot meet the performance requirements of military products. Therefore, in military products, only paints of different colors of the same brand within a specified range can be mixed for color matching. Furthermore, the colors of the finished paints are not pure standard colors (helicopter topcoat colors are in accordance with GB / T 3181 "Paint Film Color Standard," most of which contain different proportions of other hues), which makes color matching quite difficult. For example, if a colorimeter shows that the sample color lacks green and blue compared to the standard color, green and blue paint should be added to reduce the color difference. However, the national standard GB / T3181 lists as many as 20 different green paints and 21 blue paints, making it impossible to determine which green and blue paints to use for color matching. In addition, even if a specific color number of paint is selected for color matching, the proportion to be added is also unknown. Therefore, ultimately, it still relies on experience, comparing the mixed color with a color swatch and making continuous adjustments. Compared to purely manual color matching, the work efficiency is not significantly improved. Summary of the Invention

[0006] The purpose of this invention is to provide a color mixing method that significantly improves the mixing efficiency of helicopter repair paint, in view of the existing problems.

[0007] The technical solution of the present invention is to provide a method for tinting helicopter topcoat using a spectrophotometer and a color wheel. The method first integrates the color wheel in GB / T 15608 "Chinese Color System" and all color numbers of paint in GB / T 3181 "Paint Film Color Standard", and identifies each color number of paint in the color wheel to establish a color wheel.

[0008] The subsequent color grading process includes the following steps:

[0009] S1. Visually compare colors to determine if the spare repair paint meets the color requirements for the repair paint. If it does, skip to step S8; otherwise, proceed to the next step.

[0010] S2. Use a spectrophotometer to measure and record the chromaticity coordinates of the sample paint film and the original paint film respectively.

[0011] S3. Based on the red-green and yellow-blue tones in the chromaticity coordinates, mark the positions of the sample paint film and the original paint film on the color wheel by drawing lines.

[0012] S4. Using the color line of the original paint film as the axis of symmetry, draw the mirror line of the color line of the sample paint film, which is the color line where paint needs to be added.

[0013] S5. Determine the corresponding paint color number to be added based on the color line of the color to be added;

[0014] S6. Prepare repair paint by weight ratio: add paint = 1:1 to mix the paint;

[0015] S7. Visually compare the colors to determine if the prepared repair paint meets the color requirements of the repair paint. If it does, skip to step S8. If it does not meet the requirements, adjust the ratio of the spare repair paint to the added paint by weight according to the color bias of the sample paint film, and return to step S7.

[0016] S8. Compare the brightness with the original paint film. When there is a difference in brightness between the old and new paint films, the brightness can be finely adjusted by adding a small amount of white or black paint to the repair paint.

[0017] Advantageously, in step S1, the spare repair paint is sprayed onto a test board with an existing primer, and after drying, it is visually compared with the original paint film.

[0018] Advantageously, in step S2, the colorimetric coordinate values ​​of the sample paint film and the original paint film are measured using a spectrophotometer, including the values ​​of L*, a*, and b*.

[0019] Advantageously, in step S3, the color coordinate value a* represents the red-green hue, with a positive value of a* indicating a red hue and a negative value indicating a green hue; the color coordinate value b* represents the yellow-blue hue, with a positive value of b* indicating a yellow hue and a negative value indicating a blue hue. Based on the measured a* and b* values ​​of the sample paint film and the original paint film, the quadrants of the two are determined in the color wheel, and the hue lines of the sample paint film and the original paint film are drawn according to the proportion of each hue.

[0020] Advantageously, the red tone proportion = |a*| / (|a*|+|b*|)×100%; the yellow tone proportion = |b*| / (|a*|+|b*|)×100%.

[0021] Advantageously, in step S5, the paint color line that is closest to the color line to be added is the paint color line to be added.

[0022] Advantageously, in step S8, when the new paint film is brighter than the old paint film, a fine-tuning is made by adding a trace amount of black paint to the touch-up paint.

[0023] Advantageously, in step S8, when the new paint film is darker than the old paint film, a fine adjustment is made by adding a trace amount of white paint to the touch-up paint.

[0024] The beneficial effects of this invention are as follows: This invention addresses the color matching of helicopter repair paint, providing an accurate and rapid method that significantly improves work efficiency. It has high practical value in the helicopter painting process. Attached Figure Description

[0025] When read in conjunction with the accompanying drawings, the exemplary embodiments, preferred modes of use, other objects, and description thereof will be best understood by referring to the following detailed description of examples of the invention, wherein:

[0026] Figure 1 The color wheel in GB / T 15608 "Chinese Color System";

[0027] Figure 2 This is a partial color code table from GB / T 3181 "Standard for Paint Film Colors";

[0028] Figure 3 This is a schematic diagram of the color wheel after combining standard color codes with standard color tone circles.

[0029] Figure 4 This is a schematic diagram of the hue position when adjusting colors in the color wheel in the embodiment. Detailed Implementation

[0030] The disclosed examples will be described more fully with reference to the accompanying drawings, in which some (but not all) of the disclosed examples are shown. In fact, many different examples may be described, and these examples should not be construed as limited to those set forth herein. Rather, these examples are described so that this disclosure will be thorough and complete, and will fully convey the scope of this disclosure to those skilled in the art.

[0031] See Figure 4 The represented color grading example includes the following steps:

[0032] 1. Visual color comparison: Spray the prepared repair paint onto the test board with the existing primer. After drying, visually compare the color with the original paint film. If there is a significant color difference between the new and old paint films, the repair paint needs to be adjusted.

[0033] 2. Measure the color coordinate values: Use a spectrophotometer to measure and record the color coordinate values ​​(i.e., the values ​​of L*, a*, b*) of the sample paint film and the original paint film respectively.

[0034] 3. Based on the red-green and yellow-blue hue values ​​in the chromaticity coordinates, mark the positions of the sample paint film and the original paint film on the color wheel by drawing lines: Since the chromaticity coordinate value a* represents the red-green hue (a positive value of a* indicates red, and a negative value indicates green), and the chromaticity coordinate value b* represents the yellow-blue hue (a positive value of b* indicates yellow, and a negative value indicates blue), based on the measured a* and b* values ​​of the sample paint film and the original paint film, in Figure 4 Determine the quadrant of the two hues in the color wheel shown, and draw the hue lines of the sample paint film and the original paint film respectively according to the proportion of each hue (red hue proportion value = |a*| / (|a*|+|b*|)×100%; yellow hue proportion value = |b*| / (|a*|+|b*|)×100%).

[0035] 4. Draw the color tone line to be added: Using the original paint film color tone line as the axis of symmetry, draw the mirror line of the sample paint film color tone line. This line is the color tone line to be added with paint.

[0036] 5. Determine the paint color number and mixing ratio to be added: Figure 4 The paint color number that is closest to the hue line to be added is the paint color number to be added. For example, the hue to be added in the figure is about 5.6GY, and its corresponding paint color number is GY02.

[0037] 6. Prepare the repair paint by weight ratio: add the oil paint in a 1:1 ratio;

[0038] 7. In the embodiment, the test panel with the existing primer was re-sprayed. After drying, the color was visually compared with the original paint film. There was no obvious color difference between the new and old paint films. The light and dark differences between the new and old paint films were further judged. In the embodiment, the sample paint film was slightly darker than the original paint film. A small amount of white was added to the spare repair paint to make a fine adjustment to meet the requirements.

[0039] The various examples of systems, apparatuses, and methods disclosed herein include a wide range of components, features, and functions. It should be understood that the various examples of systems, apparatuses, and methods disclosed herein may include any of the components, features, and functions of any of the other examples of systems, apparatuses, and methods disclosed herein in any combination or sub-combination, and all such possibilities are intended to fall within the scope of the invention.

[0040] Descriptions of various advantageous arrangements have been shown for illustrative and descriptive purposes, but such descriptions are not intended to be exclusive or limited to the disclosed forms. Many modifications and variations will be apparent to those skilled in the art. Furthermore, different advantageous examples may describe different advantages compared to other advantageous examples. One or more examples have been selected and described in order to best illustrate the principles and practical application of the examples, and to enable those skilled in the art to understand that this disclosure contains various examples with various modifications suitable for the particular intended use.

Claims

1. A method for tinting helicopter topcoat using a spectrophotometer and a color wheel, characterized in that: This method first integrates the color wheel in GB / T 15608 "Chinese Color System" and all color numbers of paint in GB / T 3181 "Paint Film Color Standard", and identifies each color number of paint in the color wheel to establish a color wheel; The subsequent color grading process includes the following steps: S1. Visually compare colors to determine if the spare repair paint meets the color requirements for the repair paint. If it does, skip to step S8; otherwise, proceed to the next step. S2. Use a spectrophotometer to measure and record the chromaticity coordinates of the sample paint film and the original paint film respectively. S3. Based on the red-green and yellow-blue tones in the chromaticity coordinates, mark the positions of the sample paint film and the original paint film on the color wheel by drawing lines. S4. Using the color line of the original paint film as the axis of symmetry, draw the mirror line of the color line of the sample paint film, which is the color line where paint needs to be added. S5. Determine the corresponding paint color number to be added based on the color line of the color to be added; S6. Prepare repair paint by weight ratio: add paint = 1:1 to mix the paint; S7. Visually compare the colors to determine if the prepared repair paint meets the color requirements of the repair paint. If it does, skip to step S8. If it does not meet the requirements, adjust the ratio of the spare repair paint to the added paint by weight according to the color bias of the sample paint film, and return to step S7. S8. Compare the brightness with the original paint film. When there is a difference in brightness between the old and new paint films, the brightness can be finely adjusted by adding a small amount of white or black paint to the repair paint.

2. The helicopter topcoat color matching method according to claim 1, characterized in that: In step S1, the spare repair paint is sprayed onto the test board with the existing primer. After drying, the paint is visually compared with the original paint film.

3. The helicopter topcoat color matching method according to claim 1, characterized in that: In step S2, the colorimetric coordinate values ​​of the sample paint film and the original paint film are measured using a spectrophotometer, including the values ​​of L*, a*, and b*.

4. The helicopter topcoat color matching method according to claim 3, characterized in that: In step S3, the color coordinate value a* represents the red-green hue, with a positive value indicating red and a negative value indicating green; the color coordinate value b* represents the yellow-blue hue, with a positive value indicating yellow and a negative value indicating blue. Based on the measured a* and b* values ​​of the sample paint film and the original paint film, the quadrants of the two are determined in the color wheel, and the hue lines of the sample paint film and the original paint film are drawn according to the proportion of each hue.

5. The helicopter topcoat color matching method according to claim 4, characterized in that: Red tone proportion = |a*| / (|a*|+|b*|)×100%; Yellow tone proportion = |b*| / (|a*|+|b*|)×100%).

6. The helicopter topcoat color matching method according to claim 1, characterized in that: In step S5, the paint color line that is closest to the color line to be added is the paint color line to be added.

7. The helicopter topcoat color matching method according to claim 1, characterized in that: In step S8, when the new paint film is brighter than the old paint film, a fine adjustment is made by adding a small amount of black paint to the touch-up paint.

8. The helicopter topcoat color matching method according to claim 1, characterized in that: In step S8, when the new paint film is darker than the old paint film, a fine adjustment is made by adding a small amount of white paint to the touch-up paint.

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