Powder spraying quick color changing process for automotive interior parts

Abstract

The application discloses a kind of automobile interior part powder spraying quick color change processes, belong to automobile interior part processing technical field, comprising the following steps: one, obtains current spraying color and target color difference;Two, current color change level is judged based on preset color difference-color change level mapping rule;Three, current color change cleaning strategy is judged based on color change level-color change cleaning strategy mapping rule;Four, color change cleaning is carried out based on current color change cleaning strategy;Five, normal powder supply is carried out after color change cleaning powder color change spraying;The application is based on the three stimulus value coordinates of current spraying color and target color, calculates color difference, determines color change level based on color difference, determines color change cleaning strategy based on color change level, carries out cleaning based on the color change cleaning strategy determined, normal powder supply is carried out after cleaning powder color change spraying, compared with prior art, can adaptively clean local or all according to color difference degree, complete the quick color change of powder spraying.

Description

Technical Field

[0001] This invention belongs to the field of automotive interior parts processing technology, specifically relating to a rapid color-changing process for powder coating of automotive interior parts. Background Technology

[0002] With increasingly stringent environmental protection requirements in the automotive industry, powder coating has been widely used in the surface treatment of automotive interior parts due to its zero emissions of volatile organic compounds, high recyclability, and excellent mechanical properties of the coating film.

[0003] As automotive interior design becomes increasingly personalized and customized, the same production line often needs to frequently switch between different colors of powder coating within a short period of time.

[0004] Current powder coating methods for automotive interior parts require stopping the production line for cleaning each time a color is changed. While this can minimize cross-contamination between different colored powders, it also results in poor color-changing efficiency.

[0005] In view of this, a rapid color-changing process for powder coating of automotive interior parts is designed to solve the above problems. Summary of the Invention

[0006] To address the problems mentioned in the background section, this invention provides a rapid color-changing process for powder coating of automotive interior parts. This process features the ability to adaptively clean up partial or complete areas based on the degree of color difference, enabling rapid color changes through powder coating.

[0007] To achieve the above objectives, the present invention provides the following technical solution: a rapid color-changing process for powder coating of automotive interior parts, comprising the following steps:

[0008] 1. Obtain the tristimulus coordinates of the current sprayed color and the target color to calculate the color difference;

[0009] 2. Determine the current color change level based on the color difference between the current sprayed color and the target color, as well as the preset color difference-color change level mapping rule;

[0010] 3. Determine the current color change and cleanup strategy based on the current color change level and the preset color change level-color change and cleanup strategy mapping rules;

[0011] IV. Perform color-changing cleanup based on the current color-changing cleanup strategy;

[0012] 5. After cleaning and color change, continue powder coating with normal powder supply.

[0013] Furthermore, in step one, the calculation of the color difference includes:

[0014] The average chroma is calculated based on the red-green and yellow-blue coordinates in the tristimulus coordinates of the current sprayed color and the target color;

[0015] Compensation factor is calculated based on average chroma;

[0016] The red and green coordinates of the current sprayed color and the target color are corrected based on the compensation factor.

[0017] The chroma and hue angles are corrected based on the red-green and yellow-blue coordinates after the current spraying color is corrected to match the target color.

[0018] The lightness difference is calculated based on the lightness values ​​in the tristimulus coordinates of the current sprayed color and the target color.

[0019] Chroma difference is calculated based on the corrected chroma;

[0020] The hue difference is calculated based on the corrected hue angle;

[0021] The average lightness is calculated based on the lightness values ​​in the tristimulus coordinates of the current sprayed color and the target color.

[0022] Calculate the average chroma based on the corrected chroma;

[0023] Calculate the average hue angle based on the corrected hue angle;

[0024] Calculate weighting coefficients and rotation interaction terms based on average lightness, average chroma, and average hue angle;

[0025] Color difference is calculated based on brightness difference, chroma difference, hue difference, weighting coefficient, and rotation interaction term.

[0026] Furthermore, in step two, the color difference-color change level mapping rule includes:

[0027] Set a first-level color-changing threshold. If the color difference is less than the first-level color-changing threshold, it is judged as a first-level color-changing.

[0028] Set a secondary color-changing threshold. If the color difference is greater than the primary color-changing threshold but less than the secondary color-changing threshold, it is judged as a secondary color-changing.

[0029] If the color difference is greater than the second-level color-changing threshold, it is judged as a third-level color-changing.

[0030] Furthermore, in step three, the mapping rules for the color change level - color change cleanup strategy include:

[0031] The color change cleanup strategy corresponding to Level 1 color change:

[0032] Stop supplying powder to the current powder hopper at the powder supply center, start the vacuum pump at the end of the powder pump to vacuum suction, and suck the powder in the powder conveying main pipe and the powder extraction pipe connected to the current powder hopper back to the current powder hopper; the powder pump sprays powder out of the air; compressed air backflushs the powder pipe inside the spray gun; negative pressure suction is applied to the powder spraying chamber.

[0033] Color change cleanup strategy corresponding to secondary color change:

[0034] Stop supplying powder to the current powder hopper at the powder supply center, start the vacuum pump at the end of the powder pump to vacuum suction, and suck the powder in the powder delivery main pipe and the powder extraction pipe connected to the current powder hopper back to the current powder hopper; the powder pump sprays powder out of the air and is supplemented by compressed air backflushing; the spray gun electrode needle is cleaned; the powder spraying chamber is vacuumed.

[0035] The corresponding color change cleanup strategy for Level 3 color change:

[0036] Stop supplying powder to the current powder hopper at the powder supply center, start the vacuum pump at the end of the powder pump to vacuum and suck the powder in the extraction pipeline connected to the current powder hopper back to the current powder hopper; clean the powder conveying main pipe; clean the powder pump; clean the spray gun; wipe the powder spraying chamber.

[0037] Compared with the prior art, the beneficial effects of the present invention are:

[0038] This invention calculates the color difference based on the tristimulus coordinates of the current spray color and the target color, determines the color change level based on the color difference, determines the color change cleaning strategy based on the color change level, performs cleaning based on the determined color change cleaning strategy, and then supplies powder normally for powder color change spraying. Compared with the prior art, it can adaptively clean part or all of the powder according to the degree of color difference, thus completing the rapid color change of powder spraying. Attached Figure Description

[0039] Figure 1 This is a process flow diagram of the present invention. Detailed Implementation

[0040] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0041] I. Steps for calculating color difference

[0042] Obtain the tristimulus coordinates of color one and color two;

[0043] The average chroma is calculated based on the red-green and yellow-blue chroma coordinates in the tristimulus coordinates of color one and color two.

[0044] Average chroma:

[0045]

[0046]

[0047]

[0048] In the formula: Indicates color chroma; This represents the red-green hue coordinates of the color. This represents the color's yellow-blue hue coordinates; Indicates color dichromaticity; This represents the red-green hue coordinates of color two; This represents the coordinates of the blue tint of the color "two yellows".

[0049] Compensation factor is calculated based on average chroma;

[0050] Compensation factor:

[0051]

[0052] In the formula: Indicates average chroma;

[0053] The red and green hue coordinates of color one and color two are corrected based on the compensation factor.

[0054] Corrected red-green coordinates:

[0055]

[0056]

[0057] In the formula: This represents the red-green hue coordinates of the color. This represents the red-green hue coordinates of color two; Indicates the compensation factor;

[0058] Chroma and hue angles are corrected based on the red-green and yellow-blue hue coordinates after color one and color two corrections;

[0059] Corrected chroma:

[0060]

[0061]

[0062] In the formula: This indicates the chroma after color correction; This represents the red-green hue coordinates after color correction; This represents the color's yellow-blue hue coordinates; This indicates the chroma after color correction; This represents the red-green hue coordinates after color correction. This represents the coordinates of the blue tint of the color "two yellows".

[0063] Corrected hue angle:

[0064]

[0065]

[0066] In the formula: This represents the red-green hue coordinates after color correction; This represents the color's yellow-blue hue coordinates; This represents the red-green hue coordinates after color correction. This represents the coordinates of the blue tint of the color "two yellows".

[0067] The difference in lightness is calculated based on the lightness values ​​in the coordinates of the tristimulus values ​​of color one and color two.

[0068] Brightness difference:

[0069]

[0070] In the formula: Indicates the brightness of a color; Indicates the brightness of a color;

[0071] Chroma difference is calculated based on the corrected chroma;

[0072] Color saturation difference:

[0073]

[0074] In the formula: This indicates the chroma after color correction; This indicates the chroma after color correction;

[0075] The hue difference is calculated based on the corrected hue angle;

[0076] Hue angle difference:

[0077]

[0078] In the formula: This represents the hue angle after color correction; This represents the hue angle after color correction.

[0079] Hue difference:

[0080]

[0081] In the formula: This indicates the chroma after color correction; This indicates the chroma after color correction; Indicates the difference in hue angle;

[0082] The average lightness is calculated based on the lightness values ​​in the tristimulus coordinates of color one and color two.

[0083] Average brightness:

[0084]

[0085] In the formula: Indicates the brightness of a color; Indicates the brightness of a color;

[0086] Calculate the average chroma based on the corrected chroma;

[0087] Average chroma:

[0088]

[0089] In the formula: This indicates the chroma after color correction; This indicates the chroma after color correction;

[0090] Calculate the average hue angle based on the corrected hue angle;

[0091] Average hue angle:

[0092]

[0093] In the formula: This represents the hue angle after color correction; This represents the hue angle after color correction.

[0094] Calculate weighting coefficients and rotation interaction terms based on average lightness, average chroma, and average hue angle;

[0095] Brightness weighting coefficient:

[0096]

[0097] In the formula: Indicates average brightness;

[0098] Chroma weighting coefficient:

[0099]

[0100] In the formula: Indicates average chroma;

[0101] Hue weighting coefficient:

[0102]

[0103] In the formula: Indicates average chroma; This represents the hue sensitivity adjustment function;

[0104] Hue sensitivity adjustment function:

[0105]

[0106] In the formula: Indicates the average hue angle;

[0107] Rotate interactive item:

[0108]

[0109] In the formula: Indicates the rotation angle; Indicates a rotating top;

[0110] Rotation angle:

[0111]

[0112] In the formula: Indicates the average hue angle;

[0113] Rotating top:

[0114]

[0115] In the formula: Indicates average chroma;

[0116] Color difference is calculated based on lightness difference, chroma difference, hue difference, weighting coefficient, and rotation interaction term;

[0117] Color difference:

[0118]

[0119] In the formula: Indicates difference in brightness; Indicates poor chroma; Indicates hue difference; This represents a human-adjustable brightness weighting factor. This represents a manually adjustable chroma weighting factor. This represents a human-adjustable hue weighting factor; This represents the brightness weighting coefficient; This represents the chroma weighting coefficient; This represents the hue weighting coefficient; This indicates a rotation interaction item.

[0120] II. Color Difference - Color Change Level Mapping Rules

[0121] A first-level color-changing threshold is set to represent similar colors. If the color difference is less than the first-level color-changing threshold, it is judged as a first-level color-changing.

[0122] A secondary color-changing threshold is set to represent medium color difference. If the color difference is greater than the primary color-changing threshold but less than the secondary color-changing threshold, it is judged as secondary color-changing.

[0123] If the color difference is greater than the second-level color-changing threshold, which indicates a high-contrast color, it is judged as a third-level color-changing.

[0124] III. Color Change Level - Color Change Cleanup Strategy Mapping Rules

[0125] The color change cleanup strategy corresponding to Level 1 color change:

[0126] Stop supplying powder to the current powder hopper at the powder supply center, start the vacuum pump at the end of the powder pump to vacuum suction, and suck the powder in the powder conveying main pipe and the powder extraction pipe connected to the current powder hopper back to the current powder hopper; the powder pump sprays powder out of the air; compressed air backflushs the powder pipe inside the spray gun; negative pressure suction is applied to the powder spraying chamber.

[0127] Color change cleanup strategy corresponding to secondary color change:

[0128] Stop supplying powder to the current powder hopper at the powder supply center, start the vacuum pump at the end of the powder pump to vacuum suction, and suck the powder in the powder delivery main pipe and the powder extraction pipe connected to the current powder hopper back to the current powder hopper; the powder pump sprays powder out of the air and is supplemented by compressed air backflushing; the spray gun electrode needle is cleaned; the powder spraying chamber is vacuumed.

[0129] The corresponding color change cleanup strategy for Level 3 color change:

[0130] Stop supplying powder to the current powder hopper at the powder supply center, start the vacuum pump at the end of the powder pump to vacuum and suck the powder in the extraction pipeline connected to the current powder hopper back to the current powder hopper; clean the powder conveying main pipe; clean the powder pump; clean the spray gun; wipe the powder spraying chamber.

[0131] IV. Quick Color Change with Powder Coating for Automotive Interior Parts

[0132] Obtain the color difference between the current sprayed color and the target color;

[0133] The current color change level is determined based on the color difference between the current sprayed color and the target color, as well as the preset color difference-color change level mapping rule;

[0134] The current color change and cleanup strategy is determined based on the mapping rules between the current color change level and the preset color change level-color change and cleanup strategy.

[0135] Perform color-changing and cleanup based on the current color-changing and cleanup strategy;

[0136] After cleaning and color change, normal powder supply is used for powder color change spraying.

[0137] Example 1

[0138] The color difference between the tristimulus coordinates (L=95, a=0, b=0) of the current sprayed color RAL9010 pure white and the tristimulus coordinates (L=93, a=-1, b=2) of the target color RAL9016 traffic white. =2.6;

[0139] The preset primary color-changing threshold is 3, then the color difference... =2.6 is judged as a level one color change;

[0140] The preset first-level color change cleaning strategy is as follows: stop the powder supply to the current powder hopper at the powder supply center; start the vacuum pump at the end of the powder pump for 45 seconds to vacuum and suck the powder in the powder supply main pipe and the powder extraction pipe connected to the current powder hopper back to the current powder hopper; the powder pump sprays powder out of the air for 30 seconds; the compressed air back-blowing of the powder pipe in the spray gun for 60 seconds; and the negative pressure suction in the powder spraying chamber for 120 seconds; for a total of 255 seconds.

[0141] Samples of automotive interior parts after powder coating were tested, and the results are as follows: The color differences of the left, center, and right sides of the first sample were 0.3, 0.4, and 0.3, respectively. Visually, the traffic white color showed no impurities, and there was no visible difference compared with the standard color chart. The color differences of the left, center, and right sides of the second sample were 0.4, 0.5, and 0.4, respectively. Visually, the traffic white color showed no impurities. The color differences of the left, center, and right sides of the third sample were 0.3, 0.4, and 0.3, respectively. Visually, the traffic white color showed no impurities. The color difference fluctuation range of the fourth to tenth samples was 0.3-0.6, and all of them showed no impurities when viewed as traffic white.

[0142] Comparative Example 1

[0143] The current spray color is RAL9010 Pure White and the target color is RAL9016 Traffic White. Stop the powder supply center from supplying powder to the current powder hopper; clean the powder hopper and the powder extraction pipeline connected to the current powder hopper for 15 minutes; clean the main powder delivery pipeline for 10 minutes; clean the powder pump for 12 minutes; clean the spray gun for 8 minutes; clean the powder spraying chamber for 10 minutes; total 55 minutes.

[0144] Samples of automotive interior parts after powder coating were tested, and the results are as follows: The color difference of the left, center and right sides of the first sample were 0.2, 0.3 and 0.2 respectively. The traffic white color was visually free of impurities and there was no visible difference compared with the standard color chart. The color difference of the left, center and right sides of the second sample were 0.3, 0.3 and 0.3 respectively. The traffic white color was visually free of impurities. The color difference of the third to tenth samples fluctuated between 0.2 and 0.5. All of them were visually free of impurities in the traffic white color.

[0145] Example 2

[0146] The color difference between the tristimulus coordinates (L=95, a=0, b=0) of the current sprayed color RAL9010 pure white and the tristimulus coordinates (L=90, a=0, b=2) of the target color RAL9002 grayish white. =5.4;

[0147] The preset primary color-changing threshold is 3, and the secondary color-changing threshold is 10, then the color difference... =5.4 is judged as a level 2 color change;

[0148] The preset secondary color change cleaning strategy is as follows: stop the powder supply to the current powder hopper at the powder supply center; start the vacuum pump at the end of the powder pump for 90 seconds to vacuum and suck the powder in the powder supply main pipe and the powder extraction pipe connected to the current powder hopper back to the current powder hopper; the powder pump sprays powder for 30 seconds and is supplemented by compressed air backflushing for 60 seconds; the spray gun electrode needle is cleaned for 30 seconds; the powder spraying chamber is vacuumed for 180 seconds; for a total of 390 seconds.

[0149] Samples of automotive interior parts after powder coating were tested, and the results are as follows: The color difference of the left, center, and right sides of the first sample was 0.5, 0.7, and 0.6, respectively. It was visually grayish-white with no impurities and showed no visible difference compared with the standard color chart. The color difference of the left, center, and right sides of the second sample was 0.6, 0.8, and 0.7, respectively. It was visually grayish-white with no impurities. The color difference of the left, center, and right sides of the third sample was 0.5, 0.6, and 0.5, respectively. It was visually grayish-white with no impurities. The color difference of the fourth to tenth samples fluctuated between 0.5 and 0.9, and all of them were visually grayish-white with no impurities.

[0150] Comparative Example 2

[0151] The current spray color is RAL9010 pure white and the target color is RAL9002 grayish white. Stop the powder supply center from supplying powder to the current powder hopper; clean the powder hopper and the powder extraction pipeline connected to the current powder hopper for 15 minutes; clean the main powder delivery pipeline for 10 minutes; clean the powder pump for 12 minutes; clean the spray gun for 8 minutes; clean the powder spraying chamber for 10 minutes; total 55 minutes.

[0152] Samples of automotive interior parts after powder coating were tested, and the results are as follows: The color difference of the left, center and right sides of the first sample were 0.4, 0.5 and 0.4 respectively. It was visually grayish-white with no impurities and there was no visible difference compared with the standard color chart. The color difference of the left, center and right sides of the second sample were 0.5, 0.6 and 0.5 respectively. It was visually grayish-white with no impurities. The color difference of the third to tenth samples fluctuated between 0.4 and 0.8. All of them were visually grayish-white with no impurities.

[0153] Example 3

[0154] The color difference between the tristimulus coordinates (L=10, a=0, b=0) of the current sprayed color RAL9005 Deep Black and the tristimulus coordinates (L=95, a=0, b=0) of the target color RAL9010 Pure White. =85;

[0155] If the preset secondary color replacement threshold is 10, then the color difference... =85 is judged as a level three color change;

[0156] The preset three-stage color change cleaning strategy is as follows: stop the powder supply to the current powder tank at the powder supply center, start the vacuum pump at the end of the powder pump for 90 seconds to vacuum the powder in the powder extraction pipeline connected to the current powder tank back to the current powder tank; clean the powder conveying main pipe for 6 minutes; clean the powder pump for 20 minutes; clean the spray gun for 10 minutes; wipe the powder spraying chamber for 15 minutes; for a total of 52.5 minutes.

[0157] Samples of automotive interior parts after powder coating were tested, and the results are as follows: The color difference of the left, center, and right sides of the first sample was 0.4, 0.5, and 0.4, respectively. It was visually pure white with no impurities and showed no visible difference compared with the standard color chart. The color difference of the left, center, and right sides of the second sample was 0.5, 0.6, and 0.5, respectively. It was visually pure white with no impurities. The color difference of the left, center, and right sides of the third sample was 0.4, 0.5, and 0.4, respectively. It was visually pure white with no impurities. The color difference of the fourth to tenth samples fluctuated between 0.4 and 0.8, and all of them were visually pure white with no impurities.

[0158] Compare with Example 3

[0159] The current spray color is RAL9005 dark black and the target color is RAL9010 pure white. The powder bucket and the powder extraction pipeline connected to the current powder bucket are cleaned for 15 minutes; the powder delivery main pipe is cleaned for 10 minutes; the powder pump is cleaned for 12 minutes; the spray gun is cleaned for 8 minutes; the powder spraying chamber is cleaned for 10 minutes; the total time is 55 minutes.

[0160] Samples of automotive interior parts after powder coating were tested, and the results are as follows: The color difference of the left, middle and right sides of the first sample is 0.3, 0.4 and 0.3 respectively. It is pure white with no impurities when viewed visually and there is no visible difference compared with the standard color chart. The color difference of the second to tenth samples fluctuates between 0.3 and 0.6. All of them are pure white with no impurities when viewed visually.

[0161] In summary, this application not only meets the quality requirements of powder coating for automotive interior parts, but also improves the speed of powder coating for automotive interior parts.

[0162] Although embodiments of the invention have been shown and described, it will be understood by those skilled in the art that various changes, modifications, substitutions and alterations can be made to these embodiments without departing from the principles and spirit of the invention, the scope of which is defined by the appended claims and their equivalents.

Claims

1. A rapid color-changing process for powder coating of automotive interior parts, characterized in that, Includes the following steps:

1. Obtain the tristimulus coordinates of the current sprayed color and the target color to calculate the color difference; 2. Determine the current color change level based on the color difference between the current sprayed color and the target color, as well as the preset color difference-color change level mapping rule; 3. Determine the current color change and cleanup strategy based on the current color change level and the preset color change level-color change and cleanup strategy mapping rules; IV. Perform color-changing cleanup based on the current color-changing cleanup strategy; 5. After cleaning and color change, continue powder coating with normal powder supply.

2. The rapid color-changing process for powder coating of automotive interior parts according to claim 1, characterized in that: In step one, the calculation steps for the color difference include: The average chroma is calculated based on the red-green and yellow-blue coordinates in the tristimulus coordinates of the current sprayed color and the target color; Compensation factor is calculated based on average chroma; The red and green coordinates of the current sprayed color and the target color are corrected based on the compensation factor. The chroma and hue angles are corrected based on the red-green and yellow-blue coordinates of the current sprayed color and the target color; The lightness difference is calculated based on the lightness values ​​in the tristimulus coordinates of the current sprayed color and the target color. Calculate the chroma difference based on the corrected chroma; The hue difference is calculated based on the corrected hue angle; The average lightness is calculated based on the lightness values ​​in the tristimulus coordinates of the current sprayed color and the target color. Calculate the average chroma based on the corrected chroma; Calculate the average hue angle based on the corrected hue angle; Calculate weighting coefficients and rotation interaction terms based on average lightness, average chroma, and average hue angle; Color difference is calculated based on brightness difference, chroma difference, hue difference, weighting coefficient, and rotation interaction term.

3. The rapid color-changing process for powder coating of automotive interior parts according to claim 2, characterized in that: In step two, the color difference-color change level mapping rule includes: Set a first-level color-changing threshold. If the color difference is less than the first-level color-changing threshold, it is judged as a first-level color-changing. Set a secondary color-changing threshold. If the color difference is greater than the primary color-changing threshold but less than the secondary color-changing threshold, it is judged as a secondary color-changing. If the color difference is greater than the second-level color-changing threshold, it is judged as a third-level color-changing.

4. The rapid color-changing process for powder coating of automotive interior parts according to claim 3, characterized in that: In step three, the mapping rules for the color change level and the color change cleanup strategy include: The color change cleanup strategy corresponding to Level 1 color change: Stop supplying powder to the current powder hopper at the powder supply center, start the vacuum pump at the end of the powder pump to vacuum suction, and suck the powder in the powder conveying main pipe and the powder extraction pipe connected to the current powder hopper back to the current powder hopper; the powder pump sprays powder out of the air; compressed air backflushs the powder pipe inside the spray gun; negative pressure suction is applied to the powder spraying chamber. Color change cleanup strategy corresponding to secondary color change: Stop supplying powder to the current powder hopper at the powder supply center, start the vacuum pump at the end of the powder pump to vacuum suction, and suck the powder in the powder delivery main pipe and the powder extraction pipe connected to the current powder hopper back to the current powder hopper; the powder pump sprays powder out of the air and is supplemented by compressed air backflushing; the spray gun electrode needle is cleaned; the powder spraying chamber is vacuumed. The color change cleanup strategy corresponding to Level 3 color change: Stop supplying powder to the current powder hopper at the powder supply center, start the vacuum pump at the end of the powder pump to vacuum and suck the powder in the extraction pipeline connected to the current powder hopper back to the current powder hopper; clean the powder conveying main pipe; clean the powder pump; clean the spray gun; wipe the powder spraying chamber.

Images