Plastic product quality detection method

Abstract

The invention relates to the technical field of quality detection, and discloses a plastic product quality detection method, which comprises the following steps: obtaining a plastic film to be detected, carrying out thickness detection, and if the thickness does not meet the standard, terminating the test; if the standard is met, transparency and uniformity testing is carried out, a light source and a receiver are arranged in the transparency testing, whether the transparency meets the standard or not is judged by comparing the ratio of the actual light intensity to the standard light intensity, and the uniformity of the transparency is judged by comparing the variance value of a gray level histogram in the uniformity testing. When the transparency and the uniformity do not meet the standard, stopping the test; and if the to-be-tested plastic film meets the standard, carrying out a puncture test, judging the penetration resistance, selecting N puncture points on the to-be-tested plastic film in the penetration resistance test, and testing whether the puncture force is greater than a set threshold value or not. When the penetration resistance does not meet the standard, the test is terminated; and if so, testing the tear strength of the puncture point of the plastic film.

Description

Technical Field

[0001] The invention relates to the technical field of quality inspection, and in particular to a method for inspecting the quality of plastic products. Background Art

[0002] In the modern plastic product manufacturing industry, plastic films are widely used in packaging, construction, medical and other fields. As people's requirements for the quality of plastic products are increasing, the quality inspection of plastic films is particularly important. At present, there are many plastic film quality inspection methods on the market, but these existing technologies still have many shortcomings and need to be improved and optimized.

[0003] First, many existing quality inspection methods only focus on a specific physical property, such as thickness, transparency or uniformity. This one-sided inspection method often cannot fully evaluate the overall quality of plastic film; existing thickness inspection technology usually relies on traditional physical measurement methods, which are relatively cumbersome to operate and easily affected by environmental factors; transparency and uniformity inspection methods often use visual inspection methods, which also have the problem of strong subjectivity; different operators may have significant differences in observation results under the same conditions, resulting in inconsistent test results; the standardization and accuracy of puncture tests are also a major shortcoming of current technology. Many inspection methods lack clear standards for the selection of puncture points and the setting of puncture force, which affects the repeatability and reliability of the test results; regarding the tear strength test, the existing methods only have tests for intact plastic films, and there are no tests for damaged plastic films.

[0004] In summary, there is an urgent need for a plastic product quality testing method that aims to improve the quality control standards of plastic films through gradual screening and multiple testing methods to meet the needs of the industry and the market. Summary of the invention

[0005] The present invention provides a plastic product quality detection method, which helps solve the problems mentioned in the above background technology.

[0006] The present invention provides the following technical solution: a plastic product quality detection method, comprising:

[0007] The plastic product is specifically a plastic film;

[0008] Obtain a plastic film that needs to be tested for quality, which is recorded as the plastic film to be tested;

[0009] Perform thickness test on the plastic film to be tested to determine whether the thickness of the plastic film to be tested meets the standard;

[0010] If the thickness of the plastic film to be tested does not meet the standard, the plastic film to be tested whose thickness does not meet the standard will no longer be tested;

[0011] If the thickness of the plastic film to be tested meets the standard, the transparency and uniformity test of the plastic film to be tested is performed to determine whether the transparency and uniformity of the plastic film to be tested meet the standard;

[0012] If the transparency and uniformity of the plastic film to be tested do not meet the standards, the plastic film to be tested whose transparency and uniformity do not meet the standards will no longer be tested;

[0013] If the transparency and uniformity of the plastic film to be tested meet the standards, a puncture test is performed on the plastic film to be tested to determine whether the anti-penetration ability of the plastic film to be tested meets the standards;

[0014] If the penetration resistance of the plastic film to be tested does not meet the standard, the plastic film to be tested whose penetration resistance does not meet the standard will no longer be tested;

[0015] If the penetration resistance of the plastic film to be tested meets the standard, the plastic film to be tested whose penetration resistance meets the standard is tested according to the first test strategy to determine whether the tear strength of the puncture point of the plastic film to be tested meets the standard.

[0016] Optionally, the step of performing thickness detection on the plastic film to be tested to determine whether the thickness of the plastic film to be tested meets the standard specifically includes:

[0017] The thickness of the standard plastic film is collected as the standard value and recorded as the standard thickness;

[0018] Set thickness control accuracy;

[0019] Use a laser thickness gauge to scan the plastic film to be tested to obtain the thickness of all positions of the plastic film to be tested;

[0020] Get the maximum value of the thickness of the plastic film to be tested;

[0021] Get the minimum value of the thickness of the plastic film to be tested;

[0022] If the standard thickness - thickness control accuracy ≤ the maximum value of the thickness of the plastic film to be tested ≤ the standard thickness + thickness control accuracy, and the standard thickness - thickness control accuracy ≤ the minimum value of the thickness of the plastic film to be tested ≤ the standard thickness + thickness control accuracy, then the thickness of the plastic film to be tested is deemed to meet the standard;

[0023] If the maximum value of the plastic film thickness to be tested is less than the standard thickness - thickness control accuracy, the minimum value of the plastic film thickness to be tested is greater than the standard thickness + thickness control accuracy, the standard thickness - thickness control accuracy is ≤ the maximum value of the plastic film thickness to be tested is ≤ the standard thickness + thickness control accuracy, and the minimum value of the plastic film thickness to be tested is less than the standard thickness - thickness control accuracy or the standard thickness - thickness control accuracy is ≤ the minimum value of the plastic film thickness to be tested is ≤ the standard thickness + thickness control accuracy, and the maximum value of the plastic film thickness to be tested is greater than the standard thickness + thickness control accuracy; then it is determined that the thickness of the plastic film to be tested does not meet the standard.

[0024] Optionally, if the thickness of the plastic film to be tested meets the standard, a transparency and uniformity test is performed on the plastic film to be tested to determine whether the transparency and uniformity of the plastic film to be tested meet the standard, specifically including:

[0025] Setting up a light source and a light source receiver;

[0026] In the absence of obstructions, obtain the light intensity received by the light source receiver, which is recorded as the standard light intensity;

[0027] Set transparency threshold;

[0028] Place a plastic film between the light source and the light source receiver, and obtain the light intensity received by the light source receiver at this time, which is recorded as the actual light intensity;

[0029] If the ratio of the actual light intensity to the standard light intensity is less than the transparency threshold, it is determined that the transparency of the plastic film to be tested does not meet the standard;

[0030] If the ratio of the actual light intensity to the standard light intensity is ≥ the transparency threshold, the transparency of the plastic film to be tested is deemed to meet the standard.

[0031] Optionally, if the thickness of the plastic film to be tested meets the standard, performing transparency and uniformity tests on the plastic film to be tested to determine whether the transparency and uniformity of the plastic film to be tested meet the standard, further comprising:

[0032] Place a light source underneath the standard plastic film;

[0033] A digital camera is placed on top of a standard plastic film;

[0034] Collect an image of a standard plastic film, which is recorded as a standard image;

[0035] Process the standard image to obtain the grayscale histogram of the standard image, which is recorded as the standard grayscale image;

[0036] Collect an image of the plastic film to be tested and record it as the actual image;

[0037] Process the actual image to obtain the grayscale histogram of the actual image, which is recorded as the actual grayscale image;

[0038] Set uniformity threshold;

[0039] Calculate the gray value variance of the standard gray image;

[0040] Calculate the gray value variance of the actual gray image;

[0041] If the gray value variance of the standard gray image - the uniformity threshold ≤ the gray value variance of the actual gray image ≤ the gray value variance of the standard gray image + the uniformity threshold, it is determined that the uniformity of the plastic film to be tested meets the standard;

[0042] If the grayscale value variance of the actual grayscale image is greater than the grayscale value variance of the standard grayscale image + the uniformity threshold or the grayscale value variance of the actual grayscale image is less than the grayscale value variance of the standard grayscale image - the uniformity threshold, it is determined that the uniformity of the plastic film to be tested does not meet the standard.

[0043] Optionally, if the transparency and uniformity of the plastic film to be tested meet the standards, a puncture test is performed on the plastic film to be tested to determine whether the penetration resistance of the plastic film to be tested meets the standards, specifically including:

[0044] Set distance threshold;

[0045] Randomly select N points on the plastic film to be tested as puncture points;

[0046] The distance between each puncture point is greater than the distance threshold.

[0047] Optionally, if the transparency and uniformity of the plastic film to be tested meet the standards, a puncture test is performed on the plastic film to be tested to determine whether the penetration resistance of the plastic film to be tested meets the standards, and further includes:

[0048] Set the puncture force threshold;

[0049] Perform a puncture test on each puncture point;

[0050] Obtain the pressure exerted on the puncture needle, recorded as the first pressure;

[0051] During the puncture test, if the first pressure decreases, the puncture test is stopped;

[0052] For each puncture point, the maximum value of the first pressure during the puncture test is obtained and recorded as the puncture force;

[0053] If the puncture forces corresponding to all puncture points are greater than the puncture force threshold, it is determined that the penetration resistance of the plastic film to be tested meets the standard;

[0054] If the puncture force corresponding to the puncture point is less than the puncture force threshold, it is determined that the penetration resistance of the plastic film to be tested does not meet the standard.

[0055] Optionally, if the penetration resistance of the plastic film to be tested meets the standard, testing the plastic film to be tested whose penetration resistance meets the standard according to the first test strategy to determine whether the tear strength of the puncture point of the plastic film to be tested meets the standard specifically includes:

[0056] Obtain all puncture points of the plastic film to be tested;

[0057] Choose any puncture point as the origin and establish a plane rectangular coordinate system on the plastic film to be tested;

[0058] Get the coordinates of all puncture points, recorded as (x 1 ,y 1 )、(x 2 ,y 2 )……(x n ,y n );

[0059] The tearing line is obtained by linear fitting based on all puncture points, specifically:

[0060] Let the linear equation of the tear line be y=ax+b;

[0061] Define the objective function

[0062] Where S is the residual sum of squares of all points, a is the slope of the tear line, and b is the intercept of the tear line;

[0063] Taking the partial derivative of the objective function with respect to a, we get:

[0064]

[0065] Taking the partial derivative of the objective function with respect to b, we get:

[0066]

[0067] make and is 0, we get:

[0068]

[0069]

[0070] Optionally, if the penetration resistance of the plastic film to be tested meets the standard, testing the plastic film to be tested whose penetration resistance meets the standard according to the first test strategy to determine whether the tear strength of the puncture point of the plastic film to be tested meets the standard further includes:

[0071] Arrange a light source below the plastic film to be tested;

[0072] Arrange a light source receiver above the plastic film to be tested;

[0073] Before performing the tear test, obtaining a value of the light intensity received by the light source receiver, which is recorded as a first value;

[0074] Perform tear tests, specifically:

[0075] Setting a tearing force, wherein the tearing force is fixed;

[0076] For each puncture point, a perpendicular line to the tear line is drawn through the puncture point on the plastic film to be tested, and the intersection points with the tear line are recorded as the first intersection point, the second intersection point, ... the Nth intersection point;

[0077] Obtain the two points with the longest distance from the first intersection point, the second intersection point, ... the Nth intersection point, and record them as the first target point and the second target point;

[0078] Connect the first target point and the second target point, and the formed line segment is recorded as a test line segment;

[0079] Set the length threshold;

[0080] Get the length of the test line segment;

[0081] If the length of the test line segment is less than or equal to the length threshold, a tearing test is performed on the test line segment, and the tearing position is the position of the test line segment;

[0082] If the length of the test line segment is greater than the length threshold, multiple tearing tests are performed on the test line segment, specifically:

[0083] Taking the first target point as the starting point, segmenting the test line segment at intervals of the length threshold on the test line segment to form a plurality of line segments, which are respectively recorded as the first line segment, the second line segment, ... the Xth line segment;

[0084] Perform tearing tests on the first line segment, the second line segment, ... the Xth line segment on the plastic film to be tested respectively;

[0085] After the tearing test is completed, a value of the light intensity received by the light source receiver is obtained and recorded as a second value;

[0086] Set the light intensity change threshold;

[0087] If the second value minus the first value ≥ the light intensity change threshold, it is determined that the tear strength of the puncture point of the plastic film to be tested does not meet the standard;

[0088] If the second value - the first value < the light intensity change threshold, it is determined that the tear strength of the puncture point of the plastic film to be tested does not meet the standard.

[0089] The present invention has the following beneficial effects:

[0090] 1. This plastic product quality inspection method sequentially inspects the thickness, transparency, uniformity, penetration resistance and tear resistance of plastic films. If any item does not meet the standard, the subsequent inspection steps are directly excluded, thus avoiding unnecessary testing steps. This layer-by-layer screening method ensures that only films that meet the preliminary standards are further tested, saving time and resources. For the manufacturing industry, saving time and resources means lower costs and higher production efficiency. Through step-by-step inspection, companies can identify unqualified products more quickly, reducing the waste of manpower and material resources. In addition, this method also improves product consistency and reliability, because each step ensures that a specific quality indicator meets the standard, ensuring the overall quality of the final product.

[0091] 2. This is a plastic product quality inspection method that uses a laser thickness gauge to scan the thickness of the plastic film to be tested and obtain thickness data at all positions. This method has extremely high accuracy and can reduce human errors. As an advanced inspection equipment, the laser thickness gauge uses a laser beam to accurately measure the thickness of an object, and has the advantages of high resolution and high repeatability. Through this non-contact measurement method, the damage to the material caused by contact in traditional measurement methods can be avoided, ensuring the integrity of the test sample. At the same time, the laser thickness gauge can fully scan the entire film to ensure the comprehensiveness and accuracy of thickness detection.

[0092] 3. A plastic product quality inspection method, in the transparency test, sets a light source and a light source receiver, and judges whether the transparency meets the standard by comparing the ratio of actual light intensity to standard light intensity. This non-contact inspection method simplifies the operation process and avoids potential damage to the film caused by human contact. The combined use of the light source and the light source receiver makes the transparency test more intuitive and simple. By setting the ratio threshold between the standard light intensity and the actual light intensity, it is possible to quickly judge whether the transparency of the film meets the requirements. This method not only improves the inspection speed, but also reduces the possibility of human error, ensuring the objectivity and reliability of the inspection results.

[0093] 4. This plastic product quality inspection method collects images of standard plastic film and plastic film to be tested, and performs grayscale histogram analysis on the images to judge the uniformity of the film. Grayscale histogram is a tool that reflects the grayscale distribution characteristics of an image. By analyzing the distribution of grayscale values, the optical properties of the film can be carefully reflected, and the accuracy of the inspection can be improved. The use of grayscale histogram can capture subtle changes in uniformity, especially when there is a small degree of unevenness on the surface of the film. This method can provide accurate inspection results. By calculating the grayscale value variance of the standard grayscale image and the actual grayscale image, and setting the uniformity threshold, it can be judged whether the uniformity of the film to be tested meets the standard. This method not only improves the scientificity and accuracy of the inspection, but also provides more comprehensive data support for product quality control. The introduction of grayscale histogram analysis makes the uniformity test not limited to the subjective judgment of naked eye observation, but an objective analysis based on mathematical models, which is of great significance for improving the reliability and consistency of the inspection results.

[0094] 5. This is a plastic product quality inspection method. The puncture test can effectively evaluate the penetration resistance of plastic film. By setting the puncture force threshold, multiple puncture points are tested to ensure the durability of the film in actual applications. Penetration resistance is an important indicator of whether the film material can withstand external forces in actual use, which is directly related to the product's application effect and user experience. By setting the puncture force threshold, the performance of the product under different pressures can be simulated to ensure that the film's penetration resistance meets actual needs. Testing multiple puncture points can comprehensively evaluate the penetration resistance of the entire film and avoid accidental errors that may be caused by a single test point. This method can simulate actual application scenarios, ensure that the product can withstand the test of various external forces, and improve the reliability and durability of the product.

[0095] 6. In this plastic product quality inspection method, in the puncture test, the distance between the selected puncture points is greater than the set distance threshold. The advantage of this is to ensure the uniformity of the test. The uniformity test is of great significance for the comprehensive evaluation of the performance of the film. By setting the distance threshold, it is possible to avoid the test being concentrated in one area, resulting in deviations in the test results. At the same time, evenly distributed puncture points can comprehensively evaluate the penetration resistance of the entire film and ensure the representativeness and comprehensiveness of the test results. The uniformity detection method can avoid the influence of local film performance differences on the overall test results, and provide a more accurate basis for subsequent quality control. This method can ensure the reliability of test data, improve the credibility of test results, and help to comprehensively evaluate the quality and performance of products.

[0096] 7. This plastic product quality inspection method requires further tear strength testing for plastic films that pass the puncture test. Tear strength is an important indicator of whether the film material can withstand tearing force in actual use. By setting the tear force and length thresholds, performing tear tests on the test segments, and evaluating the changes in light intensity, the tear resistance of the film can be fully evaluated. The tear test can simulate the tearing conditions in actual use and ensure the durability and reliability of the product during use.

[0097] 8. This plastic product quality inspection method obtains the coordinates of all puncture points and calculates the tear line, which can accurately locate the tear strength. Linear fitting is an analysis method based on a mathematical model that can improve the scientificity and accuracy of the inspection. By performing linear fitting on the coordinates of all puncture points, the slope and intercept of the tear line can be accurately calculated, and then the tear line can be subjected to a tear test. The use of this mathematical model can improve the accuracy of the inspection and provide more reliable data support for film quality assessment.

[0098] 9. This is a plastic product quality inspection method. During the tear test, the tear strength of the film is judged by evaluating the change in light intensity received by the light source receiver. The increase in the received light intensity indicates that there is an opening caused by tearing on the plastic film. This method can intuitively reflect the change in film performance during the tearing process and improve the visualization of the inspection. The change in light intensity can accurately reflect the structural changes of the film during the tearing process and provide important data for the evaluation of tear strength. By setting the light intensity change threshold, it is possible to quickly determine whether the tear resistance of the film meets the standard. BRIEF DESCRIPTION OF THE DRAWINGS

[0099] Figure 1 It is a schematic diagram of the process of the present invention.

[0100] Figure 2 It is a schematic diagram of the tearing line of the present invention. DETAILED DESCRIPTION

[0101] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0102] Example, see Figure 1 and Figure 2 , a plastic product quality detection method, comprising:

[0103] The plastic product is specifically a plastic film;

[0104] Obtain a plastic film that needs to be tested for quality, which is recorded as the plastic film to be tested;

[0105] Perform thickness test on the plastic film to be tested to determine whether the thickness of the plastic film to be tested meets the standard;

[0106] If the thickness of the plastic film to be tested does not meet the standard, the plastic film to be tested whose thickness does not meet the standard will no longer be tested;

[0107] If the thickness of the plastic film to be tested meets the standard, the transparency and uniformity test of the plastic film to be tested is performed to determine whether the transparency and uniformity of the plastic film to be tested meet the standard;

[0108] If the transparency and uniformity of the plastic film to be tested do not meet the standards, the plastic film to be tested whose transparency and uniformity do not meet the standards will no longer be tested;

[0109] If the transparency and uniformity of the plastic film to be tested meet the standards, a puncture test is performed on the plastic film to be tested to determine whether the anti-penetration ability of the plastic film to be tested meets the standards;

[0110] If the penetration resistance of the plastic film to be tested does not meet the standard, the plastic film to be tested whose penetration resistance does not meet the standard will no longer be tested;

[0111] If the penetration resistance of the plastic film to be tested meets the standard, the plastic film to be tested whose penetration resistance meets the standard is tested according to the first test strategy to determine whether the tear strength of the puncture point of the plastic film to be tested meets the standard;

[0112] This is a plastic product quality inspection method that sequentially inspects the thickness, transparency, uniformity, penetration resistance, and tear resistance of plastic films at the puncture point. If any item does not meet the standard, the subsequent inspection steps are directly excluded, thus avoiding unnecessary testing steps. This layer-by-layer screening method ensures that only films that meet the preliminary standards are further tested, saving time and resources. For the manufacturing industry, saving time and resources means lower costs and higher production efficiency. Through step-by-step inspection, companies can identify unqualified products more quickly, reducing the waste of manpower and material resources. In addition, this method also improves product consistency and reliability, because each step ensures that a specific quality indicator meets the standard, ensuring the overall quality of the final product.

[0113] The thickness detection of the plastic film to be tested to determine whether the thickness of the plastic film to be tested meets the standard specifically includes:

[0114] The thickness of the standard plastic film is collected as the standard value and recorded as the standard thickness;

[0115] Set thickness control accuracy;

[0116] Use a laser thickness gauge to scan the plastic film to be tested to obtain the thickness of all positions of the plastic film to be tested;

[0117] Get the maximum value of the thickness of the plastic film to be tested;

[0118] Get the minimum value of the thickness of the plastic film to be tested;

[0119] If the standard thickness - thickness control accuracy ≤ the maximum value of the thickness of the plastic film to be tested ≤ the standard thickness + thickness control accuracy, and the standard thickness - thickness control accuracy ≤ the minimum value of the thickness of the plastic film to be tested ≤ the standard thickness + thickness control accuracy, then the thickness of the plastic film to be tested is deemed to meet the standard;

[0120] If the maximum value of the thickness of the plastic film to be tested is less than the standard thickness - thickness control accuracy, the minimum value of the thickness of the plastic film to be tested is greater than the standard thickness + thickness control accuracy, the standard thickness - thickness control accuracy is less than the maximum value of the thickness of the plastic film to be tested is less than the standard thickness + thickness control accuracy, and the minimum value of the thickness of the plastic film to be tested is less than the standard thickness - thickness control accuracy or the standard thickness - thickness control accuracy is less than the minimum value of the thickness of the plastic film to be tested is less than the standard thickness + thickness control accuracy, and the maximum value of the thickness of the plastic film to be tested is greater than the standard thickness + thickness control accuracy; then it is determined that the thickness of the plastic film to be tested does not meet the standard;

[0121] This is a method for testing the quality of plastic products. The laser thickness gauge is used to scan the thickness of the plastic film to be tested and obtain thickness data at all positions. This method is extremely accurate and can reduce human errors. As an advanced testing equipment, the laser thickness gauge uses a laser beam to accurately measure the thickness of an object, and has the advantages of high resolution and high repeatability. Through this non-contact measurement method, the damage to the material caused by contact in traditional measurement methods can be avoided, ensuring the integrity of the test sample. At the same time, the laser thickness gauge can fully scan the entire film to ensure the comprehensiveness and accuracy of thickness detection.

[0122] If the thickness of the plastic film to be tested meets the standard, the transparency and uniformity test is performed on the plastic film to be tested to determine whether the transparency and uniformity of the plastic film to be tested meet the standard, which specifically includes:

[0123] Setting up a light source and a light source receiver;

[0124] In the absence of obstructions, obtain the light intensity received by the light source receiver, which is recorded as the standard light intensity;

[0125] Set transparency threshold;

[0126] Place a plastic film between the light source and the light source receiver, and obtain the light intensity received by the light source receiver at this time, which is recorded as the actual light intensity;

[0127] If the ratio of the actual light intensity to the standard light intensity is less than the transparency threshold, it is determined that the transparency of the plastic film to be tested does not meet the standard;

[0128] If the ratio of the actual light intensity to the standard light intensity is ≥ the transparency threshold, the transparency of the plastic film to be tested is deemed to meet the standard;

[0129] A plastic product quality inspection method, in which a light source and a light source receiver are set in the transparency test, and the transparency is judged whether it meets the standard by comparing the ratio of actual light intensity to standard light intensity. This non-contact inspection method simplifies the operation process and avoids potential damage to the film caused by human contact. The combined use of the light source and the light source receiver makes the transparency test more intuitive and simple. By setting the ratio threshold between the standard light intensity and the actual light intensity, it is possible to quickly judge whether the transparency of the film meets the requirements. This method not only improves the inspection speed, but also reduces the possibility of human error, ensuring the objectivity and reliability of the inspection results.

[0130] If the thickness of the plastic film to be tested meets the standard, then the transparency and uniformity test of the plastic film to be tested is performed to determine whether the transparency and uniformity of the plastic film to be tested meet the standard, and further comprising:

[0131] Place a light source underneath the standard plastic film;

[0132] A digital camera is placed on top of a standard plastic film;

[0133] Collect an image of a standard plastic film, which is recorded as a standard image;

[0134] Process the standard image to obtain the grayscale histogram of the standard image, which is recorded as the standard grayscale image;

[0135] Collect an image of the plastic film to be tested and record it as the actual image;

[0136] Process the actual image to obtain the grayscale histogram of the actual image, which is recorded as the actual grayscale image;

[0137] Set uniformity threshold;

[0138] Calculate the gray value variance of the standard gray image;

[0139] Calculate the gray value variance of the actual gray image;

[0140] If the gray value variance of the standard gray image - the uniformity threshold ≤ the gray value variance of the actual gray image ≤ the gray value variance of the standard gray image + the uniformity threshold, it is determined that the uniformity of the plastic film to be tested meets the standard;

[0141] If the grayscale value variance of the actual grayscale image is greater than the grayscale value variance of the standard grayscale image + the uniformity threshold or the grayscale value variance of the actual grayscale image is less than the grayscale value variance of the standard grayscale image - the uniformity threshold, it is determined that the uniformity of the plastic film to be tested does not meet the standard;

[0142] A plastic product quality inspection method collects images of a standard plastic film and a plastic film to be tested, and performs grayscale histogram analysis on the images to judge the uniformity of the film. Grayscale histogram is a tool that reflects the grayscale distribution characteristics of an image. By analyzing the distribution of grayscale values, the optical properties of the film can be carefully reflected, and the accuracy of the inspection can be improved. The use of grayscale histogram can capture subtle changes in uniformity, especially when there is a small degree of unevenness on the surface of the film. This method can provide accurate inspection results. By calculating the grayscale value variance of the standard grayscale image and the actual grayscale image, and setting the uniformity threshold, it can be judged whether the uniformity of the film to be tested meets the standard. This method not only improves the scientificity and accuracy of the inspection, but also provides more comprehensive data support for product quality control. The introduction of grayscale histogram analysis makes the uniformity test not limited to the subjective judgment of naked eye observation, but an objective analysis based on a mathematical model, which is of great significance for improving the reliability and consistency of the inspection results.

[0143] If the transparency and uniformity of the plastic film to be tested meet the standards, a puncture test is performed on the plastic film to be tested to determine whether the penetration resistance of the plastic film to be tested meets the standards, which specifically includes:

[0144] Set distance threshold;

[0145] Randomly select N points on the plastic film to be tested as puncture points;

[0146] Wherein the distance between each puncture point is greater than the distance threshold;

[0147] This is a plastic product quality inspection method. In the puncture test, the distance between the selected puncture points is greater than the set distance threshold. The advantage of this is to ensure the uniformity of the test. The uniformity test is of great significance for the comprehensive evaluation of the performance of the film. By setting the distance threshold, it is possible to avoid the test being concentrated in one area, resulting in deviations in the test results. At the same time, evenly distributed puncture points can comprehensively evaluate the penetration resistance of the entire film and ensure the representativeness and comprehensiveness of the test results. The uniformity detection method can avoid the influence of local film performance differences on the overall test results, and provide a more accurate basis for subsequent quality control. This method can ensure the reliability of test data, improve the credibility of test results, and help to comprehensively evaluate the quality and performance of products.

[0148] If the transparency and uniformity of the plastic film to be tested meet the standards, a puncture test is performed on the plastic film to be tested to determine whether the penetration resistance of the plastic film to be tested meets the standards, and further includes:

[0149] Set the puncture force threshold;

[0150] Perform a puncture test on each puncture point;

[0151] Obtain the pressure exerted on the puncture needle, recorded as the first pressure;

[0152] During the puncture test, if the first pressure decreases, the puncture test is stopped;

[0153] For each puncture point, the maximum value of the first pressure during the puncture test is obtained and recorded as the puncture force;

[0154] If the puncture forces corresponding to all puncture points are greater than the puncture force threshold, it is determined that the penetration resistance of the plastic film to be tested meets the standard;

[0155] If the puncture force corresponding to the puncture point is less than the puncture force threshold, it is determined that the anti-penetration ability of the plastic film to be tested does not meet the standard;

[0156] This is a plastic product quality inspection method. The puncture test can effectively evaluate the penetration resistance of plastic film. By setting the puncture force threshold, multiple puncture points are tested to ensure the durability of the film in actual application. Penetration resistance is an important indicator of whether the film material can withstand external forces in actual use, which is directly related to the application effect and user experience of the product. By setting the puncture force threshold, the performance of the product under different pressures can be simulated to ensure that the penetration resistance of the film meets actual needs. Testing multiple puncture points can comprehensively evaluate the penetration resistance of the entire film and avoid accidental errors that may be caused by a single test point. This method can simulate actual application scenarios, ensure that the product can withstand the test of various external forces, and improve the reliability and durability of the product.

[0157] If the penetration resistance of the plastic film to be tested meets the standard, the plastic film to be tested whose penetration resistance meets the standard is tested according to the first test strategy to determine whether the tear strength of the puncture point of the plastic film to be tested meets the standard, specifically including:

[0158] Obtain all puncture points of the plastic film to be tested;

[0159] Choose any puncture point as the origin and establish a plane rectangular coordinate system on the plastic film to be tested;

[0160] Get the coordinates of all puncture points, recorded as (x 1 ,y 1 )、(x 2 ,y 2)……(x n ,y n );

[0161] The tearing line is obtained by linear fitting based on all puncture points, specifically:

[0162] Let the linear equation of the tear line be y=ax+b;

[0163] Define the objective function

[0164] Where S is the residual sum of squares of all points, a is the slope of the tear line, and b is the intercept of the tear line;

[0165] Taking the partial derivative of the objective function with respect to a, we get:

[0166]

[0167] Taking the partial derivative of the objective function with respect to b, we get:

[0168]

[0169] make and is 0, we get:

[0170]

[0171]

[0172] This plastic product quality inspection method obtains the coordinates of all puncture points and calculates the tear line, which can accurately locate the tear strength. Linear fitting is an analysis method based on a mathematical model that can improve the scientificity and accuracy of the inspection. By performing linear fitting on the coordinates of all puncture points, the slope and intercept of the tear line can be accurately calculated, and then the tear line can be subjected to a tear test. The use of this mathematical model can improve the accuracy of the inspection and provide more reliable data support for film quality assessment.

[0173] If the penetration resistance of the plastic film to be tested meets the standard, the plastic film to be tested whose penetration resistance meets the standard is tested according to the first test strategy to determine whether the tear strength of the puncture point of the plastic film to be tested meets the standard, further comprising:

[0174] Arrange a light source below the plastic film to be tested;

[0175] Arrange a light source receiver above the plastic film to be tested;

[0176] Before performing the tear test, obtaining a value of the light intensity received by the light source receiver, which is recorded as a first value;

[0177] Perform tear tests, specifically:

[0178] Setting a tearing force, wherein the tearing force is fixed;

[0179] For each puncture point, a perpendicular line to the tear line is drawn through the puncture point on the plastic film to be tested, and the intersection points with the tear line are recorded as the first intersection point, the second intersection point, ... the Nth intersection point;

[0180] Get the two points with the longest distance from the first intersection point, the second intersection point, ... the Nth intersection point, and record them as the first target point and the second target point. Figure 2 ;

[0181] Connect the first target point and the second target point, and the formed line segment is recorded as a test line segment;

[0182] Set the length threshold;

[0183] Get the length of the test line segment;

[0184] If the length of the test line segment is less than or equal to the length threshold, a tearing test is performed on the test line segment, and the tearing position is the position of the test line segment;

[0185] If the length of the test line segment is greater than the length threshold, multiple tearing tests are performed on the test line segment, specifically:

[0186] Taking the first target point as the starting point, segmenting the test line segment at intervals of the length threshold on the test line segment to form a plurality of line segments, which are respectively recorded as the first line segment, the second line segment, ... the Xth line segment;

[0187] Perform tearing tests on the first line segment, the second line segment, ... the Xth line segment on the plastic film to be tested respectively;

[0188] After the tearing test is completed, a value of the light intensity received by the light source receiver is obtained and recorded as a second value;

[0189] Set the light intensity change threshold;

[0190] If the second value minus the first value ≥ the light intensity change threshold, it is determined that the tear strength of the puncture point of the plastic film to be tested does not meet the standard;

[0191] The second value - the first value ≥ the light intensity change threshold value means that the opening caused by the tear on the plastic film is larger;

[0192] If the second value minus the first value is less than the light intensity change threshold, it is determined that the tear strength of the puncture point of the plastic film to be tested does not meet the standard;

[0193] This is a plastic product quality inspection method. During the tear test, the tear strength of the film is determined by evaluating the change in light intensity received by the light source receiver. The increase in the received light intensity indicates that there is an opening caused by a tear in the plastic film. This method can directly reflect the change in film performance during the tearing process and improve the visualization of the inspection. The change in light intensity can accurately reflect the structural change of the film during the tearing process and provide important data for the evaluation of tear strength. By setting the light intensity change threshold, it is possible to quickly determine whether the tear resistance of the film meets the standard;

[0194] This is a plastic product quality inspection method. For plastic films that pass the puncture test, it is necessary to further test the tear strength. Tear strength is an important indicator of whether the film material can withstand tearing force in actual use. By setting the tear force and length thresholds, performing tear tests on the test segments, and evaluating the changes in light intensity, the tear resistance of the film can be comprehensively evaluated. The tear test can simulate the tearing conditions in actual use and ensure the durability and reliability of the product during use.

[0195] It should be noted that, in this article, relational terms such as first and second, etc. are only used to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Moreover, the terms "include", "comprise" or any other variants thereof are intended to cover non-exclusive inclusion, so that a process, method, article or device including a series of elements includes not only those elements, but also other elements not explicitly listed, or also includes elements inherent to such process, method, article or device.

[0196] The above is only a preferred embodiment of the present invention. It should be pointed out that for ordinary technicians in this technical field, several improvements and modifications can be made without departing from the technical principles of the present invention. These improvements and modifications should also be regarded as the scope of protection of the present invention.

Claims

1. A plastic product quality inspection method, characterized in that: include: The plastic product is specifically a plastic film; Obtain a plastic film that needs to be tested for quality, which is recorded as the plastic film to be tested; Perform thickness test on the plastic film to be tested to determine whether the thickness of the plastic film to be tested meets the standard; If the thickness of the plastic film to be tested does not meet the standard, the plastic film to be tested whose thickness does not meet the standard will no longer be tested; If the thickness of the plastic film to be tested meets the standard, the transparency and uniformity test of the plastic film to be tested is performed to determine whether the transparency and uniformity of the plastic film to be tested meet the standard; If the transparency and uniformity of the plastic film to be tested do not meet the standards, the plastic film to be tested whose transparency and uniformity do not meet the standards will no longer be tested; If the transparency and uniformity of the plastic film to be tested meet the standards, a puncture test is performed on the plastic film to be tested to determine whether the anti-penetration ability of the plastic film to be tested meets the standards; If the penetration resistance of the plastic film to be tested does not meet the standard, the plastic film to be tested whose penetration resistance does not meet the standard will no longer be tested; If the penetration resistance of the plastic film to be tested meets the standard, the plastic film to be tested whose penetration resistance meets the standard is tested according to the first test strategy to determine whether the tear strength of the puncture point of the plastic film to be tested meets the standard.

2. A plastic product quality inspection method according to claim 1, characterized in that: The thickness detection of the plastic film to be tested to determine whether the thickness of the plastic film to be tested meets the standard specifically includes: The thickness of the standard plastic film is collected as the standard value and recorded as the standard thickness; Set thickness control accuracy; Use a laser thickness gauge to scan the plastic film to be tested to obtain the thickness of all positions of the plastic film to be tested; Get the maximum value of the thickness of the plastic film to be tested; Get the minimum value of the thickness of the plastic film to be tested; If the standard thickness - thickness control accuracy ≤ the maximum value of the thickness of the plastic film to be tested ≤ the standard thickness + thickness control accuracy, and the standard thickness - thickness control accuracy ≤ the minimum value of the thickness of the plastic film to be tested ≤ the standard thickness + thickness control accuracy, then the thickness of the plastic film to be tested is deemed to meet the standard; If the maximum value of the plastic film thickness to be tested is less than the standard thickness - thickness control accuracy, the minimum value of the plastic film thickness to be tested is greater than the standard thickness + thickness control accuracy, the standard thickness - thickness control accuracy is ≤ the maximum value of the plastic film thickness to be tested is ≤ the standard thickness + thickness control accuracy, and the minimum value of the plastic film thickness to be tested is less than the standard thickness - thickness control accuracy or the standard thickness - thickness control accuracy is ≤ the minimum value of the plastic film thickness to be tested is ≤ the standard thickness + thickness control accuracy, and the maximum value of the plastic film thickness to be tested is greater than the standard thickness + thickness control accuracy; then it is determined that the thickness of the plastic film to be tested does not meet the standard.

3. A plastic product quality inspection method according to claim 1, characterized in that: If the thickness of the plastic film to be tested meets the standard, the transparency and uniformity test is performed on the plastic film to be tested to determine whether the transparency and uniformity of the plastic film to be tested meet the standard, which specifically includes: Setting up a light source and a light source receiver; In the absence of obstructions, obtain the light intensity received by the light source receiver, which is recorded as the standard light intensity; Set transparency threshold; Place a plastic film between the light source and the light source receiver, and obtain the light intensity received by the light source receiver at this time, which is recorded as the actual light intensity; If the ratio of the actual light intensity to the standard light intensity is less than the transparency threshold, it is determined that the transparency of the plastic film to be tested does not meet the standard; If the ratio of the actual light intensity to the standard light intensity is ≥ the transparency threshold, the transparency of the plastic film to be tested is deemed to meet the standard.

4. A plastic product quality inspection method according to claim 3, characterized in that: If the thickness of the plastic film to be tested meets the standard, then the transparency and uniformity test of the plastic film to be tested is performed to determine whether the transparency and uniformity of the plastic film to be tested meet the standard, and further comprising: Place a light source underneath the standard plastic film; A digital camera is placed on top of a standard plastic film; Collect an image of a standard plastic film, which is recorded as a standard image; Process the standard image to obtain the grayscale histogram of the standard image, which is recorded as the standard grayscale image; Collect an image of the plastic film to be tested and record it as the actual image; Process the actual image to obtain the grayscale histogram of the actual image, which is recorded as the actual grayscale image; Set uniformity threshold; Calculate the gray value variance of the standard gray image; Calculate the gray value variance of the actual gray image; If the gray value variance of the standard gray image - the uniformity threshold ≤ the gray value variance of the actual gray image ≤ the gray value variance of the standard gray image + the uniformity threshold, it is determined that the uniformity of the plastic film to be tested meets the standard; If the grayscale value variance of the actual grayscale image is greater than the grayscale value variance of the standard grayscale image + the uniformity threshold or the grayscale value variance of the actual grayscale image is less than the grayscale value variance of the standard grayscale image - the uniformity threshold, it is determined that the uniformity of the plastic film to be tested does not meet the standard.

5. A plastic product quality inspection method according to claim 1, characterized in that: If the transparency and uniformity of the plastic film to be tested meet the standards, a puncture test is performed on the plastic film to be tested to determine whether the penetration resistance of the plastic film to be tested meets the standards, which specifically includes: Set distance threshold; Randomly select N points on the plastic film to be tested as puncture points; The distance between each puncture point is greater than the distance threshold.

6. A plastic product quality inspection method according to claim 5, characterized in that: If the transparency and uniformity of the plastic film to be tested meet the standards, a puncture test is performed on the plastic film to be tested to determine whether the penetration resistance of the plastic film to be tested meets the standards, and further includes: Set the puncture force threshold; Perform a puncture test on each puncture point; Obtain the pressure exerted on the puncture needle, recorded as the first pressure; During the puncture test, if the first pressure decreases, the puncture test is stopped; For each puncture point, the maximum value of the first pressure during the puncture test is obtained and recorded as the puncture force; If the puncture forces corresponding to all puncture points are greater than the puncture force threshold, it is determined that the penetration resistance of the plastic film to be tested meets the standard; If the puncture force corresponding to the puncture point is less than the puncture force threshold, it is determined that the penetration resistance of the plastic film to be tested does not meet the standard.

7. A plastic product quality inspection method according to claim 1, characterized in that: If the penetration resistance of the plastic film to be tested meets the standard, the plastic film to be tested whose penetration resistance meets the standard is tested according to the first test strategy to determine whether the tear strength of the puncture point of the plastic film to be tested meets the standard, specifically including: Obtain all puncture points of the plastic film to be tested; Choose any puncture point as the origin and establish a plane rectangular coordinate system on the plastic film to be tested; Get the coordinates of all puncture points, which are recorded as (x1, y1), (x2, y2)...(x n ,y n ); The tearing line is obtained by linear fitting based on all puncture points, specifically: Let the linear equation of the tear line be y=ax+b; Define the objective function Where S is the residual sum of squares of all points, a is the slope of the tear line, and b is the intercept of the tear line; Taking the partial derivative of the objective function with respect to a, we get: Taking the partial derivative of the objective function with respect to b, we get: make and is 0, we get:

8. A plastic product quality inspection method according to claim 7, characterized in that: If the penetration resistance of the plastic film to be tested meets the standard, the plastic film to be tested whose penetration resistance meets the standard is tested according to the first test strategy to determine whether the tear strength of the puncture point of the plastic film to be tested meets the standard, further comprising: Arrange a light source below the plastic film to be tested; Arrange a light source receiver above the plastic film to be tested; Before performing the tear test, obtaining a value of the light intensity received by the light source receiver, which is recorded as a first value; Perform tear tests, specifically: Setting a tearing force, wherein the tearing force is fixed; For each puncture point, a perpendicular line to the tear line is drawn through the puncture point on the plastic film to be tested, and the intersection points with the tear line are recorded as the first intersection point, the second intersection point, ... the Nth intersection point; Obtain the two points with the longest distance from the first intersection point, the second intersection point, ... the Nth intersection point, and record them as the first target point and the second target point; Connect the first target point and the second target point, and the formed line segment is recorded as a test line segment; Set the length threshold; Get the length of the test line segment; If the length of the test line segment is less than or equal to the length threshold, a tearing test is performed on the test line segment, and the tearing position is the position of the test line segment; If the length of the test line segment is greater than the length threshold, multiple tearing tests are performed on the test line segment, specifically: Taking the first target point as the starting point, segmenting the test line segment at intervals of the length threshold on the test line segment to form a plurality of line segments, which are respectively recorded as the first line segment, the second line segment, ... the Xth line segment; Perform tearing tests on the first line segment, the second line segment, ... the Xth line segment on the plastic film to be tested respectively; After the tearing test is completed, a value of the light intensity received by the light source receiver is obtained and recorded as a second value; Set the light intensity change threshold; If the second value minus the first value ≥ the light intensity change threshold, it is determined that the tear strength of the puncture point of the plastic film to be tested does not meet the standard; If the second value - the first value < the light intensity change threshold, it is determined that the tear strength of the puncture point of the plastic film to be tested does not meet the standard.

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