Method for judging uniformity of glass in plate width direction

Abstract

The invention provides a method for judging glass uniformity in a plate width direction, and relates to the field of glass uniformity detection. Comprising the following steps: S1, respectively cutting out sample wafers with preset sizes in at least two different areas in the width direction of a glass plate; s2, carrying out multi-point test on each sample wafer by adopting an indentation method, and measuring the expansion length of a crack generated by indentation; s3, calculating a crack length test value of each sample wafer based on the crack propagation length of each test point; s4, at least one influence factor related to annealing process parameters is introduced, the crack length test value is corrected, and the actual crack length after process influence is eliminated is obtained; s5, on the basis of the actual crack lengths of all the sample wafers, a uniformity index representing the data dispersion degree is calculated; s6, according to the numerical value interval of the uniformity index, the uniformity level of the glass plate in the width direction is judged; and the glass uniformity in the plate width direction is evaluated by measuring the crack length.

Description

Technical Field

[0001] This invention relates to the field of glass uniformity testing, and in particular to a method for determining the uniformity of glass in the width direction. Background Technology

[0002] With the continuous expansion of glass applications, the requirements for quality uniformity in various types of flat glass, such as photovoltaic glass, electronic glass, and float glass, are becoming increasingly stringent. Throughout the entire glass production process, the uniformity of the glass sheet in the width direction directly determines product quality. Inconsistencies in composition or structure can easily lead to defects such as cracks, deformation, and unevenness in the glass sheet during subsequent processing or use. This not only increases the scrap rate and the consumption of raw materials and energy, but may also cause safety hazards and performance failures in downstream applications.

[0003] Currently, the assessment of glass uniformity largely relies on macroscopic performance testing of the final product (such as observation using a whole-plate stress meter) or destructive mechanical testing, which has significant limitations: First, macroscopic observation cannot accurately and quantitatively characterize microscopic uniformity; second, destructive testing is costly and time-consuming, making it unsuitable for rapid, routine monitoring on production lines; third, process parameters during tin bath forming and annealing in the annealing furnace, such as annealing rates and temperatures in different regions, significantly affect the final microstructure of the glass, while existing methods lack quantitative models that effectively correlate these key process parameters with the glass's micromechanical properties. Summary of the Invention

[0004] The main objective of this invention is to provide a method for determining the uniformity of glass in the width direction, thereby solving the technical problems of limited testing objects, high equipment and maintenance costs, poor applicability, and low consistency and yield in the prior art.

[0005] To solve the above-mentioned technical problems, the technical solution adopted by the present invention is: a method for determining the uniformity of glass in the width direction, comprising the following steps: S1: Cut samples of a preset size from at least two different regions along the width of the glass plate; S2: The indentation method is used to perform multi-point tests on each sample to measure the crack propagation length caused by the indentation. S3: Calculate the crack length test value for each sample based on the crack propagation length at each test point; S4: Introduce at least one influencing factor related to the annealing process parameters to correct the crack length test value and obtain the actual crack length after excluding the influence of the process. S5: Based on the actual crack lengths of all samples, calculate a uniformity index that characterizes the degree of data dispersion; S6: Determine the uniformity level of the glass plate in the width direction based on the numerical range of the uniformity index.

[0006] In the preferred embodiment, in S1, the at least two different regions include the left, middle, and right sides in the width direction of the plate; The preset size of the cut sample is 40mm×50mm, and the 50mm direction is consistent with the pulling direction of the glass.

[0007] In the preferred embodiment, in step S2, a square pyramidal diamond indenter with a relative face angle of 136° is used to press into the sample surface with a preset test pressure and hold for a specified time, and then the transverse crack length and longitudinal crack length of each test point are measured.

[0008] In the preferred embodiment, in step S3, multiple points are tested for each sample, and the transverse and longitudinal cracks are measured at each point. The average value is then taken. The formula for calculating the crack length of each sample is as follows: ; In the formula, N is the number of test points for a single sample. and The transverse and longitudinal cracks are measured at point i.

[0009] In the preferred embodiment, the influencing factors introduced in step S4 include the annealing rate influencing factor and the temperature in zone B influencing factor, and the formula for calculating the actual crack length L is: L= ; in, The annealing speed from the tin bath outlet to zone A of the annealing furnace was calculated based on the different areas of the plate width. The temperature was calculated based on the temperature of zone B in the annealing furnace.

[0010] In the preferred scheme, a regression model is fitted using crack length data to obtain the relationship expressions between annealing rate and zone B temperature on crack length, as follows: ; ; In the formula, and To obtain the parameter coefficients after fitting, , and represent the annealing speeds for the left side, right side, and center, respectively; This refers to the temperature in zone B of the annealing furnace.

[0011] In the preferred embodiment, in step S5, the formula for the uniformity index is: ; In the formula, U Indicates the glass uniformity index. This represents the average crack length. The standard deviation of the crack length.

[0012] In the preferred scheme, the formulas for the average and standard deviation of the crack length are as follows: ; ; In the formula, n is the sample number. Let be the actual crack length of the i-th sample.

[0013] In the preferred embodiment, in step S6, the criterion for determining the uniformity level is: when U ≤ At that time, the uniformity was good; when < U ≤ At times, the uniformity is poor, and the glass is easily broken; when U > At that time, the uniformity was poor, and the glass panel was not straight; in, and These are the maximum and minimum thresholds for the uniformity index.

[0014] In the preferred embodiment, during step S1, the cutting positions of the left, middle, and right sample pieces satisfy the following: The distance from the center of the left sample to the left edge of the glass plate is the preset plate width threshold. The distance from the center of the sample on the right to the right edge of the glass plate is the preset plate width threshold. The deviation between the center of the intermediate sample and the center line of the glass plate width does not exceed the preset deviation range; Furthermore, when cutting the sample, it is necessary to avoid the defective areas of visible bubbles, stones, and scratches on the glass plate surface. The defective area to be avoided is a circular area with a diameter not less than a preset threshold centered on the defect.

[0015] This invention provides a method for determining the uniformity of glass in the width direction, comprising the following steps: S1: cutting samples of a preset size from at least two different regions along the width direction of the glass plate; S2: performing multi-point testing on each sample using an indentation method to measure the crack propagation length generated by the indentation; S3: calculating the crack length test value for each sample based on the crack propagation length at each test point; S4: introducing at least one influencing factor related to annealing process parameters to correct the crack length test value, obtaining the actual crack length after excluding process influence; S5: calculating a uniformity index characterizing the degree of data dispersion based on the actual crack length of all samples; S6: determining the uniformity level in the width direction of the glass plate according to the numerical range of the uniformity index; by measuring the crack length to evaluate the uniformity of glass in the width direction, the uniformity of glass in the width direction can ultimately be reflected by the crack length value after excluding the influence of influencing factors, realizing detection and early warning functions, improving detection accuracy, increasing production efficiency, and reducing production costs. Attached Figure Description

[0016] The present invention will be further described below with reference to the accompanying drawings and embodiments: Figure 1 This is a flowchart of the method of the present invention. Detailed Implementation

[0017] Example 1 like Figure 1 As shown, a method for determining the uniformity of glass in the width direction includes the following steps: S1: Cut samples of a preset size from at least two different regions along the width of the glass plate.

[0018] S2: The indentation method is used to perform multi-point tests on each sample to measure the crack propagation length caused by the indentation.

[0019] S3: Calculate the crack length test value for each sample based on the crack propagation length at each test point.

[0020] S4: Introduce at least one influencing factor related to the annealing process parameters to correct the crack length test value and obtain the actual crack length after excluding the influence of the process.

[0021] S5: Based on the actual crack lengths of all samples, calculate a uniformity index that characterizes the degree of data dispersion.

[0022] S6: Determine the uniformity level of the glass plate in the width direction based on the numerical range of the uniformity index.

[0023] This embodiment obtains the crack propagation length by sampling from different regions and conducting multi-point testing using the indentation method. Then, relevant influencing factors are introduced for calculation and correction to obtain a uniformity index that characterizes the degree of data dispersion. The uniformity level is determined based on the numerical range, transforming the abstract concept of uniformity into a quantifiable uniformity index. This improves the repeatability of the method and the reliability of the data, enabling a rapid, accurate, and practical judgment of the uniformity of the glass plate in the width direction.

[0024] This embodiment uses crack length measurement to evaluate the glass uniformity in the width direction. Ultimately, the crack length value, which excludes the influence of influencing factors, can reflect the glass uniformity in the width direction.

[0025] In the float glass production process, "Area A" and "Area B" are two specific temperature control zones inside the annealing furnace. Area A is the annealing zone, and Area B is the cooling zone.

[0026] In the preferred embodiment, at least two distinct regions include the left, middle, and right sides in the width direction of the plate.

[0027] The preset size of the cut sample is 40mm×50mm, and the 50mm direction is consistent with the pulling direction of the glass.

[0028] Because the uneven distribution of glass composition leads to differences in crack length, and the crack propagation rate and length are affected by properties such as the glass's hardness and toughness, measuring the crack length at various locations along the width of the glass sheet can directly reflect the uniformity of the glass in that direction. Since parameters on the production line fluctuate over time, and factors such as the annealing rate from the glass tin bath outlet to area A and the temperature in area B can influence crack length, thus affecting the assessment of the overall uniformity of the glass sheet across its width, it is necessary to eliminate interference from other factors to ensure that crack length values ​​from different time periods are meaningful for comparison.

[0029] Based on the research in this embodiment, the main factors affecting the crack length are the annealing rate from the glass bath outlet to zone A and the temperature in zone B. The influence of these two factors on the crack length is denoted as the influencing factor. , Ultimately, the glass uniformity in the width direction can be reflected by the crack length value after eliminating the influence of influencing factors, as shown in the formula: L= ; In the formula, To measure and obtain the crack length.

[0030] The method for testing crack length selected in this embodiment is as follows.

[0031] Step S1: Take 40mm*50mm samples from the left, center and right sides along the width of the glass plate.

[0032] Then, indentation was used to create cracks on each sample, and the length of the cracks was measured.

[0033] In the preferred scheme, when selecting samples in step S1, the cutting positions of the left, middle, and right sample pieces satisfy the following: The distance from the center of the sample on the left to the left edge of the glass plate is 1 / 5 to 1 / 4 of the plate width.

[0034] The distance from the center of the sample on the right to the right edge of the glass plate is 1 / 5 to 1 / 4 of the plate width.

[0035] The deviation between the center of the intermediate sample and the center line of the glass plate width shall not exceed ±5mm.

[0036] Furthermore, when cutting the sample, it is necessary to avoid the defective areas of visible bubbles, stones, and scratches on the glass plate surface. The defective area to be avoided is a circular area with a diameter of not less than 10mm centered on the defect.

[0037] Step S2: After placing the sample on the stage, press a square pyramidal diamond indenter with an angle of 136° between its opposite faces into the sample surface with a given test pressure, and hold it for a specified time. Then, remove the test force and use a microscope to measure the length of the two diagonals of the indentation and the length of the crack propagation along the diagonal of the indentation.

[0038] Step S3: Test 10 points on each sample piece, measuring transverse and longitudinal cracks at each point, and record them as follows. and Then, substitute it into the following formula to calculate the average crack length of each sample on the left, middle, and right sides: ; In the formula, N is the number of test points for a single sample. and The transverse and longitudinal cracks measured at point i. μ After substituting, we obtain the average crack lengths on the left, middle, and right sides, which are denoted as follows: , , .

[0039] S4: To test the impact factors , The effect on crack length was investigated by testing the crack length when the annealing rate from the tin bath outlet to area A was changed within a similar time period, the crack length when the temperature in area B was changed, and the crack length when neither was changed. The test results are shown in Table 1. Table 1. Crack length data obtained by changing corresponding conditions within a similar time period.

[0040] Using the data in Table 1, we fitted the regression model and found the influencing factors. The relationship between annealing rate and its effect on crack length is as follows: ; In the formula, and To obtain the parameter coefficients after fitting, , and represent the annealing speeds for the left, right, and middle sides, respectively.

[0041] Impact Factor The relationship between temperature in region B and its effect on crack length is as follows: ; In the formula, This refers to the temperature in zone B.

[0042] In this embodiment, an accurate model obtained by fitting experimental data is used to introduce the annealing rate influence factor and the B-zone temperature influence factor and correct the test values. This allows the final result to isolate the influence of annealing process fluctuations and truly reflect the uniformity of the glass material itself in the width direction. Apart from key process interference, this significantly improves the accuracy and authenticity of the judgment. Step S5: Obtain the actual crack length of all samples, and then calculate the uniformity index, which characterizes the degree of data dispersion.

[0043] In this embodiment, the influence of influencing factors on the test data is eliminated, and the crack length values ​​are obtained as shown in Table 2.

[0044] In this embodiment, the data in Table 2, i.e., the crack length value L after excluding the influence of influencing factors, is substituted into the following formula: ; ; ; in, U This represents the glass uniformity index; the higher the value, the better the glass uniformity. The standard deviation of crack length reflects the degree of dispersion in crack length. This represents the average crack length, reflecting the overall crack length level; n is the sample number, which depends on the number of test samples. Let be the actual crack length of the i-th sample.

[0045] This embodiment establishes a comprehensive and sensitive uniformity index model. The defined uniformity index combines the average level of crack length with the degree of dispersion, thereby accurately capturing the performance fluctuations at different locations across the plate width and thus more comprehensively and accurately characterizing the quality of uniformity.

[0046] Table 2 Crack length data excluding the influence of influencing factors on test data

[0047] Table 3. Glass homogeneity data obtained after optimization method

[0048] The results obtained after calculation using the above formula are shown in Table 3.

[0049] Comparison revealed that when the annealing rate or the temperature in zone B changes, the crack length of the glass also changes. This has a significant impact on judging the uniformity of the glass using crack length. However, by finding the corresponding relationship between the influencing factors through function fitting and eliminating the interference of influencing factors, a crack length value that can accurately reflect the actual uniformity of the glass can be obtained.

[0050] The glass uniformity index calculated directly using the crack length without excluding influencing factors is shown in Table 4.

[0051] Table 4. Glass homogeneity data obtained by the original method.

[0052] In the preferred scheme, the criterion for judging the uniformity level in step S6 is: when U ≤ At that time, the uniformity was good; when < U ≤ At times, the uniformity is poor, and the glass is easily broken; when U > At that time, the uniformity was poor, and the glass panel was not straight; in, and These are the maximum and minimum thresholds for the uniformity index.

[0053] This embodiment achieves quality early warning and production guidance through clear grading judgment standards and operation guidelines. By setting thresholds such as Umin and Umax, the uniformity of glass is clearly graded, providing intuitive and clear action instructions for the production line. It combines early warning and detection functions, improving the practicality and accuracy of detection.

[0054] In addition, when the uniformity index of multiple batches of glass was tested and compared with the cold end data (the following statistics represent the total number of large panels that showed abnormalities on that day), some of the results are shown in Table 5: Table 5. Data on glass uniformity index from multiple batches.

[0055] Based on the data statistics in Table 5, this embodiment sets... and The values ​​are 1500 and 1000 respectively, and can be adjusted adaptively.

[0056] Step S6: Through statistical analysis over a certain period of time, this embodiment found that when the glass uniformity index is greater than 1000, the glass uniformity in the width direction is poor, mainly manifested as easy breakage. When the glass uniformity index is greater than 1500, the glass uniformity in the width direction is poor, mainly manifested as the whole plate is not straight. When the glass uniformity index is less than or equal to 1000, it indicates that the glass in the width direction of this batch has good uniformity.

[0057] For easily broken glass, the production line can control the speed of the glass movement on the production line, especially during cutting and processing. Appropriately reducing the speed can decrease mechanical stress and lower the risk of glass breakage. The pressure applied to the glass during processing and forming can also be adjusted. Excessive pressure can cause glass deformation or breakage, thus requiring proper adjustment. For glass that is not perfectly straight, the melting and forming process can be optimized to ensure uniform thickness and density during forming. Appropriate melting and forming processes can reduce uneven stress on the glass sheet during production, thereby reducing the likelihood of the sheet being crooked. Temperature control during the production process, especially during the cooling stage, can also be chosen to prevent bending or crookedness caused by different cooling rates in different parts of the glass sheet.

[0058] The key technical points of this embodiment are: 1. Assessing the compositional uniformity of glass materials through crack length is simpler and more efficient than the previous method of judging the uniformity of molten glass through optical means. 2. By using the influencing factor formula of function fitting, the influence of major influencing factors such as temperature in zone B and annealing rate on crack length can be eliminated, so as to obtain a crack length value that more accurately reflects the actual situation for calculating the glass uniformity index. 3. Using the obtained glass uniformity index value, the degree of glass uniformity and possible defects can be determined, facilitating adjustments based on the problems.

[0059] This embodiment utilizes a method for calculating the glass uniformity index based on crack length to achieve accurate quantitative judgment of the uniformity of the glass sheet in the width direction. This eliminates interference from production fluctuations, provides early warning of quality risks, and detects non-uniformity issues in the glass sheet early. Based on this, corresponding adjustments are made, improving production efficiency and reducing production costs. Further optimization of the production process and quality control not only maximizes the use of raw materials and reduces resource waste but also lowers energy consumption during production.

[0060] The above embodiments are merely preferred technical solutions of the present invention and should not be considered as limitations on the present invention. The scope of protection of the present invention should be limited to the technical solutions described in the claims, including equivalent substitutions of the technical features described in the claims. That is, equivalent substitutions and improvements within this scope are also within the scope of protection of the present invention.

Claims

1. A method for determining the uniformity of glass in the width direction, characterized in that, Includes the following steps: S1: Cut samples of a preset size from at least two different regions along the width of the glass plate; S2: The indentation method is used to perform multi-point tests on each sample to measure the crack propagation length caused by the indentation. S3: Calculate the crack length test value for each sample based on the crack propagation length at each test point; S4: Introduce at least one influencing factor related to the annealing process parameters to correct the crack length test value and obtain the actual crack length after excluding the influence of the process. S5: Based on the actual crack lengths of all samples, calculate a uniformity index that characterizes the degree of data dispersion; S6: Determine the uniformity level of the glass plate in the width direction based on the numerical range of the uniformity index.

2. The method for determining the uniformity of glass in the width direction according to claim 1, characterized in that, In S1, the at least two different regions include the left, middle, and right sides in the width direction of the plate; The preset size of the cut sample is 40mm×50mm, and the 50mm direction is consistent with the pulling direction of the glass.

3. The method for determining the uniformity of glass in the width direction according to claim 1, characterized in that, In step S2, a square pyramidal diamond indenter with a relative face angle of 136° is used to press into the sample surface with a preset test pressure and hold for a specified time, and then the transverse crack length and longitudinal crack length at each test point are measured.

4. The method for determining the uniformity of glass in the width direction according to claim 1, characterized in that, In step S3, multiple points are tested for each sample. At each point, both transverse and longitudinal cracks are measured, and the average value is taken. Therefore, the formula for calculating the crack length of each sample is: ； In the formula, N is the number of test points for a single sample. and The transverse and longitudinal cracks are measured at point i.

5. The method for determining the uniformity of glass in the width direction according to claim 1, characterized in that, In step S4, the introduced influencing factors include the annealing rate influencing factor and the temperature in zone B influencing factor. The formula for calculating the actual crack length L is as follows: L= ； in, The annealing speed from the tin bath outlet to zone A of the annealing furnace was calculated based on the different areas of the plate width. The temperature was calculated based on the temperature of zone B in the annealing furnace.

6. The method for determining the uniformity of glass in the width direction according to claim 5, characterized in that, Using crack length data, a regression model was fitted to obtain the relationship expressions between annealing rate and zone B temperature on crack length, as follows: ； ； In the formula, and To obtain the parameter coefficients after fitting, , and represent the annealing speeds for the left side, right side, and center, respectively; This refers to the temperature in zone B of the annealing furnace.

7. The method for determining the uniformity of glass in the width direction according to claim 1, characterized in that, In S5, the formula for the uniformity index is: ； In the formula, U Indicates the glass uniformity index. This represents the average crack length. The standard deviation of the crack length.

8. The method for determining the uniformity of glass in the width direction according to claim 7, characterized in that, The formulas for the mean and standard deviation of crack length are as follows: ； ； In the formula, n is the sample number. Let be the actual crack length of the i-th sample.

9. The method for determining the uniformity of glass in the width direction according to claim 7, characterized in that, In step S6, the criterion for judging the uniformity level is: when U ≤ At that time, the uniformity was good; when < U ≤ At times, the uniformity is poor, and the glass is easily broken; when U > At that time, the uniformity was poor, and the glass panel was not straight; in, and These are the maximum and minimum thresholds for the uniformity index.

10. The method for determining the uniformity of glass in the width direction according to claim 2, characterized in that, In step S1, when selecting a sample, the cutting positions of the left, middle, and right sample pieces satisfy the following: The distance from the center of the left sample to the left edge of the glass plate is the preset plate width threshold. The distance from the center of the sample on the right to the right edge of the glass plate is the preset plate width threshold. The deviation between the center of the intermediate sample and the center line of the glass plate width does not exceed the preset deviation range; Furthermore, when cutting the sample, it is necessary to avoid the defective areas of visible bubbles, stones, and scratches on the glass plate surface. The defective area to be avoided is a circular area with a diameter not less than a preset threshold centered on the defect.

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